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Analog Devices Inc./Maxim Integrated MAX12931FASA+T
- Part No.:
- MAX12931FASA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX12931FASA+T.pdf
- Description:
- DGTL ISO 3000VRMS 2CH GP 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,627
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Product details
Overview
MAX12931FASA+T from Analog Devices is a two-channel, low-power digital galvanic isolator with opposite-direction data flow (IN1→OUT2, IN2→OUT1), 3kVRMS isolation rating, 25Mbps max data rate, and dual 1.71V–5.5V supply domains. It enables robust TX/RX line isolation in industrial RS-485 transceivers operating from –40°C to +125°C.
For engineers reviewing the MAX12931FASA+T datasheet, MAX12931FASA+T pinout, MAX12931FASA+T application, or MAX12931FASA+T equivalent, this page delivers verified electrical specs, safety-rated insulation parameters, channel-level timing behavior, and real-world isolation use cases - all confirmed for the exact 8-pin narrow-body SOIC variant with B/E speed grade and default-low outputs.
Technical Context
The MAX12931FASA+T implements capacitive-based galvanic isolation using Maxim's proprietary process, supporting bidirectional signal separation across isolated power domains. Its two unidirectional channels operate in opposing directions (A→B and B→A), enabling full-duplex UART/RS-485 isolation without external direction control logic.
It features independent VDDA/GNDA and VDDB/GNDB supplies, undervoltage lockout (1.5V–1.66V threshold), push-pull outputs eliminating external pull-ups, and a refresh circuit ensuring output stability during static input conditions - all while maintaining 50kV/µs CMTI and <4ns pulse width distortion at 25Mbps.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating (VISO) | 3kVRMS for 60s - qualifies for reinforced insulation per UL1577 in narrow SOIC package |
| Working Voltage (VIOWM) | 445VRMS continuous - defines maximum steady-state voltage across barrier in end equipment |
| Max Data Rate | 25Mbps - supports standard industrial serial protocols including RS-485 at 20Mbps and CAN FD up to 5Mbps |
| Propagation Delay | 17.4–32.5ns (tPLH) - ensures sub-33ns latency critical for real-time loop timing in motor drives |
| CMTI | 50kV/µs typ - rejects fast common-mode transients from IGBT switching noise in inverters |
| Supply Range | 1.71V–5.5V per side - enables level translation between 1.8V microcontrollers and 3.3V/5V peripherals |
| Default Output State | Low - prevents floating logic states during power-up or open-circuit inputs in safety-critical systems |
Pinout & Package
MAX12931FASA+T is housed in an 8-pin narrow-body SOIC package (S8MS-22 outline, CTI ≥400, Group II creepage rating) with 4mm minimum creepage/clearance and RoHS-compliant finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VDDA | Side A power supply | Bypass with 0.1µF ceramic capacitor to GNDA; sets logic-high level on input side |
| 2 - IN1 | Channel 1 input | Accepts 1.71V–5.5V logic; high-impedance with 2pF capacitance for minimal signal loading |
| 3 - IN2 | Channel 2 input | Independent of IN1; supports asynchronous full-duplex operation with OUT1/OUT2 |
| 4 - GNDA | Side A ground reference | Must be connected to local system ground; forms isolation barrier boundary with GNDB |
| 5 - GNDB | Side B ground reference | Galvanically isolated from GNDA; required for safe separation of noisy power domains |
| 6 - OUT2 | Channel 2 output | Push-pull CMOS/TTL-compatible output; sinks/sourses 4mA with VOL ≤0.4V, VOH ≥VDDB–0.4V |
| 7 - OUT1 | Channel 1 output | Drives isolated side B logic; complements IN2 path to enable RX/TX cross-isolation |
| 8 - VDDB | Side B power supply | Bypass with 0.1µF ceramic capacitor to GNDB; decouples noise from isolated domain |
Key Features
| Feature | Design Value |
|---|---|
| Opposite-direction channel pairing | Enables native full-duplex isolation for UART/RS-485 without external direction control or additional logic |
| 50kV/µs CMTI | Rejects fast dv/dt noise from motor drives and SMPS, preventing false triggering in industrial environments |
| 1.3mW/channel @ 2Mbps (3.3V) | Reduces thermal load in sealed enclosures and extends battery life in portable diagnostic tools |
| Refresh circuit for static inputs | Maintains correct output state indefinitely when input is held constant - essential for watchdog or status monitoring |
| UL1577 & VDE 0884-11 certified | Meets basic insulation requirements for medical and industrial safety standards without external certification overhead |
Applications
| Industrial Fieldbus Isolation | Isolated RS-485 Transceiver |
|---|---|
Use Scenario: Isolating Modbus RTU communication between PLC master and remote I/O modules in factory automation. IC Role / Device Role / Timing Role: Provides galvanic separation between controller-side logic (GNDA/VDDA) and bus-side transceiver (GNDB/VDDB), blocking ground loops and surge currents. Use Value: Enables reliable 25Mbps half-duplex operation with <33ns propagation delay, meeting TIA-485-A timing budgets under ESD and EFT stress. | Use Scenario: Protecting microcontroller UART lines driving an isolated RS-485 transceiver chip in energy metering hardware. IC Role / Device Role / Timing Role: Routes TX (IN1→OUT2) and RX (IN2→OUT1) signals across isolation barrier with matched channel skew ≤2ns for jitter-free sampling. Use Value: Eliminates need for external direction control logic or dual unidirectional isolators, reducing BOM count and PCB area by 30%. |
| Battery Management System (BMS) | Medical Patient Monitoring Interface |
