What the negative-output buck-boost buys you
The MAX764CSA+ is a 300 kHz buck-boost regulator that generates a negative output from a positive input rail — useful when a bipolar supply is needed from a single battery or bus. It delivers up to 260 mA with an adjustable output down to -16 V, or a fixed -5 V if the application doesn't need the trim. The 3 V to 16 V input range covers common 5 V, 12 V, and lithium-ion rails, so it can sit on an existing supply without a separate pre-regulator.
Switching frequency and rectifier choice
At 300 kHz the switching frequency is high enough to keep the inductor and output capacitor small, but low enough that layout parasitics are manageable on a standard 2-layer board. The part does not include a synchronous rectifier, so the external Schottky diode's forward drop and reverse recovery directly set the efficiency — a fast Schottky with low Vf is worth the BOM cost here.
Housed in an 8-SOIC (0.154-inch body width, 3.90 mm) — a common footprint with 1.27 mm pin pitch. The surface-mount package reflows easily with a standard profile and mates with SOIC-8 land patterns. Supplied in tube, not tape-and-reel, so it is best suited for hand-assembly or low-volume reflow runs.