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Analog Devices Inc./Maxim Integrated MAX9940AXK+T
- Part No.:
- MAX9940AXK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Surge Suppression Ics
- Package:
- 5-TSSOP, SC-70-5, SOT-353
- Datasheet:
-
MAX9940AXK+T.pdf
- Description:
- IC OVERVOLTAGE PROTECTOR SC70-5
- Quantity:
- Payment:
- Shipping:
Inventory:16,171
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Product details
Overview
MAX9940AXK+T from Maxim Integrated is a signal-line overvoltage protector IC designed for low-voltage digital communication ports, featuring 28V fault protection on EXT, ±4kV IEC 61000-4-2 contact ESD rating, 60ns fault reaction time, and operation from +2.2V to +5.5V supply - deployed in 1-Wire interface protection for notebook computers and industrial equipment.
For engineers reviewing the MAX9940AXK+T datasheet, MAX9940AXK+T pinout, MAX9940AXK+T application, or MAX9940AXK+T equivalent, key selection criteria include EXT voltage threshold tracking VCC (±0.16V hysteresis), sub-10nA INT fault leakage at 3.3V, 38pF INT-to-GND off-capacitance, and SC70-5 package compatibility with space-constrained portable designs.
Technical Context
The MAX9940AXK+T integrates a high-speed comparator with 128mV typical hysteresis to monitor EXT voltage relative to VCC, triggering a series DMOS/HV-pMOS switch to isolate INT within 60ns when VEXT exceeds VCC + 0.30V. It operates without internal ESD diode from INT to VCC, enabling INT to float at VDD even with VCC = 0.
Its fault-handling architecture supports three power schemes: ENABLE-controlled shutdown (zero quiescent current), direct VDD biasing, or microcontroller I/O-powered operation - all maintaining 28V DC withstand capability on EXT regardless of VCC state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | +2.2V to +5.5V - enables direct interface with 3.3V and 2.5V microcontrollers without level-shifting. |
| Quiescent Current | 13µA (typ) - allows continuous operation from microcontroller GPIO pins without VOH degradation. |
| EXT Fault Threshold | VCC + 0.26V (typ) rising, VCC + 0.13V (typ) falling - provides robust noise margin against false triggering on noisy lines. |
| On-Resistance | 43.5Ω (min) to 77.5Ω (max) - ensures <100mV voltage drop at ±10mA signal currents, preserving VIH/VIL margins. |
| INT Off-Capacitance | 27pF - minimizes signal distortion and timing skew on high-speed 1-Wire and I²C buses. |
| Fault Reaction Time | 60ns - limits transient energy transfer during ESD events, protecting downstream logic gates. |
| Operating Temperature | -40°C to +125°C - qualified for under-hood automotive and industrial control environments. |
Pinout & Package
MAX9940AXK+T is housed in a lead(Pb)-free, RoHS-compliant 5-pin SC70 package (package code X5-1), measuring 2.0mm × 1.25mm × 0.9mm, suitable for automated SMT assembly and high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VCC | Power supply input | Accepts +2.2V to +5.5V; may be driven by microcontroller ENABLE pin for zero-power shutdown mode. |
| 2 - GND | Ground reference | Common return path for internal comparator, switch, and leakage current paths. |
| 3 - N.C. | No connection | Internally unconnected; must remain floating - no external tie or pull-up/pull-down. |
| 4 - INT | Internal-side I/O port | Connects to microcontroller data line; features no internal ESD diode to VCC, enabling safe VDD-biasing when VCC = 0. |
| 5 - EXT | External connector port | Withstands -0.7V to +28V DC faults and ±4kV IEC 61000-4-2 ESD; includes internal HV-pMOS clamp structure. |
Key Features
| Feature | Design Value |
|---|---|
| 28V EXT fault tolerance | Enables direct protection of 1-Wire/I²C ports connected to unregulated external connectors without series resistors. |
| 60ns fault reaction time | Prevents latch-up or gate oxide damage in downstream CMOS I/O by isolating INT before transient energy propagates. |
| VCC-tracking thresholds | Rising/falling thresholds scale with supply voltage, eliminating recalibration across 2.5V/3.3V/5V systems. |
| Zero-power shutdown mode | VCC = 0 disables internal circuitry while retaining 28V EXT withstand - critical for battery safety during GND shorts. |
| 27pF INT off-capacitance | Preserves rise/fall times on 1-Wire bus (≤1MHz) and standard-mode I²C (100kHz), avoiding timing violations. |
Applications
| 1-Wire Port Protection | I²C Interface Protection |
|---|---|
|
Use Scenario: Notebook computer docking station with exposed 1-Wire ID pins subject to accidental 24V adapter misconnection. IC Role / Device Role / Timing Role: Series switch isolator placed between host microcontroller and external 1-Wire slave device. Use Value: Prevents permanent damage to 3.3V microcontroller I/O while maintaining <100ns timing budget for 1-Wire presence detection. |
Use Scenario: Industrial sensor node using I²C to communicate with remote transducers via long cables prone to induced surges. IC Role / Device Role / Timing Role: Bidirectional signal-line protector on SDA/SCL lines, operating transparently during normal communication. Use Value: Eliminates need for external TVS diodes and series resistors, preserving I²C timing integrity and reducing BOM count by two components. |
| Battery-Powered Diagnostic Tool | Automotive Body Control Module |
|
Use Scenario: Handheld diagnostic tool connecting to vehicle ECUs via exposed OBD-II 1-Wire pins, risking ESD and battery reverse-connection. IC Role / Device Role / Timing Role: Fault-isolating interface IC powered from microcontroller ENABLE pin to enable full shutdown during idle. Use Value: Reduces standby current to <1nA (VCC = 0), extending lithium coin-cell life beyond 5 years in storage mode. |
