The MAX856–MAX859 are high-efficiency, CMOS, step up, DC-DC switching regulators for small, low input voltage or battery-powered systems.
The MAX856/MAX858 accept a positive input voltage between 0.8V and VOUT and convert it to a higher, pin-selectable output voltage of 3.3V or 5V. The MAX857/MAX859 adjustable versions
accept 0.8V to 6.0V input voltages and generate higher adjustable output voltages in the 2.7V to 6.0V range.
Typical efficiencies are greater than 85%. Typical quies cent supply current is 25µA (1µA in shutdown).
The MAX856–MAX859 combine ultra-low quiescent supply current and high efficiency to give maximum battery life. An internal MOSFET power transistor permits high switching frequencies. This benefit, combined with internally set peak inductor current limits, permits the use of small, low-cost
inductors. The MAX856/MAX857 have a 500mA peak inductor current limit. The MAX858/MAX859 have a 125mA peak inductor current limit.
Feature
- 90% Efficiency for 30mA to 2A Load Currents
- Up to 24W Output Power
- 110μA (max) Supply Current
- 5μA (max) Shutdown Current
- 2V to 16.5V Input Range
- Preset 12V or Adjustable Output Voltage
- Current-Limited PFM Control Scheme
- Up to 300kHz Switching Frequency
- Evaluation Kit Available
Applications
- Battery-Powered Applications
- Flash Memory Programming
- High-Power RF Power-Amplifier Supply
- Palmtops/Handheld Terminals
- Portable Communicators
- Positive LCD-Bias Generators
