LF398 Sample and Hold Circuit
The data sheet clearly says "operates from +/- 5V to +/- 18V supplies"

ie it needs a minimum of 10V from V+ to V- to operate (and a maximum of 36V).
Why would you expect it to operate on only 5V?

It does not care if you ground V- and use +10V or ground V+ and use -10V but you need 10V minimum supply.

Note that at the top of each data table it says that the figures apply for
 V- + 3.5V &lt; Vin &lt; V+-3.5V.
 ie signals must not be closer than 3.5V from either supply rail.
So on a +/- supply you get +/- 1.5V signal range.

There is a small chance that it will run on slightly less voltage than specified, but if it did there would be no guarantee re performance.

The world is awash with ways of making dual supplies. Two batteries, voltage divider from one supply, two winding power supply. ... . That's a reasonably nice IC that you are using - it deserves to be fed properly. You say that you only have +5V. Why? How? 

About the cheapest build your own solution is to use an MC34063  - various application circuits with PCB layout in datasheet. But you can buy modules for a few dollars on ebay that do what you want.