SBAU383A June   2021  – February 2022 BUF802

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Configuration and Usage
  4. 3 Power Connections
  5. 4 Input and Output Connections
  6. 5 Stand-Alone Buffer Configuration
  7. 6 Composite Loop Configuration
  8. 7 External Clamping
  9. 8 Schematic
  10. 9 Layout Prints
  11. 10Related Documentation
  12. 11Revision History

5 Stand-Alone Buffer Configuration

The bottom half of the board features the BUF802 in a standalone circuit configuration. This circuit is very similar to the one used to generate AC performance data in the BUF802 datasheet. In this configuration the BUF802 acts as a simple AC coupled buffer with a 50-Ω input impednace created by R29. With the input AC coupled, the test point T9 MUST be bonnected to a DC bias voltage for the circuit to function properly. The voltage on T9 sets the bias to the input stage of the BUF802 and should be set within the input common mode range of the device. To DC couple the input, the capacitor C44 can be replaced with a zero Ohm resistor and then the DC portion of the input signal will provide the bias to the input of the amplifier and the connection to T9 is no longer needed.

The output of the circuit features a resistor network (R24, R25, R27) that presents a 100-Ω load to the BUF802 while providing a 50-Ω impednace match for connecting to test equipment. This matching network creates an attenuation of approximately 0.27 V/V that should be accounted for when making measurements.