DC-DC Converter has Dual LDO Outputs

May 18, 2006 11:56 AM

Micrel’s MIC2800 flexible power management IC features an input range of 2.7 V to 5.5 V, three voltage outputs and a power-on reset (POR). The device features an input range of 2.7 V to 5.5 V, three voltage outputs and a power-on reset. Output 1 is a high frequency, high efficiency dc-dc switching regulator for up to 600 mA, while outputs 2 and 3 are low dropout (LDO) linear regulators.

One of the linear regulators works from a low input voltage, allowing it to post-regulate the switching regulator for best efficiency. For example, the high speed dc-dc converter can step down the Li-Ion battery input to 1.8 V and the LDO can provide 1.6 V by post-regulating the 1.8 V rail with greater than 80% efficiency.

One additional low-noise linear output can provide a third voltage such as 2.8 V for an analog rail. The IC also offers a LOWQ mode, which reduces the total current drawn to less than 50 μA. The MIC2800 operates with small ceramic output capacitors. The dc-dc converter provides low noise in light load mode and 75 μV_RMS output noise in LOWQ mode. The solution operates at 2 MHz PWM in normal mode, more than 93% efficiency and requires a 2.2 μF output capacitor and a 2.2 μH inductor for stability.

The MIC2800 is available in a 3-mm x 3-mm MLF-16 package. Volume pricing starts at $2.25 for 1000 pieces.