Part A
MCR12DSMT4G
Công ty Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 28814 PCS
- Package
- TO-252-3
- Series
- Thyristors - SCRs
Replacement verdict
Compatible functional replacement candidate
The MCR12DSMT4G and MCR12LD are both 12 A SCRs in DPAK packages with comparable voltage and gate characteristics, making the MCR12DSMT4G a viable functional replacement candidate for the MCR12LD in most applications. Designers should verify gate trigger current, holding current, and thermal performance against the specific circuit requirements before committing to the substitution.
Current Rating
High match
Package Type
High match
Gate Trigger Characteristics
Validation required
Holding Current
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | MCR12DSMT4G | MCR12LD | Why it matters |
|---|---|---|---|
| Manufacturer | Littelfuse (formerly ON Semiconductor) | Littelfuse (formerly ON Semiconductor) | Confirms both parts originate from the same source family, aiding cross-reference and second-sourcing decisions. |
| Package / Mounting | DPAK (TO-252) surface mount | TO-220AB through-hole | Determines board layout, assembly method, and thermal path; the two packages are not drop-in compatible. |
| Thyristor Type | SCR (silicon controlled rectifier) | SCR (silicon controlled rectifier) | Both are SCRs, so the basic switching function and gate-triggered conduction behavior are equivalent. |
| On-State RMS Current (IT(RMS)) | 12 A | 12 A | Sets the continuous load current the device can handle; matching ratings supports similar power capability. |
| Peak Repetitive Off-State Voltage (VDRM/VRRM) | 400 V | 400 V | Defines the maximum blocking voltage; equal ratings mean comparable voltage withstand in the application. |
| Gate Trigger Current (IGT) | Typically 20 mA max | Typically 20 mA max | Determines the drive current needed from the control circuit to latch the SCR on. |
| Holding Current (IH) | Typically 30 mA max | Typically 30 mA max | Affects the minimum load current required to keep the SCR conducting after trigger removal. |
| Peak Surge Current (ITSM) | 100 A (one cycle) | 100 A (one cycle) | Indicates inrush or fault current tolerance; equal surge ratings support similar robustness. |
| Thermal Resistance (RθJC) | Typically 2.0 °C/W | Typically 1.5 °C/W | Governs heat dissipation from junction to case; the TO-220 typically offers better thermal performance than DPAK. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | MCR12DSMT4G | MCR12LD |
|---|---|---|
| Supplier | Littelfuse Inc. | onsemi,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Voltage - Off State | 600 V | 400 V |
| Voltage - Gate Trigger(Vgt)(Max) | 1 V | 800 mV |
| Current - Gate Trigger(Igt)(Max) | 200 µA | 8 mA |
| Voltage - On State(Vtm)(Max) | 1.9 V | 2.2 V |
| Current - On State(It(AV))(Max) | 7.6 A | 7.6 A |
| Current - On State(It(RMS))(Max) | 12 A | 12 A |
| Current - Hold(Ih)(Max) | 6 mA | 20 mA |
| Current - Off State(Max) | 10 µA | 10 µA |
| Current - Non Rep Surge5060 Hz(Itsm) | 100A @ 60Hz | 100A @ 60Hz |
| SCR Type | Sensitive Gate | Standard Recovery |
| Operating Temperature | -40°C ~ 110°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Through Hole |
Frequently asked questions
What are the main differences between the MCR12DSMT4G and the MCR12LD?
The MCR12DSMT4G is a surface-mount SCR in a DPAK (TO-252) package from Littelfuse (formerly ON Semiconductor), while the MCR12LD is a through-hole SCR in a TO-220 package. Both are 12 A RMS silicon-controlled rectifiers with similar voltage and current ratings, but they differ in package, mounting style, and thermal characteristics.
Are the MCR12DSMT4G and MCR12LD electrically interchangeable?
They share similar SCR ratings, including 12 A RMS forward current and 400 V repetitive peak off-state voltage, but the MCR12DSMT4G is a sensitive-gate SCR with lower gate trigger current, while the MCR12LD has different gate trigger specifications. Circuit designers must verify gate drive, holding current, and latching current requirements before substituting one for the other.
What is the package type of the MCR12DSMT4G?
The MCR12DSMT4G is supplied in a DPAK (TO-252) surface-mount package, which is suitable for reflow soldering and compact PCB layouts. The "T4G" suffix indicates tape-and-reel packaging with Pb-free (RoHS-compliant) construction.
What is the package type of the MCR12LD?
The MCR12LD is supplied in a TO-220 through-hole package, which allows for heatsink mounting and is commonly used in applications requiring higher power dissipation through an external heatsink.
What is the repetitive peak off-state voltage (VDRM) rating for both devices?
Both the MCR12DSMT4G and MCR12LD are rated for 400 V repetitive peak off-state voltage (VDRM) and 400 V repetitive peak reverse voltage (VRRM), making them suitable for AC line applications up to approximately 120 V RMS or 240 V RMS with appropriate derating.
What is the average on-state current rating for these SCRs?
Both devices have an RMS on-state current rating of 12 A and an average on-state current rating of approximately 7.6 A at a case temperature of 80 °C, depending on the specific thermal conditions and conduction angle.
Can the MCR12DSMT4G directly replace the MCR12LD on an existing PCB?
No. The MCR12DSMT4G is a surface-mount DPAK device, while the MCR12LD is a through-hole TO-220 device. They have different footprints, lead configurations, and thermal management requirements, so a direct drop-in replacement on the same PCB is not possible without a board redesign.
Which applications are typical for the MCR12DSMT4G and MCR12LD?
Both SCRs are commonly used in phase control, overvoltage protection, crowbar circuits, motor control, and power switching applications. The MCR12DSMT4G is preferred for compact surface-mount designs, while the MCR12LD is used where through-hole mounting and heatsinking are required.