The MAX1672 integrates a step-up DC-DC converter with a linear regulator to provide step-up/down voltage conversion. This device provides a constant output voltage for inputs that vary above and below the output voltage. 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 also selectable, permitting the use of smaller inductors in low-current applications. The linear regulator also 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 also has a PGI/PGO-bar low-battery detector.
The MAX1672 comes in a 16-pin QSOP package (same size as a standard 8-pin SO). For a larger device that delivers more output current, refer to the MAX710/MAX711. The preassembled MAX1672 evaluation kit is available to speed designs.
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