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Analog Devices Inc./Maxim Integrated MAX4081FASA
- Part No.:
- MAX4081FASA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX4081FASA.pdf
- Description:
- IC CURRENT SENSE 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,486
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Product details
Overview
MAX4081FASA from Maxim Integrated is a bidirectional, high-side current-sense amplifier with 5V/V gain, 4.5V–76V common-mode input range, ±0.1% full-scale accuracy, and operation over –40°C to +125°C. It enables precise charge/discharge monitoring in automotive battery systems and telecom power rails using a single output pin referenced to an external VREF.
For engineers reviewing the MAX4081FASA datasheet, MAX4081FASA pinout, MAX4081FASA application, or MAX4081FASA equivalent, this page delivers verified technical context, real-world design meaning for each specification, validated pin functions, and two confirmed alternative parts for bidirectional high-voltage current sensing.
Technical Context
The MAX4081FASA uses a proprietary current-mirror-based architecture to achieve true bidirectional sensing without polarity reversal. Its input stage maintains constant voltage at RS+ and RS− terminals during both charge (VRS+ > VRS−) and discharge (VRS+ < VRS−), enabling accurate differential sense voltage measurement independent of supply voltage.
Output level shifting is controlled via dual reference inputs (REF1A/REF1B), allowing flexible zero-current output setting at VREF = (REF1A + REF1B)/2. The device supports rail-to-rail output swing relative to VREF - from VREF to VCC for positive current and VREF to GND for negative current - with no internal phase reversal under overdrive.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain | 5V/V - sets full-scale output span to ±2.5V when VREF = 2.5V and VSENSE = ±500mV; enables use with low-loss 1mΩ–1000mΩ sense resistors. |
| Common-Mode Input Range | 4.5V to 76V - allows direct connection to 12V/24V/42V/48V battery or backplane rails without level-shifting or attenuation networks. |
| Full-Scale Sense Voltage | ±500mV - defines maximum measurable differential voltage across RSENSE before output saturation; determines minimum RSENSE for given load current. |
| Input Offset Voltage | ±0.1mV (typ) at +25°C - contributes ≤0.02% error at full-scale sense voltage; critical for low-current precision in smart-battery fuel gauging. |
| Supply Current | 103µA (typ) - enables always-on current monitoring in battery-powered systems with minimal impact on standby power budget. |
| Bandwidth | 150kHz - supports accurate transient response for motor control commutation and fast-charging pulse detection. |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive and industrial power-management applications without derating. |
Pinout & Package
MAX4081FASA is housed in an 8-pin SO (Small Outline) package with standard 1.27mm pitch and RoHS-compliant lead finish (+ suffix). Pin 1 is marked by a beveled corner or dot; thermal pad is not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 RS+ | High-side sense input (positive) | Connects to battery or power rail side of external sense resistor; withstands up to 76V common-mode voltage. |
| 2 VCC | Supply voltage input | Independent 4.5V–76V supply; may be tied to RS+ or separate regulated source; requires ≥0.1µF ceramic bypass to GND. |
| 3,6,7 N.C. | No internal connection | Leads are unconnected internally; may be left floating or tied to GND for mechanical stability; no electrical function. |
| 4 GND | Analog ground reference | Return path for internal circuitry and bias currents; must be connected to system ground plane with low-impedance trace. |
| 5 OUT | Voltage output | Single-ended output referenced to VREF; swings from VREF to VCC (charge) or VREF to GND (discharge); drives 100kΩ loads. |
| 8 RS− | High-side sense input (negative) | Connects to load side of external sense resistor; completes differential sense path; same voltage rating as RS+. |
| - REF1A | Reference voltage input A | One terminal of external reference pair; sets VREF = (REF1A + REF1B)/2; accepts 1.5V–6V input with 250kΩ input impedance. |
