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Analog Devices Inc./Maxim Integrated LM4040CEM3-2.1
- Part No.:
- LM4040CEM3-2.1
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Reference
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM4040CEM3-2.1.pdf
- Description:
- PRECISION MICROPOWER SHUNT VREF
- Quantity:
- Payment:
- Shipping:
Inventory:2,173
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Product details
Overview
LM4040CEM3-2.1 from Maxim Integrated is a precision 2.048V two-terminal shunt voltage reference in SOT23-3 package, rated for -40°C to +125°C operation, with 0.5% initial accuracy, ±100ppm/°C temperature coefficient, and 60µA–15mA operating current range. It serves as a stable reference in battery-powered analog signal chains, ADC/DAC biasing, and industrial sensor conditioning circuits.
For engineers reviewing the LM4040CEM3-2.1 datasheet, LM4040CEM3-2.1 pinout, LM4040CEM3-2.1 application, or LM4040CEM3-2.1 equivalent, key selection criteria include guaranteed high-temp performance, no external capacitor requirement, low 28µVRMS noise (10Hz–10kHz), and compatibility with space-constrained PCB layouts requiring subminiature fixed-voltage references.
Technical Context
The LM4040CEM3-2.1 uses bandgap-based shunt regulation to maintain a precise 2.048V reverse breakdown voltage across its terminals without series pass elements. Its internal laser-trimmed resistor network ensures 0.5% initial accuracy over the full -40°C to +125°C range, while dynamic impedance remains ≤0.9Ω at 1mA (120Hz).
It operates as a two-terminal device: cathode (Pin 1) and anode (Pin 2), with Pin 3 unconnected or tied to Pin 2. Stability is maintained across capacitive loads up to 10µF and shunt currents from 60µA to 15mA, eliminating need for output capacitance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.048V nominal; tight tolerance enables direct interface with 12-bit ADCs (e.g., LSB = 0.5mV at 2.048V full-scale) |
| Initial Accuracy | ±0.5% at +25°C; supports calibration-free designs in portable instrumentation |
| Tempco | ±100ppm/°C max; contributes ≤±12.3mV drift over -40°C to +125°C span |
| Operating Current | 60µA to 15mA; allows ultra-low-power sleep modes and high-current transient response |
| Noise (10Hz–10kHz) | 28µVRMS; suitable for precision 16-bit SAR ADC reference inputs |
| Dynamic Impedance | ≤0.9Ω at 1mA; minimizes output voltage shift under load transients |
| Long-Term Stability | 120ppm after 1000h; ensures reference integrity in sealed industrial modules |
Pinout & Package
LM4040CEM3-2.1 is housed in a RoHS-compliant 3-pin SOT23 surface-mount package (2.92mm × 1.3mm × 1.0mm), optimized for automated assembly and thermal dissipation in high-density layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (+) | Cathode | Reverse-biased terminal; connects to regulated voltage node (e.g., ADC REF+) |
| 2 (−) | Anode | Reference ground return; must be connected to system ground plane for stability |
| 3 (N.C.) | No Connection | Must remain unconnected or shorted to Pin 2; floating connection risks ESD susceptibility |
Key Features
| Feature | Design Value |
|---|---|
| Shunt architecture | Enables simple two-terminal design with no series regulator or external feedback components |
| No output capacitor required | Reduces BOM count and board area; stable with any capacitive load up to 10µF |
| Ultra-low quiescent current | 60µA minimum operating current enables use in coin-cell-powered IoT sensors |
| High-temp grade | -40°C to +125°C rating supports under-hood automotive and industrial control applications |
| Laser-trimmed accuracy | 0.5% initial tolerance eliminates post-assembly trimming in production test flow |
Applications
| Portable Medical Sensors | Industrial PLC Analog Inputs |
|---|---|
Use Scenario: Battery-powered pulse oximeter front-end conditioning analog signals before 12-bit ADC conversion. IC Role / Device Role / Timing Role: Provides stable 2.048V reference for ratiometric sensor excitation and ADC full-scale calibration. Use Value: Enables <1 LSB error over temperature without recalibration, extending battery life via 60µA min current draw. | Use Scenario: 4–20mA loop-powered transmitter with isolated analog input stage. IC Role / Device Role / Timing Role: Supplies precision reference for current-sense amplifier gain setting and DAC output scaling. Use Value: Maintains ±0.5% accuracy across -40°C to +125°C ambient, ensuring compliance with IEC 61000-6-2 immunity requirements. |
| Automotive Cabin Temperature Modules | Smart Energy Meter Reference |
Use Scenario: NTC thermistor-based cabin temperature sensing in HVAC control units. IC Role / Device Role / Timing Role: Delivers stable 2.048V reference for thermistor bridge excitation and microcontroller ADC reference. Use Value: ±100ppm/°C tempco limits measurement drift to <±0.25°C over full automotive temperature range. | Use Scenario: Polyphase electricity meter using 24-bit sigma-delta ADC for revenue-grade metrology. IC Role / Device Role / Timing Role: Supplies low-noise 2.048V reference to ADC's internal PGA and reference buffer. Use Value: 28µVRMS wideband noise prevents degradation of ENOB below 21 bits at 1ksps sampling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLV431ACDBVR | Adjustable 1.24V–18V output; 0.5% initial accuracy; 100ppm/°C tempco; SOT23-3; 60µA–15mA range | Requires two external resistors for 2.048V setting; higher output impedance than LM4040CEM3-2.1 | Select when programmability or tighter supply rejection (>60dB) is needed; verify resistor tolerance impact on final accuracy |
| MAX6002AEUR+T | Fixed 2.048V; 0.1% initial accuracy; 50ppm/°C tempco; SOT23-3; 50µA–10mA range | Narrower current range and lower max current limit; superior accuracy/tempco but reduced drive capability | Choose for highest-precision applications where 15mA shunt current is unnecessary and ±50ppm/°C drift is critical |
Compared with TLV431ACDBVR and MAX6002AEUR+T, LM4040CEM3-2.1 offers optimal balance of fixed-output simplicity, high-temp reliability, and robust 15mA sink capability-making it preferred for industrial and automotive systems where layout simplicity and thermal resilience outweigh marginal accuracy gains.
