component
FS431M
Public Made by Adomby adom
FOSAN Voltage Reference, SOT-23. Pinout extracted from the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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Contents
README
markdownFS431M
FOSAN · Voltage Reference · SOT-23
FS431M from FOSAN, in a SOT-23. 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 | REF | input | Reference input. Compared internally against the 2.495 V bandgap reference; typically driven from an external R1/R2 divider between Cathode and Anode to program the regulation voltage. Input current ~1.8 µA typ (4 µA max). |
| 2 | K | passive | Cathode. Shunt regulation terminal; sinks 1-100 mA to hold VKA at the programmed voltage (up to 40 V absolute max, 36 V programmable). Dynamic impedance 0.27 Ω typ. |
| 3 | A | passive | Anode. Common/ground return for the shunt regulator; the resistor divider low side and Vref return are referenced here. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | FOSAN |
| Package | SOT-23 |
| Category | PMIC |
| Pins | 3 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Reference Input Voltage (0.3% grade) | VREF | 2.488 | 2.495 | 2.502 | V | VKA=VREF IKA=10mA | 2 |
| Reference Input Voltage (0.5% grade) | VREF | 2.483 | 2.495 | 2.507 | V | VKA=VREF IKA=10mA | 2 |
| Reference Input Voltage (1% grade) | VREF | 2.47 | 2.495 | 2.52 | V | VKA=VREF IKA=10mA | 2 |
| Deviation of reference input voltage over temperature | ΔVREF/ΔT | 3 | 17 | mV | VKA=VREF IKA=10mA, -20 ~ +70℃ | 2 | |
| Ratio of change in reference input voltage to change in cathode voltage (ΔVKA=10V~VREF) | ΔVREF/ΔVKA | -0.4 | 0 | 2.7 | mV/V | IKA=10mA, ΔVKA=10V~VREF | 2 |
| Ratio of change in reference input voltage to change in cathode voltage (ΔVKA=36V~10V) | ΔVREF/ΔVKA | -0.4 | 0 | 2 | mV/V | IKA=10mA, ΔVKA=36V~10V | 2 |
| Reference input current | IREF | 1.8 | 4 | µA | IKA=10mA, R1=10kΩ, R2=∞ | 2 | |
| Deviation of reference input current over full temperature range | ΔIREF/ΔT | 0.4 | 1.2 | µA | IKA=10mA, R1=10kΩ, R2=∞, TA=-20 ~ +85℃ | 2 | |
| Minimum cathode current for regulation | IKA(MIN) | 0.25 | 0.5 | mA | VKA=VREF | 2 | |
| Off-state cathode current | IKA(OFF) | 0.17 | 1 | µA | VKA=40V, VREF=0V | 2 | |
| Dynamic impedance | ZKA | 0.27 | 0.5 | Ω | VKA=VREF, IKA=1 ~ 100mA, f≤1kHz | 2 | |
| Cathode to anode voltage | VKA | 40 | V | 1 | |||
| Cathode current range | IK | -100 | 150 | mA | 1 | ||
| Reference input current range | IREF | -0.05 | 10 | mA | 1 | ||
| Power dissipation | PD | 200 | mW | 1 | |||
| Thermal resistance junction-ambient | RΘJA | 625 | ℃/W | 1 | |||
| Junction and storage temperature | TJ,Tstg | -40 | 125 | ℃ | 1 | ||
| Operating ambient temperature | Top | -20 | 70 | ℃ | 1 |
CAD (KiCad official)
- Symbol:
FS431M - Footprint:
Package_TO_SOT_SMD:SOT-23 - 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files:
fs431m-etched.step/fs431m-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);fs431m.step/fs431m.glbare the bare package body.
3D model downloads
Two STEP files. Same geometry, different body top:
| File | Size | Use it when |
|---|---|---|
fs431m.step |
59 KB | You want the bare part, or you mark your own boards. |
fs431m-etched.step |
1.1 MB | You want the part with FS431M already on it. |
The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 288 faces against 69 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: FOSAN datasheet (4 pp, sha256
44eae1ca9d167d08, 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).