FEDL7020-02

1Semiconductor

ML7020

2/19

BLOCK DIAGRAM

* CPT: Call progress tone

* The state shown of each switch is that when the register is set to “0”.

DTMF

Reception

TO

TI–

TI+

TIO

MCU I/F

1.2 k

Ω

LI1–

LI1+

LI1O

LI2–

LI2O

SG

SGC

1.2 k

Ω

–1

LO–

+1

SWI

SGO

LO+

Oscillator

Circuit

CPT

Detection

Modem

Reception

SP

RD

DETB

CPT

Transmission

Modem

Transmission

DTMF

Transmission

Post-

LPF

XD

SW1

SW2

SW4

SW5

SW3

Input Amplifier 1

Input Amplifier 2

Input Amplifier 3

Output Amplifier 1

Output Amplifier 2

Output Amplifier 3

ATT

X1

X2

CLKO