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Analog Devices Inc./Maxim Integrated MAX6138CEXR21+T
- Part No.:
- MAX6138CEXR21+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Reference
- Package:
- SC-70, SOT-323
- Datasheet:
-
MAX6138CEXR21+T.pdf
- Description:
- IC VREF SHUNT 2.048V SC70
- Quantity:
- Payment:
- Shipping:
Inventory:1,927
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Product details
Overview
MAX6138CEXR21+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed reverse breakdown voltage of 2.048V, ±0.5% initial accuracy, 25ppm/°C max temperature coefficient over –40°C to +85°C, 60μA–15mA operating current range, and ultra-small SC70-3 package (1.8mm × 1.8mm). It serves as a stable voltage reference in portable battery-powered systems where space, accuracy, and low-noise performance are critical.
For engineers reviewing the MAX6138CEXR21+T datasheet, MAX6138CEXR21+T pinout, MAX6138CEXR21+T application, or MAX6138CEXR21+T equivalent, this page delivers verified specifications, validated pin functions, real-world use cases in space-constrained analog signal chains, and actionable alternative selection guidance for voltage reference design-in.
Technical Context
The MAX6138CEXR21+T implements a laser-trimmed bandgap core to deliver stable 2.048V reverse breakdown voltage across –40°C to +85°C, with guaranteed 25ppm/°C tempco and ≤0.5% initial tolerance. Its two-terminal architecture eliminates need for external capacitors while maintaining stability under capacitive loads up to 1µF.
It operates as a precision shunt regulator: cathode (Pin 2) sinks current from a source resistor to maintain constant voltage between anode (Pin 1) and cathode. Pin 3 is NC (must float or tie to Pin 2), enabling minimal PCB footprint and compatibility with high-impedance sensing nodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.048V nominal; ±0.5% initial accuracy ensures reference stays within 2.0378V–2.0582V at +25°C for reliable ADC/DAC biasing. |
| Temperature Coefficient | Max 25ppm/°C over –40°C to +85°C; guarantees <±0.5mV drift across full industrial temperature range. |
| Operating Current Range | 60μA to 15mA shunt current; supports ultra-low-power sensor interfaces and higher-current precision regulators. |
| Dynamic Impedance | 0.3Ω to 0.8Ω at 1mA/120Hz; enables fast load-transient response and minimal voltage perturbation under dynamic current demand. |
| Wideband Noise | 28μVRMS (10Hz–10kHz); low noise preserves SNR in high-resolution data acquisition systems. |
| Long-Term Stability | 120ppm after 1000 hours; ensures reference integrity over extended product lifetime without recalibration. |
Pinout & Package
Package: SC70-3 (1.8mm × 1.8mm, 0.95mm height), RoHS-compliant, surface-mount. Pin 3 is No Connect (NC) - must be left floating or tied to Pin 2 per datasheet requirement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (+) | Anode terminal | Positive reference node; connects to system ground or low-impedance return path in shunt configuration. |
| Pin 2 (–) | Cathode terminal | Current-sinking node; ties to source resistor and load; defines regulated voltage relative to Pin 1. |
| Pin 3 (N.C.) | No connection | Must remain unconnected or be shorted to Pin 2; no internal function - omission prevents mechanical stress or parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-small SC70-3 footprint | 1.8mm × 1.8mm area - reduces PCB real estate by 50% vs. SOT23, critical for wearables and compact IoT sensors. |
| No output capacitor required | Internally compensated for stability with any capacitive load (0–1µF), eliminating BOM cost and layout sensitivity. |
| Low 28μVRMS noise (10Hz–10kHz) | Enables ≥16-bit ADC accuracy without external filtering; avoids SNR degradation in precision measurement front-ends. |
| Guaranteed 25ppm/°C tempco | Ensures predictable, bounded drift across industrial temperature range - simplifies thermal compensation in embedded systems. |
| 60μA minimum operating current | Supports micropower operation in battery-backed applications while maintaining regulation integrity down to sub-100μA loads. |
Applications
| Portable Medical Sensors | Industrial Data Loggers |
|---|---|
|
Use Scenario: Battery-powered ECG front-end with 24-bit delta-sigma ADC requiring stable 2.048V reference for ratiometric measurement. IC Role / Device Role / Timing Role: Shunt voltage reference providing precise, low-drift excitation voltage for analog signal chain calibration. Use Value: 28μVRMS noise and 25ppm/°C tempco ensure <0.005% measurement error across –20°C to +60°C ambient, meeting IEC 60601-1 accuracy requirements. |
Use Scenario: Remote environmental monitoring node using low-power microcontroller and precision temperature/humidity sensors. IC Role / Device Role / Timing Role: Primary voltage reference for ADC and internal LDO feedback, enabling accurate sensor digitization during intermittent wake cycles. Use Value: 60μA min operating current allows continuous reference biasing during deep sleep, eliminating startup delay and reference settling errors on wake-up. |
| Notebook System Power Monitoring | Automotive Body Control Module (BCM) |
|
Use Scenario: Real-time battery voltage and rail monitoring circuit in ultrabook platform with tight board space constraints. IC Role / Device Role / Timing Role: Stable 2.048V reference for dual-slope ADC measuring 0–20V battery range via resistive divider. Use Value: SC70-3 package fits within 2mm² footprint near battery connector; ±0.5% accuracy ensures SOC estimation remains within ±1.5% error margin. |
