Cirrus Logic CS4390-KS, CS4390-KP, CDB4390 Datasheet

CS4390

24-Bit, Stereo D/A Converter for Digital Audio

Features

l

24-Bit Conversion

l

115 dB Signal-to-Noise-Ratio (EIAJ)

l

Complete Stereo DAC System

— 128X Interpolation Filter
— Delta-Sigma DAC
— Analog Post Filter

l

106 dB Dynamic Range

l

Low Clock Jitter Sensitivity

l

Filtered Line-Level Outputs

— Linear Phase Filtering
— Zero Phase Error Between Channels

l

Adjustable System Sampling Rates

— including 32 kHz, 44.1 kHz & 48 kHz

l

Digital De-emphasis for 32 kHz, 44.1 kHz, &
48 kHz

l

Pin-compatible with the CS4329

I

DIF0

LRCK
SCLK

SDATA

10

7
9

DIF1

20

19

Serial Input

Interface

DIF2

DEM01DEM1

12 3 6

De-emphasis

Description

The CS4390 is a complete stereo digital-to-analog out­put system. In addit ion to the tr aditional D/A function, t he
CS4390 includes a digital interpolation filter followed by
an 128X oversampled delt a-sigma modulator. The mod­ulator output controls the reference voltage input to an
ultra-linear analog low-pass filter. This architecture al­lows for infin ite adjustment of sample rate between 1 and
50 kHz while maintaining linear phase response simply
by changing the master clock frequency.

The CS4390 also includes an extremely flexible serial
port utilizing mode select pins to support multiple inter­face formats.

The master clock can be either 256, 384, or 512 times
the input sample rate, supporting various audio
environments.

ORDERING INFORMATION

CS4390-KP -10° to 70° C 20-pin Plastic DIP
CS4390-KS -10° to 70° C 20-pin Plastic SSOP
CDB4390 Evaluation Board

VA VD

2

Voltage Reference

MUTE_L

16

Interpolator

AUTO_MUTE

Cirrus Logic, Inc.
Crystal Semiconductor Products Division

P.O. Box 17847, Austin, Texas 78760
[phone] FAX: [phone]
http://www.crystal.com

11

Interpolator

5

DGND

Delta-Sigma

Modulator

Delta-Sigma

Modulator

8

MCLK

DAC

DAC

4

AGND

Copyright  Cirrus Logic, Inc. 1998

(All Rights Reserved)

Analog

Low-Pass

Filter

Analog

Low-Pass

Filter

15

MUTE_R

AOUTL+

18

AOUTL-

17

AOUTR+

14

AOUTR-

13

JUN ‘98

DS264F1

1

CS4390

ANALOG CHARACTERISTICS (T

48 kHz; Input Data = 24 Bits; SCLK = 3.072 MHz; MCLK = 12.288MHz; RL = 20kΩ differential; VD = VA = 5V;
Logic "1" = VD; Logic "0" = DGND; Measurement Bandwidth is 10 Hz to 20kHz, unweighted unless otherwise
specified.)

Parameter Symbol Min Typ Max Unit

Specified Temperature Operating Range T

= 25°C; Full-Scale Differential Output Sine wave, 997Hz; Fs =

A

A

-10 - 70 °C

Dynamic Performance

Dynamic Range 24-Bit (Note 1)

(A-Weighted)

20-Bit

(A-Weighted)

16-Bit

(A-Weighted)

Total Harmonic Distortion + Noise (Note 1)
24-Bit 0 dB

-20 dB

-60 dB

20-Bit 0 dB

-20 dB

-60 dB

16-Bit 0 dB

-20 dB

-60 dB
Idle Channel Noise / Signal-to-Noise-Ratio (Note 2) - 115 - dBFS
Interchannel Isolation (1 kHz) - -110 - dB

THD+N

98

101

-

-

-

-

-90

-78

-38

-

-

-

-

-

-

103
106
103
106

94
96

-98

-83

-43

-98

-83

-43

-93

-74

-34

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

dB
dB
dB
dB
dB
dB

dB
dB
dB
dB
dB
dB
dB
dB
dB

Combined Digital and Analog Filter Characteristics

Frequency Response 10Hz to 20kHz (Note 3) - ±0.1 - dB
Deviation from linear phase - ±0.5 - deg
Passband: to -0.1dB corner (Note 3) 0 - 21.77 kHz
Passband Ripple - - ±0.001 dB
StopBand (Note 3) 26.23 - - kHz
StopBand Attenuation (Note 3) 75 - - dB
Group Delay (Note 4) - 25/Fs - s
De-emphasis Error (referenced to 1kHz) Fs = 32kHz

