AD8316

   The AD8316 is a complete, low cost subsystem for the precise control of dual RF power amplifiers (PAs) operating in the frequency range 0.1 GHz to 2.5 GHz and over a typical dynamic range of 50 dB. The device is a dual-output version of the AD8315 and intended for use in dual-band or triband cellular hand sets and other battery-operated wireless devices where a separatepower control signal is required for each band. The logarithmic amplifier technique provides a much wider measurement range and better accuracy than is possible using controllers based on diode detectors. In particular, multiband and multimode cellu-lar designs can benefit from the temperature-stable (30°C to+85°C) operation over all cellular telephony frequencies.

  Its high sensitivity allows control at low input signal levels, thusreducing the amount of power that needs to be coupled to thedetector. The selected output, OUT1 or OUT2, has the voltage range and current drive to directly connect to the gain control pin of most handset power amplifiers; the deselected output is pulled low to ensure that the inactive PA remains off. Each output has a dedicated integrating filter capacitor that allows separate control loop settings for each PA. OUT1 and OUT2 can swing from 125 mV above ground to within 100 mV below the supply voltage. Load currents of up to 12 mA can be supported. The setpoint control input applied to pin VSET has an operating range of 0.25 V to 1.4 V. The input resistance of the setpoint Interface is over 100 M Ω, and the bias current is typically 0.5 µA.The AD8316 is available in 10-lead MSOP and 16-leadLFCSP packagesandconsumes 8.5 mA from a 2.7 V to 5.5 V supply.When it is powered down, the sleep current is 4 µA.