msm7717 Oki Semiconductor, msm7717 Datasheet - Page 4

• Manufacturer Part Number: msm7717
• Description: Msm7717-01/02/03single Rail Codec
• Manufacturer: Oki Semiconductor

¡ Semiconductor
PIN AND FUNCTIONAL DESCRIPTIONS
AIN+, AIN–, GSX
Transmit analog input and transmit level adjustment.
AIN+ is a non-inverting input to the op-amp; AIN– is an inverting input to the op-amp; GSX is
connected to the output of the op-amp.
The level adjustment should be performed in any method shown below. When not using AIN–
and AIN+, connect AIN– to GSX and AIN+ to SG. During power-saving and power-down
modes, the GSX output is at AG voltage.
AG
Analog signal ground.
VFRO
Receive filter output.
The output signal has an amplitude of 2.0 V
when the digital signal of +3 dBm0 is input to PCMIN and can drive a load of 20 kW or more.
For driving a load of less than 20 kW, connect a resistor of 20 kW or more between the pins VFRO
and PWI.
During power-saving mode this output is in a high impedance state, and during power-down
mode, the VFRO output is at an SG level.
When adjusting the receive signal on the basis of frequency characteristics, refer to the Frequency
Characteristics Adjustment Circuit.
1) Inverting input type
2) Noninverting input type
Analog input
Analog input
R5
C1
C2
R1
R3
R4
R2
GSX
AIN–
AIN+
SG
AIN+
AIN–
GSX
SG
PP
above and below the signal ground voltage (SG)
–
+
+
–
R1 : variable
R2 > 20 kW
C1 > 1/(2 ¥ 3.14 ¥ 30 ¥ R1) (F)
Gain = R2/R1 < 10
R3 > 20 kW
R4 > 20 kW
R5 > 50 kW
C2 > 1/ (2 ¥ 3.14 ¥ 30 ¥ R5) (F)
Gain = 1 + R4 / R3 £ 10
MSM7717-01/02/03
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