Precision 300MHz to 7GHz RF Detector with Gain and Offset Adjustment
Features and Benefits
- Dual Band RF Power Amplifier Control (LTC1957-2)
- Internal Schottky Diode Detector with Improved Dynamic Range vs the LTC1757A
- Wide Input Frequency Range: 850MHz to 2GHz
- Autozero Loop Cancels Offset Errors and Temperature Dependent Offsets
- Wide VIN Range: 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
- Power Control Signal Overvoltage Protection
- Low Operating Current: 1mA
- Very Low Shutdown Current: <1µA
- Available in a 8-pin MSOP Package (LTC1957-1) and 10-Pin MSOP (LTC1957-2)
- Pin Compatible with the LTC1757A-X
- Improved Start Voltage Accuracy and Range
- Improved PCTL Input Filtering
The LTC1957-2 is a dual band RF power controller for power amplifiers operating in the 850MHz to 2GHz range. The input voltage range is optimized for operation from a single lithium-ion cell or 3x NiMH. Several functions required for RF power control and protection are integrated in one small 10-pin MSOP package, thereby minimizing PCB area.
The LTC1957-1 is a single output RF power controller that is identical in performance to the LTC1957-2 except that one output (VPCA) is provided. The LTC1957-1 can be used to drive a single RF 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 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.
- Single and Dual Band GSM/GPRS Cellular Telephones
- PCS Devices
- Wireless Data Modems
- U.S. TDMA Cellular Phones
Product Lifecycle Not Recommended for New Designs
This designates products ADI does not recommend broadly for new designs.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.