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Analog Devices Inc./Maxim Integrated LM4040AEX3-2.1-T
- Part No.:
- LM4040AEX3-2.1-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Reference
- Package:
- SC-70, SOT-323
- Datasheet:
-
LM4040AEX3-2.1-T.pdf
- Description:
- PRECISION MICROPOWER SHUNT VREF
- Quantity:
- Payment:
- Shipping:
Inventory:15,000
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Product details
Overview
LM4040AEX3-2.1-T from Maxim Integrated is a precision 2.048V two-terminal shunt voltage reference in SC70-3 package, featuring 0.1% initial accuracy, ±100ppm/°C temperature coefficient, and guaranteed operation from –40°C to +125°C. It delivers stable reverse-breakdown voltage across 60μA–15mA shunt current, with low 28μVRMS noise (10Hz–10kHz), and supports space-constrained battery-powered systems requiring high-accuracy analog sensing or ADC reference.
For engineers reviewing the LM4040AEX3-2.1-T datasheet, LM4040AEX3-2.1-T pinout, LM4040AEX3-2.1-T application, or LM4040AEX3-2.1-T equivalent, this page provides verified specifications, SC70-3 terminal mapping, real-world use cases in portable instrumentation and industrial controls, and validated alternative options for thermal-stable voltage referencing.
Technical Context
The LM4040AEX3-2.1-T uses bandgap-based shunt regulation to maintain a precise 2.048V reverse breakdown voltage without external capacitors. Its laser-trimmed internal resistor network ensures 0.1% initial tolerance, while its BiCMOS process enables low dynamic impedance (≤0.8Ω at 1mA) and stable performance over full industrial temperature range.
It operates as a two-terminal device: cathode (Pin 1) and anode (Pin 2), with Pin 3 unconnected or tied to anode. The reference remains stable under capacitive loads and exhibits ≤1.0mV voltage shift across 60μA–1mA shunt current, making it suitable for low-power, high-precision feedback loops in DC-DC converters and sensor signal conditioning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.048V nominal; ±2.0mV (±0.1%) initial tolerance at +25°C - enables direct interface with 12-bit ADCs requiring ≤1 LSB error. |
| Temperature Coefficient | ±100ppm/°C max over –40°C to +125°C - ensures ≤±10.4mV drift across full range, critical for outdoor or automotive ambient monitoring. |
| Shunt Current Range | 60μA to 15mA - supports ultra-low-power sleep modes (e.g., 65μA min operating current) and higher-current regulation without external biasing. |
| Dynamic Impedance | 0.3Ω to 0.8Ω at 1mA, 120Hz - maintains output stability during load transients in precision DAC buffers and current-sense amplifiers. |
| Wideband Noise | 28μVRMS (10Hz–10kHz) - minimizes quantization uncertainty in high-resolution data acquisition systems. |
| Long-Term Stability | 120ppm after 1000 hours - guarantees reference integrity in sealed industrial modules with no field recalibration. |
Pinout & Package
LM4040AEX3-2.1-T is housed in a 3-pin SC70 surface-mount package (1.8mm × 1.8mm), 50% smaller than SOT23 equivalents. Pin 3 is NC and must be left unconnected or tied to Pin 2 (anode).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (+) | Cathode | Reverse-bias input terminal; connects to regulated voltage node (e.g., VREF rail); sinks shunt current to ground via external resistor. |
| Pin 2 (–) | Anode | Ground reference terminal; forms return path for shunt current; must be connected to system ground or low-impedance return plane. |
| Pin 3 (N.C.) | No Connection | Internally unconnected; must remain floating or be shorted to Pin 2 per datasheet - prevents parasitic coupling or ESD path misrouting. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-small SC70-3 footprint | 1.8mm × 1.8mm area - enables placement in dense portable PCB layouts where SOT23 is prohibitive (e.g., wearable biosensors). |
| No output capacitor required | Stable with any capacitive load up to 10µF - eliminates BOM cost and layout risk of external stabilization components. |
| Guaranteed wide-temp operation | Specified from –40°C to +125°C - supports deployment in engine control units, motor drives, and outdoor IoT gateways without derating. |
| Low quiescent current capability | 60μA minimum operating current - allows use in always-on battery-backed circuits with multi-year shelf life (e.g., smart meter backup reference). |
| Low output noise | 28μVRMS broadband noise - preserves SNR in 16-bit+ SAR ADC applications where reference noise dominates total error budget. |
Applications
| Portable Medical Sensors | Industrial Process Transmitters |
|---|---|
Use Scenario: Battery-powered handheld blood glucose meters requiring stable 2.048V reference for 12-bit ADC conversion of electrochemical sensor signals. IC Role / Device Role / Timing Role: Two-terminal shunt reference providing precision voltage node for analog front-end signal chain. Use Value: 0.1% initial accuracy and ±100ppm/°C TC ensure <±1 LSB error across –20°C to +50°C operating range, meeting ISO 15197 clinical accuracy requirements. |
Use Scenario: 4–20mA loop-powered pressure transmitter operating in factory environments with ambient temperatures up to +85°C. IC Role / Device Role / Timing Role: Primary voltage reference for DAC and sensor excitation circuitry within isolated analog output stage. Use Value: Guaranteed –40°C to +125°C operation and 120ppm long-term stability enable 10-year calibration-free field deployment in harsh industrial settings. |
| Notebook System Power Monitoring | Automotive Cabin Control Modules |
Use Scenario: Real-time battery voltage and rail monitoring in ultrabook platforms using integrated PMIC ADCs. IC Role / Device Role / Timing Role: External reference for PMIC's internal 10-bit ADC, improving measurement resolution beyond internal bandgap. Use Value: SC70-3 size allows placement adjacent to PMIC without routing congestion; 28μVRMS noise reduces ADC code spread during dynamic load transitions. |
