ST STA381BW User Manual

STA381BW

2.1-channel high-efficiency digital audio system

Features

■ Wide-range supply voltage

– 4.5 V to 26 V (operating range) – 30 V (absolute maximum rating)

■ I

C control with selectable device address

■ Embedded full IC protection

– Manufacturing short-circuit protection (out

vs. gnd, out vs. vcc, out vs. out) – Thermal protection – Overcurrent protection – Undervoltage protection

■ 1 Vrms stereo analog input

■ I

S interface, sampling rate 32 kHz ~ 192 kHz, with internal sampling frequency converter for fixed processing frequency

■ Three output power stage configurations

– 2.0 mode, L/R full bridges – 2.1 mode, L/R two half-bridges, subwoofer

full bridge

– 2.1 mode, L/R full bridges, PWM output for

external subwoofer amplifier

■ Driving load capabilities

– 2 x 20 W into 8 Ω ternary modulation – 2 x 9 W into 4 Ω + 1 x 20 W into 8 Ω

■ FFX

■ Fixed output PWM frequency at any input

■ Embedded RMS meter for measuring real-time

■ Two analog outputs

■ New fully programmable noise-gating function

100 dB dynamic range

sampling frequency

loudness

– Selectable headphone / line out driver with

adjustable gain via external resistors

–New F3X

analog output

Sound Terminal

Datasheet − production data

VQFN48 (7 x 7 mm)

■ Headphone

– Embedded negative charge pump – Full capless output configuration – Driving load capabilities: 40 mW into 32 Ω

■ Line out

– 2 Vrms line output capability

■ Up to 12 user-programmable biquads with

noise-shaping technology

■ Direct access to coefficients through I

shadowing mechanism

■ Fixed (88.2 kHz / 96 kHz) internal processing

sampling rate

■ Two independent DRCs configurable as a

dual-band anticlipper or independent limiters/compressors (B

■ Digital gain/att +48 dB to -80 dB with

DRC)

0.125 dB/step resolution

■ Independent (fade-in, fade-out) soft volume

update with programmable rate 48 ~ 1.5 dB/ms

■ Bass/treble tones control

■ Audio presets: 15 crossover filters,

5 anticlipping modes, nighttime listening mode

■ STSpeakerSafe

–Pre

- and post-processing DC blocking filters

protection circuitry

– Checksum engine for filter coefficients – PWM fault self-diagnosis

■ STCompressor

Table 1. Device summary

Order code Package Packing

STA381BW VQFN48 Tray

dual-band DRC

STA381BWTR VQFN48 Tape and Reel

August 2012 Doc ID 018835 Rev 7 1/171

This is information on a product in full production.

www.st.com

Contents STA381BW

Contents

1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1.1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.1 Connection diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.3 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3.4 Electrical specifications for the digital section . . . . . . . . . . . . . . . . . . . . . 22

3.5 Electrical specifications for the power section . . . . . . . . . . . . . . . . . . . . . 23

3.6 Electrical specifications for the analog section . . . . . . . . . . . . . . . . . . . . . 24

4 Device overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.1 Processing data path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.2 Input oversampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.3 STCompressorTM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.3.1 STC block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3.2 Band splitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.3.3 Level meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.3.4 Mapper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

4.3.5 Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.3.6 Dynamic attack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

4.3.7 Offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.3.8 Stereo link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4.3.9 Programming of coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4.3.10 Memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

C bus specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.1 Communication protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.1.1 Data transition or change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

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STA381BW Contents

5.1.2 Start condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.1.3 Stop condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.1.4 Data input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.2 Device addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

5.3 Write operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.3.1 Byte write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.3.2 Multi-byte write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.4 Read operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.4.1 Current address byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.4.2 Current address multi-byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.4.3 Random address byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.4.4 Random address multi-byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

5.4.5 Write mode sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

5.4.6 Read mode sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

6 Register description: New Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.1 CLK register (addr 0x00) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6.2 STATUS register (addr 0x01) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

6.3 RESET register (addr 0x02) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

6.4 Soft volume register (addr 0x03) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

6.5 MVOL register (addr 0x04) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6.6 FINEVOL register (addr 0x05) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

6.7 CH1VOL register (addr 0x06) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6.8 CH2VOL register (addr 0x07) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

6.9 POST scaler register (addr 0x08) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

6.10 OPER register (addr 0x09) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

6.11 FUNCT register (addr 0x0A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.11.1 Dual-band DRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.12 HPCFG register (addr 0x10) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.13 Configuration register A (addr 0x11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.13.1 Master clock select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

6.13.2 Interpolation ratio selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.13.3 Fault-detect recovery bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.14 Configuration register B (addr 0x12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

6.14.1 Serial data interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

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Contents STA381BW

6.14.2 Serial data first bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

6.14.3 Delay serial clock enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.14.4 Channel input mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.15 Configuration register C (addr 0x13) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.15.1 FFX compensating pulse size register . . . . . . . . . . . . . . . . . . . . . . . . . . 62

6.16 Configuration register D (addr 0x14) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.16.1 DSP bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.16.2 Post-scale link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.16.3 Biquad coefficient link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

6.16.4 Zero-detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.16.5 Submix mode enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.17 Configuration register E (addr 0x15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.17.1 Noise-shaper bandwidth selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.17.2 AM mode enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

6.17.3 PWM speed mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.17.4 Zero-crossing enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.18 Configuration register F (addr 0x16) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.18.1 Invalid input detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

6.18.2 Binary output mode clock loss detection . . . . . . . . . . . . . . . . . . . . . . . . 65

6.18.3 LRCK double trigger protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.18.4 Power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.18.5 External amplifier power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

6.19 Volume control registers (addr 0x17 - 0x1B) . . . . . . . . . . . . . . . . . . . . . . 66

6.19.1 Mute/line output configuration register (addr 0x17) . . . . . . . . . . . . . . . . 66

6.19.2 Channel 3 / line output volume (addr 0x1B) . . . . . . . . . . . . . . . . . . . . . . 68

6.20 Audio preset registers (0x1D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

6.20.1 AM interference frequency switching . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

6.20.2 Bass management crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

6.21 Channel configuration registers (addr 0x1F - 0x21) . . . . . . . . . . . . . . . . . 70

6.21.1 Tone control bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

6.21.2 EQ bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

6.21.3 Volume bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

6.21.4 Binary output enable registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

6.21.5 Limiter select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

6.21.6 Output mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.22 Tone control register (addr 0x22) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

