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Texas Instruments TLVH431CPK
- Part No.:
- TLVH431CPK
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- TO-243AA
- Datasheet:
-
TLVH431CPK.pdf
- Description:
- IC VREF SHUNT ADJ 1.5% SOT89-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,996
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Product details
Overview
TLVH431CPK from Texas Instruments is a low-voltage adjustable precision shunt regulator in SOT-89-3 package, featuring 1.24 V reference voltage (±1.5% at 25°C), 100 μA to 70 mA cathode current range, and operation from –40°C to +125°C. It serves as an error amplifier or voltage reference in isolated flyback SMPS feedback loops, replacing Zener diodes with lower leakage and sharper turn-on.
For engineers reviewing the TLVH431CPK datasheet, TLVH431CPK pinout, TLVH431CPK application, or TLVH431CPK equivalent, key selection criteria include reference voltage tolerance grade (C = ±1.5%), thermal stability over industrial/automotive temperature ranges, cathode-to-anode voltage headroom down to 1.24 V, and compatibility with optocoupler-based secondary-side regulation circuits.
Technical Context
The TLVH431CPK implements a three-terminal shunt-regulator architecture with an internal 1.24 V bandgap reference and high-gain NPN-based error amplifier driving a Darlington output stage. Its open-loop mode enables comparator functionality with integrated reference, while closed-loop operation-using external resistive divider feedback from cathode to reference pin-enables precise voltage regulation between 1.24 V and 18 V.
It operates without mandatory output capacitance due to internal compensation, supports stable regulation with capacitive loads up to 10 nF (depending on cathode voltage), and delivers 0.25 Ω typical dynamic impedance. The device meets JEDEC JESD22-C101 (±1000 V CDM) and JS-001 (±2000 V HBM) ESD ratings.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 1.24 V ±1.5% at 25°C - sets minimum regulation threshold and defines accuracy of adjustable output voltage |
| Cathode Current Range | 100 μA to 70 mA - determines minimum bias for regulation and maximum shunt capability in feedback networks |
| Operating Temperature | –40°C to +125°C - qualified for automotive under-hood and industrial control applications |
| Dynamic Impedance | 0.25 Ω typical - ensures tight output voltage regulation under varying load conditions |
| Output Voltage Range | 1.24 V to 18 V - achieved via external resistor divider, enabling flexible system-level voltage setting |
| Reference Input Current | 0.1–0.5 μA - minimizes divider current error and enables high-resistance feedback networks |
| Off-State Cathode Current | 0.02–0.1 μA - reduces standby power loss in always-on monitoring circuits |
Pinout & Package
SOT-89-3 package (4.50 mm × 2.50 mm body size) with gull-wing leads; thermally enhanced for power dissipation up to 52°C/W junction-to-ambient (RθJA).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CATHODE (Pin 1) | Shunt current input / regulated output node | Primary current path; connects to optocoupler LED anode or feedback network; sinks current when REF voltage exceeds 1.24 V |
| ANODE (Pin 2) | Common return / ground reference | Low-impedance return path for cathode current and reference bias; must be connected to system ground or common rail |
| REF (Pin 3) | Feedback input / reference threshold sense | High-impedance input sensing voltage divider output; regulates cathode voltage to maintain 1.24 V across external resistors |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage operation | Regulates down to 1.24 V cathode-to-anode voltage - enables use in 1.8 V, 2.5 V, and 3.3 V systems where legacy TL431 cannot function |
| Ultra-low reference input current | 0.1–0.5 μA - permits >1 MΩ feedback dividers without significant voltage error or thermal drift |
| Stable without output capacitor | Internally compensated - eliminates need for external stabilization capacitor in most flyback feedback designs |
| Sharp turn-on characteristic | High open-loop gain and Darlington output - provides fast response in voltage monitoring and comparator applications |
| Wide cathode current range | 100 μA minimum ensures reliable start-up in low-power isolated supplies; 70 mA max supports higher-output SMPS designs |
Applications
| Secondary-Side Regulation in Flyback SMPS | Voltage Monitoring for Power Rails |
|---|---|
Use Scenario: Used in isolated 3.3 V flyback converters with optocoupler feedback to regulate output voltage on secondary side. IC Role / Device Role / Timing Role: Acts as error amplifier and precision voltage reference, comparing divided output voltage against internal 1.24 V reference. Use Value: Enables regulation down to ~2.7 V output (1.24 V + opto LED drop), supporting modern low-voltage rails with ±1.5% initial accuracy and –40°C to +125°C stability. | Use Scenario: Monitors 5 V, 12 V, or 24 V system rails for undervoltage lockout or brownout detection. IC Role / Device Role / Timing Role: Functions as comparator with integrated reference, triggering reset or alert when rail drops below threshold set by resistor divider. Use Value: Eliminates external reference IC; 0.02–0.1 μA off-state cathode current minimizes quiescent power draw in always-on monitoring circuits. |
| Zener Diode Replacement | Adjustable Voltage Reference for Data Converters |
