Datasheet VIPER17 (STMicroelectronics) - 4

link to page 7
Pin settings VIPER17 3 Pin settings Figure 3: Connection diagram (top view)
The copper area for heat dissipation has to be designed under the DRAIN pins.
Table 3: Pin description Pin n. Name Function DIP-7 SO16
This pin represents the device ground and the source of the power 1 1...2 GND section. Not available for user. This pin is mechanically connected to the - 4 N.A. controller die pad of the frame. In order to improve the noise immunity, is highly recommended connect it to GND (pin 1-2). Supply voltage of the control section. This pin also provides the charging 2 5 VDD current of the external capacitor during startup time. 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. 3 6 CONT 2. output voltage monitoring. A voltage exceeding VOVP threshold (see Table 8: "Controller section ") shuts the IC down reducing the device consumption. This function is strobed and digitally filtered for high noise immunity. Control input for duty cycle control. Internal current generator provides bias current for loop regulation. A voltage below the threshold VFBbm 4 7 FB activates the burst-mode operation. A level close to the threshold VFBlin means that we are approaching the cycle-by-cycle over-current set point. Brownout protection input with hysteresis. A voltage below the threshold VBRth shuts down (not latch) the device and lowers the power 5 10 BR consumption. Device operation restarts as the voltage exceeds the threshold VBRth + VBRhyst. It can be connected to ground when not used. High voltage drain pin. The built-in high voltage switched startup bias 7,8 13-16 DRAIN current is drawn from this pin too. Pins connected to the metal frame to facilitate heat dissipation. 4/31 DocID14419 Rev 11