Use Scenario: HVAC control unit in passenger compartment requiring accurate thermistor-based temperature sensing under varying cabin conditions. IC Role / Device Role / Timing Role: Stable reference for microcontroller ADC sampling thermistor divider networks. Use Value: 0.1% initial accuracy and low TC minimize temperature reading offset errors across –40°C to +85°C ambient, ensuring ±0.5°C thermal control fidelity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLVH431ACDBVR | Adjustable 1.24V–18V shunt reference; 0.5% initial accuracy; 100ppm/°C TC; SOT23-3 package. | Requires external resistors to set 2.048V; higher minimum cathode current (80μA); not pretrimmed to exact 2.048V. | Choose when design flexibility across multiple reference voltages is needed and board space permits SOT23. |
| ADR3420ARJZ-R7 | Fixed 2.048V series reference; 0.1% accuracy; 30ppm/°C TC; SOT23-5 package; requires supply voltage >2.3V. | Three-terminal architecture; consumes supply current instead of shunt current; incompatible with shunt-based topologies. | Prefer when low TC is critical and system has dedicated 3.3V rail; avoid if replacing existing shunt designs without topology change. |
Compared with TLVH431ACDBVR and ADR3420ARJZ-R7, the LM4040AEX3-2.1-T offers true drop-in replacement for 2.048V shunt references with minimal layout impact, superior TC matching to legacy designs, and guaranteed SC70-3 compatibility - whereas alternatives require either resistor tuning or fundamental circuit rearchitecture.
Availability
LM4040AEX3-2.1-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial process transmitters, notebook power monitoring, and automotive cabin control modules requiring stable component supply with guaranteed long-term availability.
Supply support for LM4040AEX3-2.1-T 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
Maxim Integrated is a semiconductor company specializing in analog and mixed-signal ICs for power management, sensing, and communications applications.
The LM4040 product line delivers precision shunt voltage references optimized for space-constrained, battery-powered, and high-reliability industrial systems - designed to replace discrete Zener solutions with tighter accuracy, lower drift, and guaranteed thermal performance.
FAQ
What is the exact output voltage tolerance of LM4040AEX3-2.1-T at +25°C?
The LM4040AEX3-2.1-T has a nominal reverse breakdown voltage of 2.048V with ±2.0mV (±0.1%) initial tolerance at +25°C, as specified in the Electrical Characteristics table for the "A" grade. This tight tolerance is achieved via laser trimming and is guaranteed across all units shipped.
Can LM4040AEX3-2.1-T operate without an external capacitor?
Yes, the LM4040AEX3-2.1-T does not require an external output capacitor for stability and remains stable with any capacitive load - including 0pF up to 10µF - eliminating design risk and BOM cost associated with capacitor selection and placement.
What is the minimum shunt current required for LM4040AEX3-2.1-T to regulate properly?
The LM4040AEX3-2.1-T requires a minimum shunt current of 65μA across the full temperature range (–40°C to +125°C) to maintain regulation. At +25°C, the typical minimum is 45μA, but design must ensure ≥65μA under worst-case conditions.
Is Pin 3 of LM4040AEX3-2.1-T functional or should it be left floating?
Pin 3 of LM4040AEX3-2.1-T is labeled N.C. (No Connection) and must be left unconnected or tied directly to Pin 2 (anode). Connecting Pin 3 to any other net may cause malfunction or violate absolute maximum ratings per the official datasheet.
How does the temperature coefficient of LM4040AEX3-2.1-T affect its output over –40°C to +125°C?
With a maximum temperature coefficient of ±100ppm/°C, the LM4040AEX3-2.1-T exhibits ≤±10.4mV total drift over its full operating range (ΔT = 165°C), calculated as 2.048V × 100ppm × 165 = ±10.4mV - well within 0.1% initial accuracy band for most precision applications.
LM4040AEX3-2.1-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- SC-70, SOT-323
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 2.048V
- Voltage - Output (Max):
- -
- Current - Output:
- 15 mA
- Tolerance:
- ±0.1%
- Temperature Coefficient:
- 100ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 28µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 65 µA
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-3
LM4040AEX3-2.1-T FAQ
1.How can I place an order for LM4040AEX3-2.1-T through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4040AEX3-2.1-T 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 LM4040AEX3-2.1-T reliable?
The price and inventory of LM4040AEX3-2.1-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4040AEX3-2.1-T is usually 5 days.
3.What payment methods are accepted for LM4040AEX3-2.1-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4040AEX3-2.1-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4040AEX3-2.1-T?
LM4040AEX3-2.1-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4040AEX3-2.1-T 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 LM4040AEX3-2.1-T?
For technical support, including LM4040AEX3-2.1-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4040AEX3-2.1-T requirements.
6.How does Aetrix verify that LM4040AEX3-2.1-T is sourced from the original manufacturer or authorized distributors?
All LM4040AEX3-2.1-T 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 LM4040AEX3-2.1-T meets industry standards.
7.What is the process for return or replacement of LM4040AEX3-2.1-T?
All LM4040AEX3-2.1-T units undergo pre-shipment inspection (PSI). If there is an issue with LM4040AEX3-2.1-T, 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 LM4040AEX3-2.1-T part is unused and in its original packaging.
Return procedure for LM4040AEX3-2.1-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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