Datasheet
PCM3008
SLAS332 – APRIL 2001
13
www.ti.com
TYPICAL CHARACTERISTICS
typical circuit connection
The following figure illustrates a typical PCM3008 circuit connection.
V
COM
V
IN
R
V
IN
L
GND
V
CC
DEM0
DEM1
DOUT
V
OUT
R
V
OUT
L
PDDA
PDAD
BCK
SYSCK
LRCK
DIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
+
+
+
Right Channel IN
Left Channel IN
C
1
(see Note A)
A/D IN
C
2
(see Note B)
C
3
(see Note B)
+
C
4
(see Note C)
2.4 V
De-Emp0
De-Emp1
Control
+
+
C
6
(see Note D)
C
5
(see Note D)
POST
LPF
(see Note E)
POST
LPF
(see Note E)
Right
Channel OUT
Left
Channel OUT
D/A OUT
D/A ON/OFF
A/D ON/OFF
Bit Clock
System Clock
L/R Clock
D/A IN
A/D OUT
Digital IN/OUT
2.4 V
PDDA
PDAD
(see Note F)
PCM3008
NOTES: A. C
1
: 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. C
2
, C
3
: 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. C
4
: 0.1 µF ceramic and 10 µF chemical typical, depending on power supply quality and pattern layout.
D. C
5
, C
6
: 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 R
IN
> 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.