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6.22.1 Tone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

6.23 Dynamic control registers (addr 0x23 - 0x26 / addr 0x43 - 0x46) . . . . . . 73

6.23.1 Limiter 1 attack/release rate (L1AR addr 0x23) . . . . . . . . . . . . . . . . . . . 73

6.23.2 Limiter 1 attack/release threshold (L1ATRT addr 0x24) . . . . . . . . . . . . . 73

6.23.3 Limiter 2 attack/release rate ( L2AR addr 0x25) . . . . . . . . . . . . . . . . . . 73

6.23.4 Limiter 2 attack/release threshold ( L2 ATRT addr 0x26) . . . . . . . . . . . . 73

6.23.5 Limiter 1 extended attack threshold (addr 0x43) . . . . . . . . . . . . . . . . . . 77

6.23.6 Limiter 1 extended release threshold (addr 0x44) . . . . . . . . . . . . . . . . . 77

6.23.7 Limiter 2 extended attack threshold (addr 0x45) . . . . . . . . . . . . . . . . . . 78

6.23.8 Limiter 2 extended release threshold (addr 0x46) . . . . . . . . . . . . . . . . . 78

6.24 User-defined coefficient control registers (addr 0x27 - 0x37) . . . . . . . . . . 78

6.24.1 Coefficient address register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.24.2 Coefficient b1 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.24.3 Coefficient b1 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.24.4 Coefficient b1 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

6.24.5 Coefficient b2 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.6 Coefficient b2 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.7 Coefficient b2 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.8 Coefficient a1 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.9 Coefficient a1 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.10 Coefficient a1 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.11 Coefficient a2 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . . 79

6.24.12 Coefficient a2 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.24.13 Coefficient a2 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.24.14 Coefficient b0 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.24.15 Coefficient b0 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.24.16 Coefficient b0 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.24.17 Coefficient write/read control register . . . . . . . . . . . . . . . . . . . . . . . . . . 80

6.24.18 User-defined EQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.24.19 Pre-scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.24.20 Post-scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.25 Fault-detect recovery constant registers (addr 0x3C - 0x3D) . . . . . . . . . . 85

6.26 Extended configuration register (addr 0x47) . . . . . . . . . . . . . . . . . . . . . . 85

6.26.1 Extended post-scale range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.26.2 Extended attack rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.26.3 Extended biquad selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

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Contents STA381BW

6.27 PLL configuration registers

(address 0x52; 0x53; 0x54; 0x55; 0x56; 0x57) . . . . . . . . . . . . . . . . . . . . 87

6.28 Short-circuit protection mode registers SHOK (address 0x58) . . . . . . . . 89

6.29 Extended coefficient range up to -4...4 (address 0x5A) . . . . . . . . . . . . . . 90

6.30 Miscellaneous registers (address 0x5C, 0x5D) . . . . . . . . . . . . . . . . . . . . 91

6.30.1 Rate power-down enable (RPDNEN) bit . . . . . . . . . . . . . . . . . . . . . . . . 91

6.30.2 Bridge immediately off (BRIDGOFF) bit (address 0x4B, bit D5) . . . . . . 91

6.30.3 Channel PWM enable (CPWMEN) bit . . . . . . . . . . . . . . . . . . . . . . . . . . 92

6.30.4 External amplifier hardware pin enabler (LPDP, LPD LPDE) bits . . . . . 92

6.30.5 Power-down delay selector (PNDLSL[2:0]) bits . . . . . . . . . . . . . . . . . . . 92

6.30.6 Short-circuit check enable bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

6.31 Bad PWM detection registers (address 0x5E, 0x5F, 0x60) . . . . . . . . . . . 93

6.32 Enhanced zero-detect mute and input level measurement

(address 0x61-0x65, 0x3F, 0x40, 0x6F) . . . . . . . . . . . . . . . . . . . . . . . . . . 94

6.33 Headphone/Line out configuration register (address 0x66) . . . . . . . . . . . 96

6.34 F3XCFG (address 0x69; 0x6A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

6.35 STCompressorTM configuration register (address 0x6B; 0x6C) . . . . . . . 98

6.36 Charge pump synchronization (address 0x70) . . . . . . . . . . . . . . . . . . . . . 98

6.37 Coefficient RAM CRC protection (address 0x71-0x7D) . . . . . . . . . . . . . . 99

6.38 MISC4 (address 0x7E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

7 Register description: Sound Terminal compatibility . . . . . . . . . . . . . 103

7.1 Configuration register A (addr 0x00) . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

7.1.1 Master clock select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

7.1.2 Interpolation ratio select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

7.1.3 Fault-detect recovery bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

7.2 Configuration register B (addr 0x01) . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

7.2.1 Serial data interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

7.2.2 Serial audio input interface format . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

7.2.3 Serial data first bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

7.2.4 Delay serial clock enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

7.2.5 Channel input mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

7.3 Configuration register C (addr 0x02) . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

7.3.1 FFX compensating pulse size register . . . . . . . . . . . . . . . . . . . . . . . . . 112

7.4 Configuration register D (addr 0x03) . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

7.4.1 DSP bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

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7.4.2 Post-scale link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

7.4.3 Biquad coefficient link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

7.4.4 Zero-detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

7.4.5 Submix mode enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

7.5 Configuration register E (addr 0x04) . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

7.5.1 Noise-shaper bandwidth selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

7.5.2 AM mode enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

7.5.3 PWM speed mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

7.5.4 Zero-crossing enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

7.5.5 Soft volume update enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

7.6 Configuration register F (addr 0x05) . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

7.6.1 Output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

7.6.2 Invalid input detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

7.6.3 Binary output mode clock loss detection . . . . . . . . . . . . . . . . . . . . . . . 121

7.6.4 LRCK double trigger protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

7.6.5 IC power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

7.6.6 External amplifier power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

7.7 Volume control registers (addr 0x06 - 0x0A) . . . . . . . . . . . . . . . . . . . . . 122

7.7.1 Mute/line output configuration register . . . . . . . . . . . . . . . . . . . . . . . . . 122

7.7.2 Master volume register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.7.3 Channel 1 volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.7.4 Channel 2 volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.7.5 Channel 3 / line output volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7.8 Audio preset registers (addr 0x0C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.8.1 Audio preset register (addr 0x0C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

