Package and mounting
The Maxim Integrated MAX636ACSA+ is a buck regulator that can also run in an inverted topology to generate a negative output rail. It delivers up to 200 mA from a positive input between 2.3 V and 16.5 V, with the output adjustable down to -12 V or fixed at -1.31 V. The part is in an 8-SOIC package and rated for 0°C to 70°C ambient, so it's a commercial-temperature part; don't expect it to hold regulation in an unheated enclosure.
Output voltage range — what you can actually get
The output can be set anywhere from -1.31 V down to -12 V, depending on the feedback resistor divider. The fixed -1.31 V option is useful if you just need a small negative bias for an op-amp or a charge-pump reference. The -12 V ceiling is the practical limit for a 16.5 V input rail; if you need a deeper negative rail, this isn't the part.
Lifecycle and sourcing reality
The MAX636ACSA+ is listed as Active with ROHS3 compliance. No last-time-buy notice, no NRND flag. That means you can still design it into a new BOM without worrying about an imminent EOL.