LF398 Sample & Hold



A fun and easy build at 7 parts. Operates from +/-5V to +/-18V. 

The PCBs have 4 mounting holes in each corner, compatible with standard 4-40 standoffs. The pins on the edges are compatible with 0.1" (2.54mm) pitch pin headers and connectors. The signal in, logic in (trigger), and output pads are labelled and have square ground holes next to them, for easy wiring to jacks.


Click here to download the schematic.


The perfect sized hold capacitor was a little tricky to find (some low leakage caps are really huge), so pay close attention if sourcing your own parts.

 Parts list:

  • 2 x 0.01uF bypasscaps
  • 1 x 0.1uF polypropylene hold cap
  • 1 x LF398 Monolithic Sample & Hold IC
  • 1 x 1k Resistor
  • 1 x 5.1V Zener (1N4733)
  • 1 x DIP8 socket


    Here's a Mouser Cart with all components, as well (not including jacks).


    The build is pretty straightforward. R1 and D1 (the 1k resistor and 5V zener diode) are both installed vertically. Make sure the black stripe on the silkscreen matches the black stripe on the diode! 


    Here's a pic of the first completed PCB. I'm using one of our 2&4ON4 PCBs to hold the jacks.

    Tons of info will remain over on the:

    SuperLF398 S&H Kickstarter.