7.8.2 AM interference frequency switching . . . . . . . . . . . . . . . . . . . . . . . . . . 125

7.8.3 Bass management crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

7.9 Channel configuration registers (addr 0x0E - 0x10) . . . . . . . . . . . . . . . . 126

7.9.1 Tone control bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

7.9.2 EQ bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7.9.3 Volume bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7.9.4 Binary output enable registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7.9.5 Limiter select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

7.9.6 Output mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

7.10 Tone control register (addr 0x11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

7.10.1 Tone control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

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7.11 Dynamic control registers (addr 0x12 - 0x15) . . . . . . . . . . . . . . . . . . . . 129

7.11.1 Limiter 1 attack/release rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

7.11.2 Limiter 1 attack/release threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

7.11.3 Limiter 2 attack/release rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

7.11.4 Limiter 2 attack/release threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

7.11.5 Limiter 1 extended attack threshold (addr 0x32) . . . . . . . . . . . . . . . . . 133

7.11.6 Limiter 1 extended release threshold (addr 0x33) . . . . . . . . . . . . . . . . 133

7.11.7 Limiter 2 extended attack threshold (addr 0x34 . . . . . . . . . . . . . . . . . ) 134

7.11.8 Limiter 2 extended release threshold (addr 0x35) . . . . . . . . . . . . . . . . 134

7.12 User-defined coefficient control registers (addr 0x16 - 0x26) . . . . . . . . . 134

7.12.1 Coefficient address register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

7.12.2 Coefficient b1 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . 134

7.12.3 Coefficient b1 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . 134

7.12.4 Coefficient b1 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

7.12.5 Coefficient b2 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.6 Coefficient b2 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.7 Coefficient b2 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.8 Coefficient a1 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.9 Coefficient a1 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.10 Coefficient a1 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.11 Coefficient a2 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.12.12 Coefficient a2 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.12.13 Coefficient a2 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.12.14 Coefficient b0 data register bits 23:16 . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.12.15 Coefficient b0 data register bits 15:8 . . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.12.16 Coefficient b0 data register bits 7:0 . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.12.17 Coefficient write/read control register . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.12.18 User-defined EQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

7.12.19 Pre-scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

7.12.20 Post-scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

7.13 Fault-detect recovery constant registers (addr 0x2B - 0x2C) . . . . . . . . . 141

7.14 Device status register (addr 0x2D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

7.15 EQ coefficients configuration register (addr 0x31) . . . . . . . . . . . . . . . . . 141

7.16 Extended configuration register (addr 0x36) . . . . . . . . . . . . . . . . . . . . . 142

7.16.1 Dual-band DRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

7.16.2 Extended post-scale range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

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7.16.3 Extended attack rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

7.16.4 Extended BIQUAD selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

7.17 EQ soft volume configuration registers (addr 0x37 - 0x38) . . . . . . . . . . 145

7.18 Extra volume resolution configuration registers (address 0x3F; 0x40) . . 146

7.19 PLL configuration registers

(address 0x41; 0x42; 0x43; 0x44; 0x45; 0X46) . . . . . . . . . . . . . . . . . . . 147

7.20 Short-circuit protection mode registers SHOK (address 0x47) . . . . . . . 149

7.21 Extended coefficient range up to -4...4 (address 0x49, 0x4A) . . . . . . . . 151

7.22 Miscellaneous registers (address 0x4B, 0x4C) . . . . . . . . . . . . . . . . . . . 151

7.22.1 Rate power-down enable (RPDNEN) bit (address 0x4B, bit D7) . . . . . 151

7.22.2 Bridge immediately off (BRIDGOFF) bit (address 0x4B, bit D5) . . . . . 152

7.22.3 Channel PWM enable (CPWMEN) bit (address 0x4B, bit D2) . . . . . . . 152

7.22.4 External amplifier hardware pin enabler (LPDP, LPD LPDE) bits

(address 0x4C, bit D7, D6, D5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7.22.5 Power-down delay selector (PNDLSL[2:0]) bits

(address 0x4C, bit D4, D3, D2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

7.22.6 Short-circuit check enable bit (address 0x4C, bit D0) . . . . . . . . . . . . . 153

7.23 Bad PWM detection registers (address 0x4D, 0x4E, 0x4F) . . . . . . . . . . 154

7.24 Enhanced zero-detect mute and input level measurement

(address 0x50-0x54, 0x2E, 0x2F and 0x5E) . . . . . . . . . . . . . . . . . . . . . 155

7.25 Headphone/Line out configuration register (address 0x55) . . . . . . . . . . 157

7.26 F3XCFG (address 0x58; 0x59) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

7.27 STCompressorTM configuration register (address 0x5A; 0x5B) . . . . . . 159

7.28 Charge pump synchronization (address 0x5F) . . . . . . . . . . . . . . . . . . . 160

7.29 Coefficient RAM CRC protection (address 0x60-0x6C) . . . . . . . . . . . . . 161

7.30 MISC3 (address 0x6E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

7.31 MISC4 (address 0x7E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

8 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

8.1 Application schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

8.2 Headphone and 2 Vrms line out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

8.3 Typical output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

9 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

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List of tables STA381BW

List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Table 2. Pin list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Table 3. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 4. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Table 5. Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 6. Electrical specifications - digital section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 7. Electrical specifications - power section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Table 8. Electrical specifications for the analog section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Table 9. Coefficients extended-range configuration 0x74h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Table 10. Compressor ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Table 11. Conversion example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Table 12. STC coefficients memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Table 13. STC band splitter filters memory map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Table 14. Default register map table: NEW MAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Table 15. CLK register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Table 16. STATUS register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Table 17. RESET register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Table 18. Soft volume register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Table 19. Master volume register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Table 20. Fine volume register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Table 21. Channel 1 volume register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table 22. Channel 2 volume register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Table 23. OPER register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Table 24. OPER configuration selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Table 25. FUNCT register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Table 26. HPCFG register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 27. Master clock select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Table 28. Input sampling rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 29. Internal interpolation ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 30. IR bit settings as a function of the input sampling rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 31. Fault-detect recovery bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Table 32. Serial data first bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Table 33. Support serial audio input formats for MSB-first (SAIFB = 0) . . . . . . . . . . . . . . . . . . . . . . . 60

Table 34. Supported serial audio input formats for LSB-first (SAIFB = 1) . . . . . . . . . . . . . . . . . . . . . 61

