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1N4728APF
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ST(Semtech) Zener Diodes, DO-41. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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1N4728APF
ST(Semtech) · Zener Diodes · DO-41
1N4728APF from ST(Semtech), in a DO-41. 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 | K | passive | Cathode, marked by the cathode band on the glass DO-41 case; the zener (breakdown) voltage of 3.14 V min to 3.47 V max at IZT = 76 mA is established with this lead positive relative to the anode. |
| 2 | A | passive | Anode lead of the DO-41 glass case (end opposite the cathode band); forward voltage is 1.2 V max at IF = 200 mA. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | ST(Semtech) |
| Package | DO-41 |
| Category | Diodes |
| Pins | 2 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Zener Voltage Nominal | VZnom | 3.3 | V | at IZT = 76 mA, Ta = 25℃ | 3 | ||
| Zener Voltage Tolerance (suffix A) | -5 | 5 | % | Add suffix "A" for ±5% tolerance | 1 | ||
| Zener Voltage Range | VZT | 3.14 | 3.47 | V | at IZT = 76 mA, tested with pulses tp = 20 ms | 3 | |
| Test Current | IZT | 76 | mA | 3 | |||
| Dynamic Resistance | ZZT | 10 | Ω | at IZT | 3 | ||
| Dynamic Resistance (knee) | ZZK | 400 | Ω | at IZK = 1 mA | 3 | ||
| Reverse Current | IR | 150 | µA | at VR = 1 V | 3 | ||
| Maximum Surge Current | IZSM | 1375 | mA | 1/2 square wave or equivalent sine wave pulse of 1/120 second duration superimposed on IZT | 3 | ||
| Maximum Regulator Current | IZM | 275 | mA | leads at 8 mm from case kept at ambient temperature | 3 | ||
| Temperature Coefficient of Zener Voltage | -0.08 | -0.05 | %/℃ | at IZT | 3 | ||
| Forward Voltage | VF | 1.2 | V | IF = 200 mA, Ta = 25℃ | 3 | ||
| Power Dissipation | Ptot | 1 | W | Ta = 25℃; leads at 8 mm from case kept at ambient temperature | 1 | ||
| Junction Temperature | Tj | 175 | ℃ | Ta = 25℃ | 1 | ||
| Storage Temperature Range | Tstg | -65 | 175 | ℃ | Ta = 25℃ | 1 | |
| Thermal Resistance Junction to Ambient Air | RθJA | 150 | ℃/W | leads at 8 mm from case kept at ambient temperature | 1 |
CAD (KiCad official)
- Symbol:
1N4728APF - Footprint:
Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal - 3D model: DO-41 (KiCad packages3D, STEP)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: ST(Semtech) datasheet (5 pp, sha256
7a466624e3746c12, retrieved 2026-10-22, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-sonnet-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).
# 1N4728APF
**ST(Semtech)** · Zener Diodes · DO-41
1N4728APF from ST(Semtech), in a DO-41. 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 | K | passive | Cathode, marked by the cathode band on the glass DO-41 case; the zener (breakdown) voltage of 3.14 V min to 3.47 V max at IZT = 76 mA is established with this lead positive relative to the anode. |
| 2 | A | passive | Anode lead of the DO-41 glass case (end opposite the cathode band); forward voltage is 1.2 V max at IF = 200 mA. |
## Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | ST(Semtech) |
| Package | DO-41 |
| Category | Diodes |
| Pins | 2 |
## Electrical characteristics
Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Zener Voltage Nominal | VZnom | | 3.3 | | V | at IZT = 76 mA, Ta = 25℃ | 3 |
| Zener Voltage Tolerance (suffix A) | | -5 | | 5 | % | Add suffix "A" for ±5% tolerance | 1 |
| Zener Voltage Range | VZT | 3.14 | | 3.47 | V | at IZT = 76 mA, tested with pulses tp = 20 ms | 3 |
| Test Current | IZT | | 76 | | mA | | 3 |
| Dynamic Resistance | ZZT | | | 10 | Ω | at IZT | 3 |
| Dynamic Resistance (knee) | ZZK | | | 400 | Ω | at IZK = 1 mA | 3 |
| Reverse Current | IR | | | 150 | µA | at VR = 1 V | 3 |
| Maximum Surge Current | IZSM | | | 1375 | mA | 1/2 square wave or equivalent sine wave pulse of 1/120 second duration superimposed on IZT | 3 |
| Maximum Regulator Current | IZM | | | 275 | mA | leads at 8 mm from case kept at ambient temperature | 3 |
| Temperature Coefficient of Zener Voltage | | -0.08 | | -0.05 | %/℃ | at IZT | 3 |
| Forward Voltage | VF | | | 1.2 | V | IF = 200 mA, Ta = 25℃ | 3 |
| Power Dissipation | Ptot | | | 1 | W | Ta = 25℃; leads at 8 mm from case kept at ambient temperature | 1 |
| Junction Temperature | Tj | | | 175 | ℃ | Ta = 25℃ | 1 |
| Storage Temperature Range | Tstg | -65 | | 175 | ℃ | Ta = 25℃ | 1 |
| Thermal Resistance Junction to Ambient Air | RθJA | | | 150 | ℃/W | leads at 8 mm from case kept at ambient temperature | 1 |
## CAD (KiCad official)
- Symbol: `1N4728APF`
- Footprint: `Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal`
- 3D model: DO-41 (KiCad packages3D, STEP)
## Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- **Datasheet:** [ST(Semtech) datasheet](docs/1n4728apf-datasheet.pdf) (5 pp, sha256 `7a466624e3746c12`, retrieved 2026-10-22, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-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/1n4728apf-datasheet.pdf)