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Integrated heat sink is one of a range of features for new micromodule

Published: 1 September 2014 - Marianne Evans

Linear Technology has introduced the LTM4634, a triple output step-down µModule (micromodule) regulator in a 15mm x 15mm x 5.01mm BGA package with integrated heat sink. The thermally efficient package enables the LTM4634 to deliver full current on all three outputs (5A, 5A, and 4A), more than 70W of output power at 65°C ambient with 200LFM airflow. Combined with only 13 ceramic capacitors and three resistors, the LTM4634 solution fits within 4.5cm² 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 0.8V to 5.5V, with the third channel from 0.8V to 13.5V, 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 12V, 5V and 3.3V in instrumentation, communications and industrial applications.

The LTM4634’s three switchers operate from an input voltage from 4.75V to 28V. Separate input power pins for each switcher enables channel one and/or channel two to be supplied from a 12.5V, 50W 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 minimise input ripple. For loads in excess of 5A, channels 1 and 2 can be paralleled to support up to 10A. 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. 

Summary of Features: LTM4634

  • Triple Output, 28VIN, 70W Step-Down Solution in Less Than 4.5cm²
    • Only a Few Ceramic Capacitors and Resistors Required for a Complete Solution
  • 15 x 15 x 5.01mm BGA with Integrated Heat Sink
  • Full Output Current (5A, 5A, 4A) on All Channels at 65°C Ambient with 200LFM Airflow, no External Heatsink
  • 4.75V to 28V Operating VIN Range with Separate Inputs for each Channel
  • ±1.5% Accurate User Adjustable VOUT Between:
  • Channel 1: 0.8V to 5.5V
  • Channel 2: 0.8V to 5.5V
  • Channel 3: 0.8V to 13.5V
  • Channel 1 and Channel 2 Can Be Paralleled to Deliver up to 10A 
Industry Connections: Linear Technology (UK) Ltd

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