GENERAL DESCRIPTION

The TC660 DC-to-DC voltage converter generates a negative voltage supply, that can support a 100mA maximum load, from a positive voltage input of 1.5V to 5.5V. Only two external capacitors are required. Power supply voltage is stored on an undedicated capacitor then inverted and transferred to an output reser voir capacitor. The on-board oscillator normally runs at a frequency of 10kHz with V+ at 5V. This frequency can be lowered by the addition of an external capacitor from OSC (pin 7) to ground, or raised to 90kHz by connecting the frequency control pin (FC) to V+, in order to optimize capacitor size, quiescent current, and output voltage ripple frequency. Operation using input voltage between 1.5V and 3.0V is accommodated by grounding the LV input (pin 6). Operation at higher input voltages (3.0V to 5.5V) is accomplished by leaving LV open.

FEATURES

■ Pin Compatible with TC7660

■ High Output Current ..................................... 100mA

■ Converts (+1.5V to 5.5V) to (– 1.5V to – 5.5V)

■ Power Efficiency @100mA......................... 88% typ

■ Low Power Consumption ................200µA @ 5 VIN

■ Low Cost and Easy to Use

— Only Two External Capacitors Required

■ Selectable Oscillator Frequency ....... 10kHz/90kHz

■ ESD Protection ...................................................4kV

APPLICATIONS

■ Laptop Computers

■ µP Based Controllers

■ Process Instrumentation

■ Automotive Instruments