Datasheet LTC1696 (Analog Devices) - 7

LTC1696
PIN FUNCTIONS FB1 (Pin 1):
First Feedback Input. FB1 monitors and senses
FB2 (Pin 5):
Second Feedback Input. FB2 monitors and the first supply output voltage through an external resistor senses the second supply output voltage through an divider. This voltage is then compared with an internal external resistor divider. This voltage is then compared reference voltage of 0.88V, which sets the threshold for with an internal reference voltage of 0.88V, which sets the an overvoltage fault detection. If the sense voltage exceeds threshold for an overvoltage fault detection. If the sense the threshold level, the output response time at the OUT voltage exceeds the threshold level, the output response pin is dependent on the feedback overdrive above the time at the OUT pin is dependent on the feedback over- threshold level. The higher the feedback overdrive, the drive above the threshold level. The higher the feedback faster will be the response time. overdrive, the faster will be the response time.
GND (Pin 2):
Power Ground. Return path for all device
TIMER/RESET (Pin 6):
Glitch Filter Timer Capacitor, currents. Reset and External Trigger Input. The external capacitor
VCC (Pin 3):
Power Supply. The pin is connected separately connected to this pin programs the internal glitch filter from the power supply output that the chip is monitoring. time delay. The internal current source used to charge the Its input range is from 2.7V to 27V. The quiescent current timer capacitor is typically 10µA with feedback overdrive is typically 100µA in standby mode when the device is of less than 20mV above the feedback trip threshold from operating at 5V. The quiescent current increases to 170µA one feedback input. The current source increases to 12µA when operating at 12V. when the feedback overdrive increases to more than 100mV. It further increases to 18µA if larger overdrive
OUT (Pin 4):
Output Current Limit Driver. Capable of deliv- occurs from both feedback inputs. The default glitch filter ering continuous current, typically 80mA, at high supplies. time delay without an external timer capacitor is fixed by The output current decreases with lower supply voltage. an internal capacitor of 5pF with the internal reference This pin directly drives the SCR crowbar at high supply voltage of 1.185V. The delay reduces with increases in voltage. It can also provide gate drive for an N-channel first and second feedback input overdrive. This pin also MOSFET or the base of an NPN transistor, which drives serves as a reset input to clear the internal latch during the gate of an external SCR at low supply voltage. It is an overvoltage fault condition. If pulled low, it resets the normally in the inactive low state in the standby mode. In active high state of the internal latch. The reset signal to the event of an overvoltage fault condition, the OUT pin is this pin should be an open drain type. This pin can also be latched into the active high state. The latched active high driven high externally to activate the OUT pin active high state is reset by pulling the TIMER/RESET pin low through if the FB1 and FB2 voltages remain below the feedback an N-channel MOSFET switch or if the supply voltage at trip threshold. the VCC pin goes below the undervoltage lockout threshold voltage of 1.94V. 1696fb For more information www.linear.com/LTC1696 7