Buck-boost charge pump optimises efficiency, says Analog Devices
Analog Devices, which recently acquired Linear Technology, offers the LTC3246, a compact, low noise buck-boost charge pump with integrated watchdog timer capable of up to 500mA of output current.
The LTC3246 uses multi-mode switched capacitor conversion to maintain regulation over a wide 2.7 to 38V input voltage range and produces a regulated 3.3, 5.0V, or externally adjustable (2.5 to 5.0V) output. Internal circuitry automatically selects a conversion ratio of 2:1, 1:1 or 1:2 to optimise efficiency as input voltage and load conditions vary. Low operating current (20-microA regulating with no load, 1.5-microA in shutdown), low electromagnetic interference (EMI) switching and low external device count (three small ceramic capacitors and no inductors) make the LTC3246 suitable for noise-sensitive space constrained automotive applications such as engine control unit/controlled area network (ECU/CAN) transceiver supplies, says Analog Devices. The LTC3246 can also be used as industrial housekeeping supplies and for efficient low power 12 to 5.0V conversion.
Analog Devices goes on to explain that the LTC3246’s switched capacitor architecture, with inherent soft switching, provides lower radiated noise and EMI compared with conventional switching regulators. Timing control for the reset timeout and the windowed watchdog timeout can be adjusted using external capacitors on the RT and WT pins, or fixed internally via pin strapping.
The accurate threshold of the reset input can be used for additional supply monitoring, or can be configured as a pushbutton reset. The LTC3246 also provides stability with ceramic capacitors, foldback current limiting to prevent excessive current flow during start-up, as well as short-circuit and thermal protection.
The LTC3246 is available in a compact, thermally enhanced 16-lead MSOP package. The E and I grades feature a -40 to +125 degree C operating junction temperature, the H grade has a -40 to +150 degree C operating junction temperature, and the MP grade is specified for -55 to +150 degree C operation.