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RS421AYSF3
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Jiangsu RUNIC Tech Voltage Reference, SOT-23. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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RS421AYSF3
Jiangsu RUNIC Tech · Voltage Reference · SOT-23
RS421AYSF3 from Jiangsu RUNIC Tech, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | Cathode | passive | Shunt current/voltage input; the datasheet recommends a continuous cathode current of 0.5 mA to 100 mA and a cathode voltage from VREF to 36 V. |
| 2 | Ref | input | Threshold input referenced to the common anode; the output is set with two external resistors to any value between VREF (about 1.18 V) and 36 V. |
| 3 | Anode | power_in | Common pin, normally connected to ground; all voltages are referenced to the GND pin. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Jiangsu RUNIC Tech |
| Package | SOT-23 |
| Category | Power Management (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 output voltage (initial tolerance at 25°C) | -0.5 | 0.5 | % | TA=25°C | 1 | ||
| Reference Output Voltage | VREF | 1.174 | 1.18 | 1.186 | V | VKA=VREF, IKA=10mA | 6 |
| Deviation of reference input voltage over temperature | ΔVREF | 10 | 20 | mV | VKA=VREF, IKA=10mA, TA= -40°C ~ +125°C | 6 | |
| Ratio of change in reference input voltage to change in cathode voltage | ΔVREF/ΔVKA | -0.08 | -0.2 | mV/V | IKA=10mA, ΔVKA=10V~VREF | 6 | |
| Ratio of change in reference input voltage to change in cathode voltage | ΔVREF/ΔVKA | -0.06 | -0.2 | mV/V | IKA=10mA, ΔVKA=36V~10V | 6 | |
| Reference input current | IREF | 0.4 | 1.2 | uA | IKA=10mA, R1=10kΩ, R2=∞ | 6 | |
| Deviation of reference input current over full temperature range | ΔIREF | 0.3 | 1.2 | uA | IKA=10mA, R1=10kΩ, R2=∞, TA= -40°C ~ +125°C | 6 | |
| Minimum cathode current for regulation | IKA (min) | 0.17 | 0.3 | mA | VKA=VREF, TA= 25°C | 6 | |
| Off-state cathode current | IKA (OFF) | 5 | 10 | uA | VKA=36V, VREF=0V, TA= 25°C | 6 | |
| Off-state cathode current | IKA (OFF) | 0.03 | 0.1 | uA | VKA=18V, VREF=0V, TA= 25°C | 6 | |
| Dynamic impedance | ZKA | 0.1 | 0.4 | Ω | VKA=VREF, IKA=1mA to 100mA, f≤1.0KHz | 6 | |
| Cathode voltage (recommended operating) | VKA | 36 | V | 5 | |||
| Cathode current range (continuous, recommended operating) | IKA | 0.5 | 100 | mA | 5 | ||
| Operating ambient temperature range | TA | -40 | 125 | °C | 5 | ||
| Cathode voltage (absolute maximum) | VKA | -0.3 | 37 | V | 5 | ||
| Cathode current range (continuous, absolute maximum) | IKA | -100 | 155 | mA | 5 | ||
| Reference input current range (absolute maximum) | IREF | -0.05 | 10 | mA | 5 | ||
| Operating junction temperature | Topr | -40 | 150 | °C | 5 | ||
| Power dissipation | PD | 370 | mW | 5 | |||
| Storage temperature | Tstg | -55 | 150 | °C | 5 | ||
| Electrostatic discharge, human-body model (HBM) | V(ESD) | -4000 | 4000 | V | 5 | ||
| Electrostatic discharge, charge device model (CDM) | V(ESD) | -200 | 200 | V | 5 | ||
| Junction-to-ambient thermal resistance | RθJA | 185.6 | °C/W | SOT23 3-pin | 5 | ||
| Junction-to-case (top) thermal resistance | RθJC (top) | 104.3 | °C/W | SOT23 3-pin | 5 | ||
| Junction-to-board thermal resistance | RθJB | 54.5 | °C/W | SOT23 3-pin | 5 | ||
| Junction-to-top characterization parameter | ψJT | 31 | °C/W | SOT23 3-pin | 5 | ||
| Junction-to-board characterization parameter | ψJB | 54.5 | °C/W | SOT23 3-pin | 5 |
CAD (KiCad official)
- Symbol:
RS421AYSF3 - Footprint:
Package_TO_SOT_SMD:SOT-23 - 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files:
rs421aysf3-etched.step/rs421aysf3-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);rs421aysf3.step/rs421aysf3.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Jiangsu RUNIC Tech datasheet (11 pp, sha256
5330799985f35142, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-sonnet-5-5(agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish. - CAD: KiCad official libraries (CC-BY-SA 4.0).
