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Texas Instruments LM431CIM/NOPB
- Part No.:
- LM431CIM/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM431CIM/NOPB.pdf
- Description:
- IC VREF SHUNT -0.6%/+0.4% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,047
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Product details
Overview
LM431CIM/NOPB from Texas Instruments is a precision adjustable shunt voltage regulator with 2.5 V reference voltage, ±17 mV reference voltage deviation over temperature, 0.5 Ω dynamic output impedance, 1 mA minimum cathode current for regulation, and operation up to 36 V cathode voltage - used in feedback loops of linear/switching power supplies and voltage monitoring circuits.
For engineers reviewing the LM431CIM/NOPB datasheet, LM431CIM/NOPB pinout, LM431CIM/NOPB application, or LM431CIM/NOPB equivalent, this page delivers verified electrical specs, SOIC-8 package mapping, thermal derating guidance, and real-world implementation context for stable reference design and Zener replacement.
Technical Context
The LM431CIM/NOPB operates as a 3-terminal programmable shunt regulator: its reference pin senses a divided fraction of cathode voltage, triggering internal amplification to adjust shunt current and maintain precise output regulation. It functions in closed-loop mode with external resistor dividers or open-loop comparator mode with independent reference biasing.
Its architecture ensures temperature-stable regulation across –40°C to +85°C via on-chip compensation, with low 50 ppm/°C average temperature coefficient and fast turn-on response suitable for dynamic load transient suppression and crowbar protection circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (VREF) | 2.5 V nominal (2.485–2.51 V min/max at 25°C); sets base regulation point for external resistor divider programming. |
| Reference voltage deviation | ±17 mV over full –40°C to +85°C range; defines worst-case output voltage drift without external trimming. |
| Dynamic output impedance | 0.5 Ω typical at DC; enables tight regulation under varying load currents and suppresses output ripple. |
| Minimum cathode current | 1 mA required to maintain regulation; determines minimum series resistor value in shunt configurations. |
| Cathode voltage range | 2.5 V to 36 V; supports wide-range output programming while maintaining stability and thermal safety. |
| Reference input current | 2–4 μA typical; enables high-impedance feedback networks with minimal loading error. |
| ESD rating (HBM) | ±2500 V; requires standard ESD handling but no special protection circuitry in board layout. |
Pinout & Package
LM431CIM/NOPB uses an 8-pin SOIC (D) package measuring 4.90 mm × 3.91 mm, rated for industrial temperature range (–40°C to +85°C), with moisture sensitivity level (MSL) 1 and lead finish Sn (matte tin).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (pins 2, 3, 6, 7) | Ground return path | Internally tied together; must be connected to system ground for proper shunt current path and reference biasing. |
| Cathode (pin 1) | Regulated output node | Delivers programmed output voltage (2.5–36 V); sinks total load + shunt current; connects to supply rail via series resistor. |
| Reference (pin 8) | Feedback sense input | Monitors voltage divider output; regulates cathode voltage when divider ratio equals (VOUT/VREF) – 1. |
| NC (pins 4, 5) | No internal connection | Not bonded; must remain unconnected to avoid parasitic coupling or mechanical stress on die. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage | Programmable from 2.5 V to 36 V using two external resistors - eliminates need for multiple fixed-voltage Zeners. |
| Low-output noise | Enables clean reference generation in sensitive analog circuits (e.g., ADC references, sensor excitation) without added filtering. |
| Fast turn-on response | Supports rapid regulation recovery after line/load transients - critical for overvoltage crowbar and fault-detection circuits. |
| Temperature-compensated operation | Stable performance across –40°C to +85°C without external compensation components or calibration. |
| Low dynamic output impedance | Maintains <1% output variation under 10–100 mA cathode current changes - ideal for current-source/sink topologies. |
Applications
| Switch-Mode Power Supply Feedback | Voltage Monitoring & Protection |
|---|---|
Use Scenario: Secondary-side feedback loop in isolated flyback or forward converters to regulate output voltage. IC Role / Device Role / Timing Role: Shunt regulator providing error signal to optocoupler input, replacing TL431 in cost-sensitive designs. Use Value: Enables accurate 2.5–36 V output programming with ±17 mV reference drift, reducing need for post-production trimming. |
Use Scenario: Overvoltage detection circuit triggering shutdown or crowbar action when input exceeds threshold. IC Role / Device Role / Timing Role: Precision voltage comparator with built-in reference; drives SCR gate or MOSFET gate upon threshold breach. Use Value: Delivers 50 ppm/°C stability and fast turn-on to respond within microseconds to overvoltage events. |
| Current Source/Sink Circuits | Zener Diode Replacement |
Use Scenario: Constant-current LED driver or sensor biasing circuit requiring stable current over temperature. IC Role / Device Role / Timing Role: Regulated shunt element controlling current through external pass transistor or load resistor. Use Value: Achieves <1% current accuracy using only one external resistor, leveraging 0.5 Ω dynamic impedance and low IREF. |
Use Scenario: Replacing discrete 2.5–36 V Zener diodes in legacy power rails and reference nodes. IC Role / Device Role / Timing Role: Drop-in functional replacement with superior temperature stability, lower impedance, and programmability. Use Value: Eliminates binning and improves long-term reliability - no aging-related voltage drift like glass-encapsulated Zeners. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar adjustable shunt regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TL431ACDR | Fixed 2.5 V reference; same SOIC-8 package; ±1% initial tolerance vs. LM431CIM/NOPB's ±0.4% (2.485–2.51 V); higher 2.5 Ω dynamic impedance. | Limited to 2.5 V output unless used with external amplifier; less suitable for wide-range programmable supplies. | Select TL431ACDR only when fixed 2.5 V reference suffices and tighter initial tolerance is unnecessary. |
| LM431BIM/NOPB | Same SOIC-8 package and pinout; tighter ±10 mV reference deviation over temperature (vs. ±17 mV); identical 0.5 Ω rZ and 1 mA IZ(MIN). | Higher-grade variant for applications demanding lower thermal drift - e.g., precision instrumentation, metrology references. | Choose LM431BIM/NOPB where thermal hysteresis and long-term stability are prioritized over cost. |
Compared with TL431ACDR and LM431BIM/NOPB, the LM431CIM/NOPB offers optimal balance of wide output programmability (2.5–36 V), industrial temperature range (–40°C to +85°C), and cost-effective SOIC-8 packaging - making it preferred for general-purpose power supply feedback and voltage supervision where ±17 mV reference drift is acceptable.
