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Diodes Incorporated ZTL431ACSTZ
- Part No.:
- ZTL431ACSTZ
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Datasheet:
-
ZTL431ACSTZ.pdf
- Description:
- IC VREF SHUNT ADJ 1% TO92
- Quantity:
- Payment:
- Shipping:
Inventory:1,351
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Product details
Overview
ZTL431ACSTZ from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 1% initial reference voltage tolerance (2.5 V ±1%), -40°C to +125°C operating temperature range, 0.2 Ω typical dynamic output impedance, and 1 mA to 100 mA cathode sink current capability. It replaces discrete Zener diodes in feedback loops of linear regulators, opto-coupler-based isolated power supplies, and overvoltage protection circuits.
For engineers reviewing the ZTL431ACSTZ datasheet, ZTL431ACSTZ pinout, ZTL431ACSTZ application, or ZTL431ACSTZ equivalent, this device serves as a cost-effective, high-stability voltage reference for programmable shunt regulation where thermal drift, output impedance, and wide cathode voltage range (2.5 V to 20 V) are critical selection criteria.
Technical Context
The ZTL431ACSTZ implements a bandgap-referenced error amplifier driving an NPN output stage, enabling precise regulation via external resistor divider between cathode and reference pins. Its internal architecture delivers stable operation across ambient temperatures from -40°C to +125°C with <34 mV reference deviation over that full range.
It features low 0.2 Ω dynamic output impedance at 10 mA cathode current and maintains stability with ≥4.7 nF anode-to-cathode capacitance - a key design requirement for closed-loop feedback systems requiring phase margin assurance in isolated DC-DC converters and voltage monitors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.5 V ±1% at +25°C - sets minimum programmable output voltage and defines accuracy baseline for external resistor divider design. |
| Cathode Voltage Range | 2.5 V to 20 V - enables direct use in 3.3 V, 5 V, 12 V, and 15 V regulated rails without level-shifting circuitry. |
| Sink Current Range | 1 mA to 100 mA - supports both low-power biasing and higher-current shunt regulation in SMPS feedback networks. |
| Dynamic Output Impedance | 0.2 Ω typical - ensures minimal load-induced voltage shift under dynamic current transients in precision references. |
| Temp. Range | -40°C to +125°C - qualified for automotive under-hood, industrial motor drives, and outdoor power equipment applications. |
| Ref Input Current | 2 μA typical - reduces divider resistor power loss and improves high-impedance feedback network accuracy. |
| Max Cathode Current | 150 mA absolute max - defines safe operating area limit during fault conditions or startup surge. |
Pinout & Package
ZTL431ACSTZ is packaged in SOT-23 (TO-236AB), a surface-mount plastic package with 3 terminals and 1.3 mm × 2.9 mm footprint. Thermal resistance is 380°C/W at TA = +25°C, supporting up to 330 mW dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Reference ground node | Common return path for reference input current; must be connected to system ground or lowest potential point in shunt loop. |
| Cathode (Pin 2) | Regulated output node | Source of regulated current; connects to feedback node of switching controller or pass transistor base/gate. |
| Reference (Pin 3) | Voltage sense input | High-impedance input monitoring divided cathode voltage; determines regulation setpoint via R1/R2 ratio. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable reference voltage | Programmable from 2.5 V to 20 V using two external resistors - eliminates need for multiple fixed-voltage Zeners. |
| Low output impedance | 0.2 Ω typical - minimizes output voltage variation under load changes, critical for tight-tolerance feedback paths. |
| Wide temperature stability | ≤34 mV reference deviation over -40°C to +125°C - enables reliable operation in uncontrolled thermal environments. |
| Low reference input current | 2 μA typical - allows use of high-value divider resistors, reducing quiescent power and improving noise immunity. |
| Lead-free & RoHS compliant | Fully compliant per EU Directive 2011/65/EU - meets environmental requirements for industrial and consumer end-equipment. |
Applications
| Optocoupler-Based Isolated SMPS | Overvoltage Protection Circuit |
|---|---|
|
Use Scenario: Feedback signal conditioning in flyback converters with primary-side regulation via optocoupler. IC Role / Device Role / Timing Role: Shunt regulator providing stable 2.5 V reference to optocoupler LED anode, enabling precise secondary-side voltage sensing. Use Value: Replaces Zener diode to reduce temperature-induced reference drift, improving cross-regulation and line/load transient response. |
Use Scenario: Monitoring DC bus voltage in battery-powered systems to trigger shutdown before overvoltage damage. IC Role / Device Role / Timing Role: Adjustable threshold detector comparing sensed bus voltage against programmable reference via resistor divider. Use Value: Enables single-component, field-adjustable trip point from 2.5 V to 20 V without redesigning comparator circuitry. |
| Linear Regulator Error Amplifier | Three-Terminal Fixed Regulator Enhancement |
|