Table 35. Delay serial clock enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 36. Channel input mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 37. FFX compensating pulse size bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Table 38. Compensating pulse size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 39. DSP bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 40. Post-scale link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 41. Biquad coefficient link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Table 42. Zero-detect mute enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 43. Submix mode enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 44. Noise-shaper bandwidth selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 45. AM mode enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Table 46. PWM speed mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 47. Zero-crossing enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 48. Invalid input detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

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STA381BW List of tables

Table 49. Binary output mode clock loss detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Table 50. LRCK double trigger protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 51. IC power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 52. External amplifier power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Table 53. Line output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Table 54. Mute configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Table 55. Channel 3 volume as a function of CH3VOL[7:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Table 56. AM interference frequency switching bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Table 57. Audio preset AM switching frequency selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Table 58. Bass management crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Table 59. Bass management crossover frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 60. Tone control bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Table 61. EQ bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 62. Volume bypass register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 63. Binary output enable registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 64. Channel limiter mapping as a function of C3LS bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Table 65. Channel output mapping as a function of C3OM bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 66. Tone control boost/cut as a function of BTC and TTC bits . . . . . . . . . . . . . . . . . . . . . . . . . 72

Table 67. Limiter attack rate as a function of LxA bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Table 68. Limiter release rate as a function of LxR bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Table 69. Limiter attack threshold as a function of LxAT bits (AC mode) . . . . . . . . . . . . . . . . . . . . . . 76

Table 70. Limiter release threshold as a function of LxRT bits (AC mode). . . . . . . . . . . . . . . . . . . . . 76

Table 71. Limiter attack threshold as a function of LxAT bits (DRC mode) . . . . . . . . . . . . . . . . . . . . 77

Table 72. Limiter release threshold as a function of LxRT bits (DRC mode) . . . . . . . . . . . . . . . . . . . 77

Table 73. RAM block for biquads, mixing, scaling and bass management. . . . . . . . . . . . . . . . . . . . . 84

Table 74. Extended post-scale range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 75. Extended attack rate, limiter 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Table 76. Extended attack rate, limiter 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 77. Extended biquad selector, biquad 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 78. Extended biquad selector, biquad 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 79. Extended biquad selector, biquad 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Table 80. PLL factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Table 81. PLL register 0x54 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 82. PLL register 0x55 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 83. PLL register 0x56 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Table 84. PLL register 0x57 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Table 85. Coefficients extended range configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Table 86. External amplifier enabler configuration bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Table 87. PNDLSL bits configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Table 88. Zero-detect threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Table 90. Manual threshold register 0x3F, 0x40 and 0x6F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Table 89. Zero-detect hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Table 91. Headphone/Line out configuration bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Table 92. F3X configuration register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Table 93. F3X configuration register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Table 94. Register STCCFG0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 95. STCCFG0 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 96. Register STCCFG1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 97. STCCFG1 register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 98. Charge pump sync configuration bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Table 99. Misc register 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Table 100. I

C registers summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

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List of tables STA381BW

Table 101. Master clock select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Table 102. Input sampling rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Table 103. Internal interpolation ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Table 104. IR bit settings as a function of the input sampling rate . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Table 105. Fault-detect recovery bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Table 106. Serial audio input interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Table 107. Serial data first bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Table 108. Support serial audio input formats for MSB-first (SAIFB = 0) . . . . . . . . . . . . . . . . . . . . . . 109

Table 109. Supported serial audio input formats for LSB-first (SAIFB = 1) . . . . . . . . . . . . . . . . . . . . 110

Table 110. Delay serial clock enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 111. Channel input mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Table 112. FFX compensating pulse size bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Table 113. Compensating pulse size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Table 114. DSP bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Table 115. Post-scale link. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Table 116. Biquad coefficient link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Table 117. Zero-detect mute enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Table 118. Submix mode enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Table 119. Noise-shaper bandwidth selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Table 120. AM mode enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Table 121. PWM speed mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Table 122. Zero-crossing enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Table 123. Soft volume update enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Table 124. Output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Table 125. Output configuration engine selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Table 126. Invalid input detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Table 127. Binary output mode clock loss detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Table 128. LRCK double trigger protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Table 129. IC power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Table 130. External amplifier power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Table 131. Line output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Table 132. Mute configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Table 133. Master volume offset as a function of MVOL[7:0]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Table 134. Channel volume as a function of CxVOL[7:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

Table 135. AM interference frequency switching bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Table 136. Audio preset AM switching frequency selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Table 137. Bass management crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Table 138. Bass management crossover frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Table 139. Tone control bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Table 140. EQ bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Table 141. Volume bypass register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Table 142. Binary output enable registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Table 143. Channel limiter mapping as a function of CxLS bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Table 144. Channel output mapping as a function of CxOM bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Table 145. Tone control boost/cut as a function of BTC and TTC bits . . . . . . . . . . . . . . . . . . . . . . . . 128

Table 146. Limiter attack rate as a function of LxA bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Table 147. Limiter release rate as a function of LxR bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Table 148. Limiter attack threshold as a function of LxAT bits (AC mode) . . . . . . . . . . . . . . . . . . . . . 132

Table 149. Limiter release threshold as a function of LxRT bits (AC mode). . . . . . . . . . . . . . . . . . . . 132

Table 150. Limiter attack threshold as a function of LxAT bits (DRC mode) . . . . . . . . . . . . . . . . . . . 133

Table 151. Limiter release threshold as a function of LxRT bits (DRC mode) . . . . . . . . . . . . . . . . . . 133

Table 152. RAM block for biquads, mixing, scaling and bass management. . . . . . . . . . . . . . . . . . . . 140

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Table 153. Status register bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Table 154. Extended post-scale range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

Table 155. Extended attack rate, limiter 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Table 156. Extended attack rate, limiter 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Table 157. Extended biquad selector, biquad 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Table 158. Extended biquad selector, biquad 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Table 159. Extended biquad selector, biquad 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Table 160. Soft volume update enable, increase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Table 161. Soft volume update enable, decrease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Table 162. Volume fine-tuning steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Table 163. Extra volume resolution enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Table 164. PLL factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Table 165. PLL register 0x43 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Table 166. PLL register 0x44 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Table 167. PLL register 0x45 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

Table 168. PLL register 0x46 bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

Table 169. Coefficients extended range configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

Table 170. External amplifier enabler configuration bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

