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Diodes Incorporated ZTL431BFTA
- Part No.:
- ZTL431BFTA
- Manufacturer:
- Diodes Incorporated
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
ZTL431BFTA.pdf
- Description:
- IC VREF SHUNT ADJ 0.5% SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:56,634
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Product details
Overview
ZTL431BFTA from Diodes Incorporated is a 0.5%-tolerance adjustable precision shunt regulator in SOT23 package, providing stable 2.5 V reference voltage with ±0.013 V initial accuracy at +25°C, 0.2 Ω typical dynamic output impedance, and 1 mA to 100 mA sink current capability. It operates across –40°C to +125°C and replaces Zener diodes in feedback loops of isolated DC-DC converters.
For engineers reviewing the ZTL431BFTA datasheet, ZTL431BFTA pinout, ZTL431BFTA application, or ZTL431BFTA equivalent, key selection criteria include reference voltage tolerance, temperature drift (±14 mV over –40°C to +125°C), cathode-anode voltage range (2.5 V to 20 V), and SOT23 thermal resistance (380°C/W).
Technical Context
The ZTL431BFTA functions as a programmable two-terminal shunt reference with internal bandgap reference and error amplifier. Its regulation relies on external resistor divider feedback to the REF pin, enabling precise output voltage setting from VREF to 20 V.
It exhibits low dynamic output impedance (0.2 Ω typ) and high open-loop gain stability across frequency, requiring ≥4.7 nF anode–cathode capacitance for guaranteed phase margin in closed-loop configurations such as optocoupler-based feedback networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.500 V ±0.013 V at +25°C - enables accurate voltage setpoints in feedback networks |
| Initial Tolerance | 0.5% (B grade) - reduces calibration burden in production-grade power supplies |
| Temp Drift (–40°C to +125°C) | ±14 mV max - ensures stable regulation across automotive under-hood and industrial ambient conditions |
| Sink Current Range | 1 mA to 100 mA - supports direct drive of optocoupler LEDs and higher-current shunt loads |
| Dynamic Output Impedance | 0.2 Ω typical - minimizes output voltage perturbation under fast load transients |
| Cathode-Anode Voltage Range | 2.5 V to 20 V - allows use with 3.3 V, 5 V, 12 V, and 19 V input rails |
| Operating Temperature | –40°C to +125°C - qualified for extended-temperature industrial and automotive applications |
Pinout & Package
Package: SOT23 (3-pin, surface-mount, JEDEC TO-236AB). Thermal resistance θJA = 380°C/W at TA = +25°C; maximum power dissipation = 330 mW.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Anode) | Current return path / ground reference | Connected to system ground or low-side return; must be referenced to cathode for proper regulation |
| Pin 2 (Cathode) | Output terminal / regulated voltage source | Sinks current to maintain programmed voltage; connects to primary-side controller feedback or optocoupler anode |
| Pin 3 (Ref) | Feedback input / reference sense node | High-impedance input (2 μA typ) that samples resistor-divider voltage; sets regulation point when equal to 2.5 V |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | Settable from 2.5 V to 20 V using two external resistors - eliminates need for multiple fixed-voltage references |
| Low output impedance | 0.2 Ω typical - maintains tight regulation despite varying load or line conditions |
| Wide operating temperature | –40°C to +125°C ambient - supports deployment in engine control units and industrial PLCs |
| Lead-free & RoHS compliant | Fully EU RoHS 2 (2011/65/EU) and halogen/antimony-free - meets global environmental compliance requirements |
| Stability assurance | Guaranteed stable with ≥4.7 nF anode–cathode capacitor - simplifies layout for isolated flyback feedback designs |
Applications
| Isolated Flyback Feedback | Programmable Linear Regulator |
|---|---|
|
Use Scenario: Secondary-side voltage sensing in 5–24 V isolated DC-DC converters with optocoupler-coupled primary-side PWM control. IC Role / Device Role / Timing Role: Shunt regulator providing precise 2.5 V reference to optocoupler LED, enabling closed-loop regulation of output voltage. Use Value: Enables ±1% output voltage accuracy over line, load, and temperature without secondary-side controller IC. |
Use Scenario: Adjustable 3.3 V to 15 V linear regulator using PNP pass transistor and external resistor network. IC Role / Device Role / Timing Role: Precision reference and error amplifier driving base of series pass transistor. Use Value: Delivers lower dropout and better PSRR than standard three-terminal regulators while maintaining 0.5% reference accuracy. |
| Overvoltage Protection Circuit | Zener Diode Replacement |
|
Use Scenario: Monitoring 12 V automotive battery rail for overvoltage events (>15.5 V) triggering shutdown via comparator or microcontroller GPIO. IC Role / Device Role / Timing Role: Programmable threshold detector with REF pin tied to resistor divider; cathode drives protection latch. Use Value: Provides 10× tighter threshold tolerance (0.5%) vs. standard 5% Zener, reducing false trips in noisy environments. |
