FSA4157P6X from onsemi, in a SC-70-6(SOT-363). Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	B1	passive	Analog switch data port B1. Connected to common port A when the control input S is HIGH. Bidirectional signal path with ~1.15 Ω max Ron at 4.5 V VCC; signal voltage must remain within 0 V to VCC.
2	GND	power_in	Device ground reference (0 V).
3	B0	passive	Analog switch data port B0. Connected to common port A when the control input S is LOW. Bidirectional analog signal path with ~1.15 Ω max Ron at 4.5 V VCC; signal voltage must remain within 0 V to VCC.
4	A	passive	Common analog switch data port A. Routed to B0 (S = LOW) or B1 (S = HIGH) via break-before-make action. Bidirectional; signal voltage must remain within 0 V to VCC.
5	VCC	power_in	Positive supply. Operating range 1.65 V to 5.5 V (FSA4157) or 2.7 V to 5.5 V (FSA4157A). Absolute maximum −0.5 V to +6.0 V. Typical ICC ≈ 0.1 µA.
6	S	input	TTL-compatible select input. LOW connects B0↔A; HIGH connects B1↔A. Must be driven HIGH or LOW at all times (must not float). Over-voltage tolerant control circuitry; VIH ≥ 2.0 V (VCC = 2.7-3.6 V) or ≥ 2.4 V (4.5-5.5 V).

Key specifications

Parameter	Value
Manufacturer	onsemi
Package	SC-70-6(SOT-363)
Category	Interface
Pins	6

Ordering variants

Same part, different packaging or reel option.

FSA4157P6X
FSA4157P6X_NL
FSA4157AP6
FSA4157AP6X
FSA4157AP6X_NL
FSA4157L6X
FSA4157AL6X

CAD (KiCad official)

Symbol: FSA4157P6X
Footprint: Package_TO_SOT_SMD:SOT-363_SC-70-6
3D model: SC-70-6(SOT-363) (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: onsemi datasheet (14 pp, sha256 c76205c0678a3f86, retrieved 2026-08-17, tier: lcsc)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF