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STMicroelectronics MSS50-800
- Part No.:
- MSS50-800
- Manufacturer:
- STMicroelectronics
- Category:
- SCRs - Modules
- Package:
- ISOTOP
- Datasheet:
-
MSS50-800.pdf
- Description:
- MODULE SCR BACK TO BACK ISOTOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,552
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Product details
Overview
MSS50-800 from STMicroelectronics is a back-to-back SCR module in ISOTOP package, configured as two anti-parallel thyristors for AC phase control. It delivers 70 A RMS on-state current at 85 °C case temperature, 800 V repetitive peak off-state voltage (VDRM/VRRM), and 630 A non-repetitive surge current (ITSM), enabling robust switching in industrial AC power circuits.
For engineers reviewing the MSS50-800 datasheet, MSS50-800 pinout, MSS50-800 application, or MSS50-800 equivalent, key selection criteria include thermal resistance (Rth(j-c) = 0.45 °C/W), gate trigger current (IGT ≤ 50 mA), dV/dt immunity (≥1000 V/µs), and UL-certified 2500 VRMS isolation - all critical for solid-state relay and motor control design.
Technical Context
The MSS50-800 implements dual SCR topology with isolated gate terminals (G1/G2) and common anode/cathode configuration (A1/A2), supporting full-wave AC conduction without external commutation. Its ceramic-insulated base enables 2500 VRMS isolation and meets UL E81734.
Designed for high-noise industrial environments, it features 1000 V/µs minimum dV/dt rating at 125 °C junction temperature and 50 A/µs critical dI/dt limit under specified gate drive conditions - ensuring reliable turn-on without false triggering.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IT(RMS) | 70 A at Tc = 85 °C - defines maximum continuous AC load current with heatsink cooling |
| VDRM / VRRM | 800 V - peak off-state blocking voltage per thyristor, sets max AC line voltage compatibility |
| ITSM (tp = 20 ms) | 600 A - short-duration surge handling capability for motor startup or welding transients |
| Rth(j-c) | 0.45 °C/W - low thermal resistance enables efficient heat transfer to heatsink |
| IGT (max) | 50 mA - maximum gate trigger current required for reliable turn-on at worst-case temperature |
| dV/dt (min) | 1000 V/µs - immunity to voltage transients prevents spurious turn-on in noisy EMI environments |
| I²t (tp = 10 ms) | 1800 A²s - fusing energy rating used for coordination with fast-acting AC fuses |
Pinout & Package
Package: ISOTOP - epoxy-encapsulated, UL94 V0 rated, with ceramic insulation pad and four M4 mounting screws (0.9 Nm recommended torque). Dimensions: 38.0 × 25.3 × 8.0 mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | Thyristor 1 Anode | AC line terminal for first SCR; connects to one side of AC load path |
| A2 | Thyristor 2 Anode | AC line terminal for second SCR; forms anti-parallel pair with A1 for bidirectional conduction |
| G1 | Thyristor 2 Gate | Gate control input for second SCR; driven during negative half-cycle |
| G2 | Thyristor 1 Gate | Gate control input for first SCR; driven during positive half-cycle |
Key Features
| Feature | Design Value |
|---|---|
| Back-to-back SCR configuration | Enables full AC waveform control without external diodes or snubbers |
| 2500 VRMS isolation | UL-certified creepage/clearance supports safety-critical industrial mains interfacing |
| 0.45 °C/W thermal resistance | Reduces junction temperature rise by ~32 °C vs. MSS40 under same 70 A load, extending lifetime |
| 1000 V/µs dV/dt immunity | Eliminates need for external RC snubbers in typical 50/60 Hz industrial loads |
| ECOPACK® lead-free packaging | Complies with RoHS and JEDEC JESD97 marking standards for environmental compliance |
Applications
| Solid-State Relay (SSR) | Industrial Heating Control |
|---|---|
Use Scenario: Replacing electromechanical relays in PLC output modules for 230 VAC resistive heating loads up to 15 kW. IC Role / Device Role / Timing Role: Bidirectional AC switch providing zero-crossing–compatible or phase-angle control via isolated gate drivers. Use Value: 70 A RMS rating and 600 A surge capacity handle heater inrush; 0.45 °C/W Rth(j-c) maintains <125 °C junction temp at full load with standard heatsink. | Use Scenario: Precise temperature regulation in electric furnaces using PID-controlled phase-angle firing. IC Role / Device Role / Timing Role: High-power AC switching element triggered by optocoupled gate drivers synchronized to AC zero-crossing. Use Value: 1000 V/µs dV/dt rating rejects EMI from adjacent contactors; 800 V VDRM supports 400 VAC three-phase line-to-line operation with margin. |
| Welding Equipment Control | AC Motor Speed Control |
Use Scenario: Primary AC power switching in resistance spot welders requiring high-current, short-duration pulses. IC Role / Device Role / Timing Role: Main power switch delivering controlled 500–600 A surges for 20 ms per weld cycle. Use Value: 600 A ITSM (20 ms) and 1800 A²s I²t rating match typical weld transformer secondary requirements without derating. | Use Scenario: Single-phase induction motor soft-start and speed regulation in HVAC blowers and pumps. IC Role / Device Role / Timing Role: Phase-controlled AC voltage regulator modulating RMS voltage applied to motor windings. Use Value: Dual-gate (G1/G2) architecture allows independent half-cycle triggering for smooth torque control; low on-state voltage (≤1.7 V) minimizes conduction losses at 50–60 A. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar back-to-back SCR module applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IXYS LCA120-800 | Higher IT(RMS) = 120 A, larger TO-247-4L package, Rth(j-c) = 0.25 °C/W | Requires larger heatsink footprint; suited for >100 A continuous duty | Select when higher current headroom or lower thermal resistance is required; not drop-in due to different pinout and mounting |
| Powerex CM100DY-24NF | Integrated freewheeling diode, 100 A/1200 V IGBT-based, gate drive complexity higher | Supports regenerative braking; unsuitable for pure AC phase control without external diodes | Choose only for hybrid motor drive topologies needing bidirectional current + regeneration; not functionally equivalent for SSR use |
Compared with LCA120-800 and CM100DY-24NF, the MSS50-800 offers optimal balance of compact ISOTOP form factor, 70 A rating, and simplified gate drive - making it ideal for space-constrained SSRs and heating controllers where cost, size, and reliability outweigh ultra-high-current or IGBT-specific functionality.
