SW

LM3402

GND

CS

8V

~ 0.67

5

Module

Connector

Module

Connector

500

5

1 k

5

SW

LM3402

GND

CS

8V

~ 0.67

5

Module

Connector

Module

Connector

1 k

5

LM3402, LM3402HV

SNVS450E – SEPTEMBER 2006 – REVISED MAY 2013

www.ti.com

CS PIN PROTECTION WITH OVP

When designing output overvoltage protection into the switching converter circuit using a zener diode, transient

protection on the CS pin requires additional consideration. As shown in Figure 26, adding a zener diode from the

output to the CS pin (with the series resistor) for output overvoltage protection will now again allow the transient

energy to be passed through the CS pin’s ESD structure thereby damaging it.

Adding an additional series resistor to the CS pin as shown in Figure 27 will result in the majority of the transient

energy to pass through the sense resistor thereby protecting the LM340X device.

Figure 26. CS Pin with OVP, Transient Path

Figure 27. CS Pin with OVP, Transient Path with Protection

20

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