The TC1121 is a charge pump converter with 100mA output current capability. It converts a 2.4V to 5.5V input to a corresponding negative output voltage. As with all charge pump converters, the TC1121 uses no inductors saving cost, size, and EMI. An on-board oscillator operates at a typical frequency of 10kHz (at V + = 5V) when the frequency control input (FC) is connected to ground. The oscillator frequency increases to 200kHz when FC is connected to V + , allowing the use of smaller capacitors. Operation at sub-10kHz frequencies results in lower quiescent current and is accomplished with the addition of an external capacitor from OSC (pin 7) to ground. The TC1121 also can be driven from an external clock connected OSC. Typical supply current at 10kHz is 50µA, and falls to less than 1µA when the shutdown input is brought low, whether the internal or an external clock is used. The TC1121 is available in 8-pin SOIC, MSOP, and PDIP packages.

Optional High-Frequency Operation Allows Use of Small Capacitors
Low Operating Current (FC = GND) ........50uA
High Output Current ..........................100mA
Converts a 2.4V to 5.5V Input Voltage to a Corresponding Negative Output Voltage (Inverter Mode)
Uses Only 2 Capacitors; No Inductors Required!
Selectable Oscillator Frequency ............10kHz to 200kHz
Power-Saving Shutdown Input