Fs = 44.1kHz

Fs = 48kHz

-

-

-

-

-

-

+0.3/-0.3
+0.2/-0.4

+0.1/-0.45

dB
dB
dB

dc Accuracy

Interchannel Gain Mismatch - 0.1 - dB
Gain Error - ±2 ±5 %
Gain Drift - 200 - ppm/°C

Power Supplies

Power Supply Current: Normal Operation

Power-down

Power Dissipation Normal Operation

Power-down

Power Supply Rejection Ratio (1kHz) PSRR - 60 - dB

I
I

IA+I

A
D

D

-

-

-

-

-

-

30
12
42

500
210

2.5

-

-

45

-

225

-

mA
mA
mA

µA

mW
mW

2 DS264F1

CS4390

ANALOG CHARACTERISTICS (CONTINUED)

Parameter Symbol Min Typ Max Unit

Analog Output

Differential Full Scale Output Voltage (Note 5) 1.90 2.0 2.10 Vrms
Output Common Mode Voltage - 2.2 - V
Differential Offset - 3 15 mV
AC Load Resistance R
Load Capacitance C

Notes:1.Triangular PDF Dithered Data

2.AUTO-MUTE

active. See parameter definitions

3.The passband and stopband edges scale with frequency. For input sample rates, Fs, other than 48kHz,

the passband edge is 0.4535×Fs and the stopband edge is 0.5465×Fs.

4.Group Delay for Fs=48kHz 25/48kHz=520µs

5.Specified for a fully differential output ±((AOUT+)-(AOUT-)). See Figure 12.

L
L

4--k

- - 100 pf

Ω

SWITCHING CHARACTERISTICS (T

1=VD=VA=5.25 to 4.75 Volts; C

=20pF)

L

=-10 to 70°C; Logic 0 = AGND=DGND; Logic

A

Parameter Symbol Min Typ Max Unit

Input Sample Rate Fs 1 - 50 kHz
MCLK Pulse Width High MCLK / LRCK = 512 10 - - ns
MCLK Pulse Width Low MCLK / LRCK = 512 10 - - ns
MCLK Pulse Width High MCLK / LRCK = 384 21 - - ns
MCLK Pulse Width Low MCLK / LRCK = 384 21 - - ns
MCLK Pulse Width High MCLK / LRCK = 256 31 - - ns
MCLK Pulse Width Low MCLK / LRCK = 256 32 - - ns

External SCLK Mode

SCLK Pulse Width Low t
SCLK Pulse Width High t
SCLK Period t

SCLK rising to LRCK edge delay t
SCLK rising to LRCK edge setup time t
SDATA valid to SCLK rising setup time t
SCLK rising to SDATA hold time t

sclkl

sclkh

sclkw

slrd

slrs

sdlrs

sdh

20--ns
20--ns

1

-------------------­128Fs()

--ns

20--ns
20--ns
20--ns
20--ns

Internal SCLK Mode

SCLK Period SCLK / LRCK = 64 t

SDATA valid to SCLK rising setup time t

SCLK rising to SDATA hold time MCLK / LRCK = 256 or
512

SCLK rising to SDATA hold time MCLK / LRCK = 384 t

sclkw

sdlrs

t

sdh

sdh

1

----------------­64Fs()

1

-------------------­512Fs()

1

-------------------­512Fs()

1

-------------------­384Fs()

--ns

10+

15+

15+

--ns

--ns

--ns

DS264F1 3

LRCK

SCLK

SDATA

t

slrs

t

t

slrd

t

sdlrs

sclkl

t

sdh

t

External Serial Mode Input Timing

CS4390

sclkh

LRCK

SDATA

*INTE R NA L S C LK

* The SCLK pin must be terminated to ground.
The SCLK pulses shown are internal to the CS4390.

t

sdlrstsdh

Internal Serial Mode Input Timing

t

sclkw

4 DS264F1

CS4390

DIGITAL CHARACTERISTICS (T

Parameter Symbol Min Typ Max Unit

High-Level Input Voltage V
Low-Level Input Voltage V
Input Leakage Current V
Digital Input Capacitance - 10 - pF

= 25°C; VD = 5 V ±5%)

A

IH
IL

in

2.0 - - V

--0.8V

--±10.0µA

ABSOLUTE MAXIMUM RATINGS (AGND = 0 V, all voltages with respect to ground.)

