are specified for ±15kV Air-Gap Discharge and ±6kV

Contact Discharge IEC 61000-4-2 on the CD+ and CD-

pins.

The major difference between tests done using the

Human Body Model and IEC 61000-4-2 is a higher peak

current in IEC 61000-4-2, due to lower series resistance.

Hence, the ESD withstand voltage measured to IEC

61000-4-2 generally is lower than that measured using

the Human Body Model. Figure 5 shows the IEC 61000-

4-2 model. The Contact Discharge method connects the

probe to the device before the probe is charged. The

Air-Gap Discharge test involves approaching the device

with a charged probe.

Overvoltage-Protection Controller

with USB ESD Protection

8

_______________________________________________________________________________________

CHARGE-CURRENT-

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE

CAPACITOR

Cs

150pF

50M

Ω TO 100MΩ

330

Ω

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

Figure 5. IEC 61000-4-2 ESD Test Model

OVERCURRENT

FAULT

IN

CD+

CD-

OUT

CHARGE

PUMP

CONTROL

LOGIC

MAX4987AE/

MAX4987BE

ACOK

PHONE

LOAD

REFERENCE

+

-

+

-

OV

UV

EN

USB

CONNECTOR

VBUS

D+

D-

USB

TRANSCEIVER

D+

D-

GND

BATTERY

CHARGER

Typical Operating Circuit

Chip Information

PROCESS: BiCMOS