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Semtech Corporation SC431LC5SK-.5TR
- Part No.:
- SC431LC5SK-.5TR
- Manufacturer:
- Semtech Corporation
- Category:
- Voltage Reference
- Package:
- SC-74A, SOT-753
- Datasheet:
-
SC431LC5SK-.5TR.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,766
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Product details
Overview
SC431LC5SK-.5TR from Semtech is a three-terminal adjustable shunt regulator with ±0.5% reference voltage tolerance, 1.24 V to 20 V programmable output via two external resistors, and 0.05 Ω typical dynamic output impedance. It operates over –40°C to +125°C (industrial grade), supports cathode current from 100 µA to 100 mA, and replaces Zener diodes in precision voltage reference and error amplifier applications.
For engineers reviewing the SC431LC5SK-.5TR datasheet, pinout, applications, or equivalent options, key selection criteria include its SOT-23-5 package, thermal-stable bandgap reference, low dynamic impedance, sharp turn-on characteristic, and compatibility with switching power supply feedback loops and low-voltage instrumentation circuits.
Technical Context
The SC431LC5SK-.5TR implements a trimmed bandgap reference core with active output circuitry enabling fast, sharp turn-on behavior-critical for stable feedback in isolated DC-DC converters. Its internal architecture delivers high PSRR and low temperature drift (±20 ppm/°C typical) across the full industrial temperature range.
It functions as a 2-terminal programmable shunt regulator when used with external resistive divider, or as a 3-terminal adjustable reference when configured with separate reference input. The device requires no minimum load and maintains regulation down to 100 µA cathode current, supporting ultra-low-power battery-operated systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 1.24 V ±0.5% (VREF at IZ = 10 mA); sets precise output voltage via R1/R2 divider |
| Dynamic Output Impedance | 0.05 Ω typical (f < 1 kHz); ensures minimal output voltage shift under transient load changes |
| Cathode Current Range | 100 µA to 100 mA; enables operation from standby sleep mode to full-load regulation |
| Operating Temperature | –40°C to +125°C; qualified for industrial environments without derating |
| Output Voltage Range | 1.24 V to 20 V (programmable); covers most isolated flyback and forward converter feedback needs |
| Reference Tempco | ±20 ppm/°C typical; maintains accuracy across wide ambient swings in embedded systems |
| Package | SOT-23-5; surface-mount footprint compatible with high-density PCB layouts and automated assembly |
Pinout & Package
SOT-23-5 package with gull-wing leads, 0.95 mm pitch, 2.80 mm × 2.90 mm body size, and exposed thermal pad (no internal connection). RoHS-compliant, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (K) | Regulated output node | Connects to primary-side feedback point in isolated converters; sinks current to maintain VOUT |
| Anode (A) | Ground reference | Common return path; must be low-impedance to minimize noise coupling into reference |
| Reference (REF) | Precision voltage sense input | High-impedance node tied to resistor divider midpoint; determines regulated output voltage |
| NC (Pin 4) | No connect | Internally unconnected; left floating or grounded per layout best practice (no electrical function) |
| NC (Pin 5) | No connect | Internally unconnected; no routing required; avoids unintended parasitic coupling |
Key Features
| Feature | Design Value |
|---|---|
| Trimmed bandgap reference | ±0.5% initial accuracy (SC431LC5SK-.5TR variant) enables single-resistor calibration in production test |
| Low dynamic impedance | 0.05 Ω typical ensures <1 mV output perturbation during 10 mA load transients in feedback loops |
| Sharp turn-on characteristic | Active output stage eliminates Zener knee uncertainty-critical for stable loop gain in SMPS |
| Wide cathode current range | 100 µA minimum operating current supports energy harvesting and ultra-low-power sensor nodes |
| Industrial temperature rating | –40°C to +125°C operation allows deployment in automotive cabin electronics and industrial motor drives |
Applications
| Isolated Flyback Converter Feedback | Battery Management Reference |
|---|---|
Use Scenario: Primary-side voltage sensing in AC/DC adapters and USB PD chargers using optocoupler-coupled feedback. IC Role / Device Role / Timing Role: Adjustable shunt regulator providing precise 2.5 V reference to optocoupler LED anode; sets regulated output voltage via R1/R2 divider. Use Value: ±0.5% VREF tolerance ensures ±1% output voltage accuracy across line/load/temperature-meeting IEC 61000-3-2 compliance margins. | Use Scenario: Precision voltage reference for cell voltage monitoring in Li-ion battery packs with integrated fuel gauging. IC Role / Device Role / Timing Role: Stable 1.24 V reference source for ADC biasing and comparator thresholds in battery protection ICs. Use Value: 100 µA minimum cathode current enables operation during deep sleep modes, extending battery shelf life beyond 10 years. |
| Programmable LDO Error Amplifier | Low-Voltage Instrumentation Reference |
Use Scenario: External error amplifier in adjustable linear regulators where internal reference lacks required accuracy or temperature stability. IC Role / Device Role / Timing Role: Programmable shunt reference replacing internal bandgap; sets output voltage of PMOS pass transistor-based LDOs. Use Value: 0.05 Ω dynamic impedance prevents phase margin erosion in closed-loop LDO control, maintaining ≥45° phase margin at 100 kHz. | Use Scenario: Calibration reference in portable multimeters and handheld oscilloscopes requiring sub-0.1% absolute accuracy. IC Role / Device Role / Timing Role: Primary voltage reference for auto-zeroing amplifiers and ratiometric sensor excitation circuits. Use Value: ±20 ppm/°C tempco limits reference drift to <0.03% over –20°C to +70°C operating range-enabling Class II meter certification. |
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, SOT-23-5, but rated only to +85°C ambient; higher 0.15 Ω dynamic impedance | Limited to commercial-temperature applications; less suitable for under-hood automotive or industrial enclosures | Select TLV431ACDBVR only if ambient stays below 85°C and loop stability margins exceed 15° |
| AS431ASTUZTR-G1 | ±0.5% VREF, SOT-23-5, –40°C to +125°C, but 0.12 Ω dynamic impedance and 200 µA min IZ | Higher minimum cathode current reduces ultra-low-power viability; slightly lower PSRR above 10 kHz | Prefer AS431ASTUZTR-G1 only when legacy qualification data exists and 200 µA standby current is acceptable |
Compared with TLV431ACDBVR and AS431ASTUZTR-G1, the SC431LC5SK-.5TR offers superior dynamic impedance (0.05 Ω vs. ≥0.12 Ω) and guaranteed industrial temperature performance-making it optimal for high-reliability feedback paths where loop stability and long-term drift matter most.
