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

New Products |
By Jean-Pierre Joosting

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.

The LTC3623’s 400kHz to 4MHz switching capability enables the use of tiny, low cost capacitors and inductors, and combined with its compact QFN package, offers a very compact solution footprint for multirail applications. Additional device features include: programmable wire drop compensation, an input supply voltage regulation loop for extracting power from high impedance sources such as solar panels, an output current monitor, a power good voltage monitor, external synchronization capability and thermal protection.

The LTC3623 is available in a thermally enhanced, 24-lead 3mm x 5mm QFN package, with both E and I grades specified for an operating junction temperature of –40°C to 125°C. Devices are in stock, and pricing for the E grade starts at $3.95 each in 1,000-piece quantities.

For more information, visit


Linked Articles
eeNews Europe