Micrel’s MIC2570 is a micropower boost switching regulator that operates from two alkaline, two nickel-metal-hydride cells, or one lithium cell.

The MIC2570 accepts a positive input voltage between 1.3V and 15V. Its typical no-load supply current is 130µA.

The MIC2570 is available in selectable fixed output or adjustable output versions. The MIC2570-1 can be configured for 2.85V, 3.3V, or 5V by connecting one of three separate feedback pins to the output. The MIC2570-2 can be configured for an output voltage ranging between its input voltage and 36V, using an external resistor network.

The MIC2570 has a fixed switching frequency of 20kHz. An external SYNC connection allows the switching frequency to be synchronized to an external signal.

The MIC2570 requires only four components (diode, inductor, input capacitor and output capacitor) to implement a boost regulator. A complete regulator can be constructed in a 0.6 in2 area.

All versions are available in an 8-lead SOIC with an operating range from –40°C to +85°.

• Operates from a two-cell supply
• 1.3V to 15V operation
• 130µA typical quiescent current
• Complete regulator fits 0.6 in2 area
• 2.85V/3.3V/5V selectable output voltage (MIC2570-1)
• Adjustable output up to 36V (MIC2570-2)
• 1A current limited pass element
• Frequency synchronization input
• 8-lead SOIC package

• LCD bias generator
• Glucose meters
• Single-cell lithium to 3.3V or 5V converters
• Two-cell alkaline to ±5V converters
• Two-cell alkaline to –5V converters
• Battery-powered, hand-held instruments
• Palmtop computers
• Remote controls
• Detectors
• Battery Backup Supplies