MAX222

5V DUAL RS232 LINE DRIVER/RECEIVER

WITH ±15kV ESD PROTECTION

SLLS590D − SEPTEMBER 2003 − REVISED AUGUST 2004

9

POST OFFICE BOX 655303

APPLICATION INFORMATION

100

150

200

50

0

1.5

1

0.5

0

Time − ns

VHBM = 2 kV

DUT = 10-V, 1-

Ω Zener Diode

Figure 6. Typical HBM Current Waveform

Machine Model

The Machine Model (MM) ESD test applies to all pins using a 200-pF capacitor with no discharge resistance.

The purpose of the MM test is to simulate possible ESD conditions that can occur during the handling and

assembly processes of manufacturing. In this case, ESD protection is required for all pins, not just RS-232 pins.

However, after PC board assembly, the MM test no longer is as pertinent to the RS-232 pins.