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Analog Devices Inc./Maxim Integrated MAX6138AEXR21-T
- Part No.:
- MAX6138AEXR21-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Reference
- Package:
- SC-70, SOT-323
- Datasheet:
-
MAX6138AEXR21-T.pdf
- Description:
- VOLTAGE REFERENCE
- Quantity:
- Payment:
- Shipping:
Inventory:9,413
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Product details
Overview
MAX6138AEXR21-T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed reverse breakdown voltage of 2.0480 V, ±0.1% initial accuracy, and 25 ppm/°C max temperature coefficient over –40°C to +85°C. It operates from 60 µA to 15 mA shunt current, delivers 28 µVRMS wideband noise (10 Hz–10 kHz), and requires no output capacitor while remaining stable with capacitive loads - ideal for high-accuracy ADC/DAC biasing in space-constrained portable systems.
For engineers reviewing the MAX6138AEXR21-T datasheet, MAX6138AEXR21-T pinout, MAX6138AEXR21-T application, or MAX6138AEXR21-T equivalent, key selection criteria include its SC70-3 package footprint, guaranteed 2.0480 V output tolerance, low dynamic impedance (≤0.8 Ω), long-term stability (120 ppm/1000 h), and compatibility with battery-powered instrumentation requiring minimal quiescent current and thermal drift control.
Technical Context
The MAX6138AEXR21-T implements a laser-trimmed BiCMOS bandgap core to achieve precise 2.0480 V regulation without series pass elements. Its two-terminal architecture functions as a programmable current sink, maintaining stable reverse breakdown voltage across 60 µA–15 mA shunt current while rejecting supply variations via dynamic impedance below 0.8 Ω at 120 Hz.
Temperature compensation is achieved through curvature-corrected bandgap design, delivering ≤25 ppm/°C TC over –40°C to +85°C and typical ±4 ppm/°C behavior. The device exhibits no load-capacitance sensitivity - stable with 0–1 µF output capacitance - and supports fast load-transient response (≤4 µs settling for ±25 µA steps at 100 µA bias).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.0480 V ±0.1% (±2.05 mV) at +25°C - enables direct interface with 12-bit SAR ADCs and 16-bit DACs without gain calibration. |
| Initial Accuracy | 0.1% max (Grade A) - eliminates post-manufacturing trimming in production test for cost-sensitive portable designs. |
| Temp Coefficient | 25 ppm/°C max over –40°C to +85°C - ensures ≤±1.7 mV total drift across industrial temperature range. |
| Shunt Current Range | 60 µA to 15 mA - supports ultra-low-power sensor nodes (e.g., 60 µA sleep mode) and high-current precision references (e.g., 12 mA for 16-bit data acquisition). |
| Dynamic Impedance | 0.3–0.8 Ω at 120 Hz - minimizes output voltage perturbation under varying load currents, critical for multiplexed analog front-ends. |
| Wideband Noise | 28 µVRMS (10 Hz–10 kHz) - meets SNR requirements for 16-bit converters without external filtering. |
| Long-Term Stability | 120 ppm after 1000 h - ensures reference integrity over product lifetime without recalibration in field-deployed equipment. |
Pinout & Package
MAX6138AEXR21-T is housed in a 3-pin SC70-3 surface-mount package (1.8 mm × 1.8 mm × 0.9 mm), 50% smaller than SOT23 equivalents. Pin 3 is NC and must be left floating or tied to Pin 2 per datasheet requirement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (+) | Positive terminal (anode) | Connects to regulated output node; sinks shunt current when reverse-biased above 2.0480 V. |
| Pin 2 (–) | Negative terminal (cathode) | Reference ground return path; forms voltage drop across external source resistor (RS) in typical operating circuit. |
| Pin 3 (N.C.) | No connection | Must remain unconnected or shorted to Pin 2 - not used for signal or thermal enhancement. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-small SC70-3 package | 1.8 mm × 1.8 mm footprint - saves PCB area in handheld medical devices and wearables where board space is constrained. |
| No output capacitor required | Stable with 0–1 µF capacitive loads - simplifies layout, reduces BOM count, and avoids capacitor aging effects on long-term accuracy. |
| Low 28 µVRMS noise | 10 Hz–10 kHz integrated bandwidth - preserves effective number of bits (ENOB) in precision data converters without added filtering. |
| 60 µA minimum operating current | Enables operation from micro-power LDOs or high-impedance dividers - extends battery life in coin-cell-powered IoT sensors. |
| Laser-trimmed accuracy | 0.1% initial tolerance achieved via on-die resistor trimming - guarantees performance without system-level calibration overhead. |
Applications
| Portable Data Acquisition | Medical Sensor Signal Conditioning |
|---|---|
|
Use Scenario: Battery-powered handheld multimeter acquiring 16-bit voltage measurements with <1 LSB error. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 2.0480 V reference for SAR ADC conversion. Use Value: 0.1% initial accuracy and 25 ppm/°C TC ensure full-scale error remains within ±0.02% across temperature, eliminating field recalibration. |
Use Scenario: Wearable ECG monitor digitizing biopotential signals with >100 dB SNR requirement. IC Role / Device Role / Timing Role: Low-noise 2.0480 V reference for 24-bit delta-sigma ADC front-end. Use Value: 28 µVRMS noise contributes <0.001% of full-scale noise floor, preserving diagnostic-grade signal fidelity. |
| Industrial Process Transmitters | Smart Energy Metering |
|
Use Scenario: Loop-powered 4–20 mA transmitter operating from 12–36 V supply with 0.1% measurement repeatability. IC Role / Device Role / Timing Role: Precision shunt reference generating stable bias for current-sense amplifier and DAC. Use Value: Wide 60 µA–15 mA shunt current range allows robust operation across supply and load variations without external regulators. |
