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Analog Devices Inc. LT1431MPS8#TRPBF
- Part No.:
- LT1431MPS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1431MPS8#TRPBF.pdf
- Description:
- IC VREF SHUNT ADJ 0.4% 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,458
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Product details
Overview
LT1431MPS8#TRPBF from Analog Devices (formerly Linear Technology) is a precision adjustable shunt voltage regulator in an 8-lead plastic SO package, rated for –55°C to 125°C operation. It delivers 100mA sink capability, 0.4% initial reference voltage tolerance (2.5V nominal), 0.3% typical temperature stability, and 0.1Ω dynamic output impedance - enabling high-accuracy feedback in isolated DC/DC converters and programmable power supplies.
For engineers reviewing the LT1431MPS8#TRPBF datasheet, LT1431MPS8#TRPBF pinout, LT1431MPS8#TRPBF application, or LT1431MPS8#TRPBF equivalent, key selection considerations include its guaranteed 0.4% VREF tolerance over full industrial/military temperature range, ability to configure as a self-contained 5V shunt regulator using internal resistors, and support for external current limiting via GND-F/GND-S separation - critical for robust overcurrent protection in flyback and buck topologies.
Technical Context
The LT1431MPS8#TRPBF integrates a 2.5V bandgap reference, transconductance amplifier (gm = 4mA/V), and open-collector NPN output transistor. Its internal 5kΩ–5kΩ resistive divider enables 5V regulation without external components, while REF, RTOP, RMID, and COMP pins allow flexible configuration as adjustable reference (2.5V–36V), current-limited shunt, or compensated error amplifier in optocoupler-based feedback loops.
It operates with V+ input from 2.5V to 36V, features <1µA reference pin current (typical), 0.2Ω dynamic impedance at 1kHz, and fast turn-on response - making it suitable for high-stability secondary-side regulation where low drift and minimal load dependence are required across wide temperature and line variations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.500 V ±0.4% (guaranteed initial accuracy at TA = 25°C, VKA = 5V, IK = 2mA) |
| Temperature Drift (∆VREF/∆T) | ≤50 ppm/°C (max over –55°C to 125°C, ensures <±10mV total drift across full range) |
| Sink Current Capability | 1 mA to 100 mA (supports direct regulation of up to 100mA load; current limit adjustable via external resistor) |
| Dynamic Output Impedance | 0.2 Ω (typical at 1kHz, IK = 1–100mA; enables tight regulation under dynamic load steps) |
| Reference Pin Current (IREF) | 0.2 µA typical (enables high-impedance feedback networks without significant error contribution) |
| Operating Voltage Range (V+) | 2.5 V to 36 V (minimum V+ equals VREF; supports wide-input isolated supplies) |
| Junction Temperature Range | –55°C to 150°C (matches –55°C to 125°C ambient rating; allows high-reliability military/aerospace use) |
Pinout & Package
LT1431MPS8#TRPBF uses the 8-lead plastic SO (S8) package, 150 mil body width, with gull-wing leads and RoHS-compliant matte tin finish. Thermal resistance θJA = 170°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COLL (Pin 1) | Open-collector output transistor collector | Connects to cathode of regulated output; handles up to 100mA sink current; max voltage 36V |
| COMP (Pin 2) | Base node of output transistor driver | Enables external compensation or shutdown; must be left open if unused; max DC voltage 6V |
| V+ (Pin 3) | Bias supply input | Powers internal circuitry; min operating voltage = VREF (2.5V); quiescent current ≈0.6mA |
| RTOP (Pin 4) | Top of internal 5kΩ–5kΩ divider | Tied to COLL for 5V self-contained operation; left open otherwise; max DC voltage 6V |
| GND-S (Pin 5) | Sense ground for internal divider | Reference for on-chip resistors; used with GND-F to set external current limit |
| GND-F (Pin 6) | Force ground / emitter of output transistor | Emitter connection and die substrate; forms current-sense path with GND-S for adjustable ILIM |
| RMID (Pin 7) | Middle node of internal divider | Tied to REF for 5V operation; provides access to midpoint for custom divider configurations |
| REF (Pin 8) | 2.5V threshold control input | Compares against internal reference; bias current cancellation active above 3V V+ |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed 0.4% initial VREF tolerance | Ensures ≤±10mV absolute error at 2.5V without trimming - critical for precision feedback in medical and test equipment |
| On-chip 5kΩ–5kΩ resistor divider | Enables true 5V shunt regulation with 1% initial tolerance and zero external parts - reduces BOM count and layout area |
| Adjustable current limit via GND-F/GND-S | Allows setting precise ILIM thresholds (e.g., 50mA or 75mA) using one external resistor - improves fault robustness vs fixed-limit alternatives |
| 0.1Ω typical dynamic output impedance | Maintains regulation stability under rapid load transients - essential for digitally controlled SMPS with dynamic load profiles |
| Low 0.2µA typical IREF | Minimizes error in high-resistance feedback dividers (e.g., >1MΩ top resistor), preserving accuracy in ultra-low-power designs |
Applications
| Isolated Flyback Converter Feedback | Programmable Lab Power Supply |
|---|---|
Use Scenario: Secondary-side voltage sensing in 5V/±15V isolated flyback converter with optocoupler feedback loop. IC Role / Device Role / Timing Role: Shunt regulator providing precise 2.5V reference to optocoupler LED driver; sets output voltage via feedback divider. Use Value: Enables ±0.5% output regulation across line, load, and temperature - meeting telecom and industrial PSU standards. |
Use Scenario: Adjustable 2.5V–30V bench power supply with digital DAC-controlled voltage setpoint and current limit. IC Role / Device Role / Timing Role: Programmable shunt reference generating stable reference for op-amp error amplifier; GND-F/GND-S pair sets current limit. Use Value: Delivers 0.1% voltage resolution and 1% current limit accuracy - satisfying lab-grade calibration requirements. |
| 5V Power Supply Monitor | Low-Dropout PNP Regulator Reference |
