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Analog Devices Inc./Maxim Integrated MAX14939GWE+T
- Part No.:
- MAX14939GWE+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX14939GWE+T.pdf
- Description:
- DGTL ISO 2750VRMS RS485 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,231
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Product details
Overview
The MAX14939GWE+T from Maxim Integrated is a 2.75kVRMS galvanically isolated, half-duplex RS-485/PROFIBUS-DP transceiver with integrated 5V LDO, ±35kV HBM ESD protection on cable-side pins (A/B), and 20Mbps data rate capability. It features true fail-safe receiver operation, undervoltage lockout on both UART and cable sides, and thermal shutdown protection - deployed in industrial automation for robust serial communication across ground-potential differences.
For engineers reviewing the MAX14939GWE+T datasheet, MAX14939GWE+T pinout, MAX14939GWE+T application, or MAX14939GWE+T equivalent, key selection criteria include isolation voltage rating (2750VRMS/60s), cable-side LDO output capability (5V @ up to 10mA), differential driver output voltage (≥2.1V into 54Ω), receiver input impedance (¼-unit load), and PROFIBUS-DP compliance under IEC 61158.
Technical Context
This device implements capacitive galvanic isolation between UART-side (GNDA/VDDA) and cable-side (GNDB/VDDB) domains, enabling signal integrity in high-noise industrial environments with ground potential differences up to ±12V. Its integrated LDO powers the isolated side from VLDO (4.68–14V), eliminating need for external isolated DC/DC converters.
The transceiver supports PROFIBUS-DP timing requirements via 20Mbps maximum data rate, <68ns driver/receiver propagation delay, and >35kV/μs common-mode transient immunity (CMTI). True fail-safe logic ensures RXD = high when A/B are open, shorted, or bus is idle - critical for deterministic PLC control loop behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 2750VRMS for 60s - meets basic insulation requirement per UL1577 and IEC 60747-5-5, enabling safe interface between safety-critical and non-safety zones. |
| Data Rate | 20Mbps - supports high-speed PROFIBUS-DP Class 3 (12Mbps) and RS-485 fast mode without oversampling or timing margin loss. |
| LDO Output | 5V ±5% at up to 10mA - powers termination resistors and optional bus biasing components directly from VLDO, reducing BOM count. |
| ESD Protection | ±35kV HBM on A/B pins to GNDB - exceeds IEC 61000-4-2 Level 4 for field-deployed equipment in harsh factory environments. |
| Receiver Input Load | ¼-unit load (≥48kΩ) - allows up to 128 nodes on single RS-485 bus, supporting large-scale distributed I/O architectures. |
| Fail-Safe Threshold | Receiver asserts high when (VA–VB) ≥ –50mV - guarantees known state during cable disconnect, bus contention, or power loss on remote nodes. |
| CMTI | ≥35kV/μs - maintains data integrity during fast transients from motor drives, VFDs, or switching power supplies coupled onto shared ground planes. |
Pinout & Package
Package: 16-pin wide-body SOIC (W SOIC), creepage/clearance ≥8mm, rated for –40°C to +105°C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, VDDA | UART-side supply input | 1.71–5.5V logic power; bypass with 0.1µF + 1µF to GNDA for noise suppression and ESD immunity. |
| 2, 8, GNDA | UART-side ground reference | Reference for TXD, RXD, DE, RE, PV; must be separated from GNDB by ≥8mm isolation barrier. |
| 3, RXD | Receiver data output | CMOS-level output; high-impedance when RE = high; fails high during undervoltage or bus fault. |
| 4, RE | Receiver enable input | Active-low; internal 4.5µA pull-down to GNDA; enables RXD when low, disables to Hi-Z when high. |
| 5, DE | Driver enable input | Active-high; internal 4.5µA pull-down to GNDA; enables A/B outputs when high, disables to Hi-Z when low. |
| 6, TXD | Driver input | CMOS-level input; internal 4.5µA pull-up to VDDA; controls polarity of A/B differential output. |
| 7, PV | Power valid indicator input | Hold low during power-up sequencing; internal 4.5µA pull-up to VDDA; disables driver until stable. |
| 9, 15, GNDB | Cable-side ground reference | Reference for A, B, VDDB, VLDO, DEM; must be physically isolated from GNDA with no copper bridges. |
| 10, DEM | Driver enable monitor output | Open-drain output referenced to GNDB; high when DE = high and VDDB ≥ VUVLOB; used for system diagnostics. |
| 11, VLDO | LDO input voltage | 4.68–14V input to internal LDO; leave unconnected or tie to GNDB to disable LDO and use external VDDB supply. |
| 12, A | Noninverting driver output / receiver input | Differential bus pin; ±35kV HBM ESD protected to GNDB; requires 120Ω termination at bus ends. |
| 13, B | Inverting driver output / receiver input | Differential bus pin; ±35kV HBM ESD protected to GNDB; complements A for noise rejection. |
| 14, N.C. | No connection | Not internally bonded; must remain unconnected on PCB to preserve isolation integrity. |
| 16, VDDB | Cable-side supply output/input | 5V LDO output (when VLDO powered) or external 4.5–5.5V input; powers driver/receiver circuitry and up to 10mA load. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5V LDO | Eliminates need for external isolated DC/DC converter; reduces layout area and cost while powering termination resistors and bus bias networks. |
