MS4553S from Hangzhou Ruimeng Tech, in a SOT-23-8. 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	VCCB	power_in	B-side supply voltage, 2.3 V ≤ VCCB ≤ 5.5 V. Sets the reference rail for the B-side I/O (B1, B2). Must satisfy VCCA ≤ VCCB.
2	B1	bidirectional	B-side bidirectional I/O channel 1, referenced to VCCB. Paired with A1 (pin 7) for level translation. Supports open-drain and push-pull operation.
3	B2	bidirectional	B-side bidirectional I/O channel 2, referenced to VCCB. Paired with A2 (pin 6) for level translation. Supports open-drain and push-pull operation.
4	OE	input	Output enable, referenced to VCCA. Drive OE low to place all I/Os in Hi-Z; drive high (VIH ≥ VCCA×0.8) for normal translation. Should be tied to VCCA through a pull-up resistor to preserve Hi-Z during supply ramp.
5	GND	power_in	Ground reference for the device (0 V).
6	A2	bidirectional	A-side bidirectional I/O channel 2, referenced to VCCA. Paired with B2 (pin 3) for level translation. Supports open-drain and push-pull operation.
7	A1	bidirectional	A-side bidirectional I/O channel 1, referenced to VCCA. Paired with B1 (pin 2) for level translation. Supports open-drain and push-pull operation.
8	VCCA	power_in	A-side supply voltage, 1.65 V ≤ VCCA ≤ 5.5 V, with VCCA ≤ VCCB. Sets the reference rail for the A-side I/O (A1, A2) and the OE input threshold.

Key specifications

Parameter	Value
Manufacturer	Hangzhou Ruimeng Tech
Package	SOT-23-8
Category	Logic
Pins	8

Ordering variants

Same part, different packaging or reel option.

MS4553S

CAD (KiCad official)

Symbol: MS4553S
Footprint: Package_TO_SOT_SMD:SOT-23-8
3D model: SOT-23-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ms4553s.step`	123 KB	You want the bare part, or you mark your own boards.
`ms4553s-etched.step`	1.9 MB	You want the part with `MS4553S` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 465 faces against 147 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: Hangzhou Ruimeng Tech datasheet (16 pp, sha256 fc4ff4ffb6f9dcff, retrieved 2026-08-17, tier: lcsc)
Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
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