Features and Benefits
- Input Voltage Range: 5.5V to 38V
- Independently Enabled 5V and 3.3V Fixed Outputs
- 5V Output: 100mA Max
- 3.3V LDO Output: 250mA Max
- 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
The LTC3256 is a wide input range switched capacitor step-down DC/DC converter that produces two regulated outputs: a 5V output via direct connection to the charge pump output, and a 3.3V output via a low dropout (LDO) linear post-regulator. The device provides up to 350mA of total output current. At 12V VIN and maximum load on both outputs, power dissipation is reduced by over 2W compared to a dual LDO regulator solution.
The LTC3256 maximizes efficiency by running the charge pump in 2:1 mode over as wide an operating range as pos- sible, and automatically switches to 1:1 mode as needed due to VIN and load conditions. Controlled input current and switching slew rates minimize conducted and radiated EMI. An integrated watchdog timer, independent power good outputs and reset input ensure reliable system operation and fault monitoring. A buffered 1.1V reference output enables system self-testing for safety critical applications.
The LTC3256 has numerous safety features including overcurrent fault protection, overtemperature protection and tolerance of 38V input transients. The LTC3256 is available in a thermally enhanced 16-lead MSOP plastic package with exposed pad (MSE16).
- Automotive ECU/CAN Transceiver Supplies
- Industrial/Telecom Housekeeping Supplies
- Low Power 12V to 5V and 3.3V Conversion
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Demonstration Circuit 2375A is a dual output 350mA step down charge pump with a post-regulator LDO and watchdog timer featuring the LTC3256EMSE. The LTC3256 operates with a wide input voltage range from 5.5V to 38V and is engineered for diagnostic coverage in ISO262262 systems. The LTC3256 can provide up to 350mA of output current from a 12V battery with 2W less power dissipation than 2 ideal linear regulators. The DC2375A was populated with automotive grade components for evaluation.
Because of the wide input operating range it is possible to exceed the specified operating junction temperature and even reach thermal shutdown with heavy loads. Please refer to the data sheet for additional information on the thermal limitations of the device.
LTC3256 Companion Parts
Recommended Related Parts
Product Selector Card (1)
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ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.