The MC1121 is a charge pump converter with 100mA output current capability. It translates the 2.4V to 5.5V input to the corresponding negative output voltage. As with all charge pump converters, the MC1121 uses inductorless to save cost, size, and reduce EMI. The frequency control input (FC) when the on-board oscillator (typical frequency is 10kHz VDD = 5V) is connected to ground. When FC is connected to VDD the oscillator frequency is increased to 200kHz, allowing the use of smaller capacitors. The operation is done with a lower quiescent current at a frequency of 10kHz and an additional external capacitor from the OSC (pin 7) to ground. The MC1121 can oscillate from an external clock drive connection. Typical supply current is 50mA at 10kHz, dropping to less than 1mA with the shutdown input brought low, whether for internal or external clocking. The MC1121 is available in the Micro-8 package.

Features • A 2.4V to 5.5V input voltage is converted to the corresponding negative output voltage (inverter mode)
• Use only 2 capacitors, no inductors required!
• High output current: 100mA
• Selectable oscillator frequency: 10kHz to 200kHz • Power saving shutdown input • Selectable high operating frequency allows use of small capacitors • Low operating current (FC = GND) Current: 50mA
• Test operating temperature range: -40°C to +85°C

Typical Applications • Notebook Computers • Medical Instruments • Disk Drives • MP-Based Controllers • Process Instrumentation