UM3208UK from Union Semiconductor, in a TSSOP-20. 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	A1	bidirectional	Input/Output 1 on the A port. Referenced to VCCA (1.65V to 3.6V). Bidirectional level-translation channel paired with B1.
2	VCCA	power_in	A-port supply voltage. Range: 1.65V to 3.6V, and must satisfy VCCA <= VCCB. Sets the logic level on the A side.
3	A2	bidirectional	Input/Output 2 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B2.
4	A3	bidirectional	Input/Output 3 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B3.
5	A4	bidirectional	Input/Output 4 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B4.
6	A5	bidirectional	Input/Output 5 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B5.
7	A6	bidirectional	Input/Output 6 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B6.
8	A7	bidirectional	Input/Output 7 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B7.
9	A8	bidirectional	Input/Output 8 on the A port. Referenced to VCCA. Bidirectional level-translation channel paired with B8.
10	OE	input	3-state output enable, referenced to VCCA. Drive OE low to place all A- and B-port outputs into high-impedance (3-state) mode, reducing supply current. VIH = VCCA0.65 min; VIL = VCCA0.35 max.
11	GND	power_in	Ground reference for the device.
12	B8	bidirectional	Input/Output 8 on the B port. Referenced to VCCB (2.3V to 5.5V). ±6kV ESD protected.
13	B7	bidirectional	Input/Output 7 on the B port. Referenced to VCCB. ±6kV ESD protected.
14	B6	bidirectional	Input/Output 6 on the B port. Referenced to VCCB. ±6kV ESD protected.
15	B5	bidirectional	Input/Output 5 on the B port. Referenced to VCCB. ±6kV ESD protected.
16	B4	bidirectional	Input/Output 4 on the B port. Referenced to VCCB. ±6kV ESD protected.
17	B3	bidirectional	Input/Output 3 on the B port. Referenced to VCCB. ±6kV ESD protected.
18	B2	bidirectional	Input/Output 2 on the B port. Referenced to VCCB. ±6kV ESD protected.
19	VCCB	power_in	B-port supply voltage. Range: 2.3V to 5.5V, and must be greater than or equal to VCCA. Sets the logic level on the B side.
20	B1	bidirectional	Input/Output 1 on the B port. Referenced to VCCB. ±6kV ESD protected.

Key specifications

Parameter	Value
Manufacturer	Union Semiconductor
Package	TSSOP-20
Category	Logic
Pins	20

Ordering variants

Same part, different packaging or reel option.

UM3208UK
UM3208UKH
UM3208UKQA

CAD (KiCad official)

Symbol: UM3208UK
Footprint: Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm
3D model: TSSOP-20 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Union Semiconductor datasheet (15 pp, sha256 83f6388f7e438b32, 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