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Analog Devices Inc./Maxim Integrated MAX22518AWA+T
- Part No.:
- MAX22518AWA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MAX22518AWA+T.pdf
- Description:
- DUAL CHANNEL DIGITAL ISOLATOR WI
- Quantity:
- Payment:
- Shipping:
Inventory:4,465
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Product details
Overview
The MAX22518AWA+T from Analog Devices is a dual-channel, self-powered digital galvanic isolator with integrated isolated DC-DC converter, 3.5kVRMS withstand isolation voltage (60s), ±1kV line-to-ground surge tolerance, and open-drain logic-side outputs. It enables robust field-side signal monitoring in industrial relay contact detection systems without external isolated power.
For engineers reviewing the MAX22518AWA+T datasheet, MAX22518AWA+T pinout, MAX22518AWA+T application, or MAX22518AWA+T equivalent, this page delivers verified electrical specs, validated pin functions, confirmed safety certifications (UL1577, cUL), real-world protection ratings (±2kV line-to-line, 24VAC short-tolerant), and precise alternative part comparisons for industrial I/O design.
Technical Context
The MAX22518AWA+T implements unidirectional field-to-logic data transfer using capacitive isolation with integrated 750MHz switching DC-DC converter generating VDDF (nominal 3.3V) from VDDL (3.0–5.5V). Its input charge pump delivers 5.25V boost voltage and 5μA typical current to clean relay contacts.
It features dual open-drain outputs (OUT1L/OUT2L) with high-impedance default state during undervoltage, field-side input protection via external 10kΩ resistors, and guaranteed CMTI ≥50kV/μs. All channels operate continuously without enable control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Withstand Voltage | 3.5kVRMS for 60s - certifies basic insulation per UL1577 for single-protection applications |
| Continuous Working Voltage | 445VRMS - defines maximum steady-state voltage across isolation barrier |
| Surge Immunity | ±1kV line-to-ground (IEC 61000-4-5, 1.2/50μs) - enables direct connection to 24VAC field inputs with 10kΩ series resistor |
| Field-Side Supply Capability | 220μA at <100kbps - powers external window comparators or contact-sense circuitry without auxiliary supply |
| Data Rate | 1Mbps - supports fast status polling of multiple relays in industrial PLC I/O modules |
| Common-Mode Transient Immunity | ≥50kV/μs - prevents false triggering in noisy motor drive or solenoid environments |
| Operating Temperature | -40°C to +125°C - qualified for use inside enclosures near industrial heat sources |
Pinout & Package
Package: 8-pin wide-body SOIC (W8MS+1), 5.5mm creepage/clearance, CTI ≥400 (Group II), RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 IN1F | Field-side input channel 1 | Accepts 24VAC/DC signals; includes internal charge pump (5.25V, 5μA) for relay contact cleaning |
| 2 IN2F | Field-side input channel 2 | Identical function to IN1F; independent channel for dual-contact monitoring |
| 3 VDDF | Field-side regulated supply output | 3.3V nominal output from integrated DC-DC; powers internal circuitry and ≤220μA external load |
| 4 GNDF | Field-side ground reference | Isolated return path for field-side circuits; must be separated from GNDL by ≥5.5mm |
| 5 GNDL | Logic-side ground reference | Return for VDDL and logic outputs; forms isolation barrier boundary with GNDF |
| 6 VDDL | Logic-side supply input | 3.0–5.5V input powering both logic side and isolated DC-DC converter |
| 7 OUT2L | Logic-side open-drain output 2 | Requires external pullup to VDDL; defaults to high-impedance during UVLO or open-circuit input |
| 8 OUT1L | Logic-side open-drain output 1 | Same behavior as OUT2L; provides isolated status indication for IN1F |
Key Features
| Feature | Design Value |
|---|---|
| Integrated isolated field-side supply | Eliminates need for external isolated DC-DC module, reducing BOM count and PCB area in space-constrained I/O modules |
| Input charge pump with 5.25V boost | Delivers wetting current to break oxide layers on relay contacts, enabling reliable detection of low-current closures |
| ±2kV line-to-line surge tolerance | Withstands common-mode transients between field inputs without external TVS, simplifying protection design |
| 24VAC continuous short protection | Allows direct connection to AC field wiring without risk of latch-up or damage when contacts weld closed |
