Description
19-0388; Rev 1; 3/96 UAL IT MAN TION K A ET U E L H A S EV TA WS DA FOLLO Low-Noise, Regulated, -2V GaAsFET Bias _______________General .
The MAX840/MAX843/MAX844 low-noise, inverting charge-pump power supplies are ideal for biasing GaAsFETs in cellular telephone transmitter amplifiers.
Features
* o Fixed -2V or Adjustable -0.5V to -9.4V Output at 4mA (MAX840) o 2.5V to 10V Input Voltage Range o Operate with Small Capacitors (as low as 0.22µF) o 1mVp-p Output Voltage Ripple o Charge-Pump Switching Frequency: 100kHz in Normal Operation 20kHz in Shutdown Mode (MAX844) o 1µA Max Logic-Level Shut
Applications
* Cellular Phones GaAsFET Power Amplifier Modules Personal Communicators, PDAs Wireless Data Loggers Continuously Adjustable GaAsFET Bias LCD-Bias Contrast Control Regulated Negative Power Supplies
__________Typical Operating Circuit
VIN = 2.5V to 10.0V (3 CELLS)
* Dice are specified at TA = +25