X9470
RF Power Amplifier (PA) Bias Controller
Not Recommended for New Designs.Contact our Technical Support Center at 1-888-INTERSIL.
Typical Diagram
Key Features
- Programmable Bias Controller IC for Class A and AB LDMOS Power Amplifiers
- Adaptive System on Chip Solution
- Bias Current Calibration to better than ±4% using Reference Trim DCP
- Automatic Bias Point Tracking and Calibration
- IDQ Sensing and Tracking
- Programmable Instrumentation Amplifier to Scale Wide Range of IDQ
- Programmable Gate Bias Driver
- All Programmable settings are Nonvolatile
- All Settings Recalled at Power-up.
- 28V Maximum VDD
- 2 Wire Interface for Programming Bias Setting and Optimizing IDQ Set Point
- Bias Level Comparator
- Shutdown Control pin for PA Signal
- Slave address to allow for multiple devices
- 24-pin TSSOP Package
- Applications: Cellular Base Stations (GSM, UMTS, CDMA, EDGE), TDD applications, Pointto- multipoint, and other RF power transmission systems
Description
The Intersil X9470 RF PA Bias Controller contains all of the necessary analog components to sense the PA drain current through an external sense resistor and automatically control the gate bias voltage of an LDMOS PA. The external sense resistor voltage is amplified by an instrumentation amplifier and the output of the amplifier along with an external reference voltage is fed to the inputs of a comparator. The comparator output indicates which direction the LDMOS gate bias voltage will move in the next calibration cycle. System calibration is accomplished by enabling the X9470 and providing a clock to the SCL pin. The LDMOS drain current can be maintained constant over temperature and aging changes by periodic calibration. The VOUT pin can be used to monitor the average power by tracking the drain current. Up to eight X9470 or additional Intersil Digital Potentiometers can be controlled via a twowire serial bus.
