The MAX1947 is a compact, high-efficiency, step-up DC-DC converter that regulates output voltages from 1.8V to 3.3V to power µP/DSP cores, memory, and I/O rails in 1- and 2-cell alkaline/NiMH/NiCd battery-powered systems. It features an internal 800mA switch and synchronous rectifier to achieve up to 94% efficiency and to eliminate the need for an external Schottky diode. High-frequency switching (up to 2MHz) results in low ripple and small external components, while automatic pulse skipping at light loads reduces supply current to just 70µA for extended battery life. Maxim’s proprietary True Shutdown™ reduces supply current to just 2µA and fully discharges the output to ground. The convert- er is offered in fixed-output voltages of 1.8V, 2.5V, 3.0V, and 3.3V, requiring no feedback or compensation net- work. A 75ms RESET output flag provides for power-on reset (POR) and undervoltage detection. The MAX1947 is available in a space-saving 8-pin TDFN package.
The MAX1947 provides a low‑input (0.7 V) to low‑output (1.8 V) step‑up conversion with up to 94 % efficiency. It integrates an 800 mA internal switch and a synchronous rectifier, eliminating the need for an external Schottky diode. Fixed output versions are available at 1.8 V, 2.5 V, 3.0 V and 3.3 V, and the device includes a 75 ms active‑low RESET output for microcontroller monitoring.
Typical applications include battery‑powered MP3 players, PDAs, digital cameras, cordless phones and other portable equipment. The part is offered in an 8‑pin TDFN package and supports a wide range of inductors and low‑ESR ceramic capacitors to achieve low ripple and small board size.
| Input Voltage Range | 0.7 V – 3.6 V |
|---|---|
| Efficiency | up to 94 % |
| Internal Switch Current | 800 mA |
| Light‑Load Supply Current | 70 µA typ. |
| Shutdown Supply Current | 2 µA (typ.) |
| Package | 8‑pin TDFN (3 mm × 3 mm) |
The device can start up with an input voltage as low as 0.7 V.
The RESET output goes high after a minimum of 75 ms once the output voltage exceeds 90 % of its final value.
In shutdown mode the supply current is reduced to about 2 µA.