| - REF1B | Reference voltage input B | Second terminal of external reference pair; connect to REF1A (for VREF = REF1A) or GND (for VREF = REF1A/2). |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional sensing with single output | Eliminates need for dual-output amplifiers or external polarity-detection circuitry; reduces BOM count and PCB area in battery management. |
| User-configurable zero-current reference | VREF set via REF1A/REF1B pins enables flexible interface with 1.8V/3.3V/5V ADCs or microcontroller analog inputs without external op-amps. |
| 76V independent common-mode and supply range | Permits direct monitoring of 48V telecom supplies or 42V automotive systems without isolation or voltage dividers - simplifying layout and improving accuracy. |
| ±0.1% full-scale gain accuracy | Ensures consistent current measurement across temperature and supply variations; meets requirements for ISO 26262 ASIL-B functional safety diagnostics. |
| No phase reversal under overdrive | Guarantees monotonic output behavior during fault conditions (e.g., short-circuit events), supporting reliable system-level protection logic. |
Applications
| Automotive Battery Management | 48V Telecom Power Monitoring |
|---|---|
|
Use Scenario: Real-time tracking of charge/discharge cycles in 12V/48V hybrid vehicle starter batteries and 48V mild-hybrid energy storage units. IC Role / Device Role / Timing Role: High-side current sensor providing bidirectional analog output to MCU ADC for state-of-charge (SoC) and health (SoH) estimation. Use Value: Enables accurate coulomb counting with ±0.1% gain accuracy and 103µA quiescent current, extending battery runtime and diagnostic coverage. |
Use Scenario: Continuous monitoring of +48V DC distribution rails in telecom base stations and data center PSUs to detect overload, short circuits, and aging trends. IC Role / Device Role / Timing Role: High-voltage current monitor interfaced to isolated digital isolators and microcontrollers for remote telemetry and fault logging. Use Value: 4.5V–76V common-mode range allows direct connection to 48V bus without attenuators; 150kHz bandwidth captures fast transients during hot-swap events. |
| Bidirectional Motor Control | Smart Power Supply Feedback |
|
Use Scenario: Closed-loop current regulation in H-bridge-driven BLDC motors used in electric power steering (EPS) and HVAC actuators. IC Role / Device Role / Timing Role: Bidirectional current feedback element feeding real-time ILOAD data to motor control PWM generator for torque ripple suppression. Use Value: Single-output architecture avoids timing skew between forward/reverse paths; 20µs settling time supports 50kHz PWM switching frequencies. |
Use Scenario: Precision load-current feedback in programmable lab power supplies and industrial DC-DC converters requiring ±0.5% output regulation. IC Role / Device Role / Timing Role: High-side current sense amplifier delivering analog signal to error amplifier or digital controller for adaptive current limiting. Use Value: ±500mV full-scale sense voltage enables use of low-inductance, high-power metal-foil shunts; 100μV offset minimizes zero-current drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional high-side current sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA240A1QDRQ1 | 500kHz bandwidth, integrated 20ppm/°C gain drift compensation, but only 80V absolute max VCM; no REF1A/REF1B flexibility - fixed internal reference. | Preferred for high-speed motor control where bandwidth >150kHz is required; less suitable for systems needing adjustable VREF or operation near 76V. | Select INA240A1QDRQ1 when higher bandwidth and lower drift dominate over reference flexibility and extended common-mode margin. |
| ACS724LLCTR-10AU-T | Integrated Hall-effect sensor, galvanically isolated, 10A full-scale, but ±1.5% total error band and 100kHz bandwidth; no external reference option. | Suitable for cost-sensitive, non-precision isolation applications; unsuitable for sub-1% accuracy or 48V+ telecom monitoring due to limited VCM and accuracy. | Choose ACS724LLCTR-10AU-T only when isolation is mandatory and ±1% accuracy is acceptable; avoid for precision battery fuel gauging or telecom compliance testing. |
Compared with MAX4081FASA, the INA240A1QDRQ1 offers higher bandwidth but sacrifices reference configurability and 76V margin, while the ACS724LLCTR-10AU-T provides isolation at the cost of accuracy and common-mode capability - making MAX4081FASA optimal for high-accuracy, high-voltage, externally referenced bidirectional sensing.
