# HER508 TB

**YFW** · High Effic Rectifier · DO-27

HER508 TB from YFW, in a DO-27. 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 lead, the end marked with the cathode band on the DO-201AD/DO-27 body; HER508 blocks up to 1000 V VRRM and passes 5.0 A average forward current. |
| 2 | A | passive | Anode lead, the unmarked end of the DO-201AD/DO-27 axial body; HER508 has a forward current rating of 5.0 A average at Tc = 100 °C. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | YFW |
| Package | DO-27 |
| 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 |
|---|---|---|---|---|---|---|---|
| Maximum Repetitive Peak Reverse Voltage | VRRM |  |  | 1000 | V |  | 1 |
| Maximum RMS Voltage | VRMS |  |  | 700 | V |  | 1 |
| Maximum DC Blocking Voltage | VDC |  |  | 1000 | V |  | 1 |
| Maximum Average Forward Rectified Current | IF(AV) |  |  | 5 | A | Tc = 100 °C | 1 |
| Maximum DC Reverse Current | IR |  |  | 10 | μA | Ta = 25 °C, at rated DC blocking voltage | 1 |
| Maximum DC Reverse Current | IR |  |  | 500 | μA | Ta = 125 °C, at rated DC blocking voltage | 1 |
| Operating and Storage Temperature Range | Tj, Tstg | -55 |  | 150 | °C |  | 1 |
| Typical Junction Capacitance | Cj |  | 100 |  | pF |  | 1 |
| Typical Thermal Resistance | RθJA |  | 65 |  | °C/W |  | 1 |

## CAD (KiCad official)

- Symbol: `HER508 TB`
- Footprint: `Diode_THT:D_DO-27_P15.24mm_Horizontal`
- 3D model: DO-27 (KiCad packages3D, STEP)

## Provenance

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

- **Datasheet:** [YFW datasheet](docs/her508-tb-datasheet.pdf) (3 pp, sha256 `d1a425c5ca09d862`, 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/her508-tb-datasheet.pdf)