S4020LTP LITTELFUSE SCR (Transistor Outline, Vertical) In Stock
Littelfuse S4020LTP is a 20 A, 400 V SCR (silicon controlled rectifier) in a 3-pin TO-220AB isolated package with a 30 mA maximum gate trigger current and 350 V/µs critical dV/dt rating. Features isolated tab for heatsink mounting without insulating hardware in many designs. RoHS compliant and available in stock worldwide for AC power control applications.
- Manufacturer
- LITTELFUSE
- Package
- Transistor Outline, Vertical
- Pin Count
- 3
- Lifecycle
- ACTIVE
- Datasheet
- S4020LTP Datasheet PDF
- Category
- SCR
- Price
- From $1.1232(MOQ 1)
- Temp Range
- -40.0°C to 125.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 20 A RMS on-state current capacity with 400 V blocking voltage in a TO-220AB package, covering a broad range of AC phase-control and switching applications
- 350 V/µs minimum critical rate-of-rise of off-state voltage (dV/dt) prevents spurious triggering from fast-rising line transients in industrial AC power circuits
- Isolated TO-220AB tab allows direct mounting to a common chassis heatsink without an insulating mica washer, reducing thermal resistance and simplifying assembly in motor drives and lamp dimmers
Applications
The S4020LTP is commonly used in AC motor speed controllers, light dimmers, heating element controllers, and soft-start circuits where phase-angle control of 50 Hz or 60 Hz mains voltage is required. Its 20 A current rating and 400 V blocking voltage make it suitable for single-phase AC loads up to approximately 4 kW when properly heatsinked, covering home appliance motor drives, industrial temperature regulators, and triac-less relay replacement circuits.
Specifications
| YTEOL | 6 |
| Case Connection | ISOLATED |
| Configuration | SINGLE |
| Critical Rate of Rise of Off-State Voltage-Min | 350V/us |
| DC Gate Trigger Current-Max | 30mA |
| DC Gate Trigger Voltage-Max | 1.5V |
| Holding Current-Max | 40mA |
| JEDEC-95 Code | TO-220AB |
| JESD-30 Code | R-PSFM-T3 |
| JESD-609 Code | e3 |
| Leakage Current-Max | 1mA |
| Non-Repetitive Pk On-state Cur | 300A |
| Number of Elements | 1 |
| On-state Current-Max | 12800A |
| Package Body Material | PLASTIC/EPOXY |
| Package Shape | RECTANGULAR |
| Package Style | FLANGE MOUNT |
| Peak Reflow Temperature (Cel) | 260 |
| Qualification Status | Not Qualified |
| RMS On-state Current-Max | 20A |
| Reference Standard | UL RECOGNIZED |
| Repetitive Peak Off-state Voltage | 400V |
| Repetitive Peak Reverse Voltage | 400V |
| Surface Mount | NO |
| Terminal Finish | Matte Tin (Sn) |
| Terminal Form | THROUGH-HOLE |
| Terminal Position | SINGLE |
| Time@Peak Reflow Temperature-Max (s) | 40 |
| Trigger Device Type | SCR |
| Package | Transistor Outline, Vertical |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| HTS Code | 8541.30.00.80 |
Alternate & Equivalent Parts
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
What are the key electrical ratings of the S4020LTP SCR?
The S4020LTP is rated for 20 A RMS on-state current and 400 V peak repetitive off-state voltage. Its gate trigger current maximum is 30 mA at a gate trigger voltage of 1.5 V, the holding current maximum is 40 mA, and the critical dV/dt rating is 350 V/µs minimum. These parameters make it compatible with standard SCR gate driver circuits and optocoupler trigger stages used in AC phase-control designs.
Can S4020LTP be mounted directly to a heatsink without electrical isolation hardware?
Yes, the S4020LTP features an isolated tab in the TO-220AB package, meaning the metal mounting tab is electrically isolated from the internal semiconductor die. This allows direct bolting to a metal chassis or heatsink without a mica insulator or thermal pad spacer, reducing the junction-to-heatsink thermal resistance by approximately 0.5°C/W to 1°C/W compared to isolated mounting, enabling higher continuous current operation at the same heatsink temperature.
In which AC power control topologies is S4020LTP most effectively applied?
The S4020LTP works best in single-phase half-wave or full-wave (back-to-back SCR) AC power control topologies, including light dimmers operating on 120 V or 230 V mains, resistive heating controllers, and universal motor speed regulators. For full-wave AC control of inductive loads, two S4020LTP SCRs in an anti-parallel configuration replace a single triac, providing better dV/dt immunity above 200 V/µs that some triacs cannot achieve.
How should the gate drive circuit be designed to reliably trigger the S4020LTP?
To reliably latch the S4020LTP, the gate drive pulse must supply at least 30 mA peak gate current at 1.5 V gate-cathode voltage for a minimum pulse width of 10 µs. A pulse transformer, optocoupler (such as MOC3021 with a 360 Ω gate resistor), or microcontroller GPIO through a transistor driver can provide this gate energy. The gate resistor should limit current to 20 mA to 30 mA to avoid exceeding the 40 mA average gate current rating while ensuring consistent triggering across the full operating temperature range of -40°C to 125°C.
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| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 1+ | $3.1104 | $3.11 |
| 34+ | $2.0736 | $70.50 |
| 35+ | $1.6070 | $56.24 |
| 100+ | $1.5794 | $157.94 |
| 117+ | $1.2096 | $141.52 |
| 249+ | $1.1232 | $279.68 |
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