SBOU317 September   2024

 

  1.   1
  2.   Description
  3.   Features
  4.   4
  5. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  6. 2Hardware
    1. 2.1 Power Connections
      1. 2.1.1 Split-Supply Operation
      2. 2.1.2 Single-Supply Operation
    2. 2.2 Input and Output Connections
      1. 2.2.1 Bias Mode Control Pins
      2. 2.2.2 IADJ Pin Connection
      3. 2.2.3 Optional VCM Pin Connection
  7. 3Hardware Design Files
    1. 3.1 Schematic
    2. 3.2 Board Layout
    3. 3.3 Bill of Materials
  8. 4Additional Information
    1. 4.1 Trademarks
  9. 5Related Documentation

2.2.1 Bias Mode Control Pins

The amplifier bias modes can be controlled through selecting between LOGIC 0 and LOGIC 1 positions on jumpers J6 (BIAS-1) and J7 (BIAS-2). By default, the jumper shorts are set to LOGIC 0, which pulls the input signals low, leaving the device in full-bias mode. Jumper J6 controls pin BIAS-1 and jumper J7 controls pin BIAS-2. In conjunction, the jumpers can be used to place the device in four bias modes or in shutdown.

Ultra-low bias mode requires an additional step to the other bias modes for use:

  • Put the device into low bias mode, BIAS-1 (J6) open & BIAS-2 (J7) closed
  • Use either method to raise the impedance on the IADJ pin:
    • R17 potentiometer, with default value zero-Ohms, and set to maximum 100kOhms
    • R29 zero-Ohm resistor, remove to float IADJ pin
  • Measure quiescent current and confirm ultra-low bias mode