Pin setting

VIPER26K

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DS12978 Rev 1

1

Pin setting

Figure 2. Connection diagram

Table 1. Pin description

SO16

N

Name

Function

1

GND

Ground. Connected to the source of the internal power MOSFET and

controller ground reference.

2, 3

N.C

Not internally connected. It can be connected to GND (pin 1) or left

floating.

4

N.A.

Not available for user. This pin is mechanically connected to the controller

die pad of the frame. It is highly recommended to connect it to GND (pin 1).

5

VDD

Supply voltage of the control section. This pin provides the charging

current of the external capacitor.

6

N.C.

Not available for user. It is highly recommended to connect it to GND (pin

1).

7FB

Inverting input of the internal trans-conductance error amplifier.

Connecting the converter output to this pin through a single resistor results

in an output voltage equal to the error amplifier reference voltage. An

external resistors divider is required for higher output voltages.

8

COMP

Output of the internal trans conductance error amplifier. The

compensation network has to be placed between this pin and GND to

achieve stability and good dynamic performance of the voltage control loop.

The pin is used also to directly control the PWM with an optocoupler. The

linear voltage range extends from VCOMPL to VCOMPH.

9-12

N.C.

Not internally connected. It has to be left floating.

13-16

DRAIN

High voltage drain pin. The built-in high voltage switched start-up bias

current is drawn from this pin too. Pins connected to the metal frame to

facilitate heat dissipation.