ST TS4994 User Manual

1W differential input/output audio power amplifier

Features

■ Differential inputs

■ Near-zero pop & click

■ 100dB PSRR @ 217Hz with grounded inputs

■ Operating range from V

■ 1W rail-to-rail output power @ V

THD = 1%, F = 1kHz, with 8Ω

■ 90dB CMRR @ 217Hz

■ Ultra-low consumption in standby mode (10nA)

■ Selectable standby mode (active low or active

high)

■ Ultra fast startup time: 15ms typ.

■ Available in DFN10 3x3 (0.5mm pitch) &

MiniSO-8

■ All lead-free packages

Description

The TS4994 is an audio power amplifier capable of delivering 1W of continuous RMS output power into an 8Ω load @ 5V. Due to its differential input s, it exhibits outstanding noise immunity.

An external standby mode control reduces the supply current to less than 10nA. An STBY MODE pin allows the standby to be active HIGH or LOW (except in the MiniSO-8 version). An internal thermal shutdown protection is also provided, making the de vice capable of sustain ing short-circuits.

The device is equipped with common mode feedback circuitry allowing outputs to be always

= 2.5V to 5.5V

CC

load

=5V,

TS4994

with selectable standb y

Pin connections (top view)

TS4994IQT - DFN10

1

STBY

2

V

IN -

3

STBY MODE

BYPASS

3

V

4

IN +

5

TS4994IST - MiniSO-8

STBY

biased at V

STBY

BYPASS

/2 regardless of the input common

CC

1

V

IN-

2

V

IN+

3

3 4

4

mode voltage. The TS4994 is designed for high quality audio

applications such as mobile phones and requir es few external components.

Applications

■ Mobile phones (cellular / cordless)

■ Laptop / notebook computers

■ PDAs

■ Portable audio devices

10

V

O+

V

9

DD

N/C

8

GND

7

7 6

6

V

O-

V

O+

8

Vcc

7

GND

6

V

5

O-

Order codes

Part number Temperature range Package Packing Marking

TS4994IQT

-40°C to +85°C

TS4994IST MiniSO-8 K994

December 2006 Rev 6 1/35

DFN10

Tape & reel

K994

www.st.com

35

Contents TS4994

Contents

1 Application component information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2 Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 5

3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.1 Differential configuration principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.2 Gain in typical application schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.3 Common mode feedback loop limitations . . . . . . . . . . . . . . . . . . . . . . . . . 21

4.4 Low and high frequency response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4.5 Calculating the influence of mismatching on PSRR performance . . . . . . 23

4.6 CMRR performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4.7 Power dissipation and efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.8 Decoupling of the circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

4.9 Wake-up time: t

4.10 Shutdown time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.11 Pop performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.12 Single-ended input configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

4.13 Demoboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

WU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

5 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

5.1 DFN10 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

5.2 MiniSO-8 package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2/35

TS4994 Application component information

1 Application component information

Components Functional description

C

s

C

b

R

feed

R

in

C

in

Supply bypass capacitor that provides power supply filtering. Bypass capacitor that provides half supply filtering. Feedback resistor that sets the closed loop gain in conjunction with Rin

AV= closed loop gain = R

feed/Rin

. Inverting input resistor that sets the closed loop gain in conjunction with R Optional input capacitor making a high pass filter together with Rin.

(FCL= 1/(2πRinCin).

Figure 1. Typical application, DFN10 version

Rfeed1 20k

Diff. input -

GND

Diff. Input +

Cin1

220nF

Cin2

220nF

Optional

Rin1

+

20k Rin2

+

20k

+

Cb 1u

GND

Vin-

2

Vin+

4

Bypass

5

Mode Stdby TS4994IQ

1

VCC

9 VCC

-

+

Bias

Standby GND 73

GND

+

GND

Rfeed2 20k

Cs 1u

Vo+

Vo-

.

feed

10

6

8 Ohms

GND GNDVCC VCC

3/35

Application component information TS4994

Figure 2. Typical application, MiniSO-8 version

VCC

+

Cs

GND

Rfeed2 20k

1u

Vo+

8

Vo-

5

8 Ohms

TS4994IS

Diff. input -

GND

Diff. Input +

Cin1

220nF

Cin2

220nF

Optional

Rfeed1 20k

Rin1

+

20k Rin2

+

20k

+

Cb 1u

GND

2

3

4

Vin-

Vin+

Bypass

Stdby 1

7 VCC

-

+

Bias

Standby GND 6

GND

GNDVCC

4/35

TS4994 Absolute maximum ratings and operating conditions

2 Absolute maximum ratings and operating conditions

Table 1. Absolute maximum ratings

Symbol Parameter Value Unit

(2)

