UPD9611 Datasheet, PDF (6/28 Pages) NEC – FOUR-CHANNEL PCM CODEC

µPD9611
2. CAUTIONS ON USE
(1) Absolute maximum ratings
Application of voltage or current in excess of the absolute maximum ratings to the µPD9611 may result
in damage due to latch up, etc. Be especially cautions about power supply noise, etc.
(2) Wiring pattern
The design of the ground pattern is extremely important for operating the µPD9611 with high precision.
Connect the analog ground pins (AGND1 to AGND4), digital ground pin (DGND) and substrate ground
pin (SUBGND) close to the IC pins, and connect to a wide analog ground line on the board.
(3) Addition of bypass capacitors for power supply pins
Because the µPD9611 uses many internal high-frequency operational amplifiers, high power supply
impedance can cause instability (such as oscillation) in these internal operational amplifiers. To
suppress such instability and eliminate power supply noise, connect all power supply pins (AVDD1 to
AVDD4, DVDD) close to the IC pins, and put bypass capacitors (CVDD = approximately 0.1 µF) having
superior high-frequency characteristics very close to the pins.
(4) Addition of bypass capacitors for ACOM pins
The µPD9611 incorporates references voltages for signal sources. Superposing of noise on these
reference voltages may have adverse effects on transmission characteristics, etc. Therefore, connect
the ACOMOUT pin and ACOMIN pin close to the IC pins, and put bypass capacitors (CACOM = approximately
0.1 µF) having superior high-frequency characteristics very close to the pins.
(5) Control or SPDATA pin on reset
When inputting the setting data from the SPDATA pin after the µPD9611 is reset, first input the following
patterns to reset to 0 the couter used to fetch data from the SPDATA pin.
1 clocks or more
16 clocks or more
RST
SPCLK
SPSYNC
SPDATA
After ther RST pin has been set to the high level, input 1 clock or more to the SPCLK pin, set the SPSYNC
pin to the high level and input 16 clocks more to the SPCLK pin.
During this operation, the SPDATA pin is held at the low level. Afterwards, input the setting data.
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