Table 171. PNDLSL bits configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Table 172. Zero-detect threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Table 173. Zero-detect hysteresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Table 174. Manual threshold register 0x2E, 0x2F and 0x5E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Table 175. Headphone/Line out configuration bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157

Table 176. F3X configuration register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Table 177. F3X configuration register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

Table 178. STCompressorTM configuration bits1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Table 179. STCompressorTM configuration bits 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

Table 180. Charge pump sync configuration bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Table 181. Misc register 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Table 182. MISC4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

Table 183. VQFN48 (7 x 7 x 0.9 mm) package dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

Table 184. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

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List of figures STA381BW

List of figures

Figure 1. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 2. Pin connections VQFN48 (top view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figure 3. Test circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 4. Processing path, first part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figure 5. Processing path, second part: 2.1 output with individually configurable anticlipper/DRCs. 26 Figure 6. Processing path, second part: 2.0 output with B Figure 7. Processing path, second part: 2.1 output configuration with STCompressor Figure 8. STCompressor

Figure 9. Band splitter with 4th order filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 10. STCompressor Figure 11. STCompressor

block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

behavior. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

behavior as a limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 12. Offset effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 13. Stereo link block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 14. Write mode sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 15. Read mode sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figure 16. OPER = 00 (default value) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Figure 17. OPER = 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Figure 18. OPER = 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Figure 19. OPER = 01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Figure 20. Output mapping scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Figure 21. 2.0 channels (OPER = 00) PWM slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Figure 22. 2.1 channels (OPER = 11) PWM slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Figure 23. 2.1 channels (OPER = 10) PWM slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Figure 24. B

DRC scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Figure 25. Basic limiter and volume flow diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 26. Short-circuit detection timing diagram (no short detected) . . . . . . . . . . . . . . . . . . . . . . . . . 90

Figure 27. Alternate function for INTLINE pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Figure 28. Coefficients direct access single-write operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 29. Coefficients direct access multiple-write operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 30. Coefficients direct access single-read operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 31. OCFG = 00 (default value) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Figure 32. OCFG = 01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Figure 33. OCFG = 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

Figure 34. OCFG = 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Figure 35. Output mapping scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Figure 36. 2.0 channels (OCFG = 00) PWM slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Figure 37. 2.1 channels (OCFG = 01) PWM slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

Figure 38. 2.1 channels (OCFG = 10) PWM slots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Figure 39. Basic limiter and volume flow diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Figure 40. B

DRC scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

Figure 41. Extra resolution volume scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Figure 42. Short-circuit detection timing diagram (no short detected) . . . . . . . . . . . . . . . . . . . . . . . . 150

Figure 43. Alternate function for INTLINE pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Figure 44. External audio source to line/headphone out application scheme . . . . . . . . . . . . . . . . . . 164

Figure 45. F3X (from SAI) source to line/headphone out application scheme. . . . . . . . . . . . . . . . . . 165

Figure 46. F3X auxiliary analog output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Figure 47. Headphone and line out block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

Figure 48. Output configuration for stereo BTL mode in filterlight configuration . . . . . . . . . . . . . . . . 167

DRC . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

. . . . . . . . . 27

14/171 Doc ID 018835 Rev 7

STA381BW List of figures

Figure 49. VQFN48 (7 x 7 x 0.9 mm) package outline. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

Doc ID 018835 Rev 7 15/171

Description STA381BW

1 Description

The STA381BW is an integrated solution embedding digital audio processing, digital amplification, FFX the Sound Terminal

power output stage, headphone and 2 Vrms line outputs. It is part of

family and provides full digital audio streaming from the source to the

speaker, offering cost effectiveness, low power dissipation and sound enrichment.

The STA381BW input section consists of a flexible digital input serial audio interface, feeding the digital processing unit, and an analog 1 Vrms input for a seamless connection with pure analog sources. The serial audio data input interface supports many formats, including the popular IIS format.

The STA381BW is based on an FFX technology from STMicroelectronics. FFX

(Fully Flexible Amplification) processor, proprietary

is the evolution of the ST ternary technology: the advanced processor is available for ternary, binary, binary differential and phase shift PWM modulation. The STA381BW embeds the ternary, binary and binary differential implementations, a subset of the full capability of the FFX

processor.

The STA381BW power section consists of four independent half-bridges. These can be configured via digital control to operate in different modes. A 2.1-channel setup can be implemented with two half-bridges (L/R) together with a single full-bridge (subwoofer). Alternatively, the 2.0-channel setup can be done with two full-bridges. When using this configuration, an external amplifier for the SW channel can also be driven through the PWM output. The STA381BW is able to deliver 2 x 20 W (ternary) into an 8 Ω load at 18 V or 2 x 9 W (binary) into a 4 Ω load, plus 1 x 20 W (ternary) into an 8 Ω load at 18 V.

The STA381BW also provides a capless headphone out (with embedded negative charge pump), able to deliver up to 40 mW into a 32 Ω load or, alternatively, can be configured as a 2 Vrms line output.

The STA381BW digital processing unit includes up to 12 programmable biquads (EQs), allowing perfect sound equalization and offering advanced noise-shaping techniques. Moreover, the coefficient range ensures a great variety of filter shapes (low/high-pass, low/high shelf, peak, notch, band-pass). The equalization engine is fully compatible with the ST speaker compensation technology embedded into the APWorkbench suite. A state-ofthe-art multi-band DRC, STCompressor protection with full audio quality preservation against sudden sound peaks. Moreover, STSpeakerSafe

technology offers reliable speaker protection under any condition. The

equalizes the system to provide active speaker

master clock can be from stable BICKI (64xfs, 50% duty cycle) or external XTI.

