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DA9138.005

12 April, 2006

MAS9138

ASYNCHRONOUS TO SYNCHRONOUS CONVERTER

• Pin compatible with MAS7838

• Interfaces a duplex asynchronous to synchronous channel

• Modem speeds of 600, 1.2k, 2.4k, 4.8k, 7.2k, 9.6k, 12k,

14.4k, 19.2k and 38.4k bps with a single 4.9152 MHz crystal

DESCRIPTION

MAS9138 is a single chip duplex asynchronous to

synchronous converter. It converts asynchronous start

stop characters to synchronous format, with stop bit

deletion when required as defined in the CCITT

recommendation V.14. On the receiver channel

MAS9138 converts the incoming synchronous data to

asynchronous start stop character format with stop bit

insertion when required as defined in the CCITT

recommendation V.14. MAS9138 implements the data

modes for the synchronous interface as specified in the

V.14. MAS9138 can be configured to operate at any

frequency up to 38.4 kbits/s within these modes. The

device contains a bit generator and frequency selection

logic to allow easy operation at other data rates. With

just one crystal the device can adapt to ten (10)

different bit rates so it is ideally suited to be used with

the most common modem systems ranging from V.22

to V.34.

FEATURES

APPLICATION

•

Implements CCITT recommendation V.14

•

Bypass operation

•

Character length from 8 to 11 bits including start

stop and parity bits

•

CMOS and LS-TTL compatible interface

•

Low power consumption (typically 10 mW)

•

No additional circuitry needed to perform conversion

•

Single +3.3...+5V supply

•

•

16-pin PDIP and SO package

•

Data communication systems

•

Adapts asynchronous terminals to synchronous

modems

•

Full or half card PC modems using UART as a data

source

•

Simplifying data multiplexing systems

BLOCK DIAGRAM

CL1

CL2

XESR

TMG

OSC

TSL

TXC

TDO

RXC

RDI

XASY

XHST

VSS

VDD

TDI

RDO

CONTROL

O

S

C

ASYNC

TO

SYNC

SYNC

TO

ASYNC

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MAS9138