Parameter Symbol Min Max Unit

DC Power Supply: Positive Analog

Positi ve D ig ital

|VA - VD|
Input Current, Any Pin Except Supplies I
Digital Input Voltage V
Ambient Operating Temperature (power applied) T
Storage Temperature T

WARNING: Operation at or beyond these limits may result in permanent damage to the device. Normal operation

is not guaranteed at these extremes.

RECOMMENDED OPERATING CONDITIONS

VA
VD

in

IND

A

stg

(DGND = 0V; all voltages with respect to ground)

-0.3

-0.3

0.0

-±10mA

-0.3 (VD)+0.4 V

-55 125 °C

-65 150 °C

6.0

6.0

0.4

V
V
V

Parameter Symbol Min Typ Max Unit

DC Power Supply: Positive Digital

Positi ve Analog

|VA - VD|

VD

VA

4.75

4.75

-

5.0

5.0

-

5.25

5.25

0.4

V
V
V

DS264F1 5

CS4390

Ω

10

1 µF

+

0.1 µF

+

1 µF

0.1 µF

+5V

Analog

Mode

Select

Audio

Data

Processor

External Clock

20

DIF0

19

DIF1

12

DIF2

7

LRCK

9

SCLK*

10

SDATA

1

DEM0

2

DEM1

15

MUTE_R

16

MUTE_L

11

AUTO_MUTE

8

MCLK

VD

6

DGND

CS4390

AGND

5

3

VA

AOUTL-

AOUTL+

AOUTR-

AOUTR+

4

17

Analog

Conditioning

18

13

Analog

Conditioning

14

* SCLK mus t be connec ted to D GND
for operation in Internal SCLK Mode

Figure 1. Typical Connection Diagram

6 DS264F1

CS4390

GENERAL DESCRIPTION

The CS4390 is a com plete ste reo dig ital-t o-analo g

system including 128× digital interpolation, fourth­order delta-sigma digital-to-analog conversion,
128× oversampled one-bit delta-sigma modulator
and analog filtering. This architecture provides a
high insensitivity to clock jitter. The DAC converts
digital data at a ny input sample rat e bet w een 1 and
50 kHz, including the standa rd audio rates of 48,

44.1 and 32 kHz.
The primary purpose of using delta-sigma modula-

tion techni ques is to avo id the limi tations of laser
trimmed resistive DAC architectures by using an
inherently linear 1-bit DAC. The advantages of a 1­bit DAC include: ideal differential linearity, no dis­tortion mechanisms due to resistor matching errors
and no linearity drift over time and temperature due
to variations in resist or va lues.

Digital Interpolation Filter

The digital interpolation filter increases the sample
rate by a factor of 4 and is followed by a 32× digital
sample-and hold to effectivel y achieve a 128× in­terpolation filter. This filter eliminates images of
the baseband audio s ignal w hich exi st at m ultiple s
of the input sample rate, Fs. This allows for the se­lection of a less complex analog filter based on out­of-band noise atte nuat ion requi reme nts rath er t han
anti-image filtering. Following the interpolation
filter, the resulting frequ ency spectrum ha s i ma g e s

of the input signa l at multiples of 128× the in put
sample rate. These images are removed by the ex­ternal analog filter.

Delta-Sigma Modulator

The interpola tion filter is fol lowed by a fo urth-or­der delta-sigm a modula tor whic h convert s the 24­bit interpolation filter output into 1-bit data at
128× Fs.

Switched-Capacitor Filter

The delta-sigma modulator is followed by a digital­to-analog co nverter whi ch transl ates the 1-bi t data
into a se ries of char ge packets. T he magnitud e of
the charge in each packet is determined by sam­pling of a voltage reference onto a switched capac­itor, where the polarity of each packet is controlled
by the 1-b it signa l. Thi s techn ique greatl y reduce s
the sensitivity to clock jitter and is a major im­provement over earlier generations of 1-bit digital­to-analog converters where the magnitude of
charge in the D-to-A process is determined by
switching a curr ent reference for a period of time
defined by the mast er c loc k.

The CS4390 incorporates a differential output to
maximize the output level to minimize the amount
of gain required in the output analog stage. The dif­ferential outp ut also allows for the can cellation of
common mode errors in the di fferential to si ngled­ended conve rter.

