LM3691 is a high-accuracy, miniature, 1A step-down DC-DC converter from TI that is optimized for powering ultra-low voltage circuits from a single Li-Ion cell or three cell NiMH/NiCd batteries. It provides up to 1A load current over an input voltage range from 2.3V to 5.5V. There are several different fixed voltage output options available. LM3691 has a mode-control pin that allows the user to select Forced PWM mode or ECO mode that changes modes between gated PWM mode and PWM automatically depending on the load. In ECO mode, LM3691 offers superior efficiency and very low Iq under light load conditions. ECO mode extends the battery life through reduction of the quiescent current during light load conditions and system standby. LM3691 is available in a 6-bump micro SMD package. Only three external surface-mount components are required: a 1μH inductor, a 4.7μF input capacitor and a 4.7μF output capacitor.
The LM3691 step‑down DC‑DC converter is designed for portable applications powered from a single Li‑ion cell or 3‑cell NiMH/NiCd batteries. It delivers up to 1 A load current over an input voltage range of 2.3 V to 5.5 V and offers several fixed output voltage options from 0.75 V to 1.8 V.
A mode‑control pin lets the user select Forced PWM or ECO mode, the latter providing ultra‑low quiescent current (64 µA typ.) for extended battery life. The device is packaged in a 6‑bump micro SMD package and requires only three external components: a 1 µH inductor, a 4.7 µF input capacitor, and a 4.7 µF output capacitor.
| Input Voltage Range | 2.3 V to 5.5 V |
|---|---|
| Output Voltage Options | 0.75 V to 1.8 V |
| Switching Frequency | 4 MHz |
| Quiescent Current (ECO mode) | 64 µA typ. |
| Maximum Load Current | 1 A |
| Package Type | 6‑bump micro SMD |
The LM3691 operates with an input voltage from 2.3 V to 5.5 V.
The MODE pin selects the operating mode: HIGH for Forced PWM, LOW for ECO.
Typical quiescent current in ECO mode is 64 µA.