MAX3140EEI-T Maxim Integrated, MAX3140EEI-T Datasheet

MAX3140EEI-T

Manufacturer Part Number

MAX3140EEI-T

Description

UART Interface IC

Manufacturer

Maxim Integrated

Type

SPI/MICROWIRE-Compatible UART with Integrated ESD-Protected RS-485/RS-422 Transceiverr

Datasheet

1.MAX3140EEI-T.pdf (36 pages)

Specifications of MAX3140EEI-T

Data Rate

115 Kbps, 500 Kbps, 10Mbps

Supply Voltage - Max

5.25 V

Supply Voltage - Min

4.75 V

Supply Current

0.7 mA

Maximum Operating Temperature

+ 85 C

Minimum Operating Temperature

- 40 C

Description/function

SPI/MICROWIRE-Compatible UART with integrated RS-485/RS-422 transceivers

Mounting Style

SMD/SMT

Operating Supply Voltage

5 V

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The MAX3140 is a complete universal asynchronous

receiver-transmitter (UART) and a true fail-safe RS-

485/RS-422 transceiver combined in a single 28-pin

QSOP package for space-, cost-, and power-con-

strained applications. The MAX3140 saves additional

board space as well as microcontroller (µC) I/O pins by

featuring an SPI™/QSPI™/MICROWIRE™-compatible

serial interface. It is pin-programmable for configuration

in all RS-485/RS-422 networks.

The MAX3140 includes a single RS-485/RS-422 driver

and receiver featuring true fail-safe circuitry, which

guarantees a logic-high receiver output when the

receiver inputs are open or shorted. This feature pro-

vides immunity to faults without requiring complex ter-

mination. The MAX3140 provides software-selectable

control of half- or full-duplex operation, data rate, slew

rate, and transmitter and receiver phase. The RS-485

driver slew rate is programmable to minimize EMI and

results in maximum data rates of 115kbps, 500kbps,

and 10Mbps. Independent transmitter/receiver phase

control enables software correction of twisted-pair

polarity reversal. A 1/8-unit-load receiver input imped-

ance allows up to 256 transceivers on the bus.

The MAX3140’s UART includes an oscillator circuit

derived from an external crystal, and a baud-rate gen-

erator with software-programmable divider ratios for all

common baud rates from 300 baud to 230k baud. The

UART features an 8-word-deep receive FIFO that mini-

mizes processor overhead and provides a flexible inter-

rupt with four maskable sources, including address

recognition on 9-bit networks. Two control lines are

included for hardware handshaking—one input and

one output.

The MAX3140 operates from a single +5V supply and

typically consumes only 645µA with the receiver active.

Hardware-invoked shutdown reduces supply current to

only 20µA. The UART and RS-485/RS-422 functions can

be used together or independently since the two func-

tions share only supply and ground connections (the

MAX3140 is hardware- and software-compatible with the

MAX3100 and MAX3089).

Industrial-Control

Local Area Networks

HVAC and Building Control

Point-of-Sale Devices

19-1453; Rev 1; 9/10

SPI/QSPI are trademarks of Motorola, Inc.

MICROWIRE is a trademark of National Semiconductor Corp.

Pin Configuration appears at end of data sheet.

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

SPI/MICROWIRE-Compatible UART with Integrated

________________________________________________________________ Maxim Integrated Products

True Fail-Safe RS-485/RS-422 Transceivers

General Description

Transceivers for EMI-

Sensitive Applications

Embedded Systems

Intelligent Instrumentation

Applications

o Integrated UART and RS-485/RS-422 Transceiver

o SPI/MICROWIRE-Compatible Interface Saves µC

o True Fail-Safe Receiver Output Eliminates

o Pin-Programmable RS-485/RS-422 Features

o Full-Featured UART

o Allows Up to 256 Transceivers on the Bus

o Low 20µA Hardware Shutdown Mode

o Hardware/Software-Compatible with MAX3100

+ Denotes a lead(Pb)-free/RoHS-compliant package.

MAX3140CEI+

MAX3140EEI+

in a Single 28-Pin QSOP

I/O Pins

Complex Network Termination

and MAX3089

µP

Half/Full-Duplex Operation

Slew-Rate Limiting for Reduced EMI

115kbps/500kbps/10Mbps Data Rates

Receiver/Transmitter Phase for Twisted-Pair

Programmable Up to 230k baud with a

8-Word Receive FIFO Minimizes Processor

9-Bit Address-Recognition Interrupt

PART

MICRO-

WIRE

SPI/

DOUT

SCLK

Polarity Reversal

3.6864MHz Crystal

Overhead

DIN

IRQ

Typical Application Circuit

UART

-40°C to +85°C

TEMP. RANGE

0°C to +70°C

H/F SRL

Ordering Information

CONTROL

MAX3140

LOGIC

TXP

RXP

RS-485

RS-422

HALF/FULL-DUPLEX

28 QSOP

PIN-PACKAGE

RS-485/RS-422

Features

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