Sample and hold in a hermetic can
The LF198AH is a monolithic sample-and-hold circuit from National Semiconductor, built for precision analog signal acquisition where the hold capacitor must retain the sampled voltage with low droop.
Package and mounting reality
Through-hole TO-99-8 is an 8-lead circular metal can with a 0.230-inch diameter base. The metal case is internally connected to the negative supply pin, so the heatsinking path runs through the board-mounting ring. No socket is strictly required, but a turned-pin socket eases replacement during calibration cycles. The bulk shipping format means the parts arrive loose in a bag — no tape-and-reel, no carrier — so plan for manual placement or a tube-fed insertion machine.
The LF198AH is listed as RoHS non-compliant, which means the lead (Pb) content in the solderable terminations exceeds the 0.1 % threshold. For new designs targeting RoHS compliance (EU Directive 2011/65/EU), this part requires an exemption — typically for high-reliability or military applications where lead-free solder joints risk tin whiskers. If your BOM must be fully RoHS, look at the LF198AH's lead-free siblings in the same family; the TO-99-8 package itself is available in compliant versions.
Lifecycle status and sourcing posture
That said, the TO-99 metal can is a legacy package — production volumes are lower than surface-mount equivalents, and lead times can stretch when wafer starts are batched. No LTB risk today, but if your program runs beyond five years, keep an eye on the PCN stream for any package-migration notice.