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Texas Instruments LM431CCMX
- Part No.:
- LM431CCMX
- Manufacturer:
- Texas Instruments
- Category:
- Voltage Reference
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM431CCMX.pdf
- Description:
- IC VREF SHUNT -0.6%/+0.4% 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,080
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Product details
Overview
LM431CCMX from Texas Instruments is a 3-terminal adjustable precision shunt regulator with 2.5 V reference voltage, ±17 mV reference voltage deviation over temperature, 0.5 Ω typical dynamic output impedance, and guaranteed operation from 0°C to 70°C in SOIC-8 package. It replaces Zener diodes in voltage monitoring, current source, and linear power supply feedback circuits.
For engineers reviewing the LM431CCMX datasheet, LM431CCMX pinout, LM431CCMX application, or LM431CCMX equivalent, this page delivers verified electrical specs, SOIC-8 terminal mapping, thermal derating guidance, stability boundary data, and real-world shunt regulator design constraints - all specific to the LM431CCMX commercial-grade variant.
Technical Context
The LM431CCMX operates as a two-input comparator driving an internal NPN pass transistor: the reference pin senses a fraction of cathode voltage via external resistors, and the device regulates by shunting excess current to anode (ground) when cathode voltage exceeds the programmed threshold. Its bandgap-derived reference ensures 50 ppm/°C average temperature coefficient and low thermal hysteresis.
It functions in closed-loop mode for precision voltage regulation (IZ = 1–100 mA), or open-loop mode as a temperature-compensated comparator. The SOIC-8 package supports higher power dissipation (0.81 W at 25°C) than SOT-23 or TO-92 variants, with junction-to-ambient thermal resistance of 126.9°C/W and derating of 6.5 mW/°C above 25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reference voltage (VREF) | 2.485–2.51 V at 10 mA - defines minimum programmable output (2.5 V) and sets accuracy baseline for resistor-divider designs. |
| Reference voltage deviation | ±17 mV over 0°C to 70°C - determines worst-case output error without trimming; critical for voltage monitor thresholds. |
| Dynamic output impedance | 0.5 Ω typical at DC - enables stable regulation under fast load transients; lower than most discrete Zener+transistor solutions. |
| Cathode operating current | 1–100 mA - defines external series resistor (RS) sizing range; must sustain ≥1 mA even at min input voltage and max load. |
| Max cathode voltage | 36 V - sets absolute upper limit for output programming; exceeds standard 3.3 V/5 V/12 V rails, supporting industrial supplies. |
| Average tempco | 50 ppm/°C - quantifies drift per degree; allows prediction of output shift across ambient temperature swings in unheated enclosures. |
| ESD rating (HBM) | ±2500 V - indicates handling robustness; no special ESD precautions beyond standard lab practices required. |
Pinout & Package
LM431CCMX is housed in an 8-pin SOIC (D package) with body size 4.90 mm × 3.91 mm. Pins 4 and 5 are internally not connected (NC). Anode pins (2, 3, 6, 7) are tied together internally and must be connected to ground. Cathode (pin 1) carries regulated output current; Reference (pin 8) connects to resistor divider feedback node.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (pins 2, 3, 6, 7) | Ground return path for shunt current | All four pins are electrically common; use multiple vias or wide trace to minimize ground impedance and avoid regulation error. |
| Cathode (pin 1) | Regulated output node | Connects to supply rail via series resistor (RS); carries total load + shunt current; requires low-inductance layout near bypass capacitor. |
| Reference (pin 8) | Feedback sense input | High-impedance node (IREF ≤ 4 μA); connect directly to resistor divider midpoint; keep trace short and away from noise sources. |
| NC (pins 4, 5) | No internal connection | Must remain unconnected on PCB; floating or grounded - either is acceptable, but grounding improves thermal symmetry. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable output voltage range | 2.5 V to 36 V - set precisely using two external resistors; eliminates need for multiple fixed-voltage Zeners. |
| Fast turn-on response | Enables use in crowbar and overvoltage protection circuits where sub-microsecond reaction is required to clamp fault conditions. |
| Low-output noise | Reduces ripple in precision references; avoids post-regulation filtering in sensitive analog signal chains or ADC reference supplies. |
| Temperature compensated operation | Stable regulation across full 0°C–70°C range without external compensation components - simplifies thermal design in non-climate-controlled environments. |
| Space-saving SOIC-8 package | 4.90 mm × 3.91 mm footprint supports higher power (0.81 W) than SOT-23 while maintaining surface-mount compatibility and automated assembly. |
Applications
| Adjustable Linear Power Supply Feedback | Voltage Monitoring Circuit |
|---|---|
Use Scenario: Regulating output of a transformer-rectifier-filter supply using an external PNP pass transistor controlled by LM431CCMX feedback. IC Role / Device Role / Timing Role: Precision shunt reference generating error signal that drives pass transistor base to maintain constant output voltage. Use Value: Achieves ±1% output accuracy over line/load/temperature without trimming; replaces discrete op-amp + Zener solution with single IC and two resistors. |
Use Scenario: Detecting overvoltage condition on a 24 V industrial bus to trigger shutdown before downstream damage occurs. IC Role / Device Role / Timing Role: Programmable threshold detector comparing bus voltage against 26.5 V trip point via resistor divider on Reference pin. Use Value: Provides temperature-stable trip point (±17 mV over 0°C–70°C); eliminates thermistor compensation needed with standard comparators. |
| Current Source/Sink Circuit | Zener Diode Replacement |
Use Scenario: Generating a stable 10 mA bias current for photodiode amplifier in optical sensor module. IC Role / Device Role / Timing Role: Constant-current sink with cathode grounded and anode connected to photodiode cathode; load current flows through reference resistor. Use Value: Delivers <1% current variation from 5 V to 30 V supply; outperforms discrete Zener+resistor due to low dynamic impedance and tempco. |