Use Scenario: DIN-rail energy meter requiring metrology-grade accuracy (IEC 62053-21 Class 0.2) over 10-year service life. IC Role / Device Role / Timing Role: Long-term stable reference for polyphase watt-hour measurement ICs. Use Value: 120 ppm/1000 h stability ensures reference drift stays below 0.01% over 10 years, meeting lifetime accuracy targets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar shunt voltage reference applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM4040C20IDBZR | 2.048 V output, 0.5% initial accuracy, 100 ppm/°C TC, SOT23-3 package (2.92 mm × 1.6 mm) | Lower accuracy and higher TC limit use to 12-bit systems; larger footprint increases PCB area by 80%. | Select when cost is primary constraint and 0.5% tolerance is acceptable for non-critical sensing. |
| ADR3420ARJZ-R7 | 2.048 V output, 0.1% initial accuracy, 10 ppm/°C TC, SOT23-5 package (2.92 mm × 1.6 mm), 3.5 µVRMS noise | Lower noise and TC but requires 3-pin configuration (VOUT, GND, NR) and larger package; not pin-compatible. | Select for ultra-low-noise metrology where SC70 size is secondary and 5-pin layout is feasible. |
Compared with LM4040C20IDBZR and ADR3420ARJZ-R7, MAX6138AEXR21-T uniquely combines 0.1% accuracy, SC70-3 footprint, and capacitor-free stability - making it optimal for miniaturized 16-bit data loggers where board space, thermal drift, and layout simplicity are co-constrained.
Availability
MAX6138AEXR21-T is available at Aetrix Electronics and suitable for portable data acquisition, medical sensor signal conditioning, and industrial process transmitters requiring stable component supply with guaranteed long-term availability and traceable lot control.
Supply support for MAX6138AEXR21-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 precision analog and mixed-signal ICs for demanding industrial, medical, and communications applications, with expertise in voltage references, power management, and data conversion.
The MAX6138 family was developed to deliver high-accuracy, ultra-small shunt references for space- and power-constrained systems - specifically targeting portable instrumentation, battery-operated sensors, and compact industrial modules needing stable 2.048 V, 2.5 V, or 3.3 V references.
FAQ
What is the guaranteed output voltage tolerance of MAX6138AEXR21-T over temperature?
The MAX6138AEXR21-T guarantees 2.0480 V ±0.1% initial accuracy at +25°C and maintains ≤25 ppm/°C temperature coefficient over –40°C to +85°C. This results in a maximum total deviation of ±1.7 mV across the full industrial temperature range, confirmed by production testing and box-method TC characterization per datasheet Note 2.
Can MAX6138AEXR21-T operate without an external output capacitor?
Yes, MAX6138AEXR21-T is explicitly designed to operate stably without any external output capacitor. Its internal architecture ensures unconditional stability with capacitive loads from 0 to 1 µF, eliminating capacitor-related aging, leakage, and ESR effects that degrade long-term reference accuracy - a key advantage over many legacy shunt references.
What is the minimum shunt current required for regulation in MAX6138AEXR21-T?
The MAX6138AEXR21-T requires a minimum shunt current of 60 µA to maintain regulation, as specified in the Electrical Characteristics table for the _21 variant. Operation below this threshold may result in loss of output voltage accuracy and increased temperature sensitivity, particularly at cold temperatures.
How does the noise performance of MAX6138AEXR21-T compare to other 2.048 V shunt references?
MAX6138AEXR21-T delivers 28 µVRMS wideband noise (10 Hz–10 kHz), which is significantly lower than standard shunt references like LM4040 (typically >100 µVRMS) and competitive with higher-cost series references. This low noise directly supports 16-bit converter ENOB preservation without additional filtering stages.
Is MAX6138AEXR21-T compatible with high-impedance source resistors in battery-powered applications?
Yes, MAX6138AEXR21-T supports operation down to 60 µA shunt current, enabling use with high-value source resistors (e.g., >100 kΩ) in battery-powered systems. Its low minimum current requirement allows efficient biasing from weak sources such as high-ratio voltage dividers or micropower LDOs while maintaining full accuracy specifications.
MAX6138AEXR21-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:
- 25ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 28µVrms
- 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
MAX6138AEXR21-T FAQ
1.How can I place an order for MAX6138AEXR21-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6138AEXR21-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 MAX6138AEXR21-T reliable?
The price and inventory of MAX6138AEXR21-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6138AEXR21-T is usually 5 days.
3.What payment methods are accepted for MAX6138AEXR21-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6138AEXR21-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6138AEXR21-T?
MAX6138AEXR21-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6138AEXR21-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 MAX6138AEXR21-T?
For technical support, including MAX6138AEXR21-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6138AEXR21-T requirements.
6.How does Aetrix verify that MAX6138AEXR21-T is sourced from the original manufacturer or authorized distributors?
All MAX6138AEXR21-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 MAX6138AEXR21-T meets industry standards.
7.What is the process for return or replacement of MAX6138AEXR21-T?
All MAX6138AEXR21-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6138AEXR21-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 MAX6138AEXR21-T part is unused and in its original packaging.
Return procedure for MAX6138AEXR21-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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