Use Scenario: Replaces discrete 2.5 V or 3.3 V Zener diodes in on-board regulation and biasing circuits. IC Role / Device Role / Timing Role: Provides shunt regulation with 0.25 Ω dynamic impedance and sharp knee, improving line/load regulation vs. Zener. Use Value: Reduces leakage current by >10× versus standard Zeners, enhancing accuracy in precision analog front-ends and sensor biasing. | Use Scenario: Supplies stable reference voltage to SAR or delta-sigma ADCs requiring 1.24–5 V adjustable references. IC Role / Device Role / Timing Role: Delivers low-noise, temperature-stable reference with <12 mV VREF deviation over full temperature range. Use Value: Enables ratiometric measurement accuracy without trimming; 0.1–0.5 μA IREF avoids loading high-impedance DAC/ADC reference inputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt-regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLVH431IPK | Same SOT-89-3 package; ±1% VREF tolerance (I grade); rated for –40°C to +85°C | Better initial accuracy but narrower temperature range than TLVH431CPK's –40°C to +125°C | Select TLVH431IPK when ±1% room-temperature accuracy is prioritized over extended temperature operation. |
| TLVH432CPK | Identical electrical specs; different pinout (REF/ANODE/CATHODE vs. CATHODE/REF/ANODE in TLVH431CPK) | Requires PCB layout revision due to reversed REF and CATHODE pins; not drop-in compatible | Choose TLVH432CPK only if board layout accommodates alternate pin assignment and benefits from dual-pinout flexibility. |
Compared with TLVH431IPK, TLVH431CPK trades ±1% initial tolerance for wider –40°C to +125°C qualification, making it suitable for automotive and industrial environments; compared with TLVH432CPK, it requires no layout change but mandates correct pin mapping per Figure 4-6.
Availability
TLVH431CPK is available at Aetrix Electronics and suitable for isolated flyback SMPS design, power-rail monitoring, precision ADC reference, and Zener-replacement applications requiring stable component supply across automotive, industrial, and telecom end equipment.
Supply support for TLVH431CPK 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
Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The TLVH431 product line delivers low-voltage, high-accuracy shunt references optimized for secondary-side regulation in isolated power supplies and precision voltage monitoring in harsh-temperature environments.
FAQ
What is the reference voltage tolerance of TLVH431CPK at 25°C?
The TLVH431CPK has a reference voltage tolerance of ±1.5% at 25°C, corresponding to a 1.24 V nominal VREF ranging from 1.222 V to 1.258 V. This "C-grade" tolerance is specified in Section 5.5 of the SLVS555N datasheet and applies across all temperature grades of the TLVH431CPK part number.
Can TLVH431CPK operate with cathode-to-anode voltage below 2.5 V?
Yes, TLVH431CPK is specifically designed for low-voltage operation, regulating stably with cathode-to-anode voltage as low as 1.24 V - significantly lower than the 2.5 V minimum required by TL431. This enables direct use in 1.8 V and 2.5 V system rails without additional level-shifting circuitry.
What is the minimum cathode current required for regulation in TLVH431CPK?
The TLVH431CPK requires a minimum cathode current of 100 μA to maintain regulation, as specified in Section 5.5 (IK(min)). Below this threshold, open-loop gain drops and regulation accuracy degrades; design margin should include temperature variation, where IK(min) may rise to 115 μA at +125°C.
Does TLVH431CPK require an external output capacitor for stability?
No, TLVH431CPK is internally compensated and stable without an external output capacitor between cathode and anode. However, if a capacitor is added for noise filtering or transient response, Figures 5-15 through 5-17 in the datasheet provide phase-margin guidance for capacitive loads up to 10 nF depending on cathode voltage.
How does the pinout of TLVH431CPK differ from TLVH432CPK?
TLVH431CPK uses Pin 1 = CATHODE, Pin 2 = ANODE, Pin 3 = REF (per Figure 4-6), whereas TLVH432CPK uses Pin 1 = REF, Pin 2 = ANODE, Pin 3 = CATHODE (per Figure 4-7). This reversal means TLVH432CPK is not pin-compatible with TLVH431CPK and requires PCB layout modification.
TLVH431CPK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- TO-243AA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 1.24V
- Voltage - Output (Max):
- 18 V
- Current - Output:
- 70 mA
- Tolerance:
- ±1.5%
- Temperature Coefficient:
- -
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 100 µA
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
TLVH431CPK FAQ
1.How can I place an order for TLVH431CPK through Aetrix?
Please submit a Request for Quotation (RFQ) for TLVH431CPK 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 TLVH431CPK reliable?
The price and inventory of TLVH431CPK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TLVH431CPK is usually 5 days.
3.What payment methods are accepted for TLVH431CPK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TLVH431CPK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TLVH431CPK?
TLVH431CPK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TLVH431CPK 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 TLVH431CPK?
For technical support, including TLVH431CPK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TLVH431CPK requirements.
6.How does Aetrix verify that TLVH431CPK is sourced from the original manufacturer or authorized distributors?
All TLVH431CPK 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 TLVH431CPK meets industry standards.
7.What is the process for return or replacement of TLVH431CPK?
All TLVH431CPK units undergo pre-shipment inspection (PSI). If there is an issue with TLVH431CPK, 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 TLVH431CPK part is unused and in its original packaging.
Return procedure for TLVH431CPK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
TLVH431CPK Tags
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