| High-impedance output default | Prevents false logic assertions during power brownouts or field-side supply loss - critical for fail-safe system behavior |
Applications
| Relay Contact Monitoring | Industrial PLC Digital Input Module |
|---|---|
Use Scenario: Continuous monitoring of electromechanical relay status in factory automation panels where contact oxidation causes intermittent failures. IC Role / Device Role / Timing Role: Field-side input conditioner and galvanic isolator; transfers contact closure/open states across isolation barrier with <130ns propagation delay. Use Value: Charge pump cleans relay contacts in real time, eliminating manual maintenance and improving uptime in legacy relay-based control systems. |
Use Scenario: 16-channel DIN-rail mounted digital input module accepting 24VDC field signals in harsh manufacturing environments. IC Role / Device Role / Timing Role: Dual-channel isolation interface per channel pair; provides reinforced isolation, surge immunity, and local field-side power for sensor biasing. Use Value: Integrated VDDF supply powers optocoupler bias or level-shifting circuitry, removing need for separate isolated rails and cutting transformer count by 50%. |
| Building Automation System Input | Medical Equipment Isolated Status Interface |
Use Scenario: HVAC controller reading dry-contact signals from fire dampers, door switches, and occupancy sensors across large facility wiring runs. IC Role / Device Role / Timing Role: Galvanic isolator with 5.5mm creepage; handles long cable-induced surges and ground potential differences between zones. Use Value: ±1kV line-to-ground surge rating meets IEC 61000-4-5 Level 3 requirements, ensuring reliable operation without additional transient suppressors. |
Use Scenario: Patient-connected diagnostic device requiring reinforced isolation between front-panel controls and internal microcontroller. IC Role / Device Role / Timing Role: Safety-isolated status reporter; conveys switch actuation or sensor alerts while maintaining 445VRMS working voltage compliance. Use Value: UL1577 and cUL certification supports Class I medical device safety documentation, reducing regulatory test burden. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel digital isolator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX22517AWA+T | Push-pull outputs with logic-high default; no open-drain requirement; same pinout and isolation specs | Better suited for direct MCU GPIO interfacing without pullup resistors; less tolerant of floating logic-side inputs | Select when driving CMOS inputs directly and system requires active-high default assertion on power loss |
| ISO6721DWR | 2-channel, 5000VRMS isolation, 50kV/μs CMTI, but no integrated field-side supply; requires external isolated bias | Higher isolation rating for medical/safety-critical systems; lacks self-powering capability for field-side peripherals | Select when maximum isolation robustness is required and field-side power can be provided externally |
Compared with MAX22517AWA+T, the MAX22518AWA+T's open-drain outputs reduce static power in high-impedance bus configurations, while versus ISO6721DWR, its integrated VDDF eliminates board-level DC-DC complexity - making it optimal for cost-sensitive, space-constrained industrial I/O where field-side load is ≤220μA.
Availability
MAX22518AWA+T is available at Aetrix Electronics and suitable for industrial IoT edge nodes, building automation controllers, and PLC digital input modules requiring stable component supply, long-term lifecycle support, and certified isolation performance.
Supply support for MAX22518AWA+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
Analog Devices, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision, power, and connectivity applications.
The MAX22517–MAX22519 family was designed specifically for industrial field-side signal acquisition - integrating isolation, power, and protection into a single compact package to simplify rugged I/O interface design.
FAQ
What is the isolation voltage rating of the MAX22518AWA+T and how is it certified?
The MAX22518AWA+T has a 3.5kVRMS isolation withstand voltage rated for 60 seconds per UL1577 and CSA Bulletin 5A (cUL), with a continuous working voltage of 445VRMS. It is certified under UL File E351759 for single-protection applications and meets IEC 60747-5-5 requirements for VIOWM and VISO. This rating applies across the full -40°C to +125°C operating range.
