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Semtech Corporation SC431LC5SK-2TR
- Part No.:
- SC431LC5SK-2TR
- Manufacturer:
- Semtech Corporation
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
SC431LC5SK-2TR.pdf
- Description:
- IC VREF SHUNT ADJ 2% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,630
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Product details
Overview
SC431LC5SK-2TR from Semtech is a three-terminal adjustable shunt regulator with thermal stability guaranteed over temperature, delivering 1.24 V reference voltage (VREF), ±0.25% initial tolerance, and 0.05 Ω typical dynamic output impedance. It operates across 100 µA–100 mA cathode current and supports output voltage adjustment from 1.24 V to 20 V using two external resistors - widely used in precision feedback loops of switching power supplies and low-voltage instrumentation.
For engineers reviewing the SC431LC5SK-2TR datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, SOT-23-5 terminal mapping, thermal performance data, stability guidance for load capacitance selection, and validated alternative parts for cost-performance trade-offs in voltage reference design.
Technical Context
The SC431LC5SK-2TR implements a trimmed bandgap reference core with active output circuitry enabling sharp turn-on characteristics and low dynamic impedance. Its architecture replaces discrete Zener diodes in closed-loop regulation, supporting stable operation from –40°C to +150°C junction temperature.
It features a 100 µA minimum operating cathode current, 150 mA instantaneous turn-on limit, and exhibits instability only within 10 nF–1 µF load capacitance at light loads (<3 mA), requiring either no local CL or ≥10 µF for robust transient response - a key design constraint confirmed in Semtech's stability boundary analysis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VREF | 1.24 V nominal reference voltage; sets minimum programmable output and defines accuracy baseline for resistor-divider-based voltage setting. |
| Initial Tolerance | ±0.25% at 25°C; ensures high-precision feedback without post-manufacturing trimming in critical applications like battery monitors. |
| rZ (Dynamic Impedance) | 0.05 Ω typical; maintains tight output regulation under fast load transients, outperforming standard Zener diodes by >10×. |
| IZ(MIN) | 100 µA minimum cathode current; defines lowest usable bias point before regulation degrades - critical for ultra-low-power systems. |
| TJ Range | –40°C to +150°C; enables deployment in industrial motor drives and automotive under-hood circuits without derating. |
| PD (SOT-23-5) | 0.49 W maximum power dissipation; allows up to ~40 mA continuous cathode current at 12 V output with 25°C ambient. |
| θJA | 252°C/W (SOT-23-5); quantifies thermal resistance from junction to ambient - essential for PCB copper area planning. |
Pinout & Package
SOT-23-5 package: 2.80 mm × 2.90 mm × 1.15 mm body, lead-free, RoHS-compliant, with gull-wing leads and exposed thermal pad (not electrically connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Pin 1) | Regulated output node | Connects to switched-mode converter output or feedback divider; sinks cathode current IZ to maintain VOUT = VREF(1 + R1/R2). |
| Anode (Pin 2) | Ground reference | Return path for reference current IREF; must be low-impedance to avoid ground bounce-induced regulation error. |
| Reference (Pin 3) | Bandgap voltage sense input | High-impedance node tied to resistor divider midpoint; draws only 0.5 µA typical - minimizes divider current loss. |
| No Connect (Pin 4) | Unused terminal | Internally unconnected; must remain floating or grounded per layout guidelines - not for thermal relief or signal routing. |
| No Connect (Pin 5) | Unused terminal | Internally unconnected; same handling as Pin 4 - no external connection required or recommended. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output range | 1.24 V to 20 V via external R1/R2 - enables single BOM part across multiple supply rails without redesign. |
| Thermal stability | Guaranteed over –40°C to +150°C; eliminates need for external temperature compensation in harsh environments. |
| Low dynamic impedance | 0.05 Ω typical below 1 kHz - suppresses ripple and noise in feedback paths better than TLV431A (0.2 Ω). |
| Sharp turn-on characteristic | Active output stage provides <100 ns rise time - prevents overshoot during power-up in buck converter feedback loops. |
| RoHS/WEEE compliance | Lead-free SOT-23-5 packaging with full traceability - meets global environmental directives without performance compromise. |
Applications
| Switching Power Supply Feedback | Battery Voltage Monitor |
|---|---|
Use Scenario: Used in secondary-side feedback loop of isolated DC/DC converters to regulate output voltage against line/load variation. IC Role / Device Role / Timing Role: Adjustable shunt regulator providing precise VREF-based error signal to optocoupler input. Use Value: Enables ±0.5% output regulation over temperature and lifetime, replacing less stable Zener diodes and reducing component count. |
Use Scenario: Monitors Li-ion cell voltage in portable medical devices where low quiescent current extends battery life. IC Role / Device Role / Timing Role: Precision voltage reference generating threshold for comparator-based low-battery detection. Use Value: 100 µA minimum IZ and ±0.25% tolerance ensure accurate 3.0 V cutoff detection across –20°C to +60°C operating range. |
| Industrial Sensor Signal Conditioning | Computer Disk Drive Power Sequencing |
Use Scenario: Provides stable 2.5 V reference for bridge sensor amplifiers in factory automation pressure transducers. IC Role / Device Role / Timing Role: Low-drift shunt reference supplying excitation voltage and ADC reference simultaneously. Use Value: 0.05 Ω rZ and –40°C to +150°C operation prevent gain drift caused by supply impedance or ambient temperature swings. |
Use Scenario: Generates controlled 5 V standby rail enable signal in HDD controller boards during power-up sequencing. IC Role / Device Role / Timing Role: Programmable shunt regulator defining voltage threshold for power-good assertion logic. Use Value: Sharp turn-on and 1.24 V base reference allow reliable 4.75 V trip point with minimal hysteresis and no external components. |
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% initial tolerance, 0.2 Ω rZ, 60 µA IREF, SOT-23-5 package | Higher reference current and lower accuracy reduce stability margin in low-power feedback loops | Lower-cost option where ±1% system output tolerance is acceptable and board space permits larger divider resistors. |
| AS431ASTUZTR-G1 | ±0.5% tolerance, 0.15 Ω rZ, 100 µA IZ(MIN), SOT-23-3 package | SOT-23-3 lacks NC pins; requires different PCB footprint and offers no thermal pad for high-power dissipation | Drop-in replacement only if thermal budget ≤0.25 W and existing layout uses 3-pin variant - verify stability with CL ≥10 µF. |
Compared with TLV431ACDBVR and AS431ASTUZTR-G1, the SC431LC5SK-2TR delivers superior accuracy (±0.25% vs. ±0.5%), lower dynamic impedance (0.05 Ω vs. ≥0.15 Ω), and higher thermal capability (0.49 W vs. ≤0.35 W), making it optimal for high-reliability industrial and automotive feedback designs where regulation precision and thermal headroom are critical.
