My Inquiry
My Account
Texas Instruments LM431CIM-TI
- Part No.:
- LM431CIM-TI
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM431CIM-TI.pdf
- Description:
- IC VREF SHUNT ADJ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:12,458
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM431CIM-TI from Texas Instruments is a precision 3-terminal adjustable shunt regulator with 2.495 V reference voltage, ±17 mV reference deviation over −40°C to +85°C, 0.5 Ω dynamic output impedance, and 1.0 mA minimum cathode current for regulation - used in voltage monitoring, overvoltage protection, and feedback control of switching power supplies.
For engineers reviewing the LM431CIM-TI datasheet, LM431CIM-TI pinout, LM431CIM-TI application, or LM431CIM-TI equivalent, this page delivers verified electrical parameters, SO-8 package mapping, thermal derating guidance, stability boundary conditions, and real-world use cases including crowbar circuits and three-terminal regulator output control.
Technical Context
The LM431CIM-TI implements a bandgap-referenced error amplifier driving an NPN pass transistor in a shunt configuration, enabling programmable regulation from 2.5 V to 36 V via external resistor dividers. Its internal compensation ensures stable operation with capacitive loads up to 10 nF without oscillation under defined boundary conditions.
It features temperature-compensated reference voltage (50 ppm/°C typical), low 4.0 μA reference input current, and sub-1.0 μA off-state current at 36 V cathode voltage - making it suitable for low-power sensing and precision threshold generation across industrial temperature ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference Voltage (VREF) | 2.495 V ±5 mV at 10 mA - sets base accuracy for all programmed output voltages |
| Reference Voltage Deviation | ±17 mV over −40°C to +85°C - defines worst-case regulation error across full industrial range |
| Dynamic Output Impedance (rZ) | 0.5 Ω at DC - ensures tight load regulation and minimal output voltage sag under transient current steps |
| Minimum Cathode Current (IZ(MIN)) | 1.0 mA - minimum current required to maintain regulation; critical for low-power feedback paths |
| Off-State Cathode Current | 1.0 μA max at 36 V - enables ultra-low quiescent current in undervoltage lockout or monitor circuits |
| Temperature Coefficient | 50 ppm/°C average - guarantees predictable drift behavior in temperature-sensitive references |
| Max Cathode Voltage | 37 V - defines absolute upper limit for safe operation in overvoltage clamp or crowbar designs |
Pinout & Package
LM431CIM-TI is packaged in an 8-pin SOIC (SO-8) surface-mount package per NS Package Number M08A, with thermal pad not electrically connected. Pin 1 is Cathode, Pin 2 is Anode, Pin 3 is Reference, and Pins 4–8 are NC (not internally connected).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Cathode) | Main current sink terminal | Carries full regulated current; connects to supply rail or switching node in feedback loops |
| Pin 2 (Anode) | Current return path | Connects to ground or low-side reference point; must handle full cathode current |
| Pin 3 (Reference) | High-impedance sense input | Monitors divided output voltage; draws only 4.0 μA typical - enables high-R divider networks |
| Pins 4–8 | No internal connection | Unused; may be left floating or tied to ground for mechanical stability - no electrical function |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage (2.5 V to 36 V) | Set precisely using two external resistors - eliminates need for multiple fixed-voltage Zeners |
| Guaranteed stability over full temperature range | Validated operation from −40°C to +85°C without performance degradation or calibration drift |
| Low dynamic output impedance (0.5 Ω) | Maintains regulation during fast load transients - critical for switch-mode power supply feedback |
| Sharp turn-on characteristic | Enables clean switching in comparator and crowbar applications without hysteresis or delay artifacts |
| Low reference input current (4.0 μA typ.) | Permits use of high-value resistor dividers - reduces power loss and improves noise immunity |
Applications
| Voltage Monitor | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Monitoring 12 V automotive battery voltage to detect overcharge or alternator failure. IC Role / Device Role / Timing Role: Precision shunt reference comparing scaled battery voltage against internal 2.495 V threshold. Use Value: Delivers ±17 mV reference stability over −40°C to +85°C - ensuring reliable trip points despite engine bay temperature swings. |
Use Scenario: Triggering SCR-based crowbar to short main supply during DC bus overvoltage in industrial motor drives. IC Role / Device Role / Timing Role: Adjustable shunt regulator acting as voltage-sensing element controlling gate drive to SCR. Use Value: Sharp turn-on and 1.0 μA off-state current enable fast, low-power fault detection with minimal standby leakage. |
| Output Control of Fixed Regulator | Constant Current Sink |
Use Scenario: Modifying output of LM7805 to generate 8 V for analog sensor biasing in data acquisition systems. IC Role / Device Role / Timing Role: Shunt regulator replacing ground pin of linear regulator to inject correction current into feedback node. Use Value: 0.5 Ω dynamic impedance ensures minimal interaction with regulator loop dynamics - preserves stability. |
Use Scenario: Providing precise 10 mA LED bias current in optical isolation circuits with wide ambient temperature variation. IC Role / Device Role / Timing Role: Configured as two-resistor current source with cathode-to-anode drop regulating current through load. Use Value: 50 ppm/°C tempco and 1.0 mA minimum cathode current guarantee stable current across −40°C to +85°C without trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431CDBVR | Same 2.495 V reference, but 0.2 Ω rZ, 1.0 μA IREF, SOT-23-3 package | Higher bandwidth and lower noise; limited power dissipation (0.35 W) vs LM431CIM-TI's 0.81 W SO-8 rating | Preferred for space-constrained, low-current feedback; avoid in >100 mA shunt or high-ambient thermal environments |
| AS431AT-E1Z | 2.5 V nominal reference, ±1% initial accuracy, 100 ppm/°C tempco, SO-8 package | Looser reference tolerance and higher drift - requires tighter resistor matching for same output accuracy | Cost-optimized alternative where ±2% overall output tolerance is acceptable and thermal margin is sufficient |
Compared with TL431CDBVR and AS431AT-E1Z, the LM431CIM-TI offers superior thermal robustness (0.81 W SO-8 rating), tighter reference deviation (±17 mV), and proven stability in crowbar and high-current shunt configurations - making it optimal for industrial power systems requiring long-term reliability at elevated temperatures.
