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Semtech Corporation SC431LCSK-.5 TR
- Part No.:
- SC431LCSK-.5 TR
- Manufacturer:
- Semtech Corporation
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
SC431LCSK-.5 TR.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,429
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Product details
Overview
SC431LCSK-.5 TR from Semtech is a three-terminal adjustable shunt regulator with ±0.5% reference voltage tolerance, 1.24 V to 20 V programmable output, 0.05 Ω typical dynamic impedance, and operation over –40°C to +125°C. It replaces Zener diodes in precision voltage reference and feedback circuits for switching power supplies and battery-powered instrumentation.
For engineers reviewing the SC431LCSK-.5 TR datasheet, pinout, applications, or equivalent options, key selection criteria include cathode current range (100 µA–100 mA), thermal stability across industrial temperature, SOT-23-3 package compatibility, and low-output-impedance performance in closed-loop regulation.
Technical Context
The SC431LCSK-.5 TR implements a trimmed bandgap reference core with active output circuitry enabling sharp turn-on characteristics and stable regulation down to 1.24 V. Its internal architecture supports precise voltage setting via two external resistors while maintaining low dynamic impedance (0.05 Ω) below 1 kHz.
It operates as a 3-terminal shunt regulator where cathode current (IZ) flows through an external resistor network to set VOUT per VOUT = VREF × (1 + R1/R2). Stability requires avoiding 10 nF–1 µF load capacitance at light IZ (<3 mA); recommended configurations use either no capacitor across the device or ≥10 µF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.24 V ±0.5% (VREF), adjustable up to 20 V using external resistors - enables precise, user-defined regulation thresholds. |
| Cathode Current Range | 100 µA to 100 mA - supports wide load conditions from ultra-low-power monitoring to moderate-current feedback paths. |
| Dynamic Impedance | 0.05 Ω typical (f < 1 kHz) - ensures minimal output voltage deviation under transient load changes. |
| Temperature Range | –40°C to +125°C (industrial grade) - guarantees stable operation in harsh environments without derating. |
| Package | SOT-23-3 - surface-mount, space-constrained footprint compatible with standard reflow processes and automated assembly. |
| Output Tolerance | ±0.5% at TA = 25°C, maintained over full temperature range - eliminates need for post-production trimming in most applications. |
| Off-State Cathode Current | ≤0.5 µA at VREF = 0 V, VZ = 6 V - minimizes quiescent power loss in standby or shutdown modes. |
Pinout & Package
SOT-23-3 package: 3-pin, small-outline transistor outline with gull-wing leads; dimensions 2.90 mm × 1.30 mm × 1.02 mm (L × W × H); RoHS-compliant, lead-free construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (K) | Current sink node | Primary current path; connects to input supply rail and sets regulation point via external resistor divider. |
| Anode (A) | Ground reference terminal | Return path for cathode current; must be connected to system ground or common reference plane. |
| Reference (R) | Feedback input | High-impedance input sensing voltage at divider junction; determines regulated output via VREF = 1.24 V threshold. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | 1.24 V to 20 V via two external resistors - eliminates need for multiple fixed-voltage regulators in BOM. |
| Low dynamic output impedance | 0.05 Ω typical below 1 kHz - maintains tight regulation during fast load transients in SMPS feedback loops. |
| Thermal stability | Guaranteed performance from –40°C to +125°C - avoids calibration drift in automotive or industrial control systems. |
| Zener diode replacement | Sharp turn-on characteristic and lower impedance than discrete Zeners - improves accuracy and reduces thermal drift in reference circuits. |
| RoHS/WEEE compliance | Lead-free SOT-23-3 packaging - meets global environmental directives without requiring process changeovers. |
Applications
| Battery-Operated Instrumentation | Switching Power Supply Feedback |
|---|---|
Use Scenario: Precision voltage reference in handheld multimeters and portable data loggers powered by single-cell Li-ion or alkaline batteries. IC Role / Device Role / Timing Role: Shunt regulator providing stable 2.5 V reference for ADC bias and sensor excitation. Use Value: ±0.5% tolerance and 100 µA minimum operating current extend battery life while maintaining measurement accuracy across temperature. |
Use Scenario: Secondary-side voltage sensing in isolated flyback converters for telecom and industrial power modules. IC Role / Device Role / Timing Role: Adjustable shunt regulator forming error amplifier reference in optocoupler-coupled feedback loop. Use Value: 0.05 Ω dynamic impedance ensures fast response to output load steps, improving transient regulation and reducing output ripple. |
| Computer Disk Drive Power Control | Industrial Sensor Signal Conditioning |
Use Scenario: Overvoltage protection and head actuator bias regulation in 2.5-inch HDD spindle motor drivers. IC Role / Device Role / Timing Role: Programmable shunt clamp limiting VCC rail to 12 V during startup and fault conditions. Use Value: 100 mA max cathode current handles surge events; SOT-23-3 footprint fits tight PCB real estate near motor driver ICs. |
Use Scenario: Reference source for 4–20 mA transmitter circuits in factory automation pressure/temperature sensors. IC Role / Device Role / Timing Role: Stable 1.24 V bandgap reference feeding DAC and op-amp stages in analog signal chain. Use Value: Trimmed bandgap design achieves ±0.5% initial accuracy and <20 ppm/°C drift - critical for 12-bit+ measurement resolution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV431ACDBVR | ±0.5% VREF tolerance, same SOT-23-3 package, but rated only to +85°C ambient and 30 mA max cathode current. | Limited to commercial-temperature consumer electronics; insufficient for industrial motor drives or automotive under-hood use. | Select TLV431ACDBVR only when cost sensitivity outweighs extended temperature and current requirements. |
| AS431ASTU | ±0.5% VREF, SOT-23-3, 100 mA rating, but specified dynamic impedance is 0.2 Ω (vs. 0.05 Ω), and thermal drift is ±50 ppm/°C (vs. ±25 ppm/°C). | Acceptable for non-critical references but introduces higher output variation under load transients and temperature cycling. | Prefer SC431LCSK-.5 TR where low-impedance regulation and tight thermal stability are required for precision feedback. |
Compared with TLV431ACDBVR and AS431ASTU, the SC431LCSK-.5 TR delivers superior thermal robustness (–40°C to +125°C), lower dynamic impedance (0.05 Ω), and tighter long-term stability - making it the optimal choice for industrial-grade power management where reliability under stress is non-negotiable.
