VIPER35 datasheet(7/44 Pages) STMICROELECTRONICS

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VIPer35

Pin settings

Figure 3. Connection diagram

Note:

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

Table 2. Pin description

SO16N

SDIP10

Name

Function

1, 2

GND

Device ground and source of the power MOSFET.

N.C.

Not internally connected. It can be connected to GND.

N.A.

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

the frame. In order to improve the noise immunity it should be connected to GND

(pin 1, 2).

VDD

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

external capacitor during the power-up.

ZCD

Multifunction pin:

1. Zero-current detection for quasi-resonant operations.

2. Drain current limit (IDlim) setup for overcurrent protection (RLIM).

3. Feed-forward compensation (RFF) setup.

4. Output overvoltage protection (resistor divider ROVP / RLIM) setup.

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 the cycle-by-cycle

overcurrent set-point is close.

Brown-out protection input with hysteresis. A voltage below the threshold VBRth

shuts down (not latch) the device and lowers the power consumption. The device

operation restarts as the voltage exceeds the threshold VBRth + VBRhyst. It must be

connected to ground when it is not used.

9 to 12

N.C.

Not internally connected. These pins must be left floating in order to get a safe

clearance distance.

13 to 16

6 to 10

DRAIN

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

drawn from this pin. Pins connected to the metal frame facilitate heat dissipation.

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