Interpolator

DS264F1 7

Delta-Sigma

Modulator

DAC

Figure 2. Block Diagram

Analog

Low-Pass

Filter

AOUTL+

AOUTL-

CS4390

SYSTEM DESIGN
Master Clock

The Master Clock, MCLK, is used to operate the
digital interpolation filter and the delta-sigma mod-

ulator. MCLK must be either 256×, 384× or 512×
the desired Input Sample Rate, Fs. Fs is the fre­quency at which digital audio samples for each
channel are input to the DAC and is equal to the
LRCK frequency. The MCLK to LRCK frequency
ratio is detected automatically during the initializa­tion sequence by counting the number of MCLK
transitions during a single LRCK period. Internal
dividers are then set to generate the proper clocks
for the digital filter, delta-sigma modulator and
switched-capacitor filter. LRCK must be synchro­nous with MCLK. Once the MCLK to LRCK fre­quency ratio has been detected, the phase and
frequency relationship between the two clocks
must remain fixed. If during any LRCK this rela­tionship is changed, the CS4390 will reset. Table 1
illustrates the standard audio sample rates and the
required MCLK frequencies.

Fs

(kHz)

32 8.1920 12.2880 16.3840

44.1 1 1.2896 16.9344 22.5792
48 12.2880 18.4320 24.5760

Table 1. Common Clock Frequencies

256x 384x 512x

MCLK (MHz)

DIF2 DIF1 DIF0 Format Figure

00003
00113
01023
01134
10045
10156
11067
111Calibrate-

Table 2. Digital Input Formats

Formats 0, 1, and 2 are shown in Figure 3. The au­dio data is right-justified, LSB aligned with the
trailing edge of LRCK, and latched into the serial
input data buffer on the rising edge of SCLK. For­mats 0, 1, and 2 are 16, 24, and 20-bit versions, re­spectively, and differ only in the number of data
bits required. Format 1 in the CS4390 is not com­patible with Format 1 in the CS4329.

Formats 3 and 4 are 24-bit left justified, MSB
aligned with the leading edge of LRCK, and are
identical with the exception of the SCLK edge used
to latch data. Data is latched on the falling edge of
SCLK in Format 3 and the rising edge of SCLK in
Format 4. Both formats will support 16, 18, and 20­bit inputs if the data is followed by 8, 6, or 4 zeros
to simulate a 24-bit input as shown in Figures 4 and

5. A very small offset will result if the 20, 18, or 16­bit data is followed by static non-zero data.

Serial Data Interface

The Serial Data int erface is accomplished via the
serial data input, SDATA, serial data clock, SCLK,
and the left/right clock, LRCK. The CS4390 sup­ports seven serial data formats which are selected
via the digital input format pins DIF0, DIF1 and
DIF2. The different formats control the relation­ship of LRCK to the serial data and the edge of
SCLK used to latch the data into the input buffer.
Table 2 lists the seven formats, along with the asso­ciated figure number. The serial data is represented
in 2's-complement format with the MSB-first in all

Formats 5 and 6 are compatible with the I2S serial
data protocol and are shown in Figures 6 and 7. No­tice that the MSB is delayed 1 period of SCLK fol­lowing the leading edge of LRCK and LRCK is
inverted compared to the previous formats. Data is
latched on the rising edge of SCLK. Format 5 is 16­bit I2S while Format 6 is 24-bit I2S. 20, 18, or 16­bit I2S can be implemented in Format 6 if the data
is followed by 4, 6, or 8 zeros respectively to sim­ulate a 24-bit input as shown in Figure 7. A very
small offset will result if the 20, 18, or 16-bit data
is followed by static non-zero data.

seven formats.

8 DS264F1

DS264F1 9

NOTE: Format 1 is not compatible with CS4329

Figure 3. Digital Input Format 0, 1 and 2.

Figure 4. Digital Input Format 3.

CS4390

10 DS264F1

Figure 5. Digital Input Format 4.

Figure 6. Digital Input Format 5.

Figure 7. Digital Input Format 6.

CS4390

CS4390

Serial Clock

The serial clo ck controls the shi fting of data into
the input dat a buffers. The CS4390 su pports both
external and internal serial clock generation modes.

External Serial Clock

The CS4390 will enter the external serial clock
mode if 15 or more high\low transitions are detect­ed on the SCLK pin during any phase of the LRCK
period. When this mode is enabled, internal serial
clock mode can not be accessed without ret urning
to the power down mode.

Internal Serial Clock

In the Internal Serial Cl ock Mode, the seria l clock
is internally derived and synchronous with MCLK.
The interna l SCLK / LRCK ratio is al ways 64 and
operation in this mode is identical to operation with
an external serial clock synchron ized with L RCK.
The SCLK pin must be connected to DGND for
proper operation.

De-Emphasis

Implementation of digital de-emphasis requires re­configu ration of th e digita l filter to main tain the fi l­ter response sh own in Figure 8 at m ultipl e samp le
rates. The CS4 390 is capa ble of di gital de-e mpha­sis for 32, 44.1 or 48kHz sample rates. Table 3
shows the de-emphasis con trol inputs for DEM 0
and DEM 1.

