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Analog Devices Inc./Maxim Integrated MAX9938WEUK+T
- Part No.:
- MAX9938WEUK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX9938WEUK+T.pdf
- Description:
- IC CURR SENSE 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,592
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Product details
Overview
MAX9938WEUK+T from Maxim Integrated is a unidirectional high-side current-sense amplifier with 200V/V fixed gain, 500μV max input offset voltage, <0.7% max gain error over -40°C to +85°C, and ultra-low 1μA max quiescent supply current. It operates from 1.6V to 28V input common-mode voltage and delivers voltage output for precision battery current monitoring in portable electronics.
For engineers reviewing the MAX9938WEUK+T datasheet, MAX9938WEUK+T pinout, MAX9938WEUK+T application, or MAX9938WEUK+T equivalent, key selection criteria include high common-mode rejection (94–130dB), low-voltage-drop sensing capability (15mV full-scale VSENSE), SOT23-5 package compatibility, and nanoPower operation for battery runtime optimization.
Technical Context
The MAX9938WEUK+T uses a BiCMOS-based current-mirror architecture with matched internal gain resistors (R1 = 100Ω, ROUT = 20kΩ) to achieve 200V/V gain accuracy. Its input stage accepts common-mode voltages up to 28V while rejecting noise via 130dB CMRR at DC and >94dB across 1kHz–1MHz.
No external power supply pin is required-the device derives operating bias from the sensed rail (RS+/RS−). Output settling time is 100μs to 1% final value, and small-signal bandwidth is 15kHz at 200V/V gain, enabling stable response to fast load transients in DC-DC converter feedback paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain | 200V/V - enables use of 15mV full-scale sense voltage for minimal IR drop in battery discharge paths |
| Input Offset Voltage | ±500μV max - ensures ≤0.1% measurement error at 15mV VSENSE, critical for low-current battery monitoring |
| Gain Error | ±0.7% max over -40°C to +85°C - supports accurate current reporting across industrial temperature range without calibration |
| Supply Current | 1μA max - extends battery life in always-on monitoring circuits such as smart battery gauges |
| Common-Mode Range | 1.6V to 28V - allows direct sensing on Li-ion (2.5–4.2V), 12V automotive, and 24V industrial rails |
| Output Settling Time | 100μs to 1% - supports sampling rates up to ~10kHz for dynamic load profiling in portable systems |
| Small-Signal Bandwidth | 15kHz - sufficient for filtering switching ripple from buck/boost converters while preserving DC current accuracy |
Pinout & Package
MAX9938WEUK+T is housed in a RoHS-compliant 5-pin SOT23 package (package code U5-2, outline 21-0057), measuring 2.9mm × 1.6mm × 1.1mm with gull-wing leads. The package supports reflow soldering per JEDEC J-STD-020 (peak 260°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SOT23) | OUT | Voltage output proportional to VSENSE × 200; drives ADC input or comparator with 14–26.4kΩ output resistance |
| 2 (SOT23) | RS− | Load-side connection to external sense resistor; referenced to GND for unidirectional current measurement |
| 3 (SOT23) | GND | Analog ground reference for internal circuitry and output stage; must be low-impedance path to system GND |
| 4 (SOT23) | RS+ | Power-side connection to external sense resistor; carries full load current and defines common-mode input voltage |
| 5 (SOT23) | GND | Second ground terminal-internally tied to Pin 3; improves PSRR and reduces ground bounce in noisy environments |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low quiescent current | 1μA max enables multi-year operation on coin-cell batteries in IoT sensor nodes and wearables |
| High common-mode rejection | 94–130dB CMRR suppresses noise from switching regulators and EMI-coupled interference in compact PCB layouts |
| Wide input common-mode range | 1.6V–28V supports single-device deployment across Li-ion, 3.3V logic, 12V automotive, and 24V industrial rails |
| Low-voltage-sense capability | 15mV full-scale VSENSE minimizes power loss in high-current paths-critical for thermal management in portable devices |
| Stable output drive | Output clamped to 6V with 7mA current limit protects downstream ADC inputs during overvoltage fault conditions |
Applications
| Battery Fuel Gauging | USB-C Power Delivery Monitoring |
|---|---|
|
Use Scenario: Real-time tracking of charge/discharge current in smartphone or tablet battery packs using a single sense resistor. IC Role / Device Role / Timing Role: High-side current-sense amplifier converting mV-level VSENSE into amplified voltage for microcontroller ADC sampling. Use Value: Enables ±0.5% current accuracy over full battery voltage range (2.8V–4.4V), supporting precise coulomb counting and state-of-charge estimation. |
Use Scenario: Measuring source/sink current in USB-C PD 3.0 power adapters and portable chargers with programmable voltage/current profiles. IC Role / Device Role / Timing Role: Unidirectional high-side monitor on the 5–20V output rail, feeding analog feedback to PD controller. Use Value: Maintains <0.7% gain error across 0–100°C ambient, ensuring compliance with USB PD power budget reporting requirements. |
| Industrial Portable Test Equipment | Medical Wearable Battery Management |
|
Use Scenario: Current monitoring in handheld multimeters and battery-powered oscilloscopes requiring sub-1μA standby current. IC Role / Device Role / Timing Role: Precision current sensor interfacing directly to SAR ADC with no external op-amp buffering. Use Value: 100μs settling time and 15kHz bandwidth support 10ksps sampling for real-time current waveform capture. |
Use Scenario: Continuous battery discharge monitoring in FDA-cleared wearable ECG patches with 5-year shelf life. IC Role / Device Role / Timing Role: NanoPower current amplifier driving low-leakage input of medical-grade delta-sigma ADC. Use Value: 1μA max ICC preserves >95% of battery capacity over 5 years in storage, meeting ISO 13485 reliability targets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-side current-sense amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA219BIDR | I²C digital output; 0.1% gain error; 26V common-mode; 100μA supply current | Requires MCU I²C interface; lacks analog voltage output for direct ADC connection | Select when digital bus integration and auto-ranging are prioritized over analog simplicity and ultra-low ICC |
| MAX4008AUB+ | 200V/V gain; 125μV max VOS; 2.5μA ICC; 28V common-mode; 6-pin μDFN only | Lower offset improves sub-10mA measurement resolution but doubles supply current vs. MAX9938WEUK+T | Select when highest DC accuracy is mandatory and 1.5μA additional ICC is acceptable in battery budget |
Compared with INA219BIDR and MAX4008AUB+, the MAX9938WEUK+T uniquely combines 200V/V analog gain, 1μA ICC, and SOT23-5 packaging-making it optimal for cost-sensitive, space-constrained, analog-output designs where MCU resources or board area are limited.
