The MAX881REUB low-noise, inverting power supply is designed for biasing GaAsFET power amplifiers in portable wireless applications. This device is a chargepump inverter followed by a negative linear regulator. The input voltage range is 2.5V to 5.5V. The output is preset at -2.0V or can be set, using two resistors, to any voltage from -0.5V to (-VIN + 0.6V). It can deliver up to 4mA. The internal linear regulator also filters the output to 1mVp-p ripple and noise. Other features include a power-OK (POK) output that signals when the negative voltage is within 7.5% of its set point. It protects the GaAsFET by not allowing power to be applied to the GaAsFET’s drain until it is properly biased. The signal can be routed either to a microcontroller or directly to a switch at the GaAsFET drain. The MAX881REUB is available in a 10-pin µMAX package.
Features
♦ Small µMAX Package
♦ 1mVp-p Output Voltage Ripple and Noise
♦ Power-OK Signal to Control GaAsFET Drain Switch
♦ 0.05µA Logic-Controlled Shutdown
♦ 1ms Guaranteed Startup
♦ 2.5V to 5.5V Input
♦ -0.5V to (-VIN + 0.6V) Output at up to 4mA
♦ Operates with One 4.7µF and Three 0.22µF Capacitors (no inductors needed)
Feature
- Small μMAX Package
- 1mVP-P Output Voltage Ripple and Noise
- Power-OK Signal to Control GaAsFET Drain Switch
- 0.05μA Logic-Controlled Shutdown
- 1ms Guaranteed Startup
- 2.5V to 5.5V Input
- -0.5V to (-VIN + 0.6V) Output at up to 4mA
- Operates with One 4.7μF and Three 0.22μF Capacitors (no inductors needed)
Applications
- Cell Phones Wireless Modems
- PCS Phones Two-Way Pagers
- PHS Phones Mobile Radios
- Wireless Handsets Wireless Computers