Availability
SC431LC5SK-.5TR is available at Aetrix Electronics and suitable for isolated power supplies, battery management systems, and precision instrumentation requiring stable component supply with full industrial temperature support and RoHS compliance.
Supply support for SC431LC5SK-.5TR 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 signal integrity markets.
The SC431L family was designed for precision voltage regulation in space-constrained, thermally demanding applications-including isolated DC-DC converters, battery monitors, and industrial sensors-where Zener diodes fall short in accuracy and stability.
FAQ
What is the maximum cathode voltage rating for SC431LC5SK-.5TR?
The SC431LC5SK-.5TR has an absolute maximum cathode-to-anode voltage of 20 V. Exceeding this rating risks permanent damage. In normal operation, the device regulates up to 20 V output when configured with appropriate external resistors, but the cathode voltage must never surpass 20 V relative to the anode-even during transients. Always include clamping protection if input surges are possible.
Can SC431LC5SK-.5TR replace a standard Zener diode directly on the PCB?
Yes, the SC431LC5SK-.5TR 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 active circuitry provides sharper turn-on, lower dynamic impedance (0.05 Ω vs. typical Zener's >1 Ω), and tighter tolerance (±0.5% vs. ±5%). No layout change is needed if using SOT-23-5 footprint, though resistor placement must avoid noise coupling into the REF pin.
Does SC431LC5SK-.5TR require an external capacitor for stability?
No-SC431LC5SK-.5TR does not require an external capacitor for basic regulation. However, stability depends on load capacitance: avoid 10 nF–1 µF directly across cathode-anode, as it may cause oscillation at light loads. Use either no capacitor or ≥10 µF for robust operation. Local decoupling should be placed at the load, not across the SC431LC5SK-.5TR itself.
What is the minimum cathode current needed for SC431LC5SK-.5TR to regulate accurately?
The SC431LC5SK-.5TR requires a minimum cathode current of 100 µA to maintain regulation within specifications. Below this level, reference voltage accuracy degrades and turn-on becomes unpredictable. Designers must ensure that under all operating conditions-including lowest input voltage and highest output voltage-the cathode current remains ≥100 µA, typically verified using worst-case resistor divider calculations.
How does the SC431LC5SK-.5TR differ from the SC431LSK-.5TR variant?
The SC431LC5SK-.5TR uses the SOT-23-5 package with two NC pins, while SC431LSK-.5TR uses the smaller SOT-23-3 package (no NC pins). Both share identical electrical specs-±0.5% VREF, 0.05 Ω rZ, and –40°C to +125°C rating-but the SOT-23-5 variant offers better thermal dissipation (θJA = 252°C/W vs. 363°C/W) and layout flexibility for noise-sensitive REF routing. Pin compatibility is not maintained between packages.
SC431LC5SK-.5TR 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:
- ±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-23-5
SC431LC5SK-.5TR FAQ
1.How can I place an order for SC431LC5SK-.5TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SC431LC5SK-.5TR 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-.5TR reliable?
The price and inventory of SC431LC5SK-.5TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SC431LC5SK-.5TR is usually 5 days.
3.What payment methods are accepted for SC431LC5SK-.5TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SC431LC5SK-.5TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SC431LC5SK-.5TR?
SC431LC5SK-.5TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SC431LC5SK-.5TR 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-.5TR?
For technical support, including SC431LC5SK-.5TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SC431LC5SK-.5TR requirements.
6.How does Aetrix verify that SC431LC5SK-.5TR is sourced from the original manufacturer or authorized distributors?
All SC431LC5SK-.5TR 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-.5TR meets industry standards.
7.What is the process for return or replacement of SC431LC5SK-.5TR?
All SC431LC5SK-.5TR units undergo pre-shipment inspection (PSI). If there is an issue with SC431LC5SK-.5TR, 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-.5TR part is unused and in its original packaging.
Return procedure for SC431LC5SK-.5TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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