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STMicroelectronics TL1431IZ-AP
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- Part No.:
- TL1431IZ-AP
- Manufacturer:
- STMicroelectronics
- Category:
- Voltage Reference
- Package:
- TO-226-2, TO-92-2 (TO-226AC)
- Datasheet:
-
TL1431IZ-AP.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% TO92-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,679
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Product details
Overview
TL1431IZ-AP from STMicroelectronics is an adjustable precision shunt voltage reference IC designed for feedback regulation in isolated DC-DC converters, linear regulators, and overvoltage protection circuits. It delivers 2.5 V reference input voltage with ±0.4% initial accuracy, supports 1–100 mA sink current, exhibits 0.22 Ω typical dynamic impedance, and operates across –40 °C to +125 °C for automotive-grade power supply monitoring.
For engineers reviewing the TL1431IZ-AP datasheet, TL1431IZ-AP pinout, TL1431IZ-AP application, or TL1431IZ-AP equivalent, key selection criteria include its TO-92 package compatibility, temperature-stable 2.5 V reference, low dynamic impedance, and guaranteed operation over the full automotive temperature range.
Technical Context
The TL1431IZ-AP functions as a 2.5 V bandgap-based shunt reference with internal error amplifier and NPN output stage. Its cathode-anode voltage range extends from VREF (2.5 V) to 36 V, enabling programmable output voltages up to 36 V using two external resistors per the standard feedback divider configuration.
It maintains regulation with cathode currents from 0.5 mA minimum to 100 mA maximum, achieves <±100 ppm/°C temperature coefficient, and sustains stable operation under capacitive loads up to 10 µF - critical for flyback converter feedback loops and battery management system references.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage | 2.500 V (typical), ±0.4% initial tolerance - sets precise feedback threshold in regulator control loops |
| Sink Current Range | 1 to 100 mA - supports direct drive of optocoupler LEDs or high-current error amplifiers |
| Dynamic Impedance | 0.22 Ω (typical) - ensures minimal output voltage perturbation during load transients |
| Temp. Range | –40 °C to +125 °C - qualified for under-hood automotive power rail monitoring and industrial SMPS |
| Voltage Precision | ±0.4% at 25 °C - enables tight output voltage regulation without trimming in production |
| Ref Input Current | 1.5–3.0 µA - minimizes divider resistor power loss and thermal drift in high-impedance feedback networks |
| Output Voltage Range | 2.5 V to 36 V (adjustable) - accommodates wide-input DC-DC designs including 24 V and 48 V systems |
Pinout & Package
TL1431IZ-AP uses the TO-92 plastic package (bulk or ammopack), with 3 leads in standard through-hole configuration. Pin 1 is Anode, Pin 2 is Cathode, Pin 3 is Reference (Ref). The device is internally configured as a 3-terminal shunt regulator requiring no external compensation for stability with typical feedback networks.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Current return path to ground or low-side reference node | Connects to system ground or feedback common; carries total cathode current minus reference current |
| Cathode (Pin 2) | Regulated output terminal and current sink | Drives optocoupler LED or error amplifier input; voltage at this pin is set by external resistor divider |
| Reference (Pin 3) | High-impedance precision voltage sense input | Compares feedback voltage against internal 2.5 V bandgap; draws only ~2.5 µA for bias |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Output Voltage | 2.5 V to 36 V via two external resistors - eliminates need for multiple fixed-reference SKUs |
| Automotive Temperature Range | –40 °C to +125 °C operation - meets AEC-Q100 stress requirements for engine control modules |
| Low Dynamic Impedance | 0.22 Ω typical - improves transient response and reduces output ripple in closed-loop supplies |
| High Sink Current Capability | 100 mA max cathode current - directly drives standard PC817/PC818 optocouplers without buffer transistors |
| Precision Reference Voltage | 2.500 V ±0.4% - enables ±1% output voltage tolerance in isolated flyback converters |
Applications
| Isolated Flyback Converter Feedback | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Primary-side regulated 12 V/2 A flyback supply for automotive infotainment head unit. IC Role / Device Role / Timing Role: Shunt reference providing precise 2.5 V threshold to optocoupler feedback network, enabling secondary-side voltage sensing without auxiliary winding. Use Value: Enables ±1.2% output regulation across line, load, and temperature while eliminating auxiliary bias winding complexity. | Use Scenario: 48 V battery management system detecting overvoltage condition above 57 V. IC Role / Device Role / Timing Role: Adjustable shunt reference configured as comparator input to trigger shutdown when sensed voltage exceeds 57 V via resistor divider. Use Value: Provides accurate, temperature-stable trip point without calibration, reducing BOM count versus discrete Zener + op-amp solutions. |
| Programmable Linear Regulator | Industrial Sensor Excitation Reference |
