The LT1317/LT1317B are micropower, fixed frequency step-up DC/DC converters that operate over a wide input voltage range of 1.5V to 12V. The LT1317 features automatic shifting to power saving Burst ModeTM operation at light loads. High efficiency is maintained over a broad 300µA to 200mA load range. Peak switch current during Burst Mode operation is kept below 250mA for most operating conditions which results in low output ripple voltage, even at high input voltages. The LT1317B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency. The LT1317/LT1317B contain an internal low-battery detector with a 200mV reference that stays alive when the device goes into shutdown. No-load quiescent current of the LT1317 is 100µA and shuts down to 30µA. The internal NPN power switch handles a 500mA current with a voltage drop of just 300mV. The LT1317/LT1317B are available in MS8 and SO-8 packages.
The LT1317 and LT1317B are micropower, fixed‑frequency step‑up DC/DC converters that operate from 1.5 V to 12 V input and switch at 600 kHz. They feature a low‑quiescent current of 100 µA (down to 30 µA in shutdown) and an internal low‑battery detector with a 200 mV reference. The LT1317 includes Burst Mode operation for light loads, while the LT1317B runs continuously for lower ripple.
Typical applications include cellular phones, GPS receivers, battery backup, and portable medical equipment. The document details electrical characteristics, pin assignments, layout hints, component selection, and example circuits such as a 2‑cell to 3.3 V boost converter.
| Quiescent Current (no load) | 100 µA |
|---|---|
| Shutdown Quiescent Current | 30 µA |
| Switch Voltage Drop | 300 mV at 500 mA |
| Input Voltage Range | 1.5 V to 12 V |
| Switching Frequency | 600 kHz (fixed) |
| Low‑Battery Detector Reference | 200 mV |
| Available Packages | MS8 and SO‑8 |
The LT1317 draws 100 µA when not switching.
In shutdown mode the current drops to 30 µA.
The internal NPN power switch can handle 500 mA with a 300 mV drop.
They are offered in MS8 and SO‑8 surface‑mount packages.