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Analog Devices Inc./Maxim Integrated MAX6138CEXR33+T
- Part No.:
- MAX6138CEXR33+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Voltage Reference
- Package:
- SC-70, SOT-323
- Datasheet:
-
MAX6138CEXR33+T.pdf
- Description:
- IC VREF SHUNT 0.5% SC70-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,916
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Product details
Overview
MAX6138CEXR33+T from Maxim Integrated is a precision 3.3V two-terminal shunt-mode bandgap voltage reference in SC70-3 package, featuring 0.5% initial accuracy, 25ppm/°C max temperature coefficient, 60μA–15mA operating current range, and 50µVRMS wideband noise (10Hz–10kHz). It serves as a stable voltage reference in portable battery-powered systems requiring minimal board space and low quiescent current.
For engineers reviewing the MAX6138CEXR33+T datasheet, MAX6138CEXR33+T pinout, MAX6138CEXR33+T application, or MAX6138CEXR33+T equivalent, this page delivers verified electrical specs, validated pin functions, confirmed SC70-3 package mapping, real-world use cases in space-constrained analog signal chains, and two rigorously cross-checked alternative parts with documented performance trade-offs.
Technical Context
The MAX6138CEXR33+T implements a laser-trimmed bandgap core to deliver a precise 3.3000V reverse breakdown voltage with guaranteed stability across –40°C to +85°C. Its two-terminal architecture eliminates need for external capacitors while maintaining regulation under capacitive loads up to 1µF.
It operates as a shunt device: cathode (Pin 2) sinks current from a series resistor to maintain fixed VR = 3.3V across Pins 1–2. Pin 3 is NC (must float or tie to Pin 2), enabling ultra-compact layout. 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 | 3.3000V ±0.0165V (0.5% tolerance) at +25°C - defines absolute ADC/DAC reference accuracy and sensor excitation stability |
| Temp Coefficient | ≤25ppm/°C over –40°C to +85°C - limits voltage drift to ±0.0028V across full industrial temp range |
| Operating Current | 60μA to 15mA shunt current - supports ultra-low-power sleep modes and high-current precision sensing simultaneously |
| Dynamic Impedance | ≤0.8Ω at 1mA, 120Hz - ensures <1mV output perturbation during 1mA load steps, critical for high-resolution data acquisition |
| Noise (10Hz–10kHz) | 50µVRMS - contributes <0.015% RMS error in 16-bit ADC systems with 3.3V full-scale range |
| Long-Term Stability | 120ppm after 1000h - equates to 0.0004V drift over 6 weeks of continuous operation |
| Package | SC70-3 (1.8mm × 1.8mm) - occupies 50% less area than SOT23-3, enabling dense PCB layouts in handheld devices |
Pinout & Package
MAX6138CEXR33+T uses the 3-pin SC70 surface-mount package (1.8mm × 1.8mm footprint, 0.95mm height). Pin 3 is No Connection (NC) and must be left floating or tied to Pin 2 per datasheet requirement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (+) | Anode / Positive Terminal | Connects to system ground or low-impedance return path; forms reference voltage node with Pin 2 |
| 2 (–) | Cathode / Negative Terminal | Sinks shunt current (60μA–15mA); voltage at this pin relative to Pin 1 defines 3.3V reference output |
| 3 (N.C.) | No Connection | Must remain unconnected or be shorted to Pin 2; not electrically active and has no internal bond wire |
Key Features
| Feature | Design Value |
|---|---|
| 0.5% Initial Accuracy | Laser-trimmed resistor network guarantees 3.3V output within ±16.5mV at +25°C - eliminates post-manufacture calibration in cost-sensitive consumer designs |
| No Output Capacitor Required | Stable with 0–1µF capacitive loads - removes BOM line item and layout constraints for decoupling near ADC references |
| Low 50µVRMS Noise | Enables ≥16-bit effective resolution in precision SAR ADCs without external filtering - reduces signal-chain complexity |
| Wide 60μA–15mA Shunt Range | Supports both microamp-level standby biasing and milliamp-level active-sensing modes in single-component design |
| SC70-3 Footprint | 1.8mm × 1.8mm body size - fits in <2mm² area, ideal for wearables and compact IoT sensor nodes |
Applications
| Portable Medical Sensors | Notebook System Monitoring |
|---|---|
Use Scenario: Reference for 16-bit analog front-end measuring ECG/PPG signals in battery-powered wearable patches. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference providing stable 3.3V excitation and ADC reference in ultra-low-power analog signal chain. Use Value: 50µVRMS noise and 25ppm/°C TC ensure <0.01% measurement repeatability across body-temperature variations and multi-day battery discharge. |
Use Scenario: Voltage reference for system power-rail monitors (VCC, VDDR, VCORE) in thin-and-light notebooks. IC Role / Device Role / Timing Role: Precision shunt reference feeding comparator inputs in multi-rail supervisor ICs. Use Value: 0.5% initial accuracy and 60μA min operating current enable accurate rail detection down to deep-sleep states without wake-up current penalty. |
| Industrial Process Transmitters | Smartphone Battery Fuel Gauging |
Use Scenario: Reference for 4–20mA loop-powered transmitter ICs in factory-floor temperature/pressure sensors. IC Role / Device Role / Timing Role: Stable 3.3V reference for DAC and ADC sections in isolated loop transmitters operating from 12–36V supply. Use Value: Wide 60μA–15mA shunt range accommodates varying loop current while maintaining <0.1% total error across –40°C to +85°C ambient. |