Use Scenario: Overvoltage/undervoltage detection for 5V rail with ±500mV window and 50mV hysteresis. IC Role / Device Role / Timing Role: Precision comparator reference; configured with external resistors to define trip thresholds. Use Value: Achieves <±10mV threshold error over –55°C to 125°C - eliminating need for trim pots or calibration in harsh environments. |
Use Scenario: Low-dropout 5V regulator using MJE2955 PNP pass transistor with LT1431MPS8#TRPBF as reference and error amplifier. IC Role / Device Role / Timing Role: High-gain transconductance amplifier (gm = 4mA/V) driving PNP base; COMP pin used for compensation. Use Value: Achieves 60mV dropout at 0.5A - outperforming standard 7805 by >3× while maintaining thermal stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDR | 0.5% initial VREF tolerance; 100ppm/°C max drift; no GND-F/GND-S current limit option; rated only to 85°C | Limited to commercial-temp applications; lacks precision and extended temperature capability of LT1431MPS8#TRPBF | Choose TL431ACDR only for cost-sensitive, non-military designs where ±1% output accuracy suffices. |
| LM4040CIM3-2.5 | Fixed 2.5V shunt reference; 0.5% tolerance; 100ppm/°C drift; 15mA max sink; no adjustable output or current limit | Not programmable; unsuitable for 5V or >2.5V outputs; cannot replace LT1431MPS8#TRPBF in adjustable or current-limited roles | Select LM4040CIM3-2.5 only for simple, fixed-voltage reference needs where sink current ≤15mA and temperature range ≤85°C. |
Compared with TL431ACDR and LM4040CIM3-2.5, the LT1431MPS8#TRPBF uniquely combines military-grade temperature range (–55°C to 125°C), 0.4% VREF accuracy, adjustable output (2.5V–36V), and user-configurable current limiting - making it the sole choice for high-reliability, programmable, and precision-regulated power systems.
Availability
LT1431MPS8#TRPBF is available at Aetrix Electronics and suitable for isolated DC/DC converters, programmable lab supplies, power supply monitors, and low-dropout linear regulators requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1431MPS8#TRPBF 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
Analog Devices acquired Linear Technology in 2017 and maintains its legacy of high-performance analog ICs. The company specializes in precision signal conditioning, power management, and interface solutions for demanding applications.
The LT1431 product line was designed specifically for high-accuracy, high-stability shunt regulation in isolated switching power supplies and programmable voltage sources - emphasizing low drift, low noise, and flexible configuration over wide temperature and voltage ranges.
FAQ
What is the maximum sink current supported by the LT1431MPS8#TRPBF?
The LT1431MPS8#TRPBF supports up to 100mA sink current at the COLL pin under normal operation. Its nominal internal current limit is 100mA, but this can be reduced using an external resistor between GND-F and GND-S. Absolute maximum ratings specify V+ and COLL voltages up to 36V, and the device remains functional across its full –55°C to 125°C operating temperature range.
Can the LT1431MPS8#TRPBF be used as a fixed 5V shunt regulator without external components?
Yes, the LT1431MPS8#TRPBF can operate as a fixed 5V shunt regulator with no external components by connecting RTOP to COLL and RMID to REF. This leverages its internal 5kΩ–5kΩ resistive divider, delivering 5V output with 1% initial tolerance. The configuration is explicitly validated in the datasheet's Typical Applications section and requires no trimming or calibration.
How does the LT1431MPS8#TRPBF achieve 0.4% initial reference voltage tolerance?
The LT1431MPS8#TRPBF achieves 0.4% initial VREF tolerance through laser-trimmed bandgap reference circuitry and matched internal resistors. This specification is guaranteed over the full –55°C to 125°C temperature range for the M-grade part, as confirmed in the Electrical Characteristics table (VREF = 2.500V ±0.4% at TA = 25°C, VKA = 5V, IK = 2mA). No external calibration is needed.
What is the purpose of the GND-F and GND-S pins on the LT1431MPS8#TRPBF?
GND-F (Pin 6) is the emitter of the output transistor and die substrate connection; GND-S (Pin 5) is the sense ground for the internal resistive divider. When a resistor is placed between them, it sets a precise external current limit (ILIM = 0.7V / RLIM + 3.6mA at 25°C), enabling accurate foldback or constant-current behavior not possible with standard shunt references.
Is the LT1431MPS8#TRPBF pin-compatible with the TL431?
No, the LT1431MPS8#TRPBF is not pin-compatible with the TL431. While the 3-pin LT1431CZ/IZ variants are pin-compatible with TL431, the 8-pin LT1431MPS8#TRPBF has dedicated pins for RTOP, RMID, GND-F, GND-S, and COMP - offering expanded functionality but requiring different PCB layout. Direct replacement would necessitate board redesign.
LT1431MPS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- 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:
- 50ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1431MPS8#TRPBF FAQ
1.How can I place an order for LT1431MPS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1431MPS8#TRPBF 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 LT1431MPS8#TRPBF reliable?
The price and inventory of LT1431MPS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1431MPS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1431MPS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1431MPS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1431MPS8#TRPBF?
LT1431MPS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1431MPS8#TRPBF 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 LT1431MPS8#TRPBF?
For technical support, including LT1431MPS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1431MPS8#TRPBF requirements.
6.How does Aetrix verify that LT1431MPS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1431MPS8#TRPBF 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 LT1431MPS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1431MPS8#TRPBF?
All LT1431MPS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1431MPS8#TRPBF, 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 LT1431MPS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1431MPS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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