DEM 1 DEM 0 De-emphasis

0032kHz

0144.1kHz
1048kHz
11OFF

Table 3. De-Emphasis Filter Selection

Gain

dB

T1 = 50 µs

0dB

The inte rnal serial clock mode is advant ageous in
that there are situations where improper serial
clock routin g on the printe d circuit board ca n de­grade system pe rformanc e. The use of th e intern al
serial clock mode simplifies the routing of the
printed circ uit board by allowing the serial clock
trace to be deleted and avoids possible interference
effects.

Mute Functions

The CS4390 includes an auto-mute function which
will initiate a mute if 8192 consecutive 0’s or 1’s are
input on both the Left and Right channels. The
mute will be released when non-st at ic input data is
applied to the DAC. The auto-mute function is use­ful for applicat ions, such as com pact disk playe rs,
where the idle channel noise must be minimized.
This feature is active only if the AUTO_MUTE
is low and is independent of the status of MUTE_L
and MUTE_R. Either channel can also be muted
instantaneou sly with the MUTE_L or MUT E _R.

pin

-10dB

F1

3.183 kHz

Figure 8. De-emphasis Filter Response

T2 = 15 µs

F2

10.61 kHz

Frequency

Initialization, Calibration and Power-Down

Upon initia l power -up, the DA C en ters th e po wer ­down mode. The interpolation filters and delta-sig­ma modulat ors are reset, and the in ternal voltage
reference, one-bit D/A converters and switched-ca­pacitor low-pass filters are powered down. The de­vice will remain in the power-down mode until
MCLK and LR CK are pres en te d. Once MCLK and
LRCK are detected, MCLK occurrences are count­ed over one LRCK period to determine the
MCLK/LRCK fre qu ency rati o. The ph ase and fre ­quency rela tionship between the two clocks must
remain fixed. If during any LRCK this relationship

DS264F1 11

CS4390

is changed, the CS4390 will reset. Power is applied
to the internal voltage ref erence, the D/A co nvert­ers, switched-capacitor filters and the DAC will
then enter a calibration mode to properly set the
common m ode bia s volt age and minimi ze the dif­ferential offset. This initialization and calibration
sequence requires approximately 2700 cycles of
LRCK.

A offset cali bration c an also b e invok ed by taking
the Format select pins, DIF0, DIF1 and DIF2, to a
logic 1 as shown in Table 2. During calibration, the
differential outputs are shorted together and the
common-m ode voltage a ppears at the outp ut with
approxima tely an 8 kohm ou tput impedance . Fol­lowing calibration, the analog output impedance
becomes less than 10 ohms and the common mode
voltage will move to approximat el y 2. 2 V .

The CS4390 will enter the power-down mode,
within 1 period of LRCK, if either MCLK or
LRCK is removed. The initialization sequence, as
described above , occurs when MCLK and LRCK
are restored.

Combined Digital and Analog Filter Response

The frequency response of the combined analog
switched-capacitor and digital filters is shown in
Figures 9, 10 and 11. The overall response is clock
dependent an d will sca le wit h Fs. Note t hat the re­sponse plots have been normalized to Fs and can be
de-normaliz ed by multiplyin g the X-axis scale b y
Fs, such as 48 kHz.

Analog Output and Filtering

The analog output should be operated in a differen­tial mode which allows for the cancellation of com­mon mode errors including noise, distortion and
offset voltage. E ac h output will prod uc e a nominal

2.83 Vpp (1 Vrms) output for a full scale digital in­put which equa te s to a 5. 66 Vpp (2Vrms) di fferen­tial signal as shown in Figure 12.

0

-10

-20

-30

-40

-50

-60

Magnitude (dB)

-70

-80

-90

-100

0.0 0.1 0.2 0.3 0.4 0.5 0.6
Frequency (x Fs)

Figure 9. CS4390 Combin ed Digital a nd Analog Filter

Stopband Rejection

0

-10

-20

-30

-40

-50

-60

Magnitude (dB)

-70

-80

-90

-100

0.45 0.48 0.51 0.54
Frequency (x Fs)

Figure 10. CS4390 Combined Digital and Analog Fil-

ter

0

-1

-2

-3

-4

-5

-6

Magnitude (dB)

-7

-8

-9

-10

0.46

Figure 11. Combined Digital and Analog Filter

0.47 0.48 0.49 0.50 0.51 0.52

Frequency (x Fs)

0.7

0.8 0.9 1.0

0.57

0.60

12 DS264F1

CS4390

Figure 13 displays t he CS4390 output noi se spec­trum. The n oise beyond the audio band c an be fur­ther reduced with additiona l analog filtering. The
applications note "Design Notes for a 2-Pole Fil te r
with Differential Input " discusses the second-order
Butterworth filter and differenti al to signal-ended
converter whi ch was impl emented on the CS4390
evaluation board, CDB4390. The CS4390 filter is a
linear phase design and does not include phase or
amplitude compensation for an external filter.
Therefore, the DAC system phase and amplitude
response will be de pendent on the external a nalog
circuitry .