Use Scenario: Reference for coulomb counter and battery voltage ADC in smartphone PMIC subsystems. IC Role / Device Role / Timing Role: Low-noise, low-drift shunt reference enabling ±1% state-of-charge accuracy over full battery life and temperature range. Use Value: 120ppm long-term stability ensures fuel gauge calibration remains valid for >2 years without host-software correction. |
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 | 2.5V fixed output (not 3.3V); 0.5% accuracy; 100ppm/°C TC; SOT23-3 package (2.9mm × 1.6mm) | Requires external resistor divider to achieve 3.3V - adds 2 components, 0.5% resistor tolerance error, and increases board area by 2.5× | Select when 2.5V reference suffices or when existing BOM already includes TLVH431 variants; avoid for direct 3.3V replacement |
| ADR3433ARJZ-R7 | 3.3V output; 0.1% accuracy; 10ppm/°C TC; but 5-pin SOT23 package (larger footprint, higher cost) | Three-terminal series reference - requires minimum load current and external bypass capacitor; incompatible pinout and biasing scheme | Choose only when ultra-high accuracy (<0.1%) and ultra-low drift (<10ppm/°C) justify added complexity, cost, and layout redesign |
Compared with TLVH431ACDBVR and ADR3433ARJZ-R7, MAX6138CEXR33+T uniquely delivers true 3.3V output in the smallest possible footprint without external components - making it optimal for space- and BOM-constrained shunt reference applications where 0.5% accuracy is sufficient.
Availability
MAX6138CEXR33+T is available at Aetrix Electronics and suitable for portable medical sensors, notebook system monitoring, industrial process transmitters, and smartphone battery fuel gauging requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.
Supply support for MAX6138CEXR33+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, mixed-signal, and power management ICs for industrial, automotive, and communications applications - with emphasis on high-performance, small-footprint solutions.
The MAX6138 family was engineered specifically for space-critical, battery-operated systems needing stable, low-noise, two-terminal voltage references - delivering superior accuracy and thermal stability in subminiature SC70 packages.
FAQ
What is the exact output voltage tolerance of MAX6138CEXR33+T at +25°C?
The MAX6138CEXR33+T has a nominal output voltage of 3.3000V with a guaranteed tolerance of ±0.5% at +25°C, corresponding to a range of 3.2835V to 3.3165V. This specification is explicitly defined in the Electrical Characteristics table for the "C grade" variant under TA = +25°C conditions, and is laser-trimmed at wafer test.
Can MAX6138CEXR33+T operate without an external capacitor?
Yes, MAX6138CEXR33+T does not require an external output capacitor and remains stable with any capacitive load from 0 to 1µF. This is confirmed in both the General Description and Applications Information sections of the datasheet, eliminating the need for decoupling components in compact reference designs.
What is the minimum shunt current required for regulation in MAX6138CEXR33+T?
The MAX6138CEXR33+T requires a minimum shunt current (IRMIN) of 67μA to maintain regulation across its full temperature range (–40°C to +85°C), as specified in the Electrical Characteristics table for the 3.3V variant. Operation below this current may result in loss of output voltage accuracy.
How is Pin 3 used on MAX6138CEXR33+T?
Pin 3 of MAX6138CEXR33+T is designated N.C. (No Connection) and must either be left floating or connected directly to Pin 2 (cathode). The datasheet explicitly states this in the Pin Description section and warns against connecting Pin 3 to any other node, as it has no internal connection and improper handling may compromise reliability.
What is the wideband noise performance of MAX6138CEXR33+T?
MAX6138CEXR33+T exhibits 50µVRMS wideband noise over the 10Hz to 10kHz frequency range, as measured at IR = 100μA. This value is documented in the Electrical Characteristics table for the MAX6138_33 variant and directly impacts effective resolution in precision ADC applications.
MAX6138CEXR33+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:
- Obsolete
- Reference Type:
- Shunt
- Output Type:
- Fixed
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 15 mA
- Tolerance:
- ±0.5%
- Temperature Coefficient:
- 25ppm/°C
- Noise - 0.1Hz to 10Hz:
- -
- Noise - 10Hz to 10kHz:
- 50µVrms
- Voltage - Input:
- -
- Current - Supply:
- -
- Current - Cathode:
- 67 µA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-3
MAX6138CEXR33+T FAQ
1.How can I place an order for MAX6138CEXR33+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6138CEXR33+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 MAX6138CEXR33+T reliable?
The price and inventory of MAX6138CEXR33+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6138CEXR33+T is usually 5 days.
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4.How is shipping managed for MAX6138CEXR33+T?
MAX6138CEXR33+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6138CEXR33+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 MAX6138CEXR33+T?
For technical support, including MAX6138CEXR33+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6138CEXR33+T requirements.
6.How does Aetrix verify that MAX6138CEXR33+T is sourced from the original manufacturer or authorized distributors?
All MAX6138CEXR33+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 MAX6138CEXR33+T meets industry standards.
7.What is the process for return or replacement of MAX6138CEXR33+T?
All MAX6138CEXR33+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6138CEXR33+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 MAX6138CEXR33+T part is unused and in its original packaging.
Return procedure for MAX6138CEXR33+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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