• Inverts Input Supply Voltage
• Up to 60-mA Output Current
• Only Three Small 1-µF Ceramic Capacitors Needed
• Input Voltage Range From 1.6 V to 5.5 V
• PowerSave-Mode for Improved Efficiency at Low Output Currents (TPS60400)
• Device Quiescent Current Typical 65 µA
• Integrated Active Schottky-Diode for Start-Up Into Load
• Small 5-Pin SOT23 Package
• Evaluation Module Available TPS60400EVM-178
• applications
  • LCD Bias
  • GaAs Bias for RF Power Amps
  • Sensor Supply in Portable Instruments
  • Bipolar Amplifier Supply
  • Medical Instruments
  • Battery-Operated Equipment

The TPS6040x is a family of devices that generate an unregulated negative output voltage from an input voltage ranging from 1.6 V to 5.5 V. The devices are typically supplied by a preregulated supply rail of 5 V or 3.3 V. Due to its wide input voltage range, two or three NiCd, NiMH, or alkaline battery cells, as well as one Li-Ion cell can also power them.

Only three external 1-µF capacitors are required to build a complete dc/dc charge pump inverter. Assembled in a 5-pin SOT23 package, the complete converter can be built on a 50 mm² board area. Additional board area and component count reduction is achieved by replacing the Schottky diode that is typically needed for start-up into load by integrated circuitry.

The TPS6040x can deliver a maximum output current of 60 mA with a typical conversion efficiency of greater than 90% over a wide output current range. Three device options with 20-kHz, 50-kHz, and 250-kHz fixed frequency operation are available. One device comes with a variable switching frequency to reduce operating current in applications with a wide load range and enables the design with low-value capacitors.