MAX1672EEE+T

The MAX1672 integrates a step-up, switch-mode DCDC converter with a linear regulator to provide stepup/down voltage conversion. The step-up converter contains an N-channel power MOSFET switch, while the linear regulator contains a P-channel MOSFET pass element. The step-up converter and the linear regulator share the same precision voltage reference. The MAX1672’s input range is from +1.8V to +11V, and the regulated output is internally preset to +3.3V or +5V, or can be adjusted with two external resistors. Boost efficiency typically exceeds 80% over a 2mA to 200mA load range. The device is bootstrapped with chip power derived from the stepped-up voltage output at PS. The MAX1672 typically starts up with a 0.9V input. The MAX1672’s step-up/linear-regulator configuration permits the use of a physically smaller inductor than competing SEPIC and flyback configurations because the i/2L requirements of a step-up converter are half those of SEPIC and flyback converters. Also, high-frequency switching and selectable peak inductor current limit allow for low inductor value (10μH) and low current saturation rating, respectively, further reducing the inductor’s physical dimensions. The MAX1672 maximizes efficiency in both step-up and step-down operation.

Applications

• Single-Cell, Lithium-Powered Portable Devices
• 3.3V and Other Low-Voltage Systems
• Digital Cameras

Key features

• The MAX1672 integrates a step-up DC-DC converter with a linear regulator to provide step-up/down voltage conversion.
• It has a 1.8V to 11V input range and a preset 3.3V or 5V output. The output can also be set from 1.25V to 5.5V using two resistors.
• Typical efficiency is 85%.
• The MAX1672’s step-up/linear-regulator configuration permits the use of a single, physically smaller inductor than can be used with competing SEPIC and flyback configurations.
• Switch current is selectable, permitting the use of smaller inductors in low-current applications.
• The linear regulator acts as a filter to reduce output ripple voltage.
• The MAX1672 has a low 85μA quiescent supply current, which is further reduced to 0.1μA in logic-controlled shutdown.
• The output voltage is disconnected from the input in shutdown.
• The MAX1672 has a PGl/PGO low-battery detector.
• The MAX1672 comes in a 16-pin QSOP package (same size as a standard 8-pin SO).
• Step-Up/Down Voltage Conversion
• 1.8V to 11V Input Range
• 3.3V/5V or Adjustable Output Voltage Range
• Output Current: 300mA at 5V (VIN ≥ 2.5V), 150mA at 5V (VIN ≥ 1.8V)
• Smaller Inductor than SEPIC and Flybacks
• Load Disconnects from Input in Shutdown
• Supply Current from Battery: 85μA (No-Load), 0.1μA (Shutdown)
• PGI/PGO Low-Battery Comparator
• 16-Pin QSOP Package (Same Footprint as 8-pin SO)
• No External FETs Required
• Thermal and Short-Circuit Protection