# CT304B-800S

**Changjiang Electronics Tech (CJ)** · TRIACs · TO-220

CT304B-800S from Changjiang Electronics Tech (CJ), in a TO-220. 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 | MAIN TERMINAL 1 (MT1) | passive | Main terminal 1 of the TRIAC, which carries the main on-state current with an RMS rating of IT(RMS) 4 A and a non-repetitive surge peak of 40 A (Tj(init)=25℃, tp=20ms). |
| 2 | MAIN TERMINAL 2 (MT2) | passive | Main terminal 2 of the TRIAC, which is rated for the 800 V repetitive peak off-state voltage (VDRM/VRRM) of the CT304B-800S variant and 4 A RMS on-state current. |
| 3 | GATE | input | Gate terminal used to trigger the TRIAC, with a peak gate current IGM of 4 A (tp=20µs, Tj=125℃), an average gate power PG(AV) of 1 W, a gate trigger voltage VGT of at most 1.3 V, and a gate trigger current IGT of at most 10 mA for the S suffix. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Changjiang Electronics Tech (CJ) |
| Package | TO-220 |
| Category | Transistors |
| 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 |
|---|---|---|---|---|---|---|---|
| RMS on-state current | IT(RMS) |  |  | 4 | A | TO-220BK(TC≤110℃), Fig. 1,2 | 1 |
| Repetitive peak off-state voltage (800V variant) | VDRM/VRRM |  |  | 800 | V | Tj=25℃ | 1 |
| Non repetitive surge peak on-state current | ITSM |  |  | 40 | A | Full sine wave, Tj(init)=25℃, tp=20ms; Fig. 3,5 | 1 |
| I2t value | I2t |  |  | 8 | A2s | tp=10ms | 1 |
| Critical rate of rise of on-state current | dIT/dt |  |  | 50 | A/μs | IG=2*IGT, tr≤10ns, F=120HZ, Tj=125℃ | 1 |
| Peak gate current | IGM |  |  | 4 | A | tp=20µs, Tj=125℃ | 1 |
| Average gate power | PG(AV) |  |  | 1 | W | Tj=125℃ | 1 |
| Storage temperature | TSTG | -40 |  | 150 | ℃ |  | 1 |
| Operating junction temperature | Tj | -40 |  | 125 | ℃ |  | 1 |
| Gate trigger current Ⅰ-Ⅱ-Ⅲ (S: IGT1-3≤10mA) | IGT |  |  | 10 | mA | VD=12V, Tj=25℃, RL=30Ω | 2 |
| Gate trigger voltage Ⅰ-Ⅱ-Ⅲ | VGT |  |  | 1.3 | V | VD=12V, Tj=25℃, RL=30Ω | 2 |
| Non-triggering gate voltage | VGD | 0.2 |  |  | V | VD=VDRM, Tj=125℃ | 2 |
| Holding current (S column) | IH |  |  | 15 | mA |  | 2 |
| Latching current Ⅰ-Ⅲ (S column) | IL |  |  | 25 | mA | IT=100mA, IG=1.2IGT | 2 |
| Latching current Ⅱ (S column) | IL |  |  | 30 | mA | IT=100mA, IG=1.2IGT | 2 |
| Critical rate of rise of off-state voltage (S column) | dVD/dt | 40 |  |  | V/μs | VD=67%VDRM, Gate Open, Tj=125℃ | 2 |
| On-state voltage | VTM |  |  | 1.55 | V | ITM=8.5A, tp=380μs, Fig. 4 | 2 |
| Repetitive peak off-state current at Tj=25℃ | IDRM |  |  | 5 | μA | VD=VDRM/VRRM, Tj=25℃ | 2 |
| Repetitive peak off-state current at Tj=125℃ | IRRM |  |  | 5 | mA | VD=VDRM/VRRM, Tj=125℃ | 2 |
| Thermal resistance junction to case (AC) | Rth (j-c) |  |  | 2.6 | ℃/W | AC | 2 |
| Thermal resistance junction to ambient | Rth (j-a) |  |  | 60 | ℃/W |  | 2 |

## CAD (KiCad official)

- Symbol: `CT304B-800S`
- Footprint: `Package_TO_SOT_THT:TO-220-3_Vertical`
- 3D model: TO-220 (KiCad packages3D, STEP)
- 3D model files: `ct304b-800s-etched.step` / `ct304b-800s-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ct304b-800s.step` / `ct304b-800s.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Changjiang Electronics Tech (CJ) datasheet](docs/ct304b-800s-datasheet.pdf) (4 pp, sha256 `63ac3b7b85f088b4`, retrieved 2026-10-30, 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/ct304b-800s-datasheet.pdf)