Linear DC-DC µModule step-down regulator delivers up to 144A

High efficiency and low thermal package impedance are achieved with expert analog and packaging design. The efficiency for 36A at 1V_OUT, from 12V_IN is 86% and from 5V_IN, 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.

Excellent heat dissipation, scalable and high output power capability, small footprint and low profile package of the LTM4630 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 12V_IN 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 features fast short-circuit protection where a current foldback technique reduces I_OUT 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. The LTM4630 is rated for operation from -40°C to 125°C. 1,000-piece pricing starts at $35.05 each.

Key features:

• Dual 18A or Single 36A Output,
• Input Voltage Range: 4.5V to 15V,
• Output Voltage Range: 0.6V to 1.8V,
• ±1.5% Maximum Total DC Output Error Over Line, Load & Temperature,
• Differential Remote Sense Amplifier,
• Current-Mode Control/Fast Transient Response,
• Adjustable Switching Frequency,
• Overcurrent Foldback Protection,
• Multiphase Parallel Current Sharing with Multiple LTM4630s up to 144A,
• Frequency Synchronization,
• Internal Temperature Monitor,
• Pin-Compatible with the LTM4620 & LTM4620A (Dual 13A, Single 26A) & LTM4628 (Dual 8A, Single 16A).