LTC3245 - Wide VIN Range, Low Noise, 250mA Buck-Boost Charge Pump

LTC3245 - Wide VIN Range, Low Noise, 250mA Buck-Boost Charge Pump

Powering a micro circuit from a variety of sources can be a challenge.  Linear regulators are a simple choice to drop a supply voltage to that needed by the circuit.  A switching buck supply will reduce voltage a with high efficiency but are usually more complicated than a linear regulator.  In the case where the supply voltage is less than the circuit requires, a switching boost regulator can handle the task, but again with additional complexities.

Imagine a switching regulator that could handle any supply voltage from 2.7 volts to 38 volts and provide the circuit 3.3 volts or 5 volts at up to 250 mA.  That would be pretty sweet and would allow us to use our circuit with almost any DC source.  if you've ever looked at a circuit diagram to do this, it's pretty complex, with a lot of components...

Not anymore!  Linear Technology has developed the LTC3245 that does all this magic with just 3 capacitors!

Brief information is below.  For more information, click here .

Features


    2.7V to 38V VIN Range
    IQ = 18μA Operating; 4μA in Shutdown
    12V to 5V Efficiency = 81%
    Multimode Operation (2:1, 1:1, 1:2) with Automatic Mode Switching
    Low Noise, Constant Frequency Operation
    Pin Selectable Burst Mode ® Operation
    VOUT: Fixed 3.3V, 5V or Adjustable (2.5V to 5V)
    IOUT Up to 250mA
    Overtemperature and Short-Circuit Protection
    Operating Junction Temperature: 150°C Maximum
    Thermally Enhanced 12-Pin MSOP and Low Profile 12-Pin (3mm x 4mm) DFN Packages

Typical Application

LTC3245Typical Application


LTC3245Typical Application

Description

The LTC3245 is a switched capacitor buck-boost DC/DC converter that produces a regulated output (3.3V, 5V or adjustable) from a 2.7V to 38V input. The device uses switched capacitor fractional conversion to maintain regulation over a wide range of input voltage. Internal circuitry automatically selects the conversion ratio to optimize efficiency as input voltage and load conditions vary. No inductors are required.

The unique constant frequency architecture provides a lower noise output than conventional charge pump regulators. To optimize efficiency at the expense of slightly higher output ripple, the device has pin selectable Burst Mode operation.

Low operating current (20μA with no load, 4μA in shutdown) and low external parts count (three small ceramic capacitors) make the LTC3245 ideally suited for low power, space constrained automotive/industrial applications. The device is short-circuit and overtemperature protected, and is available in thermally enhanced 12-pin MSOP and low profile 3mm x 4mm 12-pin DFN packages.

Applications

  • Automotive ECU/CAN Transceiver Supplies
  • Industrial Housekeeping Supplies
  • Low Power 12V to 5V Conversion

 

 

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