DC912A: -8V @ 90 ~ 150mA, 15V @ 45 ~ 90mA, 3 ~ 5V in, Boost

Demonstration circuit 912 features the LT®3487EDD. The demo circuit demonstrates small size and low component count in a Boost Circuit and an Inverting Circuit. The Boost Converter is designed to convert a 3V-5V input to 15V output at 45mA-90mA maximum load. The Inverting Circuit generates a -8V output at 90mA-150mA maximum load from the same input. Since the maximum Vin of the LT3487EDD is 16V, this Demo circuit will work well at higher inputs. The only limitation is that the input has to be lower than the Boost converter output (15V) in order to stay in regulation. If Vin and VBAT will be powered separately, cut trace as indicated on far side of board and use VBAT pad on top.

The LT3487EDD features integrated Schottky diodes for both outputs and requires only one resistor (per output) to set the output voltage. Internal sequencing disables switching on the negative supply until the positive has reached 87% of its final value. Both circuits are designed to demonstrate the capacitor programmable Soft-Start feature with a single capacitor, advantages of the 2MHz constant switching frequency and the internal 32V switches. Both outputs on this demo circuit can be modified for higher voltages.

These circuits are intended for space-conscious applications such as CCD Bias, TFT LCD Bias, OLED Bias and +/- Rail Generation for Op Amps.