Availability
LM431CIM-TI is available at Aetrix Electronics and suitable for voltage monitoring, overvoltage protection, and output control of fixed regulators requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for LM431CIM-TI 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 company specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability components.
The LM431 series was originally developed by National Semiconductor and integrated into TI's precision reference portfolio to serve industrial, automotive, and telecom power systems requiring programmable, temperature-stable shunt regulation.
FAQ
What is the maximum cathode voltage rating for LM431CIM-TI?
The LM431CIM-TI has an absolute maximum cathode voltage rating of 37 V. Exceeding this voltage risks permanent damage to the internal NPN pass transistor. In practice, designs should operate below 36 V to maintain guaranteed regulation performance and avoid stress near the absolute limit. The LM431CIM-TI datasheet specifies 36 V as the maximum operating cathode voltage for regulation compliance.
Does LM431CIM-TI require external compensation for stability?
The LM431CIM-TI is internally compensated and does not require external capacitors for basic shunt regulator operation. However, stability boundaries depend on output capacitance and series resistance - the datasheet defines safe operating regions (e.g., CL ≤ 10 nF with Rseries ≥ 10 Ω). Instability may occur outside these limits, especially in crowbar or comparator configurations with fast edges.
What is the minimum cathode current needed for regulation in LM431CIM-TI?
The LM431CIM-TI requires a minimum cathode current of 1.0 mA to maintain regulation, as specified in the Electrical Characteristics table under IZ(MIN). Below this current, the device exits regulation and the reference voltage becomes undefined. This value is critical when designing high-resistance feedback dividers or low-power monitoring circuits where cathode current may fall near this threshold.
How does the reference input current of LM431CIM-TI affect resistor divider design?
The LM431CIM-TI has a typical reference input current of 4.0 μA, which flows into Pin 3. This current introduces error in resistor divider networks - for example, a 100 kΩ top resistor adds ~0.4 V offset. To minimize error, designers use lower-value dividers (e.g., 10 kΩ/2.2 kΩ) or compensate mathematically. High-impedance dividers increase sensitivity to leakage and noise, reducing accuracy.
Is LM431CIM-TI pin-compatible with other SO-8 shunt regulators like TL431ACD?
No, LM431CIM-TI is not pin-compatible with TL431ACD. While both are SO-8 devices, LM431CIM-TI uses Pins 1–3 for Cathode–Anode–Reference with Pins 4–8 NC, whereas TL431ACD uses Pins 1–3 for Cathode–Ref–Anode and Pin 4 for additional functionality. Swapping them without PCB revision will result in incorrect connections and circuit failure. Always verify pinout diagrams before substitution.
LM431CIM-TI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Adjustable
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 37 V
- Current - Output:
- 100 mA
- Tolerance:
- -
- Temperature Coefficient:
- 50ppm/°C Typical
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- -
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 1 mA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM431CIM-TI FAQ
1.How can I place an order for LM431CIM-TI through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431CIM-TI 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 LM431CIM-TI reliable?
The price and inventory of LM431CIM-TI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431CIM-TI is usually 5 days.
3.What payment methods are accepted for LM431CIM-TI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431CIM-TI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431CIM-TI?
LM431CIM-TI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431CIM-TI 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 LM431CIM-TI?
For technical support, including LM431CIM-TI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431CIM-TI requirements.
6.How does Aetrix verify that LM431CIM-TI is sourced from the original manufacturer or authorized distributors?
All LM431CIM-TI 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 LM431CIM-TI meets industry standards.
7.What is the process for return or replacement of LM431CIM-TI?
All LM431CIM-TI units undergo pre-shipment inspection (PSI). If there is an issue with LM431CIM-TI, 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 LM431CIM-TI part is unused and in its original packaging.
Return procedure for LM431CIM-TI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM431CIM-TI Tags
-
TL431AIDBZR
Texas Instruments
-
TL431BQDBZR
Texas Instruments
-
AN431AN-ATRG1
Diodes Incorporated
-
LM4040CYM3-2.5-TR
Microchip Technology
-
LM4040CYM3-4.1-TR
Microchip Technology
-
LM4040EIM3-2.5/NOPB
Texas Instruments
-
AZ431LBNTR-G1
Diodes Incorporated
-
LM4040D20IDBZR
Texas Instruments
-
LM4041DIM3-ADJ/NOPB
Texas Instruments
-
LM4040DIM3X-2.5/NOPB
Texas Instruments
-
LM4040DIM3-2.5/NOPB
Texas Instruments
-
AZ431LANTR-G1
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