Use Scenario: Replacing 3.3 V or 5 V Zener diodes in low-power sensor biasing and analog front-end reference circuits. IC Role / Device Role / Timing Role: High-stability, low-impedance shunt reference replacing passive Zener with poor tempco and impedance. Use Value: Reduces reference drift from >50 mV to <14 mV over –40°C to +125°C and improves load regulation by 5×. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431BIDBVR (TI) | Same 0.5% tolerance and 2.5 V reference, but rated only to +105°C; SOT23-3 package identical pinout | Limited to commercial/industrial ambient ranges; not qualified for full automotive temperature range | Select if operating ambient stays ≤+105°C and TI supply chain preference applies |
| AS431BZTR-E1 (Diodes Inc.) | Same 0.5% tolerance and SOT23 package, but specified for 1 mA minimum cathode current (vs. 0.4 mA for ZTL431BFTA) | Less suitable for ultra-low-quiescent designs where sub-1 mA operation is required | Prefer ZTL431BFTA when designing for <1 mA regulation or extended temperature margin |
Compared with TL431BIDBVR and AS431BZTR-E1, ZTL431BFTA offers superior thermal qualification (–40°C to +125°C), lower minimum cathode current (0.4 mA), and tighter full-range drift (±14 mV), making it optimal for automotive and high-reliability industrial feedback systems.
Availability
ZTL431BFTA is available at Aetrix Electronics and suitable for isolated DC-DC converter feedback, programmable linear regulators, overvoltage protection circuits, and Zener replacement applications requiring stable component supply and long-term lifecycle support.
Supply support for ZTL431BFTA 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, automotive, and computing markets.
ZTL431BFTA belongs to Diodes' precision shunt regulator product line, designed specifically to replace Zener diodes with improved accuracy, temperature stability, and dynamic performance in feedback and protection circuits.
FAQ
What is the minimum cathode current required for regulation in ZTL431BFTA?
The ZTL431BFTA achieves stable regulation with a minimum cathode current of 0.4 mA (max) at –40°C to +125°C. This value is confirmed in the Electrical Characteristics table under IKA(MIN), enabling reliable operation in low-power feedback paths where current budgets are constrained below 1 mA.
Can ZTL431BFTA replace a standard 5% Zener diode directly?
Yes - ZTL431BFTA can directly replace most 2.5 V to 20 V Zener diodes using the same two-resistor divider configuration. Its 0.5% initial tolerance, ±14 mV full-temperature drift, and 0.2 Ω dynamic impedance provide significantly tighter regulation and lower noise than typical Zeners.
What capacitor value is required between anode and cathode for stability?
A minimum 4.7 nF ceramic capacitor is recommended between anode and cathode to ensure stability across all capacitive load conditions, as verified in the Stability Boundary graph (page 4 of DS33263). Larger values (e.g., 10 nF) further improve phase margin without degrading transient response.
Does ZTL431BFTA support operation above 125°C junction temperature?
No - the absolute maximum junction temperature is +150°C, but the recommended operating ambient temperature range is strictly –40°C to +125°C. Operation beyond +125°C ambient requires derating based on package thermal resistance (380°C/W for SOT23) and PCB copper area, and is not characterized or guaranteed.
ZTL431BFTA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 20 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.5%
- 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:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
ZTL431BFTA FAQ
1.How can I place an order for ZTL431BFTA through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTL431BFTA 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 ZTL431BFTA reliable?
The price and inventory of ZTL431BFTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTL431BFTA is usually 5 days.
3.What payment methods are accepted for ZTL431BFTA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTL431BFTA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTL431BFTA?
ZTL431BFTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTL431BFTA 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 ZTL431BFTA?
For technical support, including ZTL431BFTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTL431BFTA requirements.
6.How does Aetrix verify that ZTL431BFTA is sourced from the original manufacturer or authorized distributors?
All ZTL431BFTA 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 ZTL431BFTA meets industry standards.
7.What is the process for return or replacement of ZTL431BFTA?
All ZTL431BFTA units undergo pre-shipment inspection (PSI). If there is an issue with ZTL431BFTA, 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 ZTL431BFTA part is unused and in its original packaging.
Return procedure for ZTL431BFTA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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