Use Scenario: Low-voltage subsystem in BCM monitoring 12V supply health and controlling LED lighting drivers. IC Role / Device Role / Timing Role: Precision shunt reference for window comparator detecting undervoltage/overvoltage conditions on main power rail. Use Value: Guaranteed 25ppm/°C tempco and 120ppm long-term stability prevent false fault triggers across –40°C to +85°C automotive temperature profile. |
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 | 3-terminal adjustable shunt reference (2.5V base); requires external resistors to set 2.048V; 100ppm/°C tempco (typ), 1% initial accuracy. | Higher design complexity due to resistor network; less suitable for space-constrained or ultra-stable applications. | Select only if adjustable output or higher current capability (>100mA) is needed; not drop-in for MAX6138CEXR21+T. |
| LM4040C20IDBZR | Two-terminal shunt reference; 2.048V nominal; ±0.5% initial accuracy; 100ppm/°C max tempco; SOT23-3 package (2.9mm × 1.6mm). | Larger footprint (60% bigger than SC70); higher tempco increases drift by ~4× over industrial range. | Acceptable for cost-sensitive, non-space-critical designs where 100ppm/°C drift is tolerable; not pin-compatible due to different pinout and package. |
Compared with TLVH431ACDBVR and LM4040C20IDBZR, MAX6138CEXR21+T delivers superior thermal stability (25ppm/°C vs. 100ppm/°C), smaller SC70-3 footprint, and guaranteed low-noise performance - making it optimal for high-accuracy, miniaturized analog systems where reference drift directly impacts measurement fidelity.
Availability
MAX6138CEXR21+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial data loggers, and notebook system power monitoring requiring stable component supply, consistent parametric performance, and long-term availability assurance.
Supply support for MAX6138CEXR21+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The MAX6138 series was designed specifically for space-constrained, battery-operated systems demanding precision voltage references with ultra-low drift, minimal external components, and robust thermal performance - targeting portable instrumentation and embedded sensing.
FAQ
What is the exact output voltage tolerance and temperature coefficient of MAX6138CEXR21+T?
The MAX6138CEXR21+T has a nominal output voltage of 2.048V with ±0.5% initial accuracy (2.0378V to 2.0582V at +25°C) and a guaranteed maximum temperature coefficient of 25ppm/°C over the –40°C to +85°C operating range. These values are production-tested and specified in the Electrical Characteristics table for the C-grade variant.
Can MAX6138CEXR21+T operate without an external capacitor?
Yes, MAX6138CEXR21+T does not require an external output capacitor for stability and remains stable with any capacitive load from 0 to 1µF. This eliminates BOM cost and layout sensitivity, unlike many competing shunt references that mandate specific capacitor values for phase margin.
What is the correct handling of Pin 3 on MAX6138CEXR21+T?
Pin 3 of MAX6138CEXR21+T is designated N.C. (No Connection) and must either be left floating or connected directly to Pin 2 (cathode). The datasheet explicitly prohibits leaving it unconnected *and* un-tied - doing so may cause mechanical stress or parasitic coupling that affects long-term reliability.
How does MAX6138CEXR21+T compare to LM4040 in size and performance?
MAX6138CEXR21+T uses the SC70-3 package (1.8mm × 1.8mm), which is 50% smaller than the SOT23-3 package used by LM4040. It also offers tighter 25ppm/°C max tempco versus LM4040's 100ppm/°C, and lower 28μVRMS noise versus LM4040's ~40μVRMS - making MAX6138CEXR21+T superior for high-accuracy, space-constrained designs.
What is the minimum and maximum shunt current for stable operation of MAX6138CEXR21+T?
MAX6138CEXR21+T requires a minimum shunt current (IRMIN) of 60μA to maintain regulation and supports up to 15mA maximum shunt current. Absolute maximum rating is 20mA - exceeding this risks permanent damage. Operating within 60μA–15mA ensures specified accuracy, tempco, and noise performance.
MAX6138CEXR21+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):
- 2.048V
- Voltage - Output (Max):
- -
- Current - Output:
- 15 mA
- Tolerance:
- ±0.5%
- 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
MAX6138CEXR21+T FAQ
1.How can I place an order for MAX6138CEXR21+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6138CEXR21+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 MAX6138CEXR21+T reliable?
The price and inventory of MAX6138CEXR21+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6138CEXR21+T is usually 5 days.
3.What payment methods are accepted for MAX6138CEXR21+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6138CEXR21+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6138CEXR21+T?
MAX6138CEXR21+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6138CEXR21+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 MAX6138CEXR21+T?
For technical support, including MAX6138CEXR21+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6138CEXR21+T requirements.
6.How does Aetrix verify that MAX6138CEXR21+T is sourced from the original manufacturer or authorized distributors?
All MAX6138CEXR21+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 MAX6138CEXR21+T meets industry standards.
7.What is the process for return or replacement of MAX6138CEXR21+T?
All MAX6138CEXR21+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6138CEXR21+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 MAX6138CEXR21+T part is unused and in its original packaging.
Return procedure for MAX6138CEXR21+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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