Availability
MAX9938WEUK+T is available at Aetrix Electronics and suitable for battery fuel gauging, USB-C power delivery monitoring, and industrial portable test equipment requiring stable component supply, long-lifecycle availability, and RoHS-compliant sourcing.
Supply support for MAX9938WEUK+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 precision analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.
The MAX9938 family was designed for ultra-low-power, high-accuracy current sensing in battery-operated portable systems-emphasizing nanoPower operation, wide common-mode range, and analog output simplicity.
FAQ
What is the maximum input common-mode voltage supported by the MAX9938WEUK+T?
The MAX9938WEUK+T supports an input common-mode voltage range from +1.6V to +28V. This allows direct sensing on low-voltage Li-ion cells (down to 1.6V) and high-voltage industrial rails (up to 28V), without requiring level-shifting circuitry. The specification is guaranteed over the full -40°C to +85°C operating temperature range.
Does the MAX9938WEUK+T require an external power supply pin?
No, the MAX9938WEUK+T does not have a dedicated VCC pin. It derives all operating bias from the sensed voltage applied across RS+ and RS−. This eliminates the need for a separate supply rail and simplifies layout in space-constrained portable designs where the MAX9938WEUK+T is deployed.
What is the full-scale sense voltage (VSENSE) for the MAX9938WEUK+T at 200V/V gain?
For optimal accuracy and minimal IR drop, the recommended full-scale VSENSE for the MAX9938WEUK+T is 15mV. At 200V/V gain, this produces a 3V output swing-well within the 0–6V output clamp range and compatible with standard 3.3V ADC references. This value is derived from the 500μV max input offset and 0.7% max gain error specifications.
Can the MAX9938WEUK+T be used in bidirectional current sensing applications?
The MAX9938WEUK+T is a unidirectional high-side current-sense amplifier and cannot directly measure reverse current flow. However, bidirectional functionality can be implemented using two MAX9938WEUK+T devices-one sensing charge current (RS+ toward battery positive) and one sensing discharge current (RS+ toward load)-with outputs referenced to a common ground.
What is the output resistance and voltage swing limitation of the MAX9938WEUK+T?
The MAX9938WEUK+T has an output resistance of 14–26.4kΩ (typical 20kΩ) and features a 6V output clamp. Its output high voltage VOH is defined as VRS− − VOUT, with a typical value of 0.1–0.2V. Therefore, maximum usable VOUT is constrained by the minimum RS+ voltage minus VSENSE(max) minus VOH-e.g., at 1.6V RS+, VOUT(max) ≈ 1.6V − 0.015V − 0.2V = 1.385V.
MAX9938WEUK+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Current Sense
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- -
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 15 kHz
- Current - Input Bias:
- -
- Voltage - Input Offset:
- 100 µV
- Current - Supply:
- 1.1µA
- Current - Output / Channel:
- -
- Voltage - Supply Span (Min):
- 1.6 V
- Voltage - Supply Span (Max):
- 28 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX9938WEUK+T FAQ
1.How can I place an order for MAX9938WEUK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX9938WEUK+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 MAX9938WEUK+T reliable?
The price and inventory of MAX9938WEUK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX9938WEUK+T is usually 5 days.
3.What payment methods are accepted for MAX9938WEUK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX9938WEUK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX9938WEUK+T?
MAX9938WEUK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX9938WEUK+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 MAX9938WEUK+T?
For technical support, including MAX9938WEUK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX9938WEUK+T requirements.
6.How does Aetrix verify that MAX9938WEUK+T is sourced from the original manufacturer or authorized distributors?
All MAX9938WEUK+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 MAX9938WEUK+T meets industry standards.
7.What is the process for return or replacement of MAX9938WEUK+T?
All MAX9938WEUK+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX9938WEUK+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 MAX9938WEUK+T part is unused and in its original packaging.
Return procedure for MAX9938WEUK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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