7

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (50)668-7000 • www.exar.com SP202E,232E,233E, 30E, 32E_0_0603

C

2

+

-

V

CC

C

3

C

4

C

1

+

+

+

Phases 1 and 3: Store/Double.

Double charge from C1 onto C2.

C2 is now charged to -2xVcc

+

C

2

+

-

V

CC

C

3

C

4

C

1

+

+

+

+

C

2

+

-

V

CC

C

3

C

4

C

1

+

+

+

Phase 2 – Vss transfer from C2 to C4.

Meanwhile C1 is charged to Vcc

+

Vss

transfer from C2 to C3.

Meanwhile C1 is charged to Vcc

V

DD

V-

V+

V-

V+

V+

Patented 5,306,954

Figure . Charge pump phases

DESCRiPTion

ESD ToLERAnCE

The SP202E, 232E, 233E, 30E and 32E

devices incorporates ruggedized ESD cells on

all driver outputs and receiver input pins. The

ESD structure is improved over our previous

family for more rugged applications and envi-

ronments sensitive to electro-static discharges

and associated transients. The improved ESD

tolerance is at least +/-5kV Human Body

Model without damage nor latch-up.

The Human Body Model has been the gener-

ally accepted ESD testing method for semi-

conductors. This method is also specified in

MIL-STD-883, Method 305.7 for ESD testing.

The premise of this ESD test is to simulate

the human body's potential to store electro-

static energy and discharge it to an intergrated

circuit. The simulation is peformed by using a

test model as shown in figure 2. This method

will test the IC's capability to withstand an ESD

transient during normal handling such as in

manufacturing areas where the IC's tend to be

handled frequently.

Figure 2. ESD test circuit for Human Body

Model

SW1

Device

Under

Test

DC Power

Source

SW2