Use Scenario: Lab-grade 0–30 V bench power supply with digital voltage setting. IC Role / Device Role / Timing Role: Precision shunt reference generating stable 2.5 V reference for DAC-controlled output voltage scaling. Use Value: Delivers <0.5 mV drift over 0–70 °C, enabling 10 mV resolution and ±0.1% absolute accuracy in output setting. | Use Scenario: 4–20 mA loop-powered pressure transmitter requiring stable 2.5 V excitation for bridge sensor. IC Role / Device Role / Timing Role: Low-drift shunt reference supplying excitation voltage to Wheatstone bridge, referenced to loop ground. Use Value: Maintains <±10 ppm/°C TC and <1 µA reference current variation, ensuring <0.05% FS sensor output drift over –25 °C to +85 °C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACZ-AP | 0.25% initial accuracy, same TO-92 package and pinout | Higher precision required for metrology-grade supplies or low-tolerance battery cutoff | Select when tighter reference tolerance justifies cost premium and thermal drift is acceptable |
| TL1431IZT | Identical electrical specs but tape-and-reel packaging (vs. bulk/ammopack) | Required for automated SMT assembly lines using pick-and-place feeders | Choose for high-volume production where reel packaging enables faster placement and traceability |
Compared with TL431ACZ-AP, TL1431IZ-AP trades 0.15% accuracy for broader automotive qualification and lower cost; compared with TL1431IZT, it offers identical performance in bulk form for manual or semi-automated assembly, reducing packaging overhead.
Availability
TL1431IZ-AP is available at Aetrix Electronics and suitable for automotive power management, industrial DC-DC converters, and battery protection circuits requiring stable component supply with long-term lifecycle support.
Supply support for TL1431IZ-AP 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, microcontrollers, and automotive-grade ICs.
The TL1431 product line delivers precision shunt references optimized for feedback control in isolated switching power supplies and safety-critical voltage monitoring applications across automotive and industrial markets.
FAQ
What is the minimum cathode current required for regulation in TL1431IZ-AP?
The TL1431IZ-AP requires a minimum cathode current of 0.5 mA to maintain regulation, as specified in Table 4 of the datasheet under "Imin Minimum cathode current for regulation." This value holds across the full –40 °C to +125 °C operating range and ensures stable reference behavior even at low-power standby conditions.
Can TL1431IZ-AP replace a Zener diode in existing designs?
Yes - TL1431IZ-AP can directly replace Zener diodes in shunt regulator configurations. Unlike Zeners, it provides superior voltage accuracy (±0.4% vs. ±5–10%), lower dynamic impedance (0.22 Ω vs. >10 Ω), and stable temperature coefficient (±100 ppm/°C vs. >1000 ppm/°C), enabling tighter regulation without redesigning feedback dividers.
Does TL1431IZ-AP require external compensation for stability?
No external compensation is required for standard feedback configurations. The device is internally compensated and remains stable with capacitive loads up to 10 µF, as verified in Figure 20 of the datasheet. Stability is maintained across all operating conditions including full temperature and current ranges.
What is the meaning of "-AP" suffix in TL1431IZ-AP?
The "-AP" suffix denotes ammopack packaging - a carrier tape format compatible with automatic insertion equipment, distinct from bulk (no packaging) or tube (manual handling) variants. It retains identical electrical specifications and TO-92 mechanical dimensions as other TL1431IZ variants.
TL1431IZ-AP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- TO-226-2, TO-92-2 (TO-226AC)
- Series:
- -
- Packaging:
- Cut Tape (CT)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 36 V
- Current - Output:
- 100 mA
- Tolerance:
- ±0.4%
- Temperature Coefficient:
- 100ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92-3
TL1431IZ-AP FAQ
1.How can I place an order for TL1431IZ-AP through Aetrix?
Please submit a Request for Quotation (RFQ) for TL1431IZ-AP 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 TL1431IZ-AP reliable?
The price and inventory of TL1431IZ-AP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TL1431IZ-AP is usually 5 days.
3.What payment methods are accepted for TL1431IZ-AP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TL1431IZ-AP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TL1431IZ-AP?
TL1431IZ-AP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TL1431IZ-AP 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 TL1431IZ-AP?
For technical support, including TL1431IZ-AP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TL1431IZ-AP requirements.
6.How does Aetrix verify that TL1431IZ-AP is sourced from the original manufacturer or authorized distributors?
All TL1431IZ-AP 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 TL1431IZ-AP meets industry standards.
7.What is the process for return or replacement of TL1431IZ-AP?
All TL1431IZ-AP units undergo pre-shipment inspection (PSI). If there is an issue with TL1431IZ-AP, 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 TL1431IZ-AP part is unused and in its original packaging.
Return procedure for TL1431IZ-AP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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