CMFB 503F3950 from Nanjing Shiheng Elec, in a 0805. 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	1	passive	External electrode terminal 1 of the two-terminal NTC thermistor. Non-polarized; either terminal may be used as input or output. Resistance between terminals is ~50 kΩ at 25 °C, decreasing with temperature per the R-T table.
2	2	passive	External electrode terminal 2 of the two-terminal NTC thermistor. Non-polarized; interchangeable with terminal 1. Combined with terminal 1 forms the NTC resistance element (50 kΩ ±1% @ 25 °C, B = 3950 K).

Key specifications

Parameter	Value
Manufacturer	Nanjing Shiheng Elec
Package	0805
Category	Sensor
Pins	2

Ordering variants

Same part, different packaging or reel option.

CMFB 503F3950B

CAD (KiCad official)

Symbol: CMFB 503F3950
Footprint: Resistor_SMD:R_0805_2012Metric
3D model: 0805 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Nanjing Shiheng Elec datasheet (13 pp, sha256 b97d3c412e07c2b3, 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