(1)

(3)

6V

GND to V

CC

120 215

V

T

R

P

CC

V

oper

stg

T

thja

diss

Supply voltage Input voltage

i

Operating free air tempe rature range -40 to + 85 °C Storage temperature -65 to +150 °C Maximum junction temperature 150 °C

j

Thermal resistance junction to ambient

DFN10

MiniSO-8 Power dissipation internally limited W Human body model 2 kV

ESD

Machine model 200 V Latch-up immunity 200 mA Lead temperature (soldering, 10sec) 260 °C

1. All voltage values are measured with respect to the ground pin.

2. The magnitude of the input signal must never exceed V

3. The device is protected by a thermal shutdown active at 150°C.

Table 2. Operating conditions

+ 0.3V / GND - 0.3V.

CC

V

°C/W

Symbol Parameter Value Unit

V

CC

Supply voltage 2.5 to 5.5 V Standby mode voltage input:

V

SM

Standby active LOW Standby active HIGH

=GND

V

SM

V

SM=VCC

Standby voltage input:

V

T

STBY

SD

R

L

Device ON (VSM= GND) or device OFF (VSM=VCC) Device OFF (V

= GND) or device ON (VSM=VCC)

SM

Thermal shutdown temperature 150 °C Load resistor ≥ 8 Ω

1.5 ≤ V ≤ V

GND

STBY

≤ VCC

≤ 0.4

(1)

Thermal resistance junction to ambient

R

thja

DFN10 MiniSO-8

1. The minimum current consumption (I temperature range.

2. When mounted on a 4-layer PCB.

(2)

) is guaranteed when V

STBY

80

190

=GND or VCC (i.e. supply rails) for the whole

STBY

V

°C/W

5/35

Electrical characteristics TS4994

3 Electrical characteristics

Table 3. Electrical characteristics for VCC = +5V, GND = 0V, T

= 25°C (unless otherwise

amb

specified)

Symbol Parameter Min. Typ. Max. Unit

I

CC

I

STBY

V

oo

V

ICM

P

out

THD + N

PSRR

CMRR

SNR

Supply current No input signal, no load

Standby current No input signal, V No input signal, V

= VSM = GND, RL = 8Ω

STBY

= VSM = VCC, RL = 8Ω

STBY

Differential output offset voltage No input signal, RL = 8Ω

Input common mode voltage CMRR ≤ -60dB

Output power THD = 1% Max, F= 1kHz, RL = 8Ω

Total harmonic distortion + noise

=850mW rms, AV=1, 20Hz ≤ F ≤ 20kHz, RL=8Ω

P

out

Power supply rejection ratio with inputs grounded F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF

IG

V

ripple

= 200mV

PP

Common mode rejection ratio F = 217Hz, R

= 200mV

V

ic

= 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF

L

PP

Signal-to-noise ratio (A-weighted filter, A RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz

= 2.5)

V

(1)

47mA

10 1000 nA

0.1 10 mV

0.6 V

-0.9 V

CC

0.8 1 W

0.5 %

100 dB

90 dB

100 dB

GBP

Gain bandwidth product R

= 8Ω

L

Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω

Unweighted, A A-weighted, A Unweighted, A

V

N

A-weighted, A Unweighted, A A-weighted, A

= 1

V

= 1

V

= 2.5

V

= 2.5

V

= 7.5

V

= 7.5

V

Unweighted, Standby A-weighted, Standby

t

WU

1. Dynamic measurements - 20*log(rms(V

2. Transition time from standby mode to fully operational amplifier.

Wake-up time Cb =1μF

(2)

)/rms (V

out

ripple

)). V

ripple

6/35

2MHz

6

5.5 12

10.5 33 28

1.5 1

15 ms

is the super-imposed sinus signal relative to VCC.

μV

RMS

TS4994 Electrical characteristics

Table 4. Electrical characteristics for VCC = +3.3V (all electrical values are guaranteed with

correlation measurements at 2.6V and 5V), GND = 0V, T

= 25°C (unless otherwise

amb

specified)

Symbol Parameter Min. Typ. Max. Unit

I

CC

I

STBY

V

oo

V

ICM

P

out

THD + N

PSRR

CMRR

SNR

Supply current no input signal, no load 3 7 mA Standby current

No input signal, V No input signal, V

= VSM = GND, RL = 8Ω

STBY

= VSM = VCC, RL = 8Ω

STBY

Differential output offset voltage No input signal, RL = 8Ω

Input common mode voltage CMRR ≤ -60dB

Output power THD = 1% max, F= 1kHz, R

= 8Ω

L

Total harmonic distortion + noise

= 300mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω

P

out

Power supply rejection ratio with inputs grounded F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF

