±15kV ESD-Protected, 460kbps, 1µA,

RS-232-Compatible Transceiver

4

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Detailed Description

RS-232-Compatible Drivers

The transmitter is an inverting level translator that con-

verts CMOS-logic levels to ±3.7V EIA/TIA-232-compati-

ble levels. It guarantees data rates up to 460kbps with

worst-case loads of 3k

Ω in parallel with 1000pF. When

SHDN is driven low, the transmitter is disabled and put

into tristate. The transmitter input does not have a pull-

up resistor. Connect to ground if unused.

RS-232-Compatible Receivers

The MAX3314E’s receiver converts RS-232 signals to

CMOS-logic output levels. The receiver is rated to

receive signals to ±25V. It will remain active during

shutdown mode.

MAX3314E Shutdown Mode

In shutdown mode, the transmitter output is put into high

impedance (Table 1). This reduces supply current to 1µA.

The time required to exit shutdown is less than 2.5µs.

Applications Information

Capacitor Selection

The capacitor type used is not critical for proper opera-

tion; either polarized or nonpolarized capacitors are

acceptable. If polarized capacitors are used, connect

polarity as shown in the Typical Operating Circuit.

Transmitter Outputs When

Exiting Shutdown

Figure 1 shows the transmitter output when exiting

shutdown mode. The transmitter is loaded with 3k

Ω in

parallel with 1000pF. The transmitter output displays no

ringing or undesirable transients as the MAX3314E

comes out of shutdown.

High Data Rates

The MAX3314E maintains minimum RS-232-compatible

±3.7V transmitter output voltage even at high data rates.

Figure 2 shows a transmitter loopback test circuit.

Figure 3 shows the loopback test result at 120kbps, and

Figure 4 shows the same test at 250kbps.

±15kV ESD Protection

As with all Maxim devices, ESD-protection structures are

incorporated on all pins to protect against electrostatic

discharges encountered during handling and assembly.

The MAX3314E driver outputs and receiver inputs have

extra protection against static discharge. Maxim’s engi-

neers have developed state-of-the-art structures to pro-

tect these pins against ESD of ±15kV without damage.

The ESD structures withstand high ESD in all states: nor-

mal operation, shutdown, and powered down. After an

ESD event, Maxim’s E versions keep working without

latchup, whereas competing products can latch and

must be powered down to remove latchup.

ESD protection can be tested in various ways. The trans-

mitter outputs and receiver inputs of the product family

are characterized for protection to the following limits:

• ±15kV using the Human Body Model

• ±8kV using the Contact Discharge method specified

in IEC 1000-4-2

• ±15kV using the IEC 1000-4-2 Air-Gap method

Pin Description

PIN

NAME

FUNCTION

+5V

±5% External Power Supply. Decouple with a 0.1µF capacitor to ground.

2

SHDN

Shutdown, Active low (0 = off, 1 = on).

3

ROUT

TTL/CMOS Receiver Output

4

TIN

TTL/CMOS Transmitter Input

5

TOUT

RS-232-Compatible Transmitter Output

6

RIN

RS-232-Compatible Receiver Input

7

V-

-5V

±5% External Power Supply. Decouple with a 0.1µF capacitor to ground.

8

GND

Ground