Analog Devices Inc. LTC3256 Step-Down Charge Pump DC/DC Converters

Analog Devices Inc. LTC3256 Step-Down Charge Pump Converters are switched capacitor step-down DC/DC converters that generate two regulated outputs over a wide input range. The first regulated output is a 5V output with a direct connection to the charge pump output. The second regulated output is a 3.3V output via low dropout (LDO) linear post-regulator. The converters provide a total output current up to 350mA. Power dissipation is reduced by over 2W at 12V VIN and maximum load on the two outputs.

The LTC3256 from Analog Devices maximizes efficiency by running the charge pump in 2:1 mode over a wide operating range. The converters automatically switch to 1:1 mode as needed based on VIN and load conditions. The devices' controlled input current and switching slew rates minimize both conducted and radiated EMI. Reliable system operation and fault monitoring are ensured through an integrated watchdog timer, independent power good outputs, and reset input. LTC3256's buffered 1.1V reference output allows system self-testing for safety-critical applications.


  • 5.5V to 38V input voltage range
  • Independently enabled 5V and 3.3V fixed outputs
  • 100mA max @ 5V output
  • 250mA max @ 3.3V LDO output
  • Multimode step-down charge pump (2:1, 1:1) with automatic mode switching
  • Low Quiescent Current
    • 20μA with both outputs regulating (No Load)
    • 0.5μA in shutdown
  • Engineered for diagnostic coverage in ISO26262 systems
  • 1.1V reference output for system diagnostics
  • Power-on reset and watchdog controller with adjustable timing
  • Overcurrent fault protection on each output
  • Overtemperature protection
  • +150°C max operating junction temperature
  • Thermally enhanced 16-lead MSOP package


  • Automotive ECU/CAN transceiver supplies
  • Industrial/telecom housekeeping supplies
  • Low power 12V to 5V and 3.3V conversion

Typical Application

Application Circuit Diagram - Analog Devices Inc. LTC3256 Step-Down Charge Pump DC/DC Converters
Published: 2017-05-04 | Updated: 2022-03-24