HT7660

CMOS Switched-Capacitor Voltage Converter Features · · · · HT7660 Simple conversion of VDD to -VDD Cascade connection (two devices are connected, VOUT= -2 VDD) Boost pin for higher switching frequency Easy to use - Requires only two external capacitors · · · · No external diode required Typically with no load voltage conversion, 99.9% efficiency Typical power efficiency is 98% Wide operating voltage range: 3V to 12V Applications · · · RS-232 power supply On board negative supply for dynamic RAMS Supply voltage splitter, VO= ± VDD/2 · · · Operation amplifier supply Data acquisition systems Positive voltage doubler General Description HT7660 is a monolithic CMOS switched-capacitor voltage converter. HT7660 is designed to complete a voltage conversion from positive to negative. The only required external components are two low cost electrolytic capacitors. HT7660 includes a voltage regulator, an RC oscillator and four output power MOS switches. The frequency of an RC oscillator can be lowered by adding an external capacitor between VDD and the OSC pin, or an external clock can be connected to the OSC pin to replace the original oscillator. The LV terminal may be tied to VSS to disable the voltage regulator. By doing this, low voltage operation can be improved. Block Diagram VDD OSC BOOST RC Oscillator Voltage Level Shifter CAP+ CAP VOUT LV Voltage Regulator Logic Network VSS 1 November 30, 1999 HT7660 Pin Assignment B O O C A V C A S T P + S S P 1 8 2 7 3 6 4 5 V...