CS223-4M-TR-PBFREE - 600V 4A SOT-223 SCR | Central Semiconductor
MPN: CS223-4M-TR-PBFREE β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
CS223-4M-TR-PBFREE Overview
An SCR (silicon controlled rectifier), also called a thyristor, is a four-layer semiconductor device that acts as a latching switch: once triggered by a small gate current, it conducts from anode to cathode until the current falls below the holding level. Within the power-semiconductor hierarchy, the thyristor family sits alongside MOSFETs and IGBTs as a power switching device, and SCRs remain the preferred solution for AC line-controlled latching functions due to their ruggedness and low conduction loss.
Key features of the CS223-4M include a 600V off-state voltage rating, a maximum gate trigger voltage (Vgt) of 800 mV, and a very sensitive maximum gate trigger current (Igt) of 200 uA. This high gate sensitivity allows direct driving from low-power sensing circuits, microcontroller ports, or optocoupler outputs without an external gate driver stage, reducing bill-of-material cost and board area.
The epoxy-molded SOT-223 construction provides good thermal performance for a compact surface-mount footprint; the tab (pin 4) is electrically part of the anode path and solders to the PCB copper area for heat spreading. The device is a standard-recovery SCR, suited to 50/60 Hz line-frequency phase control and crowbar circuits rather than high-frequency switching.
Typical applications include overvoltage crowbar protection in power supplies, AC line latching control, sensing and alarm trip circuits, and industrial control systems where a small signal must latch a larger load current.
Design consideration: because the gate is highly sensitive (200 uA max Igt), keep the gate trace short and add a gate-to-cathode resistor (typically 1k ohm) to prevent false triggering from leakage or noise pickup.
This page synthesizes distributor availability data, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for CS223-4M-TR-PBFREE β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
CS223-4N
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
CS220-35M
β Drop-Inπ Reference alternative (not in catalog)
2N2324 PBFREE
β Drop-Inπ Reference alternative (not in catalog)
CS223-4M-TR-PBFREE Specifications
| Device Type | Silicon Controlled Rectifier (SCR) |
| Off-State Voltage (VDRM/VRRM) | 600 V |
| On-State RMS Current (IT(RMS)) | 4 A |
| Surge Current (ITSM) | 30 A |
| Recovery Type | Standard Recovery |
| Gate Trigger Voltage (Vgt, Max) | 800 mV |
| Gate Trigger Current (Igt, Max) | 200 uA |
| Mounting Type | Surface Mount |
| Package | SOT-223, 4-Pin (3+Tab) |
| Construction | Epoxy Molded |
| Packaging | Tape & Reel (TR) |
| Pb-Free | Yes (PBFREE) |
| RoHS Status | Compliant |
CS223-4M-TR-PBFREE Pin Configuration
| Pin 1 | G β Gate - trigger input (sensitive gate, Igt max 200 uA) |
| Pin 2 | A β Anode |
| Pin 3 | K β Cathode |
| Pin 4 | A (Tab) β Anode connection via package tab (internally common with pin 2), used for heat spreading |
Safe Operating Area
Typical Applications
CS223-4M-TR-PBFREE is suitable for 6 applications: Overvoltage Crowbar Protection, AC Line Latching Control, Sensor Trip and Alarm Latch Circuits, Industrial Control Systems, Power Supply Protection Modules, Test and Measurement Instrument Protection.
Overvoltage Crowbar Protection
The CS223-4M-TR-PBFREE is a classic crowbar SCR: placed directly across a supply rail, it is fired by a supervisory or zener-derived trigger circuit when the rail exceeds a safe threshold, deliberately shorting the output so a fuse or breaker isolates the fault. Its 600V off-state rating gives wide margin on low-voltage rails, and the 30A surge (ITSM) rating absorbs fault current long enough for the protection device to open. The 200 uA sensitive gate means a simple resistor-zener network or a small comparator can drive it without a gate-driver stage. Because the device latches, the crowbar stays engaged until power is removed, guaranteeing the fault is not masked by retry behavior.
Recommended
AC Line Latching Control
For 50/60 Hz AC line control, the CS223-4M's standard-recovery thyristor structure and 600V blocking rating suit half-wave latching control of resistive loads such as heaters, solenoids, and indicator lamps. A small DC signal on the 200 uA sensitive gate triggers conduction at a chosen phase angle, and the SCR naturally turns off at the next current zero crossing, enabling simple phase-control or latch-on circuits with minimal parts. Compared with a relay solution, the epoxy-molded SOT-223 SCR provides millions of operations with no contact wear, silent switching, and a compact surface-mount footprint. Designers should budget conduction loss from the on-state voltage at the 4A RMS load current.