Does the MAX22518AWA+T require external components to operate safely with 24VAC field inputs?
Yes - the MAX22518AWA+T requires a minimum 10kΩ series resistor on each IN1F and IN2F input to achieve ±1kV line-to-ground and ±2kV line-to-line surge immunity per IEC 61000-4-5, and to tolerate continuous shorts to 24VAC. No TVS diode is required if the resistor value and capacitor sizing follow the guidelines in the datasheet's Typical Application Circuits section.
How does the integrated field-side supply (VDDF) of the MAX22518AWA+T function and what load can it drive?
The MAX22518AWA+T generates VDDF (nominal 3.3V) from VDDL via an integrated 750MHz isolated DC-DC converter. At data rates below 100kbps, it can supply up to 220μA to external field-side circuitry such as window comparators or relay detection logic. VDDF must be bypassed with 0.1μF || 1000pF ceramic capacitors placed adjacent to the pin.
What is the purpose of the input charge pump in the MAX22518AWA+T and which pins does it affect?
The input charge pump on the MAX22518AWA+T delivers a 5.25V boost voltage and ~5μA current to IN1F and IN2F, enabling "wetting current" to clean oxidation from relay contacts during closure. This feature ensures reliable detection of low-current mechanical contacts without external circuitry and is active only on MAX22517/MAX22518 - not MAX22519.
What happens to the outputs of the MAX22518AWA+T during undervoltage conditions on VDDL or VDDF?
When either VDDL or VDDF falls below its respective undervoltage lockout threshold (2.82V typ for VDDL, 2.1V typ for VDDF), both OUT1L and OUT2L immediately enter high-impedance default state - regardless of input conditions. This fail-safe behavior prevents false logic assertions during power brownouts or field-side supply collapse, ensuring safe system response in industrial control applications.
MAX22518AWA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Capacitive Coupling
- Type:
- General Purpose
- Isolated Power:
- No
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 2/0
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 3500Vrms
- Common Mode Transient Immunity (Min):
- 50kV/µs (Typ)
- Data Rate:
- 1Mbps
- Propagation Delay tpLH / tpHL (Max):
- 130ns, 130ns
- Pulse Width Distortion (Max):
- 20ns
- Rise / Fall Time (Typ):
- 20ns, 20ns
- Voltage - Supply:
- 3V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX22518AWA+T FAQ
1.How can I place an order for MAX22518AWA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX22518AWA+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 MAX22518AWA+T reliable?
The price and inventory of MAX22518AWA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX22518AWA+T is usually 5 days.
3.What payment methods are accepted for MAX22518AWA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX22518AWA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX22518AWA+T?
MAX22518AWA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX22518AWA+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 MAX22518AWA+T?
For technical support, including MAX22518AWA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX22518AWA+T requirements.
6.How does Aetrix verify that MAX22518AWA+T is sourced from the original manufacturer or authorized distributors?
All MAX22518AWA+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 MAX22518AWA+T meets industry standards.
7.What is the process for return or replacement of MAX22518AWA+T?
All MAX22518AWA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX22518AWA+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 MAX22518AWA+T part is unused and in its original packaging.
Return procedure for MAX22518AWA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX22518AWA+T Tags
-
ISO1212DBQR
Texas Instruments
-
ISO6721BDR
Texas Instruments
-
SI8710AC-B-ISR
Skyworks Solutions Inc.
-
ISO7720FDR
Texas Instruments
-
ISO7721DR
Texas Instruments
-
ISO7721FDR
Texas Instruments
-
SI8710CC-B-ISR
Skyworks Solutions Inc.
-
ISO6741FQDWRQ1
Texas Instruments
-
ISO7721DWVR
Texas Instruments
-
ISO7762FDBQR
Texas Instruments
-
ISO7741DWR
Texas Instruments
-
ISO7741FDWR
Texas Instruments
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