Continuing on with their tiny footprint, high-efficiency step down regulators Linear Technology have announced the LTC3607 dual output buck regulator chip. No external semiconductors are necessary for the chip to supply 600 mA per output from its 3 x 3 mm Thermally Enhanced Thin QFN package.


The chip uses a relatively high switch speed of 2.25 MHz to reduce the need for large value bulky reservoir capacitors and inductors at the outputs. The diagram shows output voltages of 3.3 V and 5 V; ideal for the requirements of a typical microcontroller application. The two outputs are independently set within the range of 0.6 V to Vin by a voltage divider network at each output.


Efficiency of the chip peaks at 96 % on full load and the quiescent current is quoted at 55μA (>1 μA in shutdown mode).  The input supply range Vin is from 4.5 V to 15 V and a MODE input gives the option to trade-off output ripple noise for light-load efficiency. Burst mode operation gives best efficiency at light loads whilst Pulse-Skipping mode gives the lowest ripple noise.