±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps,

RS-232 Transceivers with AutoShutdown

10

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±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 driver outputs and receiver inputs of the

MAX3221E/MAX3223E/MAX3243E have extra protection

against static electricity. Maxim’s engineers have devel-

oped state-of-the-art structures to protect these pins

against ESD of ±15kV without damage. The ESD struc-

tures withstand high ESD in all states: normal operation,

shutdown, and powered down. After an ESD event,

Maxim’s E versions keep working without latchup, where-

as competing RS-232 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 this product family

are characterized for protection to the following limits:

1) ±15kV using the Human Body Model

2) ±8kV using the contact-discharge method specified in

IEC1000-4-2

3) ±15kV using IEC1000-4-2’s air-gap method

ESD Test Conditions

ESD performance depends on a variety of conditions.

Contact Maxim for a reliability report that documents

test setup, test methodology, and test results.

Human Body Model

Figure 6a shows the Human Body Model, and Figure

6b shows the current waveform it generates when dis-

charged into a low impedance. This model consists of

a 100pF capacitor charged to the ESD voltage of inter-

est, which is then discharged into the test device

through a 1.5k

Ω resistor.

IEC1000-4-2

The IEC1000-4-2 standard covers ESD testing and per-

formance of finished equipment; it does not specifi-

cally refer to integrated circuits. The MAX3221E/

MAX3223E/MAX3243E help you design equipment that

meets Level 4 (the highest level) of IEC1000-4-2, with-

out the need for additional ESD-protection components.

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

100pF

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

CHARGE CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

150pF

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

Figure 7a. IEC1000-4-2 ESD Test Model

tr = 0.7ns to 1ns

30ns

60ns

t

100%

90%

10%

I

Figure 7b. IEC1000-4-2 ESD Generator Current Waveform

Figure 6a. Human Body ESD Test Models

90%

36.8%

TIME

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING

(NOT DRAWN TO SCALE)

Ir

10%

0

0

AMPERES

Figure 6b. Human Body Model Current Waveform