Triple step-down regulator delivers 10A at over 50°C ambient, with no airflow or external heat sink



LTM4633 triple-output 10A step-down µModule

Linear Technology has launched the LTM4633, a triple-output 10A step-down µModule® (micromodule) regulator in a 15 x 15 x 5.01mm BGA package with integrated heat sink for enhanced heat dissipation. Combined with bypass capacitors and three resistors, the LTM4633 solution 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 1.8VOUT from 12VIN 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 improves 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 minimize 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. The µModule regulator is available for immediate delivery from stock, priced starting at $35.95 each for 1,000 piece quantities.

Linear Technology