Availability
SC431LC5SK-2TR is available at Aetrix Electronics and suitable for switching power supplies, battery-operated instrumentation, and industrial sensor conditioning requiring stable component supply with full RoHS compliance and extended temperature support.
Supply support for SC431LC5SK-2TR 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, protection, and sensing.
The SC431L family was designed specifically for precision voltage reference and shunt regulation in space-constrained, thermally demanding applications - targeting upgrade paths from TLV431 and discrete Zener solutions in industrial and computing power systems.
FAQ
What is the maximum cathode voltage rating for SC431LC5SK-2TR?
The SC431LC5SK-2TR has an absolute maximum cathode-to-anode voltage (VZ) of 20 V. Exceeding this rating risks permanent damage. In normal operation, the device regulates VOUT up to 20 V using external resistors, but the cathode voltage itself must stay within this 20 V limit relative to the anode. Always observe derating guidelines above 70°C ambient.
Can SC431LC5SK-2TR replace a standard Zener diode directly?
Yes, the SC431LC5SK-2TR is explicitly designed as a high-performance Zener diode upgrade. Unlike passive Zeners, it delivers sharp turn-on, ±0.25% initial tolerance, and 0.05 Ω dynamic impedance. However, it requires a minimum 100 µA cathode current and uses a 3-terminal configuration - so direct 2-terminal replacement is not possible without modifying the bias network.
What load capacitance values ensure stable operation of SC431LC5SK-2TR?
Stability is guaranteed only with load capacitance (CL) either ≤1 nF or ≥10 µF. Capacitances between 10 nF and 1 µF cause oscillation at cathode currents below 3 mA - confirmed in Semtech's stability boundary testing. For most designs, omitting CL entirely and decoupling at the load is the most robust and cost-effective approach.
Does SC431LC5SK-2TR require external components to function?
Yes, the SC431LC5SK-2TR requires two external resistors (R1 and R2) to set the output voltage per VOUT = VREF(1 + R1/R2). No capacitor is mandatory, but proper PCB layout - including short traces to the reference pin and low-inductance anode return - is essential for maintaining accuracy and stability per Semtech's application notes.
How does the NC pin configuration in SC431LC5SK-2TR affect thermal performance?
The SC431LC5SK-2TR uses a 5-pin SOT-23 package with Pins 4 and 5 designated as No Connect. These pins are internally unconnected and do not contribute to thermal conduction. Thermal performance relies solely on the die-to-pad path through Pins 1–3 and the exposed thermal pad - which must be soldered to a copper pour for optimal θJA = 252°C/W.
SC431LC5SK-2TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Package/Case:
- SC-74A, SOT-753
- 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:
- ±2%
- 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-23-5
SC431LC5SK-2TR FAQ
1.How can I place an order for SC431LC5SK-2TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SC431LC5SK-2TR 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 SC431LC5SK-2TR reliable?
The price and inventory of SC431LC5SK-2TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC431LC5SK-2TR is usually 5 days.
3.What payment methods are accepted for SC431LC5SK-2TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC431LC5SK-2TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC431LC5SK-2TR?
SC431LC5SK-2TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC431LC5SK-2TR 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 SC431LC5SK-2TR?
For technical support, including SC431LC5SK-2TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC431LC5SK-2TR requirements.
6.How does Aetrix verify that SC431LC5SK-2TR is sourced from the original manufacturer or authorized distributors?
All SC431LC5SK-2TR 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 SC431LC5SK-2TR meets industry standards.
7.What is the process for return or replacement of SC431LC5SK-2TR?
All SC431LC5SK-2TR units undergo pre-shipment inspection (PSI). If there is an issue with SC431LC5SK-2TR, 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 SC431LC5SK-2TR part is unused and in its original packaging.
Return procedure for SC431LC5SK-2TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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