Use Scenario: Under-dash BCM monitoring door lock status via 1-Wire sensors exposed to 12V/24V battery transients and load dump. IC Role / Device Role / Timing Role: High-reliability overvoltage guard on low-voltage data lines interfacing with external harnesses. Use Value: Qualified to AEC-Q100 Grade 0 (-40°C to +125°C), ensuring uninterrupted operation during cold-cranking and hot-soak conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar signal-line overvoltage protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPD1E05U06DPYR | Single-channel ±5.5V ESD protector (no overvoltage switching); 0.5pF IO capacitance; no VCC supply required. | Limited to ESD-only protection; cannot block sustained >5.5V DC faults like 12V battery misconnects. | Select when only IEC 61000-4-2 compliance is needed and DC fault exposure is absent. |
| SP1001-01UTG | Unidirectional 12V clamping TVS; 150W peak pulse power; no active switching or supply rail. | Clamps but does not isolate; introduces leakage and capacitance above 10pF; no hysteresis control. | Choose for cost-sensitive surge-only protection where signal integrity and low leakage are secondary. |
Compared with TPD1E05U06DPYR and SP1001-01UTG, the MAX9940AXK+T uniquely combines active DC fault isolation, VCC-synchronized thresholding, and sub-10nA fault leakage - making it the only option capable of protecting 1-Wire timing-critical interfaces against both ESD and sustained overvoltage.
Availability
MAX9940AXK+T is available at Aetrix Electronics and suitable for notebook computers, portable diagnostic tools, and industrial sensor nodes requiring stable component supply with guaranteed automotive-grade temperature performance and RoHS compliance.
Supply support for MAX9940AXK+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, automotive, and computing applications.
The MAX9940AXK+T belongs to Maxim's signal-integrity protection product line, engineered specifically to safeguard low-voltage digital interfaces from real-world field faults without compromising timing or power efficiency.
FAQ
What is the maximum continuous voltage the MAX9940AXK+T can withstand on its EXT pin?
The MAX9940AXK+T guarantees continuous DC withstand capability up to +28V on the EXT pin, with absolute maximum rating of +30V. This allows safe operation in scenarios such as 24V system misconnections or industrial cable-induced transients, while maintaining isolation of the protected INT line.
Does the MAX9940AXK+T require an external power supply, or can it operate from a microcontroller GPIO?
The MAX9940AXK+T can be powered directly from a microcontroller GPIO pin via its VCC pin, drawing only 13µA typical quiescent current - well within the drive capability of standard CMOS outputs. This eliminates the need for a dedicated LDO or regulator in space-constrained portable designs.
How does the MAX9940AXK+T behave when VCC = 0V, and is protection still active?
When VCC = 0V, the MAX9940AXK+T enters zero-power shutdown mode, disabling internal circuitry while retaining full 28V DC withstand capability on EXT. The INT pin remains isolated, and no current flows through the internal switch - a critical feature for battery safety during GND shorts.
What is the significance of the N.C. pin (Pin 3) on the MAX9940AXK+T?
Pin 3 of the MAX9940AXK+T is a true no-connect terminal - internally unconnected and electrically isolated. It must remain unconnected on the PCB; adding a trace, pad, or solder mask opening is acceptable, but no external component or net should attach to this pin.
Can the MAX9940AXK+T be used to protect I²C SDA/SCL lines, and what impact does it have on bus timing?
Yes, the MAX9940AXK+T protects bidirectional I²C lines with 27pF off-capacitance and 43.5Ω on-resistance, introducing <5ns additional propagation delay at 100kHz. Its VCC-tracking thresholds prevent false triggering during standard I²C voltage transitions, preserving ACK/NACK timing and clock stretching behavior.
MAX9940AXK+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 5-TSSOP, SC-70-5, SOT-353
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Clamping:
- 28V
- Technology:
- Internal Switch
- Number of Circuits:
- 1
- Applications:
- General Purpose
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-5
MAX9940AXK+T FAQ
1.How can I place an order for MAX9940AXK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX9940AXK+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 MAX9940AXK+T reliable?
The price and inventory of MAX9940AXK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX9940AXK+T is usually 5 days.
3.What payment methods are accepted for MAX9940AXK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX9940AXK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX9940AXK+T?
MAX9940AXK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX9940AXK+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 MAX9940AXK+T?
For technical support, including MAX9940AXK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX9940AXK+T requirements.
6.How does Aetrix verify that MAX9940AXK+T is sourced from the original manufacturer or authorized distributors?
All MAX9940AXK+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 MAX9940AXK+T meets industry standards.
7.What is the process for return or replacement of MAX9940AXK+T?
All MAX9940AXK+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX9940AXK+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 MAX9940AXK+T part is unused and in its original packaging.
Return procedure for MAX9940AXK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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