msm7540 Oki Semiconductor, msm7540 Datasheet - Page 4

• Manufacturer Part Number: msm7540
• Description: Single Rail Adpcm Codec
• Manufacturer: Oki Semiconductor

¡ Semiconductor
PIN AND FUNCTIONAL DESCRIPTIONS
AIN1, AIN2, GSX1, GSX2
Transmit analog inputs and the output for transmit gain adjustment.
AIN1 (AIN2) connects to the inverting input of the internal transmit amplifier. GSX1 (GSX2)
connects to the internal transmit amplifier output. Refer to Fig. 1 for gain adjustment.
VFRO, AOUT+, AOUT–, PWI
Receive analog output and the output for receive gain adjustment.
VFRO is the receive filter output. AOUT+ and AOUT– are differential analog signal outputs
which can directly drive Z
Analog Input
Transmit Gain:
= (R2/R1) ¥ (R4/R3)
Receive Gain:
= (R6/R5)
Z
L
=120 nF
+ 350 W
Figure 1 Analog Input/Output Interface
C1
C2
L
= 350 W + 120 nF. Refer to Fig. 1 for gain adjustment.
R1
R3
RS*
V
0
* : Side Tone Pass (Gain = R6/RS)
R2
R4
R5
R6
Analog Output
GSX1
GSX2
VFRO
PWI
AIN1
AIN2
AOUT–
AOUT+
–
+
–
+
–1
–
+
to ENCODER
from DECODER
MSM7540/7560
FEDL7540-03
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