CS4390

AOUT+

AOUT-

Full Scale Input level= (AIN+) - (AIN-)= 5.66 Vpp

Figure 12. Full Scale Input Voltage

(2.2 + 1.4)V

2.2V

(2.2 - 1.4)V
(2.2 + 1.4)V

2.2V

(2.2 - 1.4)V

Grounding and Power Supply Decoupling

As with any high resolution converter, the CS4390
requires careful attention to power supply and
grounding a rrangement s to optim ize performa nce.
Figure 1 shows the recom mended power arrange ­ments with VA connected to a clean +5volt supply.
VD should be derived from VA through a 10Ω re­sistor. VD should not be used to powe r additional
digital circui try. All mode pins whi ch require VD
should be co nnected to pin 6 of the C S4390. All
mode pins which require DGND should be con­nected to pin 5 of the CS4390. Pins 4 and 5, AGND
and DGND, should be connected together at the
CS4390. DGND for the CS4390 should not be con­fused with the ground for the d igita l sec tion of the
system. The CS4390 should be positioned over the
analog ground plane near the digital/analog ground
plane spli t. The analog and digi tal ground planes
must be connected elsewhere in the system. The
CS4390 evaluation board, CDB4390, demonstrates
this layout technique. This technique minimizes
digital noise and insures proper power supply
matching and sequencing. Decoupling capacitors
should be lo cated as nea r to the CS439 0 as possi­ble.

0

-20

-40

-60

Performance Plots

The follow ing collect ion of CS4390 measure ment
plots were taken from the CDB4390 evaluation
board using the Audio Precision Dual Domain Sys­tem Two.

-80

-100

Magnitude (dB)

-120

-140

-160
0 .25 .50 .75 1.00 1.25

Frequency (x Fs)

Figure 13. CS4390 Output Noise Spectrum

1.50

1.75 2.00

2.25

2.50

Figure 14 shows the frequency response at a
48 kH z sa mple rate. The response is fl at to 20 kHz
+/-0.1 dB as specified.

Figure 15 shows THD+ N versus signal amplit ude
for a 1 kHz 24-bit dithered input signal. Notice that
the there is no increase in disto rtion as the signal
level decreases. This indicates very good low-level
linearity, one of the key benefits of delta-sigma
digital to ana log convers ion.

DS264F1 13

CS4390

Figure 1 6 shows a 16 k FFT of a 1 k Hz full-scale
input signal. The signal has been filtered by a notch
filter within the Syste m T wo to re mov e the fun da­mental component of the signal. This minimizes
the distortion created in the analyzer analog-to-dig­ital converter. This technique is discussed by Audio
Precision i n the 10th an niversary ad dition of A U­DIO.TST.

Figure 1 7 shows a 16 k FFT of a 1 kHz -20 dBFS
input signal. The signal has been filtered by a notch
filter within the Syste m T wo to re mov e the fun da­mental com ponent of the signal.

Figure 1 8 shows a 16 k FFT of a 1 kHz -60 dBFS
input signal.

Figure 19 shows the fade-to-noise linearity. The in­put signal is a dithered 24-bit 500 Hz sine wave
which fades from -60 to -120 dBFS. During the

fade, the o utput fro m th e CS4 390 is m easure d and
compared to the ideal level. Notice the very close
tracking of the output level to the ideal, even at low
level inputs. The gradual shift of the plot away
from zero at signals l evels < - 110 dB is caused b y
the background noise starting to dominate the mea­surement.