# RS421AYSF3
**Jiangsu RUNIC Tech** · Voltage Reference · SOT-23
RS421AYSF3 from Jiangsu RUNIC Tech, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.
## Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | Cathode | passive | Shunt current/voltage input; the datasheet recommends a continuous cathode current of 0.5 mA to 100 mA and a cathode voltage from VREF to 36 V. |
| 2 | Ref | input | Threshold input referenced to the common anode; the output is set with two external resistors to any value between VREF (about 1.18 V) and 36 V. |
| 3 | Anode | power_in | Common pin, normally connected to ground; all voltages are referenced to the GND pin. |
## Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Jiangsu RUNIC Tech |
| Package | SOT-23 |
| Category | Power Management (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 output voltage (initial tolerance at 25°C) | | -0.5 | | 0.5 | % | TA=25°C | 1 |
| Reference Output Voltage | VREF | 1.174 | 1.18 | 1.186 | V | VKA=VREF, IKA=10mA | 6 |
| Deviation of reference input voltage over temperature | ΔVREF | | 10 | 20 | mV | VKA=VREF, IKA=10mA, TA= -40°C ~ +125°C | 6 |
| Ratio of change in reference input voltage to change in cathode voltage | ΔVREF/ΔVKA | | -0.08 | -0.2 | mV/V | IKA=10mA, ΔVKA=10V~VREF | 6 |
| Ratio of change in reference input voltage to change in cathode voltage | ΔVREF/ΔVKA | | -0.06 | -0.2 | mV/V | IKA=10mA, ΔVKA=36V~10V | 6 |
| Reference input current | IREF | | 0.4 | 1.2 | uA | IKA=10mA, R1=10kΩ, R2=∞ | 6 |
| Deviation of reference input current over full temperature range | ΔIREF | | 0.3 | 1.2 | uA | IKA=10mA, R1=10kΩ, R2=∞, TA= -40°C ~ +125°C | 6 |
| Minimum cathode current for regulation | IKA (min) | | 0.17 | 0.3 | mA | VKA=VREF, TA= 25°C | 6 |
| Off-state cathode current | IKA (OFF) | | 5 | 10 | uA | VKA=36V, VREF=0V, TA= 25°C | 6 |
| Off-state cathode current | IKA (OFF) | | 0.03 | 0.1 | uA | VKA=18V, VREF=0V, TA= 25°C | 6 |
| Dynamic impedance | ZKA | | 0.1 | 0.4 | Ω | VKA=VREF, IKA=1mA to 100mA, f≤1.0KHz | 6 |
| Cathode voltage (recommended operating) | VKA | | | 36 | V | | 5 |
| Cathode current range (continuous, recommended operating) | IKA | 0.5 | | 100 | mA | | 5 |
| Operating ambient temperature range | TA | -40 | | 125 | °C | | 5 |
| Cathode voltage (absolute maximum) | VKA | -0.3 | | 37 | V | | 5 |
| Cathode current range (continuous, absolute maximum) | IKA | -100 | | 155 | mA | | 5 |
| Reference input current range (absolute maximum) | IREF | -0.05 | | 10 | mA | | 5 |
| Operating junction temperature | Topr | -40 | | 150 | °C | | 5 |
| Power dissipation | PD | | | 370 | mW | | 5 |
| Storage temperature | Tstg | -55 | | 150 | °C | | 5 |
| Electrostatic discharge, human-body model (HBM) | V(ESD) | -4000 | | 4000 | V | | 5 |
| Electrostatic discharge, charge device model (CDM) | V(ESD) | -200 | | 200 | V | | 5 |
| Junction-to-ambient thermal resistance | RθJA | | 185.6 | | °C/W | SOT23 3-pin | 5 |
| Junction-to-case (top) thermal resistance | RθJC (top) | | 104.3 | | °C/W | SOT23 3-pin | 5 |
| Junction-to-board thermal resistance | RθJB | | 54.5 | | °C/W | SOT23 3-pin | 5 |
| Junction-to-top characterization parameter | ψJT | | 31 | | °C/W | SOT23 3-pin | 5 |
| Junction-to-board characterization parameter | ψJB | | 54.5 | | °C/W | SOT23 3-pin | 5 |
## CAD (KiCad official)
- Symbol: `RS421AYSF3`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `rs421aysf3-etched.step` / `rs421aysf3-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `rs421aysf3.step` / `rs421aysf3.glb` are the bare package body.
## Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- **Datasheet:** [Jiangsu RUNIC Tech datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8589839621963083776) (11 pp, sha256 `5330799985f35142`, retrieved 2026-10-18, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).
[Datasheet PDF](docs/rs421aysf3-datasheet.pdf)