LTC1757A - Single/Dual Band RF Power Controllers

Features

  • 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 VIN 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)

Typical Application

LTC1757A Typical Application

Description

The LTC1757A-2 is a dual band RF power controller for RF power amplifiers operating in the 850MHz to 2GHz range. The LTC1757A is pin compatible with the LTC1757 but has improved RF detection 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 LTC1757A-1 is a single output RF power controller that is identical in performance to the LTC1757A-2 except that one output (VPCA) 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.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC1757A-1EMS8#PBF MS-8 MS8 E 05-08-1660 Yes
LTC1757A-1EMS8#TRPBF MS-8 MS8 E 05-08-1660 Yes
LTC1757A-2EMS#PBF MS-10 MS E 05-08-1661 Yes
LTC1757A-2EMS#TRPBF MS-10 MS E 05-08-1661 Yes


LTC1757A Package Drawing
LTC1757A Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC1757A-1EMS8#PBF MS-8 E $2.00 $1.75 Yes
LTC1757A-1EMS8#TRPBF MS-8 E $1.81 Yes
LTC1757A-2EMS#PBF MS-10 E $2.10 $1.90 Yes
LTC1757A-2EMS#TRPBF MS-10 E $1.96 Yes
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* 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards

Applications

  • Single and Dual Band GSM Cellular Telephones
  • PCS Devices
  • Wireless Data Modems
  • TDMA Cellular Telephones

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support