_______________Detailed Description

±15kV ESD Protection

As with all Maxim devices, ESD protection structures

are incorporated on all pins to protect against electro-

static discharges encountered during handling and

assembly. The MAX1489E receiver inputs have extra

protection against static electricity found in normal

operation. Maxim’s engineers developed state-of-the-

art structures to protect these pins against ESD of

±15kV without damage. After an ESD event, the

MAX1489E keeps working without latchup.

ESD protection can be tested in various ways; the

receiver inputs are characterized for protection to the

following:

1) ±15kV using the Human Body Model

2) ±8kV using the Contact Discharge method speci-

fied in IEC1000-4-2 (formerly IEC801-2)

3) ±15kV using the Air-Gap Discharge method speci-

fied in IEC1000-4-2 (formerly IEC801-2).

ESD Test Conditions

Contact Maxim for a reliability report that documents

test setup, methodology, and results.

Human Body Model

Figure 2a shows the Human Body Model, and Figure

2b 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 IEC100-4-2 standard covers ESD testing and per-

formance of finished equipment; it does not specifically

refer to integrated circuits. The MAX1489E helps you

design equipment that meets Level 4 (the highest level)

of IEC1000-4-2, without additional ESD protection com-

ponents.

The major difference between tests done using the

Human Body Model and IEC1000-4-2 is higher peak cur-

rent in IEC1000-4-2. Because series resistance is lower

in the IEC1000-4-2 ESD test model (Figure 3a), the ESD

withstand voltage measured to this standard is generally

lower than that measured using the Human Body Model.

Figure 3b shows the current waveform for the ±8kV

IEC1000-4-2 Level 4 ESD Contact Discharge test.

The Air-Gap test involves approaching the device with a

charged probe. The Contact Discharge method connects

the probe to the device before the probe is energized.

±15kV ESD-Protected, Quad,

Low-Power RS-232 Line Receiver

4

_______________________________________________________________________________________

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

100pF

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

90%

36.8%

TIME

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING

(NOT DRAWN TO SCALE)

Ir

10%

0

0

AMPERES

Figure 2a. Human Body ESD Test Model

Figure 2b. Human Body Model Current Waveform