Harman Kardon HD 970, Service Manual

Page: 14 / 30

REV. 0
AD1955
PIN FUNCTION DESCRIPTIONS
Pin No. I/O Mnemonic Description
1 DVDD Digital Power Supply Connected to Digital 5 V Supply
2 Input LRCLK/EF_WCLK Left/Right Clock Input for Input Data in PCM Mode
Word Clock in External Filter Mode
3 Input BCLK/EF_BCLK Bit Clock Input for Input Data in PCM Mode
Bit Clock Input in External Filter Mode
4 Input SDATA/EF_LDATA MSB First, Twos Complement Serial Audio Data
Two Channel (left and right), 16-Bit to 24-Bit Data in PCM Mode
Left Channel Data in External Filter Mode
5 Input EF_RDATA Not used in PCM Mode
Right channel data in External Filter Mode
6 I/O DSD_SCLK Serial Clock Input for DSD Data. This clock should be 64 44.1 kHz,
2.8224 MHz or 128 44.1 kHz, 5.6448 MHz in Normal Mode, 128
44.1 kHz, 5.6448 MHz or 256 44.1 kHz, 11.2896 MHz in Phase Mode.
7 Input DSD_LDATA DSD Left Channel Data Input
8 Input DSD_RDATA DSD Right Channel Data Input
9 I/O DSD_PHASE DSD Phase Reference Signal. This clock should be 64 44.1 kHz,
2.8224 MHz. If not used, this pin should be connected low.
10 AGND Analog Ground
11 Output IOUTR+ Right Channel Positive Analog Output
12 Output IOUTR– Right Channel Negative Analog Output
13 Output FILTR Voltage Reference Filter Capacitor Connection. Bypass and decouple the
voltage reference with parallel 10
µ
F and 0.1
µ
F capacitors to AGND.
14 IREF Connection Point for External Bias Resistor
15 AVDD Analog Power Supply Connected to Analog 5 V Supply
16 Output FILTB Filter Capacitor Connection with Parallel 10
µ
F and 0.1
µ
F Capacitors to AGND
17 Output IOUTL– Left Channel Negative Analog Output
18 Output IOUTL+ Left Channel Positive Analog Output
19 AGND Analog Ground
20 Output ZEROR Right Channel Zero Flag Output. This pin goes high when the right channel
has no signal input or the DSD mute pattern is detected.
21 Output ZEROL Left Channel Zero Flag Output. This pin goes high when the left channel has
no signal input or the DSD mute pattern is detected.
22 Input MUTE Mute. Assert high to mute both stereo analog outputs. Deassert low for nor-
mal operation.
23 Input
PD/RST
Power Down/Reset. The AD1955 is placed in a reset state and the digital
circuitry is powered down when this pin is held low. The AD1955 is reset on
the rising edge of this signal. The serial control port registers are reset to the
default values. Connect high for normal operation.
24 Input CDATA Serial Control Input, MSB First, Containing 16 Bits of Unsigned Data. Used
for specifying control information and channel-specific attenuation.
25 Input
CLATCH
Latch Input for Control Data
26 Input CCLK Clock Input for Control Data. Control input data must be valid on the rising
edge of CCLK. CCLK may be continuous or gated.
27 Input MCLK Master Clock Input. Connect to an external clock source.
28 DGND Digital Ground