MCR100-8 - Diodes Incorporated
THYRISTOR SOT23 T&R 3K
Full Technical Specifications
13 Parameters| Parameter / Attribute | Specification / Value |
|---|---|
| SCR type | Sensitive Gate |
| Mounting | Surface Mount |
| Voltage - off state | 600 V |
| Voltage - on state (Vtm) | 1.5 V |
| Voltage - gate trigger (Vgt) | 800 mV |
| Current - hold (Ih) | 5 mA |
| Current - off state | 10 µA |
| Current - gate trigger (Igt) | 50 µA |
| Current - on state (It (RMS)) | 250 mA |
| Current - non rep. surge 50, 60Hz | 9A @ 60Hz |
| Operating temperature | -40°C ~ 110°C (TJ) |
| Package | Tape & Reel (TR) Cut Tape (CT) |
| Case | TO-236-3, SC-59, SOT-23-3 |
Need Stock or a Drop-in Second-Source for MCR100-8?
Package: TO-92 · Pin-compatible replacements with immediate Shenzhen spot stock
The MCR100-8 is the small sensitive-gate SCR that made lamp dimmers, timers and simple phase controls cheap: 0.8A, 600V, a TO-92 body the size of a transistor, and a gate that triggers on a couple of hundred microamps straight from an RC network. The original onsemi line is end-of-life and the market is served by second sources - the classic cross being the BT169 family and the ST X00602MA. Two facts govern every substitution: the gate sensitivity class (a heavier-gate SCR simply will not trigger in these circuits) and the lead arrangement, on which vendor documentation is famously inconsistent.
Verified Pin-Compatible Replacements (4 verified alternatives)
The Standard Cross
Shenzhen Spot Stock (24-48h Dispatch)
0.8A / 600V sensitive-gate SCR in TO-92: the most-cited drop-in for the MCR100-8, with a comparable microamp-class gate trigger.
VDRM/VRRM 600V; IT(RMS) 0.8A; ITSM 8A class; low hold current suited to dimmer and timer circuits.
The 400V Grade of the Same Part
Shenzhen Spot Stock (24-48h Dispatch)
Identical SCR at the 400V rating: same 0.8A current, same gate sensitivity - interchangeable anywhere the mains-derived peak stays well under 400V.
VDRM/VRRM 400V versus 600V on the -8 grade.
Branded Second Source
Shenzhen Spot Stock (24-48h Dispatch)
ST 0.8A / 600V sensitive-gate SCR: IGT about 200uA, hold current about 5mA - functionally the same part of the world as the MCR100-8, documented by a major vendor.
600V class; 0.8A RMS; TO-92.
Higher Current, Different Body - Read First
Shenzhen Spot Stock (24-48h Dispatch)
The 4A-class sensitive-gate SCR in a larger body: historically the dimmer workhorse one size up from the MCR100-8.
600V class in the M grade (C106D is 400V); several amps of RMS current.
Buyer & Quality Checklist for Sourcing Alternatives
- Gate sensitivity is the binding specification: the MCR100-8 triggers under 200uA. Substitutes with heavier gates will not fire in touch switches, RC dimmers and timer circuits - compare IGT on both datasheets before ordering volume.
- Lead arrangement: third-party pinout tables for the MCR100 / BT169 families contradict each other (gate position especially). Trust the manufacturer drawing of the exact part you bought, and verify one unit with a multimeter (gate-cathode reads as a diode junction) before assembling a batch.
- The voltage grade is the trailing digit: MCR100-6 is 400V, MCR100-8 is 600V. On mains-derived circuits with inductive loads, keep the 600V class.
- Hold current about 5mA: in very low-current loads (indicator lamps) the SCR may not latch reliably - check the load current against Ih before blaming the trigger.
- The original onsemi line is EOL: current supply is second-source. Buy documented fabs with photographed lots, since the sensitive-gate class is exactly what degrades silently in unverified stock.
- Surge rating about 8A one-cycle: inrush of incandescent lamps sits close to this - for repeated lamp loads, prefer the next size up (C106 class) and accept the package change.
Frequently Asked Technical Questions
Q: Can I replace an MCR100-8 with a BT169?
A: Functionally yes, in the 600V grade (BT169G): same 0.8A / TO-92 sensitive-gate class. Check the gate trigger current on the vendor datasheet and verify the lead arrangement with a multimeter first - third-party pinout tables for this family contradict each other.
Q: Why does my dimmer not trigger after replacing the SCR?
A: Two usual causes: a substitute with a heavier gate (the microamp trigger network cannot fire it), or the leads fitted in the wrong order (the pinout tables disagree and the body offers no clue). Compare IGT figures and verify the gate-cathode junction before blaming the rest of the circuit.
Q: What is the difference between MCR100-6 and MCR100-8?
A: Voltage grade only: 400V versus 600V, same 0.8A current and gate behavior. On mains circuits with inductive loads or noisy networks, stay with the 600V part.