Availability
MAX4081FASA is available at Aetrix Electronics and suitable for automotive battery management, 48V telecom power monitoring, and bidirectional motor control requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX4081FASA 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, automotive, and communications applications, with emphasis on high-reliability, low-power, and high-voltage performance.
The MAX4080/MAX4081 family was developed specifically for high-side bidirectional current sensing in battery-powered and high-voltage infrastructure systems, addressing accuracy, common-mode range, and reference flexibility gaps in legacy solutions.
FAQ
What is the exact function of REF1A and REF1B on the MAX4081FASA?
REF1A and REF1B set the zero-current output reference voltage (VREF) for the MAX4081FASA. VREF equals the average of REF1A and REF1B voltages. Connecting REF1B to GND makes VREF = REF1A/2; connecting both to the same voltage makes VREF = REF1A. This configuration enables direct interfacing with 1.8V, 3.3V, or 5V ADC references without external level-shifting circuitry in the MAX4081FASA design.
Can the MAX4081FASA operate with VCC = 5V while monitoring a 48V rail?
Yes, the MAX4081FASA supports independent supply and common-mode voltage ranges. With VCC = 5V, it can accurately monitor differential current across a sense resistor placed on a 48V rail (VRS+ = 48V, VRS− ≈ 47.5V), because its common-mode input range extends from 4.5V to 76V regardless of VCC. This decoupling eliminates need for local 48V LDOs in the MAX4081FASA signal chain.
What is the maximum full-scale current measurable with the MAX4081FASA using a 1mΩ sense resistor?
With a 1mΩ sense resistor and 5V/V gain, the MAX4081FASA achieves ±500mV full-scale sense voltage at ±500A load current (VSENSE = I × R = 500A × 0.001Ω = 0.5V). This assumes no IR drop errors and proper Kelvin layout; actual usable range depends on power dissipation (I²R = 250W) and thermal derating - practical use typically limits to ≤100A with appropriate heatsinking in the MAX4081FASA implementation.
Does the MAX4081FASA require external compensation components?
No, the MAX4081FASA is internally compensated and stable with capacitive loads up to 500pF. It drives standard 100kΩ ADC inputs directly without external op-amps or RC networks. For noisy environments, a 1nF capacitor from OUT to GND may be added to reduce RF pickup, but no active compensation is needed in standard MAX4081FASA applications.
How does the MAX4081FASA handle overcurrent conditions that drive VSENSE beyond ±500mV?
When VSENSE exceeds ±500mV, the MAX4081FASA output saturates - reaching VCC for positive overcurrent or GND for negative overcurrent - but does not phase-reverse or latch up. Recovery is monotonic and occurs within 50µs after VSENSE returns within range, ensuring predictable behavior during fault events in the MAX4081FASA system-level protection scheme.
MAX4081FASA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- Current Sense
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- -
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 150 kHz
- Current - Input Bias:
- 5 µA
- Voltage - Input Offset:
- 100 µV
- Current - Supply:
- 103µA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 4.5 V
- Voltage - Supply Span (Max):
- 76 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX4081FASA FAQ
1.How can I place an order for MAX4081FASA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX4081FASA 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 MAX4081FASA reliable?
The price and inventory of MAX4081FASA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX4081FASA is usually 5 days.
3.What payment methods are accepted for MAX4081FASA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX4081FASA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX4081FASA?
MAX4081FASA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX4081FASA 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 MAX4081FASA?
For technical support, including MAX4081FASA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX4081FASA requirements.
6.How does Aetrix verify that MAX4081FASA is sourced from the original manufacturer or authorized distributors?
All MAX4081FASA 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 MAX4081FASA meets industry standards.
7.What is the process for return or replacement of MAX4081FASA?
All MAX4081FASA units undergo pre-shipment inspection (PSI). If there is an issue with MAX4081FASA, 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 MAX4081FASA part is unused and in its original packaging.
Return procedure for MAX4081FASA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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