Power Electronics
Step-Down Regulator Delivers 70 W In 4.5 cm² Package

Step-Down Regulator Delivers 70 W In 4.5 cm² Package

The LTM4634 from Linear Technology Corporation is a triple output step-down µModule® (micromodule) regulator in a 15 mm x 15 mm x 5.01 mm BGA package with integrated heat sink. The thermally efficient package enables the LTM4634 to deliver full current on all three outputs (5 A, 5 A, and 4 A), more than 70 W of output power at 65 °C ambient with 200 LFM airflow. Combined with only 13 ceramic capacitors and three resistors, the LTM4634 solution fits within 4.5 cm² on a dual-sided PCB. The LTM4634 includes three DC/DC controllers, power switches, inductors and compensation in a single package. The regulated output voltage for channels 1 and 2 is adjustable between 0.8 V to 5.5 V, with the third channel from 0.8 V to 13.5 V, each with ±1.5% accuracy over line, load and temperature. The combination of wide output voltage range, a thermally efficient package, tight regulation accuracy and small solution size makes the LTM4634 well suited to regulate common intermediate power buses such as 12 V, 5 V and 3.3 V in instrumentation, communications and industrial applications.

The LTM4634’s three switchers operate from an input voltage from 4.75 V to 28 V. Separate input power pins for each switcher enables channel one and/or channel two to be supplied from a 12.5 V, 50 W intermediate bus generated from channel three. The three switchers, operating from the same internal or optional external clock signal, are internally phase shifted by 120° to minimize input ripple. For loads in excess of  5 A, channels 1 and 2 can be paralleled to support up to 10 A. Output overvoltage and overcurrent fault protection are included in the regulator. The LTM4634's internal temperature can be observed via two internal temperature diode monitors located next to the power stages.

The LTM4634 is available in the -40 °C to +125 °C internal operating temperature grade for immediate delivery from stock. Pricing starts at $35.95 each for 1,000-piece quantities.


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