MC145446A

MOTOROLA

1

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Single-Chip 300-Baud Modem

with DTMF Transceiver

The MC145446A is a silicon gate CMOS frequency shift keying (FSK)

modem intended for use with telemeter systems or remote control systems over

the telephone network. It replaces the MC145446.

This device is compatible with CCITT V.21 and contains the entire circuit that

provides a full–duplex or half–duplex 300–baud data communication over a pair

of telephone lines. This device also includes the DTMF generator/receiver and

call progress tone detector (CPTD).

The differential line driver has the capability of driving 0 dBm into a 600

Ω load

with a single 5 V power supply. The transmit level is controlled by the

programmable attenuator in 1 dB steps.

This device also includes a serial control interface and internal control and

status registers that permit a CPU to exercise the following built–in features:

• Single 5 V Power Supply

• Compatible with CCITT V.21

• DTMF Generator and Receiver for All 16 Standard Digits

• Capable of Driving 0 dBm into a 600 Ω Load (VCC = 5 V)

• AGC (Auto Gain Control) Amplifier for DTMF Receiver

• Imprecise Call Progress Tone (400 Hz) Detector

• A Transmit Attenuator Programmable in 1 dB Steps

• 2100 Hz Answer Tone Generator

• Serial Control Interface

• Analog Loopback Configuration for Self Test

• Power–Down Mode, Less than 1 µA

This document contains information on a new product. Specifications and information herein are subject to change without notice.

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SEMICONDUCTOR TECHNICAL DATA

MC145446A

FW SUFFIX

SOP

CASE 751M

28

1

5

4

3

2

1

10

9

8

7

6

11

12

13

14

20

21

22

23

24

25

26

19

27

28

18

17

16

15

FTLC2

CDA

Vref

GND

VCC

TLA

FTLC3

DTMF IN

R/W

VCC

GND

AGC OUT

X1

X2

TxA1

RxA

RxGC

RxBO

FTLC1

RxD

TxD

DATA I/O

SD/CD/DV

E

DSI

TxA2

SCK

VCC

PIN ASSIGNMENT

ORDERING INFORMATION

MC145446AFW

SOP

REV 1

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