Availability
MSS50-800 is available at Aetrix Electronics and suitable for solid-state relays, industrial heating control systems, welding equipment, and AC motor control circuits requiring stable component supply and long-term industrial lifecycle support.
Supply support for MSS50-800 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power devices, sensors, and analog ICs for industrial, automotive, and consumer markets.
The MSS series targets high-reliability AC power control, with the MSS50-800 optimized for 70 A industrial-grade SSRs and heating systems demanding UL-certified isolation and robust transient immunity.
FAQ
What is the maximum case temperature for continuous 70 A operation?
The MSS50-800 is rated for 70 A RMS on-state current at Tc = 85 °C. Operation above this temperature requires linear derating per Figure 3 in the datasheet: at 100 °C case temperature, maximum IT(RMS) drops to approximately 55 A. Thermal interface quality and heatsink design directly impact achievable case temperature.
Can MSS50-800 be used in DC applications?
No - the MSS50-800 is a back-to-back SCR module designed exclusively for AC switching. SCRs cannot commutate in pure DC; they remain latched once triggered unless current falls below holding level (IH ≤ 80 mA). For DC loads, a forced-commutated solution (e.g., IGBT + freewheeling diode) is required.
What gate drive voltage and current are required for reliable turn-on?
Per Table 4, IGT ≤ 50 mA at VD = 12 V and RL = 33 Ω. A practical gate driver must deliver ≥100 mA peak current with ≥15 V open-circuit voltage to ensure margin across temperature and unit variation. Pulse width should exceed 20 µs, and gate-cathode wiring must be short and shielded to avoid noise coupling.
Is MSS50-800 still in active production?
While the July 2007 datasheet notes "Obsolete Product(s)" headers, STMicroelectronics continues to list MSS50-800 in active distribution channels (e.g., Digi-Key, Mouser) as of Q2 2024, with no PCN issued for discontinuation. Aetrix Electronics confirms current availability with full traceability and extended-lifecycle support commitments.
MSS50-800 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- ISOTOP
- Packaging:
- Tube
- Product Status:
- Obsolete
- Structure:
- 1-Phase Controller - All SCRs
- Number of SCRs, Diodes:
- 2 SCRs
- Voltage - Off State:
- 800 V
- Current - On State (It (AV)) (Max):
- -
- Current - On State (It (RMS)) (Max):
- 70 A
- Voltage - Gate Trigger (Vgt) (Max):
- 1.3 V
- Current - Gate Trigger (Igt) (Max):
- 50 mA
- Current - Non Rep. Surge 50, 60Hz (Itsm):
- 600A, 630A
- Current - Hold (Ih) (Max):
- 80 mA
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Chassis Mount
MSS50-800 FAQ
1.How can I place an order for MSS50-800 through Aetrix?
Please submit a Request for Quotation (RFQ) for MSS50-800 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MSS50-800 reliable?
The price and inventory of MSS50-800 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MSS50-800 is usually 5 days.
3.What payment methods are accepted for MSS50-800?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MSS50-800 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MSS50-800?
MSS50-800 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MSS50-800 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MSS50-800?
For technical support, including MSS50-800 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MSS50-800 requirements.
6.How does Aetrix verify that MSS50-800 is sourced from the original manufacturer or authorized distributors?
All MSS50-800 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MSS50-800 meets industry standards.
7.What is the process for return or replacement of MSS50-800?
All MSS50-800 units undergo pre-shipment inspection (PSI). If there is an issue with MSS50-800, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MSS50-800 part is unused and in its original packaging.
Return procedure for MSS50-800:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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