SigmaTel, Inc.
Data Sheet
STAC9721
1.3 Filter/References/GPIO
These signals are connected to resistors, capacitors, specific voltages, or provide general purpose I/O.
Table 5. Filtering and Voltage References
Signal Name
Type
Description
Vref
O
O
Reference Voltage
Vrefout
Reference Voltage out 5mA drive (intended for mic
bias)
AFILT1
AFILT2
CAP1
O
O
O
O
O
O
O
Anti-Aliasing Filter Cap - ADC channel
Anti-Aliasing Filter Cap - ADC channel
Analog Output Hold-Off Delay
CAP2
ADC reference Cap
CAP3
Anti-Pop Power Sustain Delay
APOP
EAPD
Anti-Pop Output Ground Shunt Control
External Amplifier Power Down Control
1.4 Power and Ground Signals
Table 6. Power Signal List STAC9721/23
Signal Name
Type
STAC9721
STAC9723
AVdd1
AVdd2
AVss1
AVss2
DVdd1
DVdd2
DVss1
DVss2
I
I
I
I
I
I
I
I
Analog Vdd = 5.0V
Analog Vdd = 5.0V
Analog Gnd
Analog Vdd = 3.3V
Analog Vdd = 3.3V
Analog Gnd
Analog Gnd
Analog Gnd
Digital Vdd = 5.0V or 3.3V
Digital Vdd = 5.0V or 3.3V
Digital Gnd
Digital Vdd = 3.3V
Digital Vdd = 3.3V
Digital Gnd
Digital Gnd
Digital Gnd
9
04/07/00
04/07/00
ETC [ ETC ]
