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Analog Devices Inc./Maxim Integrated MAX6138BEXR25+T
- Part No.:
- MAX6138BEXR25+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Reference
- Package:
- SC-70, SOT-323
- Datasheet:
-
MAX6138BEXR25+T.pdf
- Description:
- IC VREF SHUNT 2.5V SC70
- Quantity:
- Payment:
- Shipping:
Inventory:2,894
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Product details
Overview
MAX6138BEXR25+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed reverse breakdown voltage of 2.500V, ±0.2% initial accuracy (Grade B), 25ppm/°C max temperature coefficient, and 60μA–15mA operating current range. It delivers stable reference voltage in space-constrained portable systems such as battery-powered instrumentation and industrial sensor front-ends.
For engineers reviewing the MAX6138BEXR25+T datasheet, MAX6138BEXR25+T pinout, MAX6138BEXR25+T application, or MAX6138BEXR25+T equivalent, key selection factors include its SC70-3 package footprint, no-output-capacitor requirement, low 35µVRMS wideband noise (10Hz–10kHz), and guaranteed stability with capacitive loads up to 1µF.
Technical Context
The MAX6138BEXR25+T implements a laser-trimmed bandgap core with BiCMOS process technology to achieve tight initial tolerance and low thermal drift. Its two-terminal architecture eliminates need for external biasing circuitry beyond a series resistor, simplifying design in high-side sensing and low-quiescent-current applications.
It operates as a precision shunt regulator: reverse current (cathode-to-anode) between 60μA and 15mA maintains a stable 2.500V across pins 1 (+) and 2 (−), while pin 3 is NC (must float or tie to pin 2). Dynamic impedance remains ≤0.8Ω at 1mA, ensuring minimal output voltage shift under load transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.500V ±0.2% at +25°C - guarantees reference accuracy within ±5mV for ADC/DAC calibration and precision analog signal chains. |
| Initial Accuracy Grade | B grade (±0.2%) - tighter than C grade (±0.5%), looser than A grade (±0.1%), enabling cost-performance trade-off in mid-tier instrumentation. |
| Temp Coefficient | ≤25ppm/°C over –40°C to +85°C - ensures <±0.21mV drift across full industrial temperature range, critical for uncalibrated field deployments. |
| Operating Current | 60μA to 15mA - supports ultra-low-power sensor nodes (e.g., 60μA @ 3V supply) and higher-current data acquisition systems without external buffering. |
| Wideband Noise | 35µVRMS (10Hz–10kHz) - low enough to avoid degrading 16-bit ADC ENOB in high-resolution measurement circuits. |
| Dynamic Impedance | ≤0.8Ω at 1mA - minimizes output voltage perturbation during fast load steps, improving transient response in closed-loop feedback systems. |
| Long-Term Stability | 120ppm after 1000 hours - predictable aging behavior enables reliable lifetime calibration in medical and test equipment. |
Pinout & Package
MAX6138BEXR25+T is housed in a 3-pin SC70-3 surface-mount package (1.8mm × 1.8mm × 0.9mm), 50% smaller than SOT23-3. Pin 3 is No Connection (NC) and must be left floating or tied to pin 2 per datasheet directive.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (+) | Anode (positive terminal) | Connects to system ground or low-impedance return path; reverse current flows into this pin to establish reference voltage. |
| 2 (−) | Cathode (negative terminal) | Reference output node; voltage measured between pin 1 and pin 2 is precisely 2.500V when reverse-biased. |
| 3 (NC) | No connection | Must remain unconnected or shorted to pin 2; not internally bonded - incorrect handling risks mechanical stress or ESD path disruption. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-small SC70-3 footprint | 1.8mm × 1.8mm area - enables placement in dense PCB layouts for handheld meters and wearable health monitors where board space is constrained. |
| No output capacitor required | Stable with 0–1µF capacitive loads - eliminates BOM cost, layout area, and reliability risk associated with external ceramic capacitors. |
| Laser-trimmed bandgap core | Guaranteed ±0.2% initial accuracy - reduces need for system-level trimming, accelerating production calibration in factory test fixtures. |
| Low dynamic impedance | ≤0.8Ω at 1mA - maintains reference integrity during rapid current changes in multiplexed sensor arrays or switched-capacitor circuits. |
| Wide operating current range | 60μA–15mA - supports both microamp-level battery monitoring and milliamp-level active filter biasing without redesign. |
Applications
| Portable Medical Sensors | Industrial Data Acquisition |
|---|---|
|
Use Scenario: Battery-powered pulse oximeter measuring photodiode current with 16-bit SAR ADC. IC Role / Device Role / Timing Role: Provides 2.500V reference for ADC conversion, directly setting full-scale input range. Use Value: ±0.2% initial accuracy and 35µVRMS noise preserve clinical-grade measurement resolution without post-processing correction. |
Use Scenario: 4–20mA loop-powered transmitter conditioning thermocouple signals in factory automation. IC Role / Device Role / Timing Role: Supplies stable reference for cold-junction compensation and DAC output scaling. Use Value: 25ppm/°C tempco ensures <±0.21mV drift over –40°C to +85°C ambient, meeting IEC 61000-6-2 immunity requirements. |
| Handheld Test Equipment | Smart Energy Meters |
|
Use Scenario: Pocket multimeter using internal 24-bit delta-sigma ADC for voltage/current measurements. IC Role / Device Role / Timing Role: Serves as primary reference for autoranging front-end gain stages and ADC reference. Use Value: 120ppm long-term stability allows 1-year calibration intervals without field recalibration, reducing service overhead. |
