特点
Supports AM Modulation in EDGE/TDMA (ANSI-136) Applications
Single Output RF Power Amplifier Control (LTC4402-1)
Dual Output RF Power Amplifier Control (LTC4402-2)
Internal Schottky Diode Detector with >40dB Range
Wide Input Frequency Range: 300MHz to 2.4GHz
Autozero Loop Cancels Offset Errors and Temperature Dependent Offsets
Wide V
IN
Range: 2.7V to 6V
450kHz Loop Bandwidth
Allows Direct Connection to Battery
RF Output Power Set by External DAC
Internal Frequency Compensation
Rail-to-Rail Power Control Outputs
Low Operating Current: 1mA
Low Shutdown Current: <10μA
PCTL Input Filter
Available in a 8-Pin MSOP Package (LTC4402-1) and 10-Pin MSOP (LTC4402-2)
典型应用
描述
The LTC?4402-2 is a multiband RF power controller for RF power amplifiers operating in the 300MHz to 2.4GHz range. The LTC4402-2 has two outputs to control dual T X PA modules with two control inputs. An internal sample and hold circuit enables the LTC4402-2 to be used with AM modulation via the carrier or PA supply. The input voltage range is optimized for operation from a single lithium-ion cell or 3x NiMH.
RF power is controlled by driving the RF amplifier power control pins and sensing the resultant RF output power. 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 LTC4402-1 is a single output RF power controller with identical performance to the LTC4402-2. The LTC4402-1 has one output to control a single T X PA or dual T X PA module with a single control input and is available in an 8-pin MSOP package.
Internal and external offsets are cancelled over temperature by an autozero control loop. The shutdown feature disables the part and reduces the supply current to <10μA.