Technical Topics



50 Ohm Buffer-Distribution Amplifier

.by by Steve Smith, G8LMX

Buffer Amplifier
50 ohm Distribution Amplifier

This 50 ohm distribution amplifier is capable of producing three outputs of 1 volt RMS from an input of 0.5 volt to 1 volt RMS. The boards can be daisy chained together on the input with the terminator on the last board.

Obviously if input requirements are different, the R1 / VR1 combination would need adjusting.

I designed the circuit around the MAX477 chip as it has a unity gain bandwidth of 300MHz, high output drive capability, and is relatively inexpensive.

Note that resistor R4 should remain about 470 ohm if the gain of the circuit is changed. Also, the outputs are not ground isolated as in Wolfgang's circuit. Apart from that it is fairly simple and self explanatory.

Circuit Schematic
Circuit Schematic

Component Layout
Component Layout Drawing

Low resolution PCB  layout
Printed Circuit Layout

These old HP cases are great!
Photograph of the amplifier board in a Rubidium standard constructed inside an old HP counter case.

Download high resolution circuit files as Adobe PDF

© 2003 Steve Smith, G8LMX