Features

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

Typical Application

Description

The LTC®3265 is a low noise dual polarity output power supply including a boost charge pump, an inverting charge pump and two low noise positive and negative LDO post regulators. The boost charge pump powers the positive LDO post regulator while the inverting charge pump powers the negative LDO regulator. Each LDO can provide up to 50mA of output current. The LDO output voltages can be adjusted using external resistor dividers.

The charge pumps employ low quiescent current Burst Mode operation or low noise constant frequency mode. During Burst Mode operation, the boost charge pump regulates its output (V_OUT ⁺) to 0.94 • 2 • VIN_P while the inverting charge pump regulates its output (V_OUT ^–) to –0.94 • V_{IN_N}. In Burst Mode operation the LTC3265 draws only 135μA of quiescent current with both LDOs on. In constant frequency mode, the boost and inverting charge pumps produce outputs equal to 2 • V_{IN_P} and –V_{IN_N} respectively and operate at a fixed 500kHz or to a programmed value between 50kHz to 500kHz using an external resistor. The LTC3265 is available in low profile 3mm × 5mm × 0.75mm 18-lead DFN and thermally enhanced 20-lead TSSOP packages.