RS2251XTSS16 from Jiangsu RUNIC Tech, in a TSSOP-16. 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	X4	bidirectional	Analog switch input/output channel 4. Selected when C,B,A = 1,0,0 with ENABLE low. Signal range GND to VCC; input/output pins are interchangeable.
2	X6	bidirectional	Analog switch input/output channel 6. Selected when C,B,A = 1,1,0 with ENABLE low. Signal range GND to VCC.
3	X	bidirectional	Common analog switch 'X' terminal (mux common). Connects to the selected X0-X7 channel when ENABLE is low. Bidirectional; ~48 Ω typical on-resistance at 5 V.
4	X7	bidirectional	Analog switch input/output channel 7. Selected when C,B,A = 1,1,1 with ENABLE low. Signal range GND to VCC.
5	X5	bidirectional	Analog switch input/output channel 5. Selected when C,B,A = 1,0,1 with ENABLE low. Signal range GND to VCC.
6	ENABLE	input	Active-low digital enable input. Drive low to enable the selected channel; drive high to disconnect all channels (no channel on). VIH >= 1.7 V, VIL <= 0.5 V. Normally tied to GND if unused.
7	NC	unconnected	No connect. Leave floating or tie to GND.
8	GND	power_in	Ground return. Connect to digital ground / system 0 V reference.
9	C	input	Digital address input C (MSB of the 3-bit channel-select word). Combined with B and A to select one of X0-X7. VIH >= 1.7 V, VIL <= 0.5 V.
10	B	input	Digital address input B. Combined with C and A to select one of X0-X7. VIH >= 1.7 V, VIL <= 0.5 V.
11	A	input	Digital address input A (LSB of the 3-bit channel-select word). Combined with C and B to select one of X0-X7. VIH >= 1.7 V, VIL <= 0.5 V.
12	X3	bidirectional	Analog switch input/output channel 3. Selected when C,B,A = 0,1,1 with ENABLE low.
13	X0	bidirectional	Analog switch input/output channel 0. Selected when C,B,A = 0,0,0 with ENABLE low.
14	X1	bidirectional	Analog switch input/output channel 1. Selected when C,B,A = 0,0,1 with ENABLE low.
15	X2	bidirectional	Analog switch input/output channel 2. Selected when C,B,A = 0,1,0 with ENABLE low.
16	VCC	power_in	Positive analog and digital supply voltage. Operating range 2.5 V to 5.5 V; absolute max 6 V. Also sets the upper limit of the analog signal range on X/X0-X7.

Key specifications

Parameter	Value
Manufacturer	Jiangsu RUNIC Tech
Package	TSSOP-16
Category	Interface
Pins	16

Ordering variants

Same part, different packaging or reel option.

RS2251XTSS16
RS2251XTSS16XS16
RS2251XTSS16XSS16
RS2251XTSS16XTQC16

CAD (KiCad official)

Symbol: RS2251XTSS16
Footprint: Package_SO:TSSOP-16_4.4x5mm_P0.65mm
3D model: TSSOP-16 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Jiangsu RUNIC Tech datasheet (13 pp, sha256 ba26af1ce12e5a62, 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