IG

V

ripple

= 200mV

PP

0.6 V

300 380 mW

(1)

10 1000 nA

0.1 10 mV

-0.9 V

CC

0.5 %

100 dB

Common mode rejection ratio F = 217Hz, R

= 200mV

V

ic

Signal-to-noise ratio (A-weighted filter, A RL = 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz

= 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF

L

PP

= 2.5)

V

90 dB

100 dB

GBP

Gain bandwidth product R

= 8Ω

L

Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω

Unweighted, A

V

= 1

A-weighted, AV = 1

V

N

A-weighted, A Unweighted, A A-weighted, A

Unweighted, A

= 2.5

V

= 2.5

V

= 7.5

V

= 7.5

V

Unweighted, Standby A-weighted, Standby

t

WU

1. Dynamic measurements - 20*log(rms(V

2. Transition time from standby mode to fully operational amplifier.

Wake-up time Cb =1μF

(2)

)/rms (V

out

ripple

)). V

ripple

2MHz

6

5.5

12

10.5 33 28

1.5 1

15 ms

is the super-imposed sinus signal relative to VCC.

μV

RMS

7/35

Electrical characteristics TS4994

Table 5. Electrical characteristics for VCC = +2.6V, GND = 0V, T

= 25°C (unless otherwise

amb

specified)

Symbol Parameter Min. Typ. Max. Unit

I

CC

I

STBY

V

ICM

P

out

THD + N

PSRR

CMRR

SNR

GBP

V

t

WU

Supply current No input signal, no load

Standby current No input signal, V No input signal, V

Differential output offset voltage

oo

No input signal, R

= VSM = GND, RL = 8Ω

STBY

= VSM = VCC, RL = 8Ω

STBY

= 8Ω

L

Input common mode voltage CMRR ≤ -60dB

Output power THD = 1% max, F= 1kHz, RL = 8Ω

Total harmonic distortion + noise

= 225mW rms, AV = 1, 20Hz ≤ F ≤ 20kHz, RL = 8Ω

P

out

Power supply rejection ratio with inputs grounded F = 217Hz, R = 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF

IG

V

= 200mV

ripple

PP

Common mode rejection ratio F = 217Hz, R Vic = 200mV

= 8Ω, AV = 1, Cin = 4.7μF, Cb =1μF

L

PP

Signal-to-noise ratio (A-weighted filter, A

= 8Ω, THD +N < 0.7%, 20Hz ≤ F ≤ 20kHz

R

L

Gain bandwidth product

= 8Ω

R

L

Output voltage noise, 20Hz ≤ F ≤ 20kHz, RL = 8Ω

Unweighted, AV = 1 A-weighted, A

V

= 1

Unweighted, AV = 2.5

N

A-weighted, A Unweighted, A A-weighted, A

= 2.5

V

= 7.5

V

= 7.5

V

Unweighted, Standby A-weighted, Standby

Wake-up time

(2)

Cb =1μF

= 2.5)

V

(1)

37mA

10 1000 nA

0.1 10 mV

0.6 V

- 0.9 V

CC

200 250 mW

0.5 %

100 dB

90 dB

100 dB

2MHz

6

5.5

12

10.5 33 28

1.5 1

15 ms

μV

RMS

1. Dynamic measurements - 20*log(rms(V

2. Transition time from standby mode to fully operational amplifier.

)/rms (V

out

ripple

)). V

ripple

8/35

is the super-imposed sinus signal relative to VCC.

TS4994 Electrical characteristics

012345

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Standby mode=0V

Standby mode=5V

Vcc = 5V No load Tamb=25°C

Current Consumption (mA)

Standby Voltage (V)

0.0 0.6 1.2 1.8 2.4

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Standby mode=0V

Standby mode=2.6V

Vcc = 2.6V No load Tamb=25°C

Current Consumption (mA)

Standby Voltage (V)

Figure 3. Current consumption vs. power

supply voltage

4.0

No load Tamb=25°C

3.5

3.0

2.5

2.0

1.5

1.0

Current Consumption (mA)

0.5

0.0

012345

Power Supply Voltage (V)

Figure 5. Current consumption vs. power

supply voltage

3.5

3.0

2.5

Standby mode=0V

Figure 4. Current consumption vs. standby

voltage

Figure 6. Current consumption vs. standby

voltage

2.0

1.5

1.0

Current Consumption (mA)

0.5

0.0

0.0 0.6 1.2 1.8 2.4 3.0

Standby mode=3.3V

Standby Voltage (V)

Figure 7. Differential DC output voltage vs.

common mode input voltage

1000

Av = 1 Tamb = 25°C

100

Vcc=2.5V

10

Voo (mV)

1

0.1

0.01

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Common Mode Input Voltage (V)

Vcc = 3.3V No load Tamb=25°C

Vcc=3.3V

Vcc=5V

Figure 8. Power dissipation vs. output power

0.6

RL=8

Ω

0.4

0.2

Power Dissipation (W)

0.0

0.0 0.2 0.4 0.6 0.8 1.0

9/35

RL=16

Ω

Output Power (W)

Vcc=5V F=1kHz THD+N<1%

Electrical characteristics TS4994

Figure 9. Power dissipation vs. output powe r Figure 10. Power dissipation vs. output power

0.3

RL=8

Ω

0.2

0.1

Power Dissipation (W)

RL=16

Ω

Vcc=3.3V F=1kHz

0.0

0.0 0.1 0.2 0.3 0.4

THD+N<1%

Output Power (W)

Figure 11. Output power vs. power supply

voltage

1.0

Cb = 1μF F = 1kHz

0.8

BW < 125kHz Tamb = 25°C

0.6

0.4

8

Ω

16

Ω

0.20

Vcc=2.6V F=1kHz THD+N<1%

0.15

RL=8

Ω

0.10

0.05

Power Dissipation (W)

0.00

0.0 0.1 0.2 0.3

RL=16

Ω

Output Power (W)

Figure 12. Output power vs. power supply

voltage

1.50

1.25

1.00

0.75

0.50

Cb = 1μF F = 1kHz BW < 125kHz Tamb = 25°C

8

Ω

16

Ω

0.2

32

Output power @ 1% THD + N (W)

0.0

2.5 3.0 3.5 4.0 4.5 5.0

Ω

Vcc (V)

0.25

Output power @ 10% THD + N (W)

0.00

2.5 3.0 3.5 4.0 4.5 5.0

Vcc (V)

Figure 13. Output power vs. load resistance Figure 14. Power derating curves

1.0

THD+N=1% Cb = 1 F

0.8

0.6

Vcc=5V

Vcc=4.5V

Vcc=4V

F = 1kHz BW < 125kHz Tamb = 25°C

0.4

Output power (W)

0.2

Vcc=3.5V

0.0

88121616 20 2424 28 3232

Vcc=3V

Vcc=2.5V

Load Resistance

1.5

with 4 layers PCB

1.0

0.5

AMR Value

DFN10 Package Power Dissipation (W)

0.0

0 25 50 75 100 125

Ambiant Temperature ( C)

32

Ω

10/35

TS4994 Electrical characteristics

0.1 1 10 100 1000 10000

-40

-20

0

20

40

60

-200

-160

-120

-80

-40

0

Gain

Phase

Gain (dB)

Frequency (kHz)

Vcc = 5V ZL = 8Ω + 500pF Tamb = 25°C

Phase (°)

Figure 15. Power derating curves Figure 16. Open loop gain vs. frequency

0.6

Nominal Value

0.4

0.2

MiniSO8 Package Power Dissipation (W)

0.0

AMR Value

0 25 50 75 100 125

Ambiant Temperature ( C)

Figure 17. Open loop gain vs. frequency Figure 18. Open loop gain vs. frequency

0

60

Gain

40

20

Gain (dB)

0

Phase

-40

-80

-120

Phase (°)

60

Gain

40

20

Gain (dB)

0

Phase

0

-40

-80

-120

Phase (°)

Vcc = 3.3V

-20

ZL = 8Ω + 500pF Tamb = 25°C

-40

0.1 1 10 100 1000 10000

Frequency (kHz)

-160

-200

Vcc = 2.6V

-20

ZL = 8Ω + 500pF Tamb = 25°C

-40

0.1 1 10 100 1000 10000

Frequency (kHz)

-160

-200

Figure 19. Closed loop gain vs. frequency Figure 20. Closed loop gain vs. frequency

10

Gain

0

-10

-20

Gain (dB)

Vcc = 5V

-30

Av = 1 ZL = 8Ω + 500pF Tamb = 25°C

-40

0.1 1 10 100 1000 10000

Frequency (kHz)

Phase

0

-40

-80

-120

-160

-200

10

Gain

0

-10

Phase (°)

-20

Gain (dB)

Vcc = 3.3V

-30

Av = 1 ZL = 8Ω + 500pF Tamb = 25°C

-40

0.1 1 10 100 1000 10000

Frequency (kHz)

Phase

11/35

0

-40

-80

-120

-160

-200

Phase (°)