14 DS264F1

CS4390

+1
+0.8
+0.6
+0.4
+0.2

d
B

+0

r
A

-0.2

-0.4

-0.6

-0.8

-1
20 20k50 100 200 500 1k 2k 5k 10k

Hz

Figure 14. Frequency Response Figure 15. THD+N vs. Amplitude

+0

-10

-20

-30

-40

-50

-60

d

-70

B

r

-80

A

-90

-100

-110

-120

-130

-140

-150

-160

2.5k 20k5k 7.5k 10k 12.5k 15k 17.5k
Hz

Figure 16. 0 dBFS FFT Figure 17. -20 dBFS FFT

-60

-65

-70

-75

-80

-85

d
B

-90

r
A

-95

-100

-105

-110

-115

-120

-60 +0-50 -40 -30 -20 -10
dBFS

+0

-10

-20

-30

-40

-50

-60

-70

d
B

-80

r

-90

A

-100

-110

-120

-130

-140

-150

-160

2.5k 20k5k 7.5k 10k 12.5k 15k 17.5k
Hz

+0

-10

-20

-30

-40

-50

-60

d

-70

B
r

-80

A

-90

-100

-110

-120

-130

-140

-150
2k 20k4k 6k 8k 10k 12k 14k 16k 18k

Hz

+5
+4
+3
+2
+1

d

B

-0

r

A

-1

-2

-3

-4

-5

-120 +0-100 -80 -60 -40 -20
dBFS

Figure 18. -60 dBFS FFT Figure 19. Fade-to-Noise Linearity

DS264F1 15

PIN DESCRIPTIONS

CS4390

PDIP and SSOP

SDATA

Power Supply Connections

VA - Positive Analog Power, PIN 3.

Positive analog sup ply. Nominally +5 volts.

VD - Positive Digital Power, PIN 6.

Positive supply fo r the digital section. Nomina lly +5 volts.

AGND - Analog Ground, PIN 4.

DEM0
DEM1

VA

AGND

DGND

VD

LRCK

MCLK

SCLK

1
2
3
4
5
6
7
8
9

20
19
18
17
16
15
14
13
12

10 11

DIF0
DIF1
AOUTL+
AOUTL­MUTE_L
MUTE_R
AOUTR+
AOUTR­DIF2
AUTO-MUTE

Analog ground reference.

DGND - Digital Ground, PIN 5.

Digital ground for the digita l section.

Analog Outputs

AOUTR+,AOUTR- - Differential Right Channel Analog Outputs, PIN 14, PIN 13.

Analog output connections for the Right channel differential outputs. Nominally 2 Vrms
(differential ) for full-sca le digital in put signa l.

AOUTL+,A OUTL- - Differential Left Chan nel Analog O utputs, P IN 18, PI N 17.

Analog output connections for the Left channel differential outputs. Nominally 2 Vrms
(differential ) for full-sca le digital in put signa l.

16 DS264F1

Digital Inputs

MCLK - Clock Input, PIN 8.

The freque ncy must b e either 25 6×, 384× or 51 2× the inpu t sample rate (Fs).

LRCK - Left/Right Clock, PIN 7.

This input determines which channel is currently being input on the Serial Data Input pin,
SDATA. The format of LRCK is controlled by DIF0, DIF1 and DIF2.

SCLK - Serial Bit Input Clock, PIN 9.

Clocks the individual bits of the serial data in from the SDATA pin. The edge used to latch
SDATA is controlled by DIF0, DIF1 and DIF2.

SDATA - Serial Data Input, PIN 10.

Two's complem ent MSB-first se rial data of e ither 16, 18, 20 or 24 bits is in put on this pi n. The
data is clocked into the CS4390 via the SCLK clock and the channel is determined by the
LRCK clock. T he format for the previous two clo cks is determin ed by the Digital Input Format
pins, DIF0, DIF1 and DIF2.

CS4390

DIF0, DIF1, DIF2 - Digital Input Format, PINS 20, 19, 12

These three p ins select one o f seven format s for the inco ming serial data stream. These pins set
the format of the SCLK and LRCK clocks with respect to SDATA. The formats are listed in
Ta b l e 2 .

DEM0, DEM1 - De-Emphasis Select, PINS 1, 2.

Controls th e activation of the standard 50/15us de-emp hasis filter for ei ther 32, 44.1 or 48 kHz
sample rates.

AUTO-MUTE

When Auto-Mute is low the analog outputs are muted following 8192 consecutive LRCK
cycles of stati c 0 or 1 data . Mute is cance led with th e return of non -static inp ut data.

MUTE_R

MUTE_L
muting funct ion for the Right channe l.

- Automatic Mute on Zero-Data, PIN 11.

