Synchronous step down regulator sources ±5A from 0V to 14.5V with single resistor

August 19, 2016 // By Nick Flaherty
 Linear Technology has launched a ±5A high efficiency, current mode synchronous buck regulator that is adjustable from 14.5V down to 0V output with a single resistor.

The LTC3623 uses an innovative architecture where a 50µA current reference is combined with a single resistor to set the output voltage.

The design enables easy current sharing between multiple regulators, setting the output voltage for all of the regulators with a single external resistor. The bipolar ±5A sink and source capability, wide VIN and VOUT capability, current mode control for tight line and load regulation, high efficiency, low external parts count and parallel capability make it ideal for modern multirail systems, in addition to tracking supplies, ASIC substrate biasing, DDR memory supplies, point-of-load power supplies, portable instruments, distributed power supply systems, battery-powered equipment and thermo electric cooler systems.

The wide 4V to 15V input voltage range is ideal for dual-cell Li-Ion applications, and fixed 5V and 12V intermediate bus systems. Low RDS(ON) integrated N-channel power MOSFETs and synchronous rectification deliver efficiencies as high as 96%. The device’s novel design allows dynamic adjustment of output voltage from 0V to VIN – 0.5V, offering virtually rail-to-rail performance. The ability to sink up to 5A down to 0VOUTenables it to power down individual rails in the system as needed. Its on-chip trimmed reference achieves high accuracy of ±1%. Furthermore, output regulation and transient response are independent of output voltage. The user can directly drive the LTC3623’s ISET pin with an external voltage supply to program the converter’s VOUT. Additionally, output voltage tracking or soft-start is easily programmed via the ISET pin for applications that require power sequencing.