Cuk controller for negative rails
The LTC3704EMS#PBF is a Cuk topology controller producing a regulated negative output from a positive input. It operates step-up/step-down and drives an external N-channel MOSFET with a switching frequency adjustable from 50 kHz to 1 MHz.
Supply range and frequency flexibility
The supply voltage (Vcc) range of 2.5 V to 36 V covers common rails. The 92% maximum duty cycle gives headroom for large step-down ratios. The switching frequency range is 50 kHz to 1 MHz and can be synchronized to an external clock.
Package and temperature grade
Housed in a 10-lead MSOP package (3.00 mm width), the LTC3704EMS#PBF is a surface-mount part suited for compact PCB layouts. The operating temperature range is -40°C to 85°C, covering the industrial and commercial temperature envelope but not extended automotive or high-temperature environments. The part is ROHS3 compliant.
Control and output configuration
The controller provides a single transistor-driver output configured for a negative output voltage. Control features include Enable and Frequency Control, allowing the designer to shut down the regulator or adjust the switching frequency with an external resistor. Synchronous rectification is not supported, so the external Schottky diode handles the catch function.