Availability
LM431CIM/NOPB is available at Aetrix Electronics and suitable for switch-mode power supply feedback, voltage monitoring systems, and current source circuits requiring stable component supply with industrial temperature support and RoHS-compliant packaging.
Supply support for LM431CIM/NOPB 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 specializing in analog, embedded processing, and power management ICs, with decades of expertise in precision reference and power control technologies.
The LM431 product line was designed for cost-sensitive, space-constrained applications requiring adjustable shunt regulation - targeting power supply feedback, voltage supervision, and Zener replacement in industrial, computing, and consumer electronics.
FAQ
What is the operating temperature range for LM431CIM/NOPB?
The LM431CIM/NOPB is rated for industrial temperature operation from –40°C to +85°C. This range is confirmed in the TI datasheet's Recommended Operating Conditions table and applies specifically to the CIM suffix variant. Its thermal characteristics - including junction-to-ambient resistance (126.9°C/W) and derating curves - are validated across this full span, ensuring reliable regulation in harsh environments without external compensation.
Can LM431CIM/NOPB replace a standard Zener diode directly?
Yes, the LM431CIM/NOPB can directly replace many Zener diodes in shunt regulator applications, provided two external resistors configure the desired output voltage and the cathode current remains between 1 mA and 100 mA. Unlike passive Zeners, it delivers superior temperature stability (50 ppm/°C), lower dynamic impedance (0.5 Ω), and programmable voltage - eliminating binning and aging concerns inherent to discrete Zeners.
What is the minimum cathode current required for regulation in LM431CIM/NOPB?
The LM431CIM/NOPB requires a minimum cathode current (IZ(MIN)) of 1 mA to maintain regulation, as specified in the Electrical Characteristics table at TA = full range. This value is critical for sizing the series resistor (RS) in shunt configurations - especially under worst-case conditions of minimum input voltage and maximum load current - to ensure continuous regulation without dropout.
Does LM431CIM/NOPB support open-loop comparator operation?
Yes, the LM431CIM/NOPB supports open-loop comparator operation per the Device Functional Modes section of the datasheet. In this mode, the reference pin is driven by an external voltage source instead of a feedback divider, allowing the device to act as a precision threshold detector - for example, triggering a crowbar circuit when input exceeds a setpoint derived from the 2.5 V internal reference.
What package type and pin count does LM431CIM/NOPB use?
The LM431CIM/NOPB uses an 8-pin SOIC (D) package with physical dimensions of 4.90 mm × 3.91 mm. Pin configuration includes cathode (pin 1), reference (pin 8), anode (pins 2, 3, 6, 7), and two no-connect terminals (pins 4, 5). This mapping is explicitly defined in the "Pin Configuration and Functions" section of the SNVS020H datasheet and verified across TI's orderable addendum.
LM431CIM/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tube
- 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:
- -0.6%, +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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM431CIM/NOPB FAQ
1.How can I place an order for LM431CIM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431CIM/NOPB 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/NOPB reliable?
The price and inventory of LM431CIM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431CIM/NOPB is usually 5 days.
3.What payment methods are accepted for LM431CIM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431CIM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431CIM/NOPB?
LM431CIM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431CIM/NOPB 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/NOPB?
For technical support, including LM431CIM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431CIM/NOPB requirements.
6.How does Aetrix verify that LM431CIM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM431CIM/NOPB 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/NOPB meets industry standards.
7.What is the process for return or replacement of LM431CIM/NOPB?
All LM431CIM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM431CIM/NOPB, 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/NOPB part is unused and in its original packaging.
Return procedure for LM431CIM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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