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STA381BW Description

1.1 Block diagram

Figure 1. Block diagram

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Pin connections STA381BW

2 Pin connections

2.1 Connection diagram

Figure 2. Pin connections VQFN48 (top view)

SDI

VDDDIG2

GNDDIG2

TESTMODESASCL

SDA

INTLINE

PWDN

RESET

LRCKI

BICKI

VCC_REG

VSS_REG

OUT2B

GND2

VCC2

OUT2A

OUT1B

VCC1

GND1

OUT1A

VDD_REG

GND_REG

F3XL

F3X_FILT

STA 381BW

F3XR

LINEINL

LINEINR

LINEHPOUT_L

LINEHPOUT_R

GNDA

VDD3V3

SOFTMUTE

CPVSS

CPM

MCLK

AGNDPLL

VREGFILT

TWARN/FFX4A

EAPD/FFX4B

FFX3B

FFX3A

GNDDIG1

VDDDIG1

VDD3V3CHP

CPP

GNDPSUB

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STA381BW Pin connections

2.2 Pin description

Table 2. Pin list

VQFN 48-pin Name Type Description

1 VCC_REG POWER VCC reg

2 VSS_REG POWER Vss reg, VCC_REG-3.3 V

3 OUT2B OUTPUT Half-bridge 2B output

4 GND2 POWER Half-bridge 2A and 2B ground

5 VCC2 POWER Half-bridge 2A and 2B supply

6 OUT2A OUTPUT Half-bridge 2A output

7 OUT1B OUTPUT Half-bridge 1B output

8 VCC1 POWER Half-bridge 1A and 1B supply

9 GND1 POWER Half-bridge 1A and 1B ground

10 OUT1A OUTPUT Half-bridge 1A output

11 VDD_REG POWER VDD reg 3.3 V

12 GND_REG POWER DC reg ground

13 F3X_FILT POWER F3X reference voltage

14 F3XL OUTPUT F3X analog out left channel

15 F3XR OUTPUT F3X analog out right channel

16 LINEINL INPUT Line in left channel

17 LINEINR INPUT Line in right channel

18 LINEHPOUT_L OUTPUT Headphone/line driver left channel

19 LINEHPOUT_R OUTPUT Headphone/line driver right channel

20 GNDA POWER Headphone/line driver power ground

21 SOFTMUTE INPUT Soft mute

22 VDD3V3 POWER +3 V LDO power supply

23 CPVSS POWER -3.3 V charge pump pin

24 CPM FILTER CHP Cfly negative

25 GNDPSUB POWER Charge pump ground

26 CPP FILTER CHP Cfly positive

27 VDD3V3CHP POWER Charge pump power supply

28 VDDDIG1 POWER I/O ring power supply

29 GNDDIG1 POWER Digital core ground

30 FFX3A OUTPUT Digital PWM line out

31 FFX3B OUTPUT Digital PWM line out

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Pin connections STA381BW

Table 2. Pin list (continued)

VQFN 48-pin Name Type Description

32 EAPD/FFX4B OUTPUT Digital PWM line out

33 TWARN/FFX4A OUTPUT Digital PWM line out

34 VREGFILT POWER Digital VDD from core

35 AGNDPLL POWER PLL analog ground

36 MCLK INPUT PLL input clock

37 BICKI INPUT IIS serial clock

38 LRCKI INPUT IIS left/right clock

39 SDI INPUT IIS serial data input

40 RESET INPUT Reset

Device power-down

41 PWDN INPUT

0 = power-down 1 = normal operation

42 INTLINE OUTPUT Fault interrupt

43 SDA I/O IIC serial data

44 SCL INPUT IIC serial clock

45 SA INPUT IIC select address (pull-down)

46 TEST_MODE INPUT

This pin must be connected to ground (pull-down)

47 GNDDIG2 POWER Digital I/O ground

48 VDDDIG2 POWER Digital core LDO supply

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STA381BW Electrical specifications

3 Electrical specifications

3.1 Absolute maximum ratings

Table 3. Absolute maximum ratings

Symbol Parameter Min Typ Max Unit

Vcc Power supply voltage (VCCxA, VCCxB) -0.3 30 V

VDD_DIG Digital supply voltage -0.3 4 V

VDD3V3 VDD3V3CHP

Top Operating junction temperature 0 150 °C

Tstg Storage temperature -40 150 °C

Line

Btl

Charge pump and analog path LDO supply -0.3 4 V

Load impedance - line driver mode 1 kΩ

Load impedance - headphone driver mode 16 Ω

Load impedance - power output-BTL mode 5 Ω

Warning: Stresses beyond those listed in Table 3 above may cause

permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “Recommended operating conditions” are not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. In the real application, power supplies with nominal values rated within the recommended operating conditions may rise beyond the maximum operating conditions for a short time when no or very low current is sunk (amplifier in mute state). In this case the reliability of the device is guaranteed, provided that the absolute maximum ratings are not exceeded.

3.2 Thermal data

Table 4. Thermal data

Symbol Parameter Min Typ Max Unit

Rth j-case Thermal resistance junction-case (thermal pad) 1.5 °C/W

Tth-sdj Thermal shutdown junction temperature 150 °C

Tth-w Thermal warning temperature 130 °C

Tth-sdh Thermal shutdown hysteresis 20 °C

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Electrical specifications STA381BW

3.3 Recommended operating conditions

Table 5. Recommended operating conditions

Symbol Parameter Min Typ Max Unit

Vcc Power supply voltage (VCCxA, VCCxB) 4.5 26 V

VDD_DIG Digital supply voltage 2.7 3.3 3.6 V

VDD3V3 VDD3V3CHP

Tamb Ambient temperature 0 70 °C

Line

Btl

Charge pump and analog path LDO supply 2.7 3.3 3.6 V

Load impedance - line driver mode 5 10 kΩ

Load impedance - headphone driver mode 16 32 Ω

Load impedance - power output-BTL mode 5 8 Ω

3.4 Electrical specifications for the digital section

The specifications given in this section are valid for the operating conditions: VDD_DIG = 3.3 V, T

(shou

Table 6. Electrical specifications - digital section

amb

= 25 °C.

Symbol Parameter Conditions Min Typ Max Unit

Low level input current without

pull-up/down device

High level input current without

pull-up/down device

Low level input voltage 0.8 V

High level input voltage 2.0 V

Low level output voltage Iol = 2 mA 0.15 V

High level output voltage Ioh = 2 mA

Pull-up/down resistance 50 kΩ

Vi = 0 V 0.5 µA

Vi = VDD_DIG = 3.3 V

VDD_DIG

-0.15

0.1 µA

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STA381BW Electrical specifications

3.5 Electrical specifications for the power section

The specifications given in this section are valid for the operating conditions: VCC=24V, f=1kHz, f

Table 7. Electrical specifications - power section

Symbol Parameter Conditions Min Typ Max Unit

dsON

gP Power Pchannel R

gN Power Nchannel R

Idss Power Pchannel/Nchannel leakage 10 µA

LDT

Output power BTL Digital limited

Output power SE R

Power Pchannel/Nchannel MOSFET ld = 1.5 A 120 mΩ

Low current dead time (static) Resistive load

Rise time Resistive load

Fall time Resistive load

Supply current from Vcc in power-down PWRDN = 0 0.1 1 µA

= 384 kHz, T

= 4 Ω Digital limited

matching ld = 1.5 A 95 %

dsON

matching ld = 1.5 A 95 %

dsON

= 25° C and RL = 8 Ω, unless otherwise specified.