Use Scenario: Replacing a 12 V, 5% tolerance Zener diode in legacy power supply feedback loop. IC Role / Device Role / Timing Role: Adjustable shunt regulator configured for 12.0 V output using R1/R2 = 3.8× ratio; anode grounded, cathode at output node. Use Value: Improves output regulation accuracy from ±5% to ±0.7% (based on VREF tolerance), with 50 ppm/°C drift vs. 100+ ppm/°C for standard Zener. |
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 | Same 2.5 V reference, ±1% initial tolerance (vs. LM431CCMX ±0.4%), 0.22 Ω dynamic impedance, SOIC-8 package. | Higher precision and lower impedance support tighter regulation in high-performance SMPS feedback, but requires careful stability compensation. | Select TL431ACDR when ±1% output accuracy and <0.3 Ω impedance are mandatory; verify phase margin with output capacitor and optocoupler CTR. |
| AS431ARTDT | 2.5 V reference, ±2% tolerance, 1.5 Ω dynamic impedance, SOT-23-3 package, 0.28 W power rating. | Smaller footprint and lower cost, but limited to ≤60 mA cathode current and unsuitable for >12 V outputs due to thermal constraints. | Choose AS431ARTDT only for space-constrained, low-power (<0.2 W) applications like battery monitors; avoid in 24 V systems or >50 mA loads. |
Compared with TL431ACDR and AS431ARTDT, the LM431CCMX offers balanced performance: tighter tolerance than AS431ARTDT, higher power handling than both alternatives, and proven stability in legacy designs - making it optimal for industrial linear supplies and voltage monitors where reliability trumps ultra-high precision.
Availability
LM431CCMX is available at Aetrix Electronics and suitable for adjustable linear power supplies, voltage monitoring systems, current source circuits, and Zener diode replacement projects requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for LM431CCMX 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 founded in 1930, designing analog and embedded processing chips for industrial, automotive, and communications markets.
The LM431 product line delivers adjustable shunt regulation for cost-sensitive, high-reliability applications - emphasizing thermal stability, ease of use, and broad package availability to simplify power system design across consumer and industrial segments.
FAQ
What is the maximum output voltage programmable with LM431CCMX?
The LM431CCMX supports output voltages from 2.5 V up to 36 V, determined by the external resistor divider ratio and cathode voltage rating. At 36 V, the device remains within absolute maximum ratings; however, thermal limits require derating above 25°C ambient - for example, at 70°C ambient, max power dissipation drops to 0.51 W in SOIC-8 package. Always verify IZ stays within 1–100 mA range across all operating conditions for stable regulation.
Can LM431CCMX replace a standard 5.1 V Zener diode directly?
Yes, LM431CCMX can directly replace a 5.1 V Zener diode by configuring R1 = 1.05 kΩ and R2 = 1 kΩ to achieve VO = 2.5 V × (1 + 1.05) ≈ 5.1 V. Unlike Zeners, LM431CCMX provides tighter tolerance (±0.4% vs. ±5%), lower dynamic impedance (0.5 Ω vs. 10–100 Ω), and stable tempco (50 ppm/°C vs. 100–500 ppm/°C). No additional components are needed, but ensure minimum cathode current (1 mA) is maintained.
What is the purpose of the four anode pins on LM431CCMX SOIC-8 package?
The LM431CCMX SOIC-8 package integrates four internally bonded anode connections (pins 2, 3, 6, 7) to reduce thermal resistance and improve current-handling capability. All four pins must be connected to the same ground net - using multiple vias or a solid copper pour minimizes voltage drop and prevents regulation error caused by ground path impedance. This multi-pin design supports higher continuous cathode current (up to 100 mA) without exceeding junction temperature limits.
How does LM431CCMX behave outside its recommended operating conditions?
Below 1 mA cathode current, LM431CCMX exits regulation and output voltage collapses; above 100 mA, thermal overload may cause temporary drift or permanent damage if sustained. At cathode voltages >36 V, internal junction breakdown occurs. Operation below 0°C or above 70°C violates the commercial-grade specification - parameters like VREF deviation and tempco are not guaranteed, and long-term reliability decreases. Always adhere to datasheet limits for production designs.
Is LM431CCMX suitable for crowbar overvoltage protection circuits?
Yes, LM431CCMX is widely used in crowbar circuits due to its fast turn-on response and precise, temperature-stable threshold. When configured with a resistor divider to detect overvoltage (e.g., 28 V on a 24 V rail), it triggers an SCR or thyristor to short the supply. Its low-reference-input-current (≤4 μA) minimizes divider loading error, and 50 ppm/°C tempco ensures consistent trip point across temperature - critical for preventing nuisance trips or delayed response in safety-critical systems.
LM431CCMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM431CCMX FAQ
1.How can I place an order for LM431CCMX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM431CCMX 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 LM431CCMX reliable?
The price and inventory of LM431CCMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM431CCMX is usually 5 days.
3.What payment methods are accepted for LM431CCMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM431CCMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM431CCMX?
LM431CCMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM431CCMX 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 LM431CCMX?
For technical support, including LM431CCMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM431CCMX requirements.
6.How does Aetrix verify that LM431CCMX is sourced from the original manufacturer or authorized distributors?
All LM431CCMX 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 LM431CCMX meets industry standards.
7.What is the process for return or replacement of LM431CCMX?
All LM431CCMX units undergo pre-shipment inspection (PSI). If there is an issue with LM431CCMX, 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 LM431CCMX part is unused and in its original packaging.
Return procedure for LM431CCMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM431CCMX Tags
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LM4040DIM3X-2.5/NOPB
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AZ431LANTR-G1
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