PCM3008 Datasheet, PDF (13/27 Pages) Texas Instruments – LOW POWER AND LOW VOLTAGE 16-BIT, SINGLE-ENDED ANALOG INPUT/OUTPUT STEREO AUDIO CODEC

PCM3008
TYPICAL CHARACTERISTICS
SLAS332 – APRIL 2001
typical circuit connection
The following figure illustrates a typical PCM3008 circuit connection.
A/D IN
C1(see Note A)
Right Channel IN ^{C2(see Note B)}
Left Channel IN ^{C3(see Note B)}
2.4 V
C4(see Note C)
Control
De-Emp0
De-Emp1
PCM3008
+1
VCOM
+ 2 _VINR
VOUTR
VOUTL
+ 3 _VINL
PDDA
4
GND
+ _{5 VCC}
PDAD
BCK
6 _DEM0
SYSCK
16 +
15 +
14
13
12
11
C6
(see Note D)
C5
(see Note D)
POST
LPF
(see Note E)
POST
LPF
(see Note E)
D/A ON/OFF
Right
Channel OUT
Left
Channel OUT
A/D ON/OFF
Bit Clock
System Clock
PDDA
PDAD
(see Note F)
D/A OUT
2.4 V
7 _DEM1
8
DOUT
10
LRCK
9
DIN
L/R Clock
D/A IN
Digital IN/OUT
A/D OUT
NOTES: A. C1: 0.1 µF ceramic and 1 µF chemical typical, gives settling time with 15 ms (1 µF × 15 kΩ) time constant in power on period.
B. C2, C3: 0.47 µF typical, gives 11 Hz cutoff frequency of input HPF in normal operation and gives settling time with 14 ms
(0.47 µF × 30 kΩ) time constant in power on and power down off period.
C. C4: 0.1 µF ceramic and 10 µF chemical typical, depending on power supply quality and pattern layout.
D. C5, C6: 1 µF typical, gives 16 Hz cut-off frequency of output HPF in normal operation and gives settling time with 10 ms (1 µF × 10 kΩ)
time constant in power on period.
E. Post low pass filter with RIN > 10 kΩ, depending on requirement of system performance.
F. Power on reset circuit in case of no power-down control requirement.
board design and layout considerations
power supply and grounding (V_CC, GND)
The analog and digital power supply lines are internally tied, and the analog and digital grounds are internally
tied due to pin count limitation. The power supply V_CC pin must be bypassed to the GND pin with 0.1 µF ceramic
and 10 µF chemical capacitors as close to the pins as possible to maximize the dynamic performance of ADC
and DAC.
V_IN pins
A chemical capacitor from 0.47 µF to 4.7 µF is recommended as an ac coupling capacitor. Capacitance of 0.47
µF gives 11 Hz cut-off frequency at input HPF. If higher full scale input voltage is required, it can be adjusted
by adding only one series resistor to V_IN pins.
V_COM input
A 0.1 µF ceramic and a 1 µF or larger chemical capacitor are recommended between V_COM and GND to ensure
low source impedance of ADC and DAC common voltage. This capacitor should be located as close as possible
to the V_COM pin to reduce dynamic errors on the ADC and DAC common voltage.
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