Linear Technology has introduced the LTM4630, a dual 18A per output or single 36A output DC/DC µModule step-down regulator capable of delivering up to 144A when four devices are current shared. The LTM4630 is a complete DC/DC regulator system in a 16mm x 16mm x 4.41mm LGA package, which includes inductors, MOSFETs, DC/DC controller and compensation circuitry.
Improved packaging design has resulted in high efficiency and low thermal package impedance. The efficiency for 36A at 1VOUT, from 12VIN is 86% and from 5VIN, is 88%. With no need for an external heat sink, the LTM4630 delivers 36A up to 60°C ambient with no airflow, 65°C with 200LFM and 69°C with 400LFM. An external heat sink increases the maximum operating ambient temperature by approximately 10°C.
Improved heat dissipation, scalable and high output power capability, small footprint and low profile package of the LTM4630 will enable system designers to lay out more densely populated boards. Typical of applications include mezzanine boards such as ATCA, µTCA, point-of-load regulation for new processors, ASICs, and the recently introduced <28nm FPGAs as well as high-speed SERDES.
Without requiring a printed circuit board layout changes, system designers can interchange four pin-compatible µModule regulators to obtain different power levels: LTM4628 dual (8A), LTM4620 and LTM4620A (dual 13A) and the LTM4630 (dual 18A). Each product’s output operates 180º out-of-phase to minimize both output ripple (when outputs share current) and input ripple, resulting in fewer and smaller capacitors.
The LTM4630 is designed to convert 12VIN to high power (up to 144A) point-of-load voltages down to 0.6V. The input voltage range is 4.5V to 15V (16V max) with output ranging from 0.6V to 1.8V. An internal remote sense amplifier guarantees +/-1.5% accurate output regulation over temperature, line and load, by sensing the voltage at the load and thus compensating for voltage droop caused by printed circuit board trace impedance.
The LTM4630 also features fast short-circuit protection where a current foldback technique reduces IOUT to a minimum, preventing the µModule regulator from overheating and protecting the load as well as upstream power supply. Once the short-circuit condition is removed, the LTM4630 resumes operation.