Regulator slashes capacitance to power sSub-28nm GPUs, FPGAs, and ASICs processors
Linear Technology has unveiled the LTM4650-1A and LTM4650-1B, dual 25A or single 50A µModule (micro power module) regulators scalable to deliver 300A to high power, low voltage sub-28nm GPUs, FPGAs, ASICs and microprocessors.
The low core voltage of these digital devices requires very accurate voltage regulation at both steady state (DC) and fast load current transients. The LTM4650-1A guarantees ±0.8% total DC voltage accuracy over reference, line, load and temperature (–40°C to 125°C), whereas the LTM4650-1B guarantees ±1.5%. Both devices can be optimized for ±3% or better total error band, including load step transients with a minimum number of ceramic capacitors to meet the core voltage window requirement of sub-28nm digital ICs.
Compared to competing power POL module regulators, the LTM4650-1A requires 60% less capacitance because of three main features (12VIN, 1VOUT, 0A to 25A load step, 25A/µs):
1. Guaranteed ±0.8% total DC voltage accuracy allows more margin (less capacitance) for the AC variation due to a load transient response to satisfy a given processor core voltage tolerance window.
2. The device can be externally adjusted (compensated) for optimum loop response to deliver load transients with fewer output capacitors. This enables use of important capacitors.
3. The device operates with phase interleaving, which reduces input and output current ripple, reducing the requirement for load capacitance.
The LTM4650-1 includes a dual-output DC-DC regulator, inductors and MOSFETs in a 16mm x 16mm x 5.01mm BGA package. The LTM4650-1 regulates an output voltage ranging from 0.6V to 1.8V from an input voltage within 4.5V to 15V. Delivering 50A, 92% efficiency is recorded at 5VIN, 1.8VOUT and 86% at 12VIN, 1VOUT. The LTM4650-1 delivers the full 50A current up to 70C ambient, from 12VIN to 1VOUT with 200LFM airflow. The LTM4650-1 can be operated in parallel to increase output current, up to six in parallel for 300A of output current. The LTM4650-1 is pin-compatible with the lower current LTM4630-1 (dual 18A or single 36A); so users can choose the correct part depending on load current without changing PCB layout, says the company.