Availability
SC431LCSK-.5 TR is available at Aetrix Electronics and suitable for switching power supplies, battery-operated instrumentation, and industrial sensor conditioning requiring stable component supply with full industrial temperature support and RoHS compliance.
Supply support for SC431LCSK-.5 TR 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
Semtech Corporation is a U.S.-based fabless semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, RF, and sensing applications.
The SC431L family was designed specifically for precision shunt regulation in space-constrained, thermally demanding power systems - targeting upgrade paths from Zener diodes in industrial, computing, and storage applications.
FAQ
What is the maximum cathode voltage rating for SC431LCSK-.5 TR?
The SC431LCSK-.5 TR has an absolute maximum cathode voltage of 20 V. Exceeding this value risks permanent damage to the internal bandgap reference circuit. Operation is guaranteed within 1.24 V to 20 V output range when configured with appropriate external resistors, and the device must never be subjected to reverse polarity or voltage spikes beyond its ratings.
Can SC431LCSK-.5 TR replace a standard Zener diode directly on the PCB?
Yes, the SC431LCSK-.5 TR can directly replace Zener diodes in most shunt regulation roles, but requires two external resistors to set the output voltage - unlike a fixed Zener. Its SOT-23-3 footprint matches many Zener packages, and its sharp turn-on and 0.05 Ω dynamic impedance provide superior regulation accuracy and stability compared to discrete Zeners.
What is the minimum cathode current needed for SC431LCSK-.5 TR to regulate properly?
The SC431LCSK-.5 TR requires a minimum cathode current of 100 µA to maintain regulation. Below this level, the reference circuit may not activate reliably, causing output voltage collapse. Designers must ensure the resistor network and load conditions sustain ≥100 µA under all operating conditions, including lowest input voltage and highest output voltage settings.
How does the SC431LCSK-.5 TR handle capacitive loads, and what CL values should be avoided?
The SC431LCSK-.5 TR exhibits instability with 10 nF to 1 µF capacitance across its cathode-anode terminals at light cathode currents (<3 mA). To ensure stable operation, use either no capacitor directly across the device or ≥10 µF. Local decoupling at the load is preferred and avoids oscillation during startup transients.
Is SC431LCSK-.5 TR compatible with lead-free reflow soldering processes?
Yes, the SC431LCSK-.5 TR is fully RoHS and WEEE compliant with lead-free terminations. It supports standard Pb-free reflow profiles (J-STD-020, peak temperature ≤260°C), and its SOT-23-3 package is qualified for both SnPb and lead-free assembly without reliability degradation.
SC431LCSK-.5 TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 16 V
- Current - Output:
- 100 µA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 100 mA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
SC431LCSK-.5 TR FAQ
1.How can I place an order for SC431LCSK-.5 TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SC431LCSK-.5 TR 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 SC431LCSK-.5 TR reliable?
The price and inventory of SC431LCSK-.5 TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC431LCSK-.5 TR is usually 5 days.
3.What payment methods are accepted for SC431LCSK-.5 TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC431LCSK-.5 TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC431LCSK-.5 TR?
SC431LCSK-.5 TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC431LCSK-.5 TR 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 SC431LCSK-.5 TR?
For technical support, including SC431LCSK-.5 TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC431LCSK-.5 TR requirements.
6.How does Aetrix verify that SC431LCSK-.5 TR is sourced from the original manufacturer or authorized distributors?
All SC431LCSK-.5 TR 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 SC431LCSK-.5 TR meets industry standards.
7.What is the process for return or replacement of SC431LCSK-.5 TR?
All SC431LCSK-.5 TR units undergo pre-shipment inspection (PSI). If there is an issue with SC431LCSK-.5 TR, 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 SC431LCSK-.5 TR part is unused and in its original packaging.
Return procedure for SC431LCSK-.5 TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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