Features

• Supports AM Modulation in EDGE/TDMA (ANSI-136) Applications
• Single Output RF Power Amplifier Control (LTC4403-1)
• Dual Output RF Power Amplifier Control (LTC4403-2)
• 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
• 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 (LTC4403-1) and 10-Pin MSOP (LTC4403-2)

Typical Application

Description

The LTC4403-2 is a multiband RF power controller for RF power amplifiers operating in the 300MHz to 2.4GHz range. The LTC4403-2 has two outputs to control dual T_X PA modules with two control inputs. An internal sample and hold circuit enables the LTC4403-2 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 LTC4403-1 is a single output RF power controller with identical performance to the LTC4403-2. The LTC4403-1 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.