Recommended
Sensor Trip and Alarm Latch Circuits
The defining feature of the CS223-4M series is its design intent for sensing circuit applications: with a maximum gate trigger current of only 200 uA and 800 mV maximum Vgt, the SCR can be fired directly by thermistors, photodiodes, pressure-switch contacts, or comparator outputs without buffering. Once triggered it latches, providing a non-volatile 'event occurred' flag that remains asserted even after the sensor condition clears - exactly the behavior required for alarm memory, interlock trip, and fault annunciator circuits. The surface-mount SOT-223 package lets designers place the latch directly on small sensor PCBs. A gate-cathode resistor is recommended to suppress leakage-induced false trips.
Recommended
Industrial Control Systems
In factory automation and industrial control panels, the CS223-4M-TR-PBFREE serves as a rugged latching switch for interlocks, motor-start latch memory, and pilot-load control on rectified 120V or 230V buses, where the 600V blocking rating provides ample headroom. The epoxy-molded SOT-223 construction withstands industrial environments, and the 4A RMS / 30A surge ratings handle contactor coil inrush and pilot-lamp cold-filament surges. Because it is surface mount, it integrates into compact PLC I/O and relay-replacement modules that previously required leaded TO-92 or TO-220 thyristors. Standard recovery behavior is acceptable at line frequency, keeping cost below fast-recovery alternatives.
Recommended
Power Supply Protection Modules
Within AC-DC power supply and battery-charger designs, the CS223-4M implements reverse-battery protection latches, fuse-coordination crowbars, and fault-memory functions. Its 30A surge rating coordinates with common fuses so the SCR survives long enough for the fuse to clear during a crowbar event, and the sensitive 200 uA gate allows the protection circuit to be powered from the very rail it protects, using only microamps of standby budget. The SOT-223 tab (anode) solders to a copper pour, providing the thermal spreading needed for repeated surge events. Being Pb-free and RoHS compliant, it fits commercial and industrial supplies shipping into regulated markets.
Recommended
Test and Measurement Instrument Protection
Bench supplies, signal sources, and measurement front ends use crowbar SCRs like the CS223-4M to clamp fault energy before it reaches sensitive circuitry or the device under test. The 600V rating covers most instrument internal rails, and the 200 uA gate sensitivity lets a fast comparator or overvoltage sense IC fire the SCR within microseconds of a fault, minimizing let-through energy. The latching behavior guarantees the fault state is visibly held for the operator rather than self-clearing. The compact SOT-223 footprint fits densely packed instrument PCBs, and the standard-recovery characteristic is irrelevant at these DC latching duties, maximizing ruggedness per dollar.
Recommended
Recommended Products Summary
Engineering reference data for CS223-4M-TR-PBFREE β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | CS223-4N | CS220-35M | 2N2324 PBFREE |
|---|---|---|---|---|
| Package | SOT-223 (4-Pin, 3+Tab) | SOT-223 (4-Pin, 3+Tab) - same | SOT-223 (4-Pin, 3+Tab) - same | TO-18 - different footprint |
| Brand | Central Semiconductor | Central Semiconductor | Central Semiconductor | Central Semiconductor |
Key Differentiators
- Extremely sensitive gate for direct sensor drive (vs CS220-35M)
- Lead-free RoHS-compliant tape-and-reel build (vs 2N2324 PBFREE)
- Trade-off: standard recovery limits speed (vs CS223-4N)
Design Notes
In the SOT-223 (3+tab) footprint, pin 4 is the tab and is common with the anode; connect it to a copper pour of at least 20x20 mm to spread heat during surge events. Estimated: at a 4A RMS load with a typical SOT-223 SCR on-state voltage near 1.5 V, conduction loss is roughly 6 W worst case in continuous duty - for continuous loads, verify theta_JA against the datasheet thermal chart and derate, or pulse the load. Confirm tab connectivity against the official datasheet package drawing before routing.
The 200 uA maximum gate trigger current that makes this SCR ideal for sensing circuits also makes it prone to false triggering. Always fit a gate-to-cathode shunt resistor (1k ohm typical) to bleed leakage from the driving network, route the gate trace short and away from switching nodes, and if the anode sees fast dv/dt steps (crowbar duty near rectified lines), add an RC snubber across anode-cathode to slow the rate of rise below the critical dv/dt limit.
Do not confuse the -4M (600V) and -4N (higher voltage grade) suffixes when ordering; both share one datasheet. The standard-recovery characteristic means this part is intended for line-frequency (50/60 Hz) latching and phase control - do not use it for high-frequency PWM. In crowbar designs, coordinate the fuse I^2t with the 30A ITSM rating so the fuse clears before the SCR exceeds its single-cycle surge limit.
Compliance Information
PBFREE suffix denotes lead-free construction; RoHS compliant per DigiKey/Mouser distributor listings. REACH, halogen-free, and conflict-minerals status not stated in provided data.
