High Voltage Boost & Inverting Charge Pumps Deliver Low Noise Dual Outputs with Post-Regulating ±50mA LDOs

Linear Technology LTC3265

Linear Technology announces the LTC3265, a high voltage, highly integrated, low noise dual output power supply which takes a single positive input supply (VIN_P) and generates low noise bipolar rails up to ±2•VIN_P without any inductors. The device includes a boost doubling charge pump, an inverting charge pump and two low dropout (LDO) regulators. The boost charge pump has a wide 4.5 V to 16 V input range and powers the positive LDO post regulator from its output, VOUT+. The inverting charge pump has an even wider input range (4.5 V to 32 V) which may be connected to either the boost input or output. The negative LDO post regulator is powered from the output of the inverting charge pump, VOUT–. The LTC3265 is well suited for a variety of applications that require low noise bipolar supplies from a high voltage input, such as industrial/instrumentation low noise bias generators, portable medical equipment and automotive infotainment systems.

Linear Technology - LTC3265

The positive and negative LDO regulators can source up to 50 mA of output current each with 100 μVRMS output noise, and their output voltages can be independently adjusted from ±1.2 V to ±32 V using external resistor dividers to generate symmetric or asymmetric output supply rails. The internal charge pumps of the LTC3265 function in either low quiescent current Burst Mode operation for highest efficiency, or constant frequency mode for lowest noise. In Burst Mode operation, the LTC3265 draws only 135 μA of quiescent current with both LDO regulators on at no load. In constant frequency mode the part operates at a fixed 500 kHz, or at a programmed value between 50 kHz and 500 kHz using an external resistor. Other IC features include low external parts count, stability with ceramic capacitors, soft-start circuitry to prevent excessive current flow during startup, plus short-circuit and thermal protection.

The LTC3265 is available in a low profile (0.75 mm) 3 mm × 5 mm 18-lead DFN package and a 20-lead TSSOP package, both with a backside thermal pad. The E- and I-grade operating junction temperature range is –40 °C to 125 °C regardless of package. The H grade operates from –40 °C to 150 °C, while the MP grade operates from –55° C to 150°C. Devices are in stock, and pricing starts at $3.80 each for the E grade in each package type.

Summary of Features: LTC3265

  • Boost Charge Pump Generates 2•VIN_P (VIN_P Range: 4.5 V to 16 V)
  • Inverting Charge Pump Generates –VIN_N (VIN_N Range: 4.5 V to 32 V)
  • Low Noise Positive LDO Post Regulator Up to 50 mA
  • Low Noise Negative LDO Post Regulator Up to 50 mA
  • 135 μA Quiescent Current in Burst Mode Operation with Both LDO Regulators On
  • 50 kHz to 500 kHz Programmable Oscillator Frequency
  • Stable with Ceramic Capacitors
  • Short-Circuit/Thermal Protection
  • Low Profile 3 mm × 5mm 18 Lead DFN & Thermally Enhanced 20-Lead TSSOP Packages

1-4 Layer PCBs $2

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