特點
Dual Band RF Power Amplifier Control (LTC1757A-2)
Improved Internal Schottky Diode Detector
Wide Input Frequency Range: 850MHz to 2GHz
Autozero Cancels Initial Offsets and Temperature Dependent Offset Errors
Wide V
IN
Range of 2.7V to 6V Allows Direct Connection to Battery
RF Output Power Set by External DAC
Fast Acquire After Transmit Enable
Internal Frequency Compensation
Rail-to-Rail Power Control Outputs
RF PA Supply Current Limiting
Battery Overvoltage Protection
Power Control Signal Overvoltage Protection
Low Operating Current: 1mA
Very Low Shutdown Current: <1μA
Available in a 8-Pin MSOP Package (LTC1757A-1) and 10-Pin MSOP (LTC1757A-2)
典型應(yīng)用
描述
The LTC1757A-1 is a single output RF power controller that is identical in performance to the LTC1757A-2 except that one output (V PCA ) is provided. The LTC1757A-1 can be used to drive a single RF channel or dual channel module with integral multiplexer. This part is available in an 8-pin MSOP package.
RF power is controlled by driving the RF amplifier power control pins and sensing the resultant RF output power via a directional coupler. The RF sense voltage is peak detected using an on-chip Schottky diode. This detected voltage is compared to the DAC voltage at the PCTL pin to control the output power. The RF power amplifier is protected against high supply voltage and current and high power control pin voltages.
Internal and external offsets are cancelled over temperature by an autozero control loop, allowing accurate low power programming. The shutdown feature disables the part and reduces the supply current to <1μA.