VIPER37LE datasheet(5/35 Pages) STMICROELECTRONICS

5 / 35 page

VIPER37

Pin settings

Doc ID 022218 Rev 1

5/35

Pin settings

Figure 3.

Connection diagram (top view)

Note:

The copper area for heat dissipation must be designed under the DRAIN pins.

Table 3.

Pin description

Pin n.

Name

Function

GND

This pin represents the device ground and the source of the power section.

2VDD

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

of the external capacitor during startup time.

3CONT

Control pin. The following functions can be selected:

1. current limit set point adjustment. The internal set default value of the cycle-by-

cycle current limit can be reduced by connecting to ground an external resistor.

2. output voltage monitoring. A voltage exceeding the VOVP threshold (see

Table 8) shuts the IC down reducing the device consumption. This function is

stropped and digitally filtered for high noise immunity.

4FB

Control input for duty cycle control. Internal current generator provides bias

current for loop regulation. A voltage below the threshold VFBbm activates the

burst mode operation. A level close to the threshold VFBlin means that we are

approaching the cycle-by-cycle overcurrent set point.

5BR

Brownout protection input with hysteresis. A voltage below the threshold VBRth

shuts down (not latched) the device and lowers the power consumption. Device

operation restarts as the voltage exceeds the threshold VBRth + VBRhyst.

It can be connected to ground when not used.

6...10

DRAIN

High voltage drain pin. The built-in high voltage switched startup bias current is

drawn from this pin too.

Pins connected to the metal frame to facilitate heat dissipation.

VIPER37LE Datasheet(PDF) 5 Page - STMicroelectronics