Use Scenario: Improving regulation accuracy of LM78xx-style fixed-output linear regulators in high-precision instrumentation. IC Role / Device Role / Timing Role: Precision shunt reference replacing internal bandgap in feedback path to override nominal output voltage. Use Value: Achieves <±1% output accuracy versus ±2–4% of standard 78xx parts, with no change to PCB layout or external components. |
Use Scenario: Boosting current capability and thermal stability of low-dropout regulators in high-current industrial sensors. IC Role / Device Role / Timing Role: External shunt regulator controlling base drive of series pass transistor, decoupling reference from LDO's internal thermal path. Use Value: Enables >100 mA output current with <10 mV load regulation error, overcoming inherent limitations of monolithic LDOs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDR | Same electrical specs but rated only to +70°C ambient; 380°C/W θJA in SOIC-8 vs. 380°C/W in SOT-23 for ZTL431ACSTZ. | Limited to commercial-grade applications; unsuitable for automotive or extended-temperature industrial use. | Select TL431ACDR only if ambient stays ≤+70°C and SOIC-8 footprint is required for legacy board compatibility. |
| AS431ARTDT-33 | 0.5% initial tolerance (B grade), but 0.5 Ω typical Rz vs. 0.2 Ω for ZTL431ACSTZ; same -40°C to +125°C rating. | Higher output impedance increases sensitivity to load transients in fast-response feedback loops. | Choose AS431ARTDT-33 when tighter reference accuracy is prioritized over dynamic regulation performance. |
Compared with TL431ACDR and AS431ARTDT-33, ZTL431ACSTZ uniquely balances 1% accuracy, ultra-low 0.2 Ω output impedance, and full -40°C to +125°C qualification in a space-constrained SOT-23 package - making it optimal for thermally demanding, size-sensitive shunt regulation tasks.
Availability
ZTL431ACSTZ is available at Aetrix Electronics and suitable for optocoupler linearization, overvoltage protection, and linear regulator enhancement requiring stable component supply across automotive, industrial control, and telecom infrastructure programs.
Supply support for ZTL431ACSTZ 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial and automotive markets.
ZTL431ACSTZ belongs to Diodes' precision shunt regulator product line, engineered specifically to replace Zener diodes in feedback-critical applications where temperature stability, low output impedance, and extended ambient range are mandatory.
FAQ
What is the maximum cathode voltage for ZTL431ACSTZ?
The absolute maximum cathode-to-anode voltage (VKA) is 20 V. Operation beyond this rating risks permanent device failure. For reliable long-term use, design cathode voltage within 2.5 V to 20 V per recommended operating conditions, with derating applied above +25°C ambient.
Can ZTL431ACSTZ replace a standard Zener diode directly?
Yes - ZTL431ACSTZ functions as a 3-pin active Zener replacement. Connect anode to ground, cathode to supply rail, and reference to voltage divider. Unlike passive Zeners, it provides tighter tolerance, lower dynamic impedance, and superior temperature stability without requiring minimum current limiting resistors.
Is external compensation required for stability?
A minimum 4.7 nF capacitor between anode and cathode is recommended to ensure stability across all capacitive loads. This mitigates instability zones observed in gain vs. frequency plots and prevents oscillation in feedback loops with long PCB traces or high-ESR output capacitors.
What does the "C" in ZTL431ACSTZ indicate?
The "C" denotes the device grade: "A" = 1% reference voltage tolerance at +25°C, "C" = SOT-23 package variant (per Diodes' ordering code convention). "STZ" suffix indicates tape-and-reel packaging in 3,000-unit reels on 8 mm carrier tape.
ZTL431ACSTZ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA) Formed Leads
- Series:
- -
- Packaging:
- Cut Tape (CT)
- Product Status:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 20 V
- Current - Output:
- 100 mA
- Tolerance:
- ±1%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 600 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92
ZTL431ACSTZ FAQ
1.How can I place an order for ZTL431ACSTZ through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTL431ACSTZ 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 ZTL431ACSTZ reliable?
The price and inventory of ZTL431ACSTZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTL431ACSTZ is usually 5 days.
3.What payment methods are accepted for ZTL431ACSTZ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTL431ACSTZ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTL431ACSTZ?
ZTL431ACSTZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTL431ACSTZ 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 ZTL431ACSTZ?
For technical support, including ZTL431ACSTZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTL431ACSTZ requirements.
6.How does Aetrix verify that ZTL431ACSTZ is sourced from the original manufacturer or authorized distributors?
All ZTL431ACSTZ 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 ZTL431ACSTZ meets industry standards.
7.What is the process for return or replacement of ZTL431ACSTZ?
All ZTL431ACSTZ units undergo pre-shipment inspection (PSI). If there is an issue with ZTL431ACSTZ, 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 ZTL431ACSTZ part is unused and in its original packaging.
Return procedure for ZTL431ACSTZ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ZTL431ACSTZ Tags
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