MAX1672

19-1307; Rev 0a; 11/97 KIT ATION EVALU E L B AVAILA Step-Up/Down DC-DC Converter in QSOP Package ____________________________Features o Step-Up/Down Voltage Conversion o 1.8V to 11V Input Range o 3.3V/5V or Adjustable Output Voltage Range o Output Current: 300mA at 5V (VIN ≥ 2.5V) 150mA at 5V (VIN ≥ 1.8V) o Smaller Inductor than SEPIC and Flybacks o Load Disconnects from Input in Shutdown o Supply Current from Battery: 85µA (No-Load) 0.1µA (Shutdown) o PGI/PGO Low-Battery Comparator o 16-Pin QSOP Package (same footprint as 8-pin SO) o No External FETs Required o Thermal and Short-Circuit Protection ________________General Description 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. Th...