, MUTE_L M ute, PINS 15, 16.

low activates a muting function for the Left channel. MUTE_R low activates a

DS264F1 17

PARAMETER DEFINITIONS

Dynamic Range

The ratio of the full scale rms value of the signal to the rms sum of all other spectral
components over the specified bandwidth. Dynamic range is a signal-to-noise measurement
over the specifi ed bandwidth made with a -60 d BFS signal. 60 dB is then added to the resulting
measurement to refer the measurement to full scale. This tech nique ensures that the distortio n
components are below the noise level and do not effect the measurement. This measurement
technique has been accepted by the Audio Engineering Society, AES17-1991, and the
Electronic Industries Asso ciation of Japan, EIAJ CP- 307.

Total H armonic Distor tion + Noise

The ratio of the rms value of the signal to the rms sum of all other spectral components over
the specified bandwidth (typically 10 Hz to 20 kHz), including distortion components.
Expressed in decibels.

Idle Channel Noise / Signa l-to-Noise-Ratio

The ratio of the rms analog output level with 1kHz full scale digital input to the rms analog
output level w ith all zeros into the digit al input. Measured A- weighted over a 10 Hz to 20 kHz
bandwidth. Units in decibels. This specification has been standardized by the Audio
Engineering Society, AES17-1991, and re ferred to as Idle Channe l Noise. This sp ecific ation has
also been standardized by the Electronic Industries Association of Japan, EIAJ CP-307, and
referred to a s Signal-to-N oise-Ratio.

CS4390

Interchannel Isolation

A measure of crosstalk between the left and right channels. Measured for each channel at the
converter’s output with all zeros to the input under test and a full-scale signal applied to the
other channel . Units in deci bels.

Frequency R esponse

A measure of th e amplitude respon se variation from 10 Hz to 20 kHz relative to the amplitude
response at 1 kHz. Units in deci bels.

De-Emphasis Error

A measure of the difference between the ideal de-emphasis filter and the actual de-emphasis
filter response. Me asured from 1 0 Hz to 20 kHz rel ative to 1 kHz. Units in decibe ls.

Interchannel Gain Mismatch

The gain di fference be tween le ft and right channe ls. Units in decibe ls.

Gain Error

The devia tion from th e nomin al full sc ale analo g output f or a full sc ale dig ital input .

Gain Drift

The change in gain value with t empera ture. Un its in ppm /°C.

18 DS264F1

PACKAGE DIMENSIONS

N

CS4390

20L SSOP PACKAGE DRAWING

1

23

TOP VIEW

D

E

e

2

b

SIDE VIEW

A2

A1

A

SEATING

PLANE

L

1

E1

END VIEW

INCHES MILLIMETERS NOTE

DIM MIN MAX MIN MAX

A -- 0.084 -- 2.13
A1 0.002 0.010 0.05 0.25
A2 0.064 0.074 1.62 1.88

b 0.009 0.015 0.22 0.38 2,3

D 0.272 0.295 6.90 7.50 1

E 0.291 0.323 7.40 8.20
E1 0.197 0.220 5.00 5.60 1

e 0.022 0.030 0.55 0.75

L 0.025 0.041 0.63 1.03

∝

0° 8° 0° 8°

Notes: 1. “D” and “E1” are reference datums and do not included mold flash or protrusions, but do include mold

mismatch and are measured at th e parting line, mold flash or pr otrusions shall not exce ed 0.20 mm per
side.

2. Dimension “b” does not include dambar protrusion/intrusion. Allowable dambar protrusion shall be

0.13 mm total in excess of “b” di mension at maximum material condition. Dambar intrusion shall not
reduce dimension “b” by more than 0.07 mm at least materi al condition.

3. These dimensions apply to the flat section of the lead between 0.10 and 0.25 mm from lead tips.

DS264F1 19

20 PIN PLASTIC (PDIP) PACKAGE DRAWING

CS4390

D

1

TOP VIEW

E1

SEATING
PLANE

b1

e

BOTTOM VIEW

A

A2

A1

b

L

INCHES MILLIMETERS

DIM MIN MAX MIN MAX

A 0.000 0.210 0.00 5.33
A1 0.015 0.025 0.38 0.64
A2 0.115 0.195 2.92 4.95

b 0.014 0.022 0.36 0.56

b1 0.045 0.070 1.14 1.78

c 0.008 0.014 0.20 0.36
D 0.980 1.060 24.89 26.92
E 0.300 0.325 7.62 8.26

E1 0.240 0.280 6.10 7.11

e 0.090 0.110 2.29 2.79

eA 0.280 0.320 7.11 8.13
eB 0.300 0.430 7.62 10.92
eC 0.000 0.060 0.00 1.52

L 0.115 0.150 2.92 3.81

∝

0° 15° 0° 15°

eB

E

∝

eA

SIDE VIEW

eC

c

20 DS264F1

• Notes •