AIC1840

PRELIMINARY AIC1840/1841 LOW-NOISE, REGULATED GaAsFET BIAS SPEC NO: DS-1840-P2 ! FEATURES " Low Output Noise: 2mV Ripple. " Work with Small Capacitors (as Low as 0.22µF). " Fixed -2V or Adjustable Output. " 2.5V to 6.5V Input Voltage Range. " Switching Frequency: 104KHz in Normal Operation. " 1µA Maximum in Shutdown Mode. ! APPLICATIONS " Cellular Phones. " GaAsFET Power Amplifier Modules. " Personal Communicators and PDAs. " Wireless Data Loggers. " LCD Bias Contrast Control. " Regulated Negative Power Supplies. ! DESCRIPTION The AIC1840/1841 is a switched-capacitor voltage inverter that generates a regulated fixed -2.0V or externally adjustable output. An internal linear post-regulator reduces the output voltage ripple to less than 2mV, making the AIC1840/1841 excellent for use as bias voltage generator for transmitter GaAsFETs in portable RF and cellular telephone applications. The operation voltage is as low as 2.5V. The AIC1840/1841 offers a -2V preset output as well as a -1.3V to -3.0V adjustable output. Input voltage range for AIC1840/1841 is 2.5V to 6.5V. Output current is 5mA at VOUT= -2V and with VIN≥2.5V. Quiescent current is 510µA at VIN=3.6V and reduces to less than 1µA in shutdown mode (3µA max. for the AIC1841). ! TYPICAL APPLICATION CIRCUIT The AIC1840 has an active-low shutdown input, while the AIC1841 has an active-high shutdown input. VBAT (+2.5 ~ +6.5V) VTX C3 3.3µF + C8 L1 C9 RF INPUT 8 RF POWER AMPLIFIER L2 T1 C1 3.3µF + 1 2 VDD CAPP VOU...