_______________General Description

The MAX3320 combines a microprocessor (µP) super-

visory circuit with an RS-232 transceiver. The power-on

reset performs a single function: it asserts a reset signal

set threshold, staying asserted for at least 100ms after

an active-low RESET output, which is guaranteed to be in

thresholds suitable for operation with a variety of supply

voltages are available.

The MAX3320 transceivers have a proprietary low-

dropout transmitter output stage, enabling true RS-232

performance with a dual charge pump powered from a

+3V to +5.5V supply. The device requires only four

small 0.1µF external charge-pump capacitors, and is

guaranteed to run at data rates of up to 250kbps. It

comes in the space-saving 20-pin SSOP package.

________________________Applications

Palmtop Computers

Portable/Battery-Powered Equipment

Hand-Held Equipment

Peripherals

Printers

____________________________Features

o Precise Monitoring of 5V and 3.3V Power-

Supply Voltages:

— 100ms (min) Power-On RESET Pulse Width

— Power-Supply Transient Immunity

o 4µA Supply Current Achieved with

AutoShutdown Plus

o Receivers Always Active

o Power-On Reset Always Active

o 4µA Low-Power Shutdown

o 250kbps Guaranteed Data Rate

3V to 5.5V, up to 250kbps True RS-232 Transceiver

with 4µA AutoShutdown Plus and Power-On Reset

________________________________________________________________

Maxim Integrated Products

1

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

C1+

C1-

GND

V-

C2-

C2+

V+

TOP VIEW

T1OUT

T2OUT

R1IN

R2IN

R2OUT

R1OUT

T2IN

T1IN

12

11

9

10

FORCEON

FORCEOFF

RESET

INVALID

MAXxxx

SSOP

MAX3320

__________________Pin Configuration

19-1253; Rev 0; 8/97

PART*

MAX3320_CAP

MAX3320_EAP

-40°C to +85°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

20 SSOP

20 SSOP

______________Ordering Information

*

This part offers a choice of reset threshold voltage. From the

table below, select the suffix corresponding to the desired

threshold and insert it into the blank to complete the part

number.

AutoShutdown Plus is a trademark of Maxim Integrated Products.

SUFFIX

A

B

RESET THRESHOLD

(V)

4.25

2.85

L

4.63

T

3.08

Typical Operating Circuit appears at end of data sheet.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 408-737-7600 ext. 3468.