amb

(1)

(2)

WOutput power SE Digital limited

815ns

10 18 ns

vcc

Supply current from Vcc in operation

PCM Input signal = -60 dBfs, Switching frequency = 384 kHz,

52 60 mA

No LC filters

Ilim Overcurrent limit 4 5 6.5 A

UVL Undervoltage protection 3.5 4.3 V

Overvoltage protection 28.25 V

Output minimum pulse width No load 20 30 60 ns

min

DR Dynamic range 100 dB

Signal-to-noise ratio, ternary mode A-weighted 100 dB

SNR

Signal-to-noise ratio, binary mode A-weighted 90 dB

THD+N Total harmonic distortion + noise

FFX stereo mode, Po = 1 W, f=1kHz

0.2 %

FFX stereo mode,

TA LK

Crosstalk

<5 kHz, one channel driven at

1 W and other channel

80 dB

measured

η Peak efficiency, FFX mode Po = 2 x 20 W into 8 Ω 90 %

1. The related THD can be defined through appropriate DRC settings (see section: 4.3: STCompressorTM)

2. Refer to Figure 3: Test circuit.

Doc ID 018835 Rev 7 23/171

Electrical specifications STA381BW

Figure 3. Test circuit

3.6 Electrical specifications for the analog section

The specifications given in this section are valid for the operating conditions: VCC = 24 V

f=1kHz, T

Table 8. Electrical specifications for the analog section

Symbol Parameter Conditions Min Typ Max Unit

Vout Output voltage for line out G

Pout Output voltage for HP out THD+N = 10%, G

DR Dynamic range for line out

X-Talk Channel separation for line out V

PSRR Power supply rejection ratio

Line input resistance 30

THD+N Total harmonic distortion + noise

1. Refer to 8.2: Headphone and 2 Vrms line out, Figure 47: Headphone and line out block diagram, Rin = R1

= 25 °C, VDD3V3 = 3.3 V, R

amb

= 2.5, THD < 1%, Rload = 5 kΩ 1.9 2.1 Vrms

Vout = 2 V Vin = 0.8 mV (-60 dBFs)

= 2 Vrms, Gv = 2.5 75 dB

out

HP mode, P

Line out mode, V

HP mode, V

Line out mode, V

= 5 kΩ, R

Line

= 2.5, Rload = 32 Ω 40 mW

, Fin = 200 Hz,

RMS

= 15 mW 70 dB

= 2 Vrms 70

Out

= 200 mV

out

Out

RMS

= 0.2 Vrms, Gv = 2.5 0.03 %

= 32 Ω, unless otherwise specified.

100 dB

(1)

, Gv = 2.5 0.03 %

kΩ

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STA381BW Device overview

4 Device overview

The mentioned hyperlink in this section relates to the default New Map Section 6: Register

description: New Map.

4.1 Processing data path

The whole STA381BW processing chain is composed of two consecutive sections. In the first one dual-channel processing is implemented (Figure 4) and then each channel is fed into the post-mixing block allowing to generate either a third channel (typically used in 2.1 output configurations together with crossover filters) or to have the channels processed by the dual-band DRC block (2.0 output configuration with crossover filters used to define the cutoff frequency of the two bands).

The first section begins with a 2x oversampling FIR filter allowing 2*Fs audio processing. Then a selectable high-pass filter removes the DC level (enabled if HFB = 0). The channel 1 and 2 processing chain can include up to 8 filters, depending on the selected configuration (bits BQL, BQ5, BQ6, BQ7 and XO[3:0]). By default, 4 independent filters per channel are enabled, plus the pre-configured Bass and Treble controls (BQL=0, BQ5=0, BQ6=0, BQ7=0).

The STA381BW offers the possibility to share the filter coefficients between the two processing channels. When this option is set (BQL=1), filters from the 1st to the 4th have the same coeffcients set. Under these conditions, filters from the 5th to 7th can be used as custom filters as well (provided the relevant BQx bits are set). Once again filter coefficients are shared between the two processing channels.

Moreover the common 8th filter, from the subsequent processing section, can be available on both channels (provided the pre-defined crossover frequencies are not used, XO[3:0]=0, and the dual-band DRC is not used).

Figure 4. Processing path, first part

Sampl i ng Fr equency = 2 xFs

Tone Control

Treble

Biquad#7

Treble

Biquad#7

I2S Input Interface

X2Ov er-

-sampl ing FIR

Sampling Frequency = Fs

X2Ov er-

-sampl ing FIR

Sampl i ng Fr equency = 2 xFs

Pre-

-scale

Pre-

-scale

Hi-Pas s

Filter

Hi-Pas s

Filter

Biquad#1Biquad#2Biquad#3Biquad

Userd Defi ned Fil ters

Biquad#1Biquad#2Biquad#3Biquad

Userd Defi ned Fil ters

De-emph

Biquad#5

De-emph

Biqua

d#5

Bass

Biquad#6

Bass

Biquad#6

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Device overview STA381BW

The second processing stage embeds a mixing block, a biquadratic/crossover filter, a DRC stage, the volume control, a DC cut filter and a post scaler. Depending on the device settings, the following configuration and features are available:

● 2.1 output with individually configurable anticlipper/DRCs (Figure 5): two individually

configurable DRC/anticlippers are available while the eighth biquadratic filter, jointly with the mixer block, can be used to perform LFE. This configuration and features ensure the backward compatibility with previous Sound Terminal

products.

Figure 5. Processing path, second part: 2.1 output with individually configurable

anticlipper/DRCs

C1Mx1

C1Mx2

C2Mx1

C2Mx2

C3Mx1

C3Mx2

Us er-Defined

Mix Coef ficients

Channel ½

Biquad#8

--------------

Hi-pass XO

Filter

Channel ½

Biquad#8

--------------

Hi-pass XO

Filter

Channel 3

Biquad#8

-- -- -- ---- ----

Low- pass XO

filter

Crossover Frequency

Determined by XO Setting

(User D efined If

XO=0000)

Channel 1

Vol ume

Channel 2

Vol ume

Channel 3

Vol ume

Anti -clipper

DRC

Anti -clipper

DRC

Anti- clipper

DRC

DC Cut

Filter

DC Cut

Filter

DC Cut

Filter

Pos t Scale

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STA381BW Device overview

● 2.0 output with B

DRC (Figure 6): the mixer and the eighth biquadratic filter are used to divide the channel into two sub-bands, then each sub-band is independently processed by a DRC block. The two bands are then re-composed and fed to the following processing blocks. The crossover frequency is user-selectable. This configuration and features ensure the backward compatibility with the previous Sound Terminal products. For further information please refer to Chapter 6.11.1: Dual-band DRC.

