MSM7728 查看數據表（PDF） - Oki Electric Industry

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产品描述 (功能)

比赛名单

MSM7728

Single Rail Linear CODEC

Oki Electric Industry 

¡ Semiconductor

MSM7728

PIN AND FUNCTIONAL DESCRIPTIONS

VDD

Power supply pin for 2.5 to 3.6 V (Typically 3.0 V).

AG

Analog signal ground.

DG

Ground pin for the digital signal circuits.

This ground is separated from the analog signal ground in this device. The DG pin must be

connected to the AG pin on the printed circuit board.

SGC

Bypass capacitor pin for generating the signal ground voltage level.

Insert a 0.1 mF capacitor with excellent high frequency characteristics between the AG pin and

the SGC pin.

MAIN, MAO

Transmit microphone input and level adjustment.

MAIN is connected to the inverting input of the op-amp, and MAO is connected to the output

of the op-amp. This amplifier can set up a gain to a maximum of 36dB by using an external

resistor.

Level adjustment should be performed in a way below.

A transmit level of +6, 0, –6, or –12dB can be selected using control data from the processor

interface.

When CODEC is turned off, the MAO output goes high impedance.

Microphone input

R2 MAO

C1

MAIN –

R1

+

SG

R1 : variable

R2 > 20 kW

C1 > 1/(2 ¥ 3.14 ¥ 30 ¥ R1) (F)

Gain = R2/R1 < 63

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