Introduces a low IQ triple output synchronous boost/buck/buck controller LTC3859, that can continuously power electronic devices in automotive start-stop and always-on systems
The document introduces the Linear Technology LTC3859, a device that combines a synchronous boost controller with two synchronous buck controllers in a single package. It is designed to maintain regulated 5V and 8.5V outputs from an automotive battery even during voltage transients caused by engine restarts or cold cranks.
The text details the internal architecture, including the constant frequency current-mode boost controller capable of handling inputs as low as 2.5V and buck controllers with a precision 0.8V reference. It explains how the device operates in different modes (Burst Mode, pulse-skipping) to achieve ultralow quiescent current for always-on systems.
| Minimum Input Voltage (Boost) | 2.5V |
|---|---|
| Output Voltage Range (Buck) | 0.8V to 24V |
| Switching Frequency Range | 300kHz to 900kHz |
| Quiescent Current (All channels on) | 80pA |
It operates as a dual output buck-boost controller, stepping up voltage to an intermediate rail when the battery drops below the buck outputs.
The outputs can be programmed between 0.8V to 24V.
The operating quiescent current is 80pA with all three channels on.