Triple 10A step-down µModule regulator needs no airflow or external heatsink

November 01, 2013 // By Graham Prophet
Linear Technology's LTM4633 is a triple-output 10A step-down µModule (micromodule) regulator in a 15 x 15 x 5.01 mm BGA package with integrated heat sink for enhanced heat dissipation; it delivers full output current at over 50°C ambient.

Combined with bypass capacitors and three resistors, the LTM4633 layout (10 capacitors and three resistors) fits within 4.5cm² on a dual-sided PCB. The LTM4633’s integrated heat sink (previously introduced in the dual-13A LTM4620A) enables each of the three outputs to deliver 10A at 1.8 V OUT from 12V IN with 88% efficiency at 52°C ambient without any external heat sink or airflow. With an external heat sink and 200LFM airflow, the operating ambient temperature is extended to 67°C. The LTM4633 includes the DC/DC controllers, power switches, inductors and compensation in a single package. The regulated output voltages are adjustable from 0.8V to 1.8V on two channels and from 0.8V to 5.5V on the third channel, with ±1.5% accuracy over line, load and temperature.

The LTM4633’s three switchers have separate input power pins and operate from input voltages between 4.7V to 16V. With the addition of an external bias supply above 4.5V, the minimum operating input voltage decreases to 2.375V. 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 10A, channels 1 and 2 can be paralleled to support up to 20A. Output overvoltage and overcurrent fault protections are included in the regulator. The LTM4633’s internal temperature can be observed via two internal temperature diode monitors located next to the power stages.

The LTM4633 is available with guaranteed performance over the -40°C to +125°C or -55°C to +125°C internal temperature range, and costs $35.95 (1,000)

Linear Technology;