Pin settings
VIPER27
3
Pin settings
Figure 3.
Connection diagram (top view)
Note:
The copper area for heat dissipation has to be designed under the DRAIN pins.
Table 3.
Pin n.
Name
DIP7
1
-
2
SO16N
1...2
4
5
GND
N.A.
VDD
This pin represents the device ground and the source of the power
section.
Not available for user. It can be connected to GND (pins 1-2) or left not
connected.
Supply voltage of the control section. This pin also provides the charging
current of the external capacitor during start-up time.
Function
Pin description
3
6
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
CONT external resistor.
2. output voltage monitoring. A voltage exceeding V
OVP
threshold (see
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 V
FBbm
activates the burst-mode operation. A level close to the threshold V
FBlin
means that we are approaching the cycle-by-cycle over-current set point.
Brownout protection input with hysteresis. A voltage below the threshold
V
BRth
shuts down (not latch) the device and lowers the power
consumption. Device operation restarts as the voltage exceeds the
threshold V
BRth
+ V
BRhyst
. It can be connected to ground when not used.
4
7
FB
5
8
BR
7,8
High voltage drain pin. The built-in high voltage switched start-up bias
13...16 DRAIN current is drawn from this pin too.
Pins connected to the metal frame to facilitate heat dissipation.
4/31
Doc ID 15133 Rev 5
STMICROELECTRONICS [ STMICROELECTRONICS ]