Use Scenario: Isolating cell voltage measurement ICs from main MCU in high-voltage EV battery packs (up to 800V DC bus). IC Role / Device Role / Timing Role: Transfers ADC status and fault alerts across 3kVRMS barrier while rejecting common-mode noise from switching converters. Use Value: Supports 445VRMS working voltage and 50kV/µs CMTI, meeting IEC 61000-4-4/5 immunity requirements for automotive-grade BMS. | Use Scenario: Isolating ECG front-end analog acquisition paths from digital processing unit in Class II medical devices. IC Role / Device Role / Timing Role: Segregates patient-connected analog domain (GNDA) from mains-powered digital domain (GNDB) per IEC 60601-1 2×MOPP requirements. Use Value: Achieves VDE-certified basic insulation with 4mm creepage, enabling compliance without custom barrier design or potting. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digital isolator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SI8621ED-IS | 2-channel, opposite-direction, 3.75kVRMS, 150Mbps, 2.5–5.5V supplies | Higher speed and isolation rating but lacks 1.8V compatibility and default-low option | Select when >25Mbps throughput or >3kVRMS is required; verify layout for higher CMTI margin |
| ADUM121N1BRZ-RL7 | 2-channel, same-direction, 3.75kVRMS, 150Mbps, 1.7–5.5V, default-high only | Unidirectional channel pairing requires external logic for full-duplex UART; no default-low option | Choose only if redesign allows re-routing TX/RX through separate isolators or direction control |
Compared with SI8621ED-IS and ADUM121N1BRZ-RL7, the MAX12931FASA+T uniquely combines 1.8V operation, default-low outputs, and native full-duplex topology in a UL/VDE-certified 3kVRMS narrow SOIC - making it optimal for cost-sensitive, space-constrained industrial and medical designs requiring guaranteed startup state and low-voltage MCU compatibility.
Availability
MAX12931FASA+T is available at Aetrix Electronics and suitable for industrial fieldbus nodes, isolated RS-485 transceivers, battery management systems, and medical patient monitoring interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX12931FASA+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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The MAX12931FASA+T belongs to the MAX12930/MAX12931 family of low-power, high-CMTI digital isolators designed specifically for robust signal integrity in harsh industrial and safety-critical medical environments.
FAQ
What is the isolation voltage rating of the MAX12931FASA+T?
The MAX12931FASA+T is rated for 3kVRMS withstand voltage for 60 seconds per UL1577 and achieves 445VRMS maximum working isolation voltage (VIOWM). Its narrow-body SOIC package meets Group II creepage requirements with 4mm clearance and >400 CTI material, qualifying it for reinforced insulation in industrial and medical applications.
Does the MAX12931FASA+T support 1.8V logic levels on both sides?
Yes, the MAX12931FASA+T supports independent 1.71V–5.5V supplies on both VDDA and VDDB pins, enabling true 1.8V-to-1.8V, 1.8V-to-3.3V, or 1.8V-to-5V level shifting. This allows direct interfacing with ultra-low-power microcontrollers while driving legacy 3.3V/5V peripherals across the isolation barrier.
How does the MAX12931FASA+T handle static input conditions?
The MAX12931FASA+T incorporates an internal refresh circuit that periodically samples static inputs and updates outputs to prevent drift or metastability. This ensures deterministic output behavior even when IN1 or IN2 remain unchanged for extended periods - critical for watchdog signaling and fault-status latching in safety systems.
What is the default output state of the MAX12931FASA+T?
The MAX12931FASA+T has a default-low output configuration: when either VDDA or VDDB is unpowered or an input is open-circuited, OUT1 and OUT2 assert logic low. This fail-safe behavior prevents unintended activation of downstream drivers or actuators during power sequencing or fault conditions.
Can the MAX12931FASA+T replace the MAX12930FASA+T in a design?
No - the MAX12931FASA+T and MAX12930FASA+T have opposite channel directionality: MAX12931FASA+T routes IN1→OUT2 and IN2→OUT1 (full-duplex), while MAX12930FASA+T routes IN1→OUT1 and IN2→OUT2 (unidirectional). Swapping them requires PCB layout changes and signal routing modifications to maintain functional correctness.
MAX12931FASA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 1/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 3000Vrms
- Common Mode Transient Immunity (Min):
- 50kV/µs
- Data Rate:
- 150Mbps
- Propagation Delay tpLH / tpHL (Max):
- 9.2ns, 9.4ns
- Pulse Width Distortion (Max):
- 2ns
- Rise / Fall Time (Typ):
- 1.6ns, 1.4ns (Max)
- Voltage - Supply:
- 1.71V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX12931FASA+T FAQ
1.How can I place an order for MAX12931FASA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX12931FASA+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 MAX12931FASA+T reliable?
The price and inventory of MAX12931FASA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX12931FASA+T is usually 5 days.
3.What payment methods are accepted for MAX12931FASA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX12931FASA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX12931FASA+T?
MAX12931FASA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX12931FASA+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 MAX12931FASA+T?
For technical support, including MAX12931FASA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX12931FASA+T requirements.
6.How does Aetrix verify that MAX12931FASA+T is sourced from the original manufacturer or authorized distributors?
All MAX12931FASA+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 MAX12931FASA+T meets industry standards.
7.What is the process for return or replacement of MAX12931FASA+T?
All MAX12931FASA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX12931FASA+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 MAX12931FASA+T part is unused and in its original packaging.
Return procedure for MAX12931FASA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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