Availability
LM4040CEM3-2.1 is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC analog inputs, automotive cabin temperature modules, and smart energy meter reference designs requiring stable component supply across extended temperature ranges.
Supply support for LM4040CEM3-2.1 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, now part of Analog Devices, designs precision analog and mixed-signal ICs for industrial, automotive, and communications markets, with emphasis on high-reliability, low-power solutions.
The LM4040 product line delivers micropower shunt voltage references optimized for space-constrained, high-temperature applications where fixed-output stability, minimal external components, and long-term reliability are critical.
FAQ
What is the maximum junction temperature and absolute maximum shunt current for LM4040CEM3-2.1?
The LM4040CEM3-2.1 has an absolute maximum junction temperature of +150°C and a maximum reverse current rating of 20mA. Its guaranteed operating range extends to +125°C ambient, but sustained 15mA shunt current at +125°C requires careful thermal design due to power dissipation (≈31mW). The device must not exceed 20mA to prevent permanent damage, as specified in Absolute Maximum Ratings.
Does LM4040CEM3-2.1 require an external output capacitor for stability?
No, LM4040CEM3-2.1 does not require an external output capacitor for stability. Its internal design ensures unconditional stability with any capacitive load, including 0–10µF. This eliminates BOM cost and PCB area associated with external capacitors while maintaining regulation integrity during load transients-verified across all operating conditions in the official datasheet.
How does the 0.5% initial accuracy of LM4040CEM3-2.1 translate to voltage error at 2.048V?
The 0.5% initial accuracy of LM4040CEM3-2.1 corresponds to a ±10.24mV voltage error at 2.048V (0.005 × 2.048V). This tolerance is guaranteed at +25°C and includes laser-trimming process variation. Over temperature, total error increases to ±20.5mV (±1%) due to ±100ppm/°C tempco across the -40°C to +125°C range, as confirmed in the Electrical Characteristics table.
Can LM4040CEM3-2.1 be used in forward-bias mode like a standard diode?
Yes, LM4040CEM3-2.1 can conduct forward current up to 10mA, behaving like a silicon diode with ~0.7V forward voltage drop. However, this mode is not intended for regulation-it is only specified for protection and transient handling. For reliable voltage reference operation, LM4040CEM3-2.1 must be operated in reverse-bias (shunt) mode with cathode at higher potential than anode.
What is the purpose of Pin 3 (N.C.) on LM4040CEM3-2.1, and how should it be handled on the PCB?
Pin 3 on LM4040CEM3-2.1 is designated "N.C." (No Connection) and must either remain unconnected or be tied directly to Pin 2 (anode). Leaving Pin 3 floating is prohibited, as it may increase susceptibility to ESD events or cause unpredictable behavior. PCB layout must ensure no unintended routing or solder mask openings that could create parasitic coupling to Pin 3.
LM4040CEM3-2.1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- 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:
- ±0.5%
- 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:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
LM4040CEM3-2.1 FAQ
1.How can I place an order for LM4040CEM3-2.1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM4040CEM3-2.1 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 LM4040CEM3-2.1 reliable?
The price and inventory of LM4040CEM3-2.1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM4040CEM3-2.1 is usually 5 days.
3.What payment methods are accepted for LM4040CEM3-2.1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM4040CEM3-2.1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM4040CEM3-2.1?
LM4040CEM3-2.1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM4040CEM3-2.1 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 LM4040CEM3-2.1?
For technical support, including LM4040CEM3-2.1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM4040CEM3-2.1 requirements.
6.How does Aetrix verify that LM4040CEM3-2.1 is sourced from the original manufacturer or authorized distributors?
All LM4040CEM3-2.1 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 LM4040CEM3-2.1 meets industry standards.
7.What is the process for return or replacement of LM4040CEM3-2.1?
All LM4040CEM3-2.1 units undergo pre-shipment inspection (PSI). If there is an issue with LM4040CEM3-2.1, 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 LM4040CEM3-2.1 part is unused and in its original packaging.
Return procedure for LM4040CEM3-2.1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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