Use Scenario: Revenue-grade electricity meter requiring metrology-grade voltage reference for ADC sampling. IC Role / Device Role / Timing Role: Generates precise 2.500V reference for isolation amplifier feedback and energy calculation IC. Use Value: SC70-3 package enables compact dual-reference layout (e.g., 2.5V + 1.22V) on isolated power domains without compromising creepage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM4040C25IDCKR | ±0.5% initial accuracy, 100ppm/°C tempco, SOT23-3 package (2.9mm × 1.6mm) | Lower precision and higher thermal drift; suitable only for non-critical biasing or low-cost consumer devices. | Select when cost is primary constraint and ±0.5% tolerance is acceptable for system accuracy budget. |
| ADR3425ARJZ-R7 | ±0.1% initial accuracy, 10ppm/°C tempco, SOT23-5 (with enable pin), higher 120µA min current | Requires enable control and higher quiescent current; better for high-precision lab equipment but incompatible with ultra-low-power designs. | Select when highest accuracy and lowest drift are mandatory, and system can accommodate SOT23-5 footprint and enable logic. |
Compared with LM4040C25IDCKR, MAX6138BEXR25+T offers 2.5× tighter initial accuracy and 4× lower tempco in a 40% smaller package; versus ADR3425ARJZ-R7, it trades 0.1% accuracy for 4× lower minimum operating current and simpler two-terminal interface - ideal for battery life–critical embedded systems.
Availability
MAX6138BEXR25+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition modules, and handheld test equipment requiring stable component supply with guaranteed long-term availability and RoHS-compliant sourcing.
Supply support for MAX6138BEXR25+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 (now part of Analog Devices) designs high-performance analog and mixed-signal semiconductors for precision, power, and interface applications, with emphasis on miniaturization and reliability.
The MAX6138 family delivers precision shunt references in ultra-small SC70 packages for space- and power-constrained systems including portable instrumentation, industrial sensors, and battery-operated IoT endpoints.
FAQ
What is the exact output voltage tolerance of MAX6138BEXR25+T at +25°C?
The MAX6138BEXR25+T has a nominal output voltage of 2.500V with a guaranteed tolerance of ±0.2% at +25°C, meaning the actual voltage falls between 2.4950V and 2.5050V under standard test conditions. This Grade B specification is confirmed in the Electrical Characteristics table for MAX6138_25 (2.5V) variant on page 3 of the official datasheet.
Can MAX6138BEXR25+T operate stably without an external output capacitor?
Yes, MAX6138BEXR25+T is explicitly designed to operate stably without any external output capacitor and remains stable with capacitive loads up to 1µF. This is verified in the General Description and Applications Information sections, eliminating capacitor-related BOM cost, footprint, and failure modes in compact designs.
What is the minimum operating current required for MAX6138BEXR25+T to maintain regulation?
The minimum operating current (IRMIN) for MAX6138BEXR25+T is 45µA (typical) and 65µA (max) across –40°C to +85°C, as specified in the Electrical Characteristics table on page 3. To ensure guaranteed regulation under worst-case conditions, design for ≥65µA shunt current at all times.
How does the temperature coefficient of MAX6138BEXR25+T affect its performance over –40°C to +85°C?
MAX6138BEXR25+T has a maximum temperature coefficient of 25ppm/°C over –40°C to +85°C, resulting in a worst-case output voltage drift of ±0.21mV across the full range. This is derived from 2.500V × 25ppm/°C × 125°C = ±0.0078V, well within typical system error budgets for 12–14-bit measurement systems.
What is the correct handling for pin 3 on MAX6138BEXR25+T?
Pin 3 of MAX6138BEXR25+T is designated NC (No Connection) and must either be left floating or connected directly to pin 2 (cathode/−) as stated in the Pin Description section and Typical Operating Circuit diagram. Connecting pin 3 to any other node may compromise device reliability or electrical performance.
MAX6138BEXR25+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- SC-70, SOT-323
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 15 mA
- Tolerance:
- ±0.2%
- Temperature Coefficient:
- 25ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 35µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 65 µA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-3
MAX6138BEXR25+T FAQ
1.How can I place an order for MAX6138BEXR25+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6138BEXR25+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 MAX6138BEXR25+T reliable?
The price and inventory of MAX6138BEXR25+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6138BEXR25+T is usually 5 days.
3.What payment methods are accepted for MAX6138BEXR25+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6138BEXR25+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6138BEXR25+T?
MAX6138BEXR25+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6138BEXR25+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 MAX6138BEXR25+T?
For technical support, including MAX6138BEXR25+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6138BEXR25+T requirements.
6.How does Aetrix verify that MAX6138BEXR25+T is sourced from the original manufacturer or authorized distributors?
All MAX6138BEXR25+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 MAX6138BEXR25+T meets industry standards.
7.What is the process for return or replacement of MAX6138BEXR25+T?
All MAX6138BEXR25+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6138BEXR25+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 MAX6138BEXR25+T part is unused and in its original packaging.
Return procedure for MAX6138BEXR25+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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