MC1121

Features:

Converts a 2.4V to 5.5V Input Voltage to a Corresponding Negative Output Voltage (Inverter Mode)
Uses Only 2 Capacitors; No Inductors Required!
High Output Current: 100mA
Selectable Oscillator Frequency: 10kHz to 200kHz
PowerSaving Shutdown Input
Optional HighFrequency Operation Allows Use of Small Capacitors
Low Operating Current (FC = GND): 50A
Tested Operating Temperature Range: 40 to +85


Application

Laptop Computers
Medical Instruments
Disk Drives
PBased Controllers
Process Instrumentation


Pinout




Specifications

Parameter	Value	Unit
VDD  Supply Voltage	6.0	V
Operating Temperature Range	40 to +85
OSC, FC, SHDN Input Voltage	0.3 to (VDD+0.3)	V
Output Short Circuit Duration	10	Sec
Storage Temperature Range	65 to +150
Package Power Dissipation (TA 70 ) Micro8 Derate by 4mW/ for TA > 70	333	mW
Lead Temperature (Soldering, 10 Seconds)	+300

Description

The MC1121 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 MC1121 uses no inductors saving cost, size, and reducing EMI.

An onboard oscillator operates at a typical frequency of 10kHz  (at V_DD = 5V) when the frequency control input (FC) is connected to ground.  The oscillator frequency of MC1121 increases to 200kHz when FC is connected to V_DD, allowing the use of smaller capacitors. Operation at sub10kHz frequencies results in lower quiescent current and is accomplished with the addition of an external capacitor from OSC (pin7) to ground. The MC1121 can be driven from an external clock connected OSC. Typical supply current at 10kHz is 50A, and falls to less than 1A when the shutdown input is brought low, whether the internal or an external clock is used. The MC1121 is available in a Micro8 package.