DRC 2

DRC 1

DRC 2

DRC

DC Cut

Filter

DC Cut

Filter

Post Scale

. When

Figure 6. Processing path, second part: 2.0 output with B

Channel 3

Vol ume

● 2.1 output with STCompressor

C1Mx1

C1Mx2

C2Mx1

C2Mx2

C3Mx1

C3Mx2

User-Def ined

Mix Coef fici ents

B2DRC

Hi-p ass XO

filter

B2DRC

Hi-p ass XO

filter

Crossover Frequency

Determined by XO Setting

(User Defi ned I f

XO=000 0)

- Channel 1 ++

Vol ume

Channel 2

Vol ume

Channel 3

Vol ume

(Figure 7): the STA381BW embeds the latest, stateof-the-art multi-band dynamic, range compressor, called STCompressor using this configuration, up to 10 biquad filters are available for dedicated processing. Please refer to Section 4.3: STCompressorTM for further information about this feature.

Figure 7. Processing path, second part: 2.1 output configuration with

STCompressor

C1Mx1

C1Mx2

C2Mx1

C2Mx2

C3Mx1

C3Mx2

User-Defined

Mix Coefficients

Channel ½

Biquad#8

--------------

Hi-p ass XO

Filter

Channel ½

Biquad#8

--------------

Hi-p ass XO

Filter

Channel 3

Biquad#8

--------------

Low-p ass XO

filter

Crossover Frequency

Determined by XO Sett ing

(User Defin ed If

XO=0000)

STCompressor

Vol ume

And

Limit er

Vol ume

And

Limit er

Vol ume

And

Limit er

DC Cut

Filter

DC Cut

Filter

DC Cut

Filter

Post Scale

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Device overview STA381BW

4.2 Input oversampling

Figure 4 shows the input oversampling block in front of the main processing. When 32 kHz

Fs is used, the default x2 oversampling ratio can be increased to a x3.

Activating this feature, it is possible to have a 384 kHz PWM switching frequency (instead of the default 256 kHz) when 32 kHz Fs is used.

When bit 0 of register PLLCFG1 is set to one, the feature is activated so that the PLL ratio is modified to generate 49.152 MHz internal clock and the audio data path (after the input oversampling block) is running at 96 kHz.

It is not recommended to use the x3 oversampling feature when Fs > 32 kHz because of the PLL maximum frequency constraint.

4.3 STCompressor

The STCompressorTM (STC from now on) is a stereo, dual-band Dynamic Range Control (DRC) and its main purpose is to provide optimum output power level control for speaker protection, preserving as much as possible the original audio quality of the signal.

Two m ai n I data flow control bits, these registers also allow enabling the checksum engine to protect the STC filters from erroneous coefficients downloads, thus improving the final application circuitry and safety of the speakers.

C registers control the STC behavior: STCCFG0 and STCCFG1. On top of the

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STA381BW Device overview

4.3.1 STC block diagram

Figure 8. STCompressorTM block diagram

DRC 0

Offs et

Band 0

In put

Ch 0

In put

Ch 1

Band

Sp li tter

Band

Sp li tter

(Low freqs)

Band 1

(High freqs)

Band 0

(Low freqs)

Band 1

(High freqs)

Level

Meter

Level

Meter

Level Meter

Mapper Attenuator

DRC 1

Mapper

DRC 2

Mapper

DRC 3

Mapper

Attenuato r

Offs et

Attenua to r

Ou tp ut

Ch 0

Ou tp ut

Ch 1

Offs et

The STC takes as input 2 channels and every channel is processed independently (i.e. an independent DRC for each band of each channel) following the steps listed below (Figure 8):

1. Splits the input signal into 2 bands (band splitter)

2. Measures the level of the signal (level meter)

3. Computes the attenuation (mapper)

4. Applies the attenuation and offset (attenuator)

The band splitter settings are common to both the processing channels while the settings of the remaining blocks can be independently set for each band of each processing channel.

Caution: All the settings explained hereafter apply only to the behavior of the STCompressor

the settings concerning other device operating configurations (see Chapter 4.1: Processing

data path) please refer to the appropriate paragraphs and registers.

4.3.2 Band splitter

The band splitter block is used to divide the signal into 2 sub-bands (typically low- and highfrequency bands). This is done through two 2 thus allowing to have up to a 4

order filter per band. This feature guarantees a totally flat band recombination (see Figure 9). Using different filtering orders, indeed, causes a nonnegligible gain around the filter’s cutoff frequency, endangering the overall audio fidelity and, eventually, also the safety of the speaker. The sub-band recombination can be enabled or disabled.

order biquads (IIR filters) for each band,

. For

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Device overview STA381BW

The band splitter filter coefficients have a user-selectable range [-1, 1), [-2, 2) and [-4, 4). The RAM coefficient 0x7 is responsible for these settings according to Tab l e 9 . The range default value is [-4, 4).

Table 9. Coefficients extended-range configuration 0x74h

CEXT_Bx[1] CEXT_Bx[0] Range

1 1 Reserved

[-1;1)

[-2;2)

[-4;4)

Please refer to Section 6.24: User-defined coefficient control registers (addr 0x27 - 0x37) and to Ta bl e 1 3 for further details.

Figure 9. Band splitter with 4

Band Splitter

Inp ut

Ch x

BQ 0

order filtering

BQ 1

Band 0

…

Output

Ch x

BQ 0

BQ 1

Band 1

…

4.3.3 Level meter

The level meter block measures the input signal level (in dB). Two kinds of measures are performed: peak and RMS. The mapper configuration and the input signal automatically determine which measurement to take into account.

4.3.4 Mapper

The mapper block computes the appropriate attenuation value (expressed in dB) to be applied to the signal, basing its calculations on the level meter output value, on the compressor threshold and on the limiter threshold.The attenuation value is then passed to the attenuator block.

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