| True Fail-Safe Receiver | Guarantees RXD = high during open/shorted bus conditions or idle bus - prevents spurious control commands in PLC and motion systems. |
| ±35kV HBM ESD on A/B | Enables direct connection to field wiring without external TVS diodes, simplifying surge protection design for IP65-rated enclosures. |
| 20Mbps Data Rate | Supports PROFIBUS-DP Class 3 (12Mbps) with timing margin, enabling deterministic cycle times ≤1ms in distributed I/O networks. |
| Thermal Shutdown | Disables driver outputs at TJ ≥ +160°C and recovers at TJ ≤ +145°C - protects against latch-up during sustained bus contention or short circuits. |
| ¼-Unit Load Receiver | Permits 128-node RS-485 networks using standard 120Ω termination, reducing need for repeaters in large HVAC or power metering deployments. |
Applications
| Industrial Automation | Programmable Logic Controllers |
|---|---|
|
Use Scenario: Connecting remote I/O modules to central controller over long RS-485 daisy-chain in factory floor environment with variable ground potentials. IC Role / Device Role / Timing Role: Isolated half-duplex transceiver providing galvanic separation between controller UART and field bus, enabling reliable 20Mbps data exchange. Use Value: Breaks ground loops that cause communication errors; ±35kV ESD protection withstands electrostatic discharge from operator handling and machinery operation. |
Use Scenario: Interfacing PLC CPU backplane to distributed PROFIBUS-DP slave devices in packaging line with multiple motor drives. IC Role / Device Role / Timing Role: PROFIBUS-DP compliant transceiver delivering deterministic 12Mbps communication with <68ns propagation delay and >35kV/μs CMTI. Use Value: Ensures cycle-time consistency under EMI stress from VFDs; integrated LDO powers slave-side termination without extra regulators. |
| HVAC Systems | Power Meters |
|
Use Scenario: Multi-drop RS-485 network linking thermostats, dampers, and chillers in commercial building management system. IC Role / Device Role / Timing Role: Half-duplex isolated transceiver supporting up to 128 nodes on single bus with ¼-unit load receiver and true fail-safe logic. Use Value: Enables scalable topology without repeaters; fail-safe behavior prevents false actuation during sensor cable disconnection or lightning-induced surges. |
Use Scenario: Smart electricity meter communicating consumption data to AMI concentrator via isolated RS-485 link in outdoor substation cabinet. IC Role / Device Role / Timing Role: Isolated transceiver with 2750VRMS withstand voltage and IEC 61000-4-5 ±10kV surge immunity on cable side. Use Value: Meets utility-grade isolation safety requirements; ±35kV HBM ESD tolerance eliminates need for external protection in humid, dust-prone enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated RS-485 transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADM2483BRWZ | 2500VRMS isolation (vs. 2750VRMS); no integrated LDO; requires external isolated power supply for cable side. | Requires additional DC/DC converter and layout space; lower ESD rating (±15kV HBM on A/B). | Select when existing isolated power architecture exists and LDO integration is unnecessary. |
| ISO1500DR | 5000VRMS isolation; 50Mbps data rate; no PROFIBUS-DP optimized drive strength or fail-safe threshold. | Higher isolation but lacks guaranteed PROFIBUS-compliant output swing (2.1V min into 54Ω) and true fail-safe behavior. | Select for ultra-high-isolation medical or test equipment where PROFIBUS timing is not required. |
Compared with ADM2483BRWZ and ISO1500DR, the MAX14939GWE+T uniquely combines 2750VRMS isolation, integrated 5V LDO, PROFIBUS-DP drive compliance, and true fail-safe receiver - making it optimal for cost-sensitive, space-constrained industrial automation designs requiring guaranteed interoperability.
Availability
The MAX14939GWE+T is available at Aetrix Electronics and suitable for industrial automation, programmable logic controllers, HVAC control systems, and smart power metering applications requiring stable component supply, long-term lifecycle support, and certified isolation performance.
Supply support for MAX14939GWE+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) designs precision analog, mixed-signal, and high-reliability ICs for industrial, automotive, and communications markets.
The MAX14939GWE+T belongs to Maxim's isolated interface product line, engineered specifically for robust serial communication in electrically noisy, ground-isolated environments such as factory automation and energy infrastructure.
FAQ
What isolation voltage rating does the MAX14939GWE+T support, and how is it certified?
The MAX14939GWE+T supports 2750VRMS isolation for 60 seconds, certified to UL1577 and CSA Bulletin 5A standards. It also meets IEC 60747-5-5 requirements with VIORM = 630VPEAK, VIOWM = 445VRMS, and 10kV surge immunity per IEC 61000-4-5. This rating applies across the full –40°C to +105°C operating temperature range and is 100% production tested at 120% of VISO for 1 second.
Does the MAX14939GWE+T include an integrated LDO, and what are its output specifications?
Yes, the MAX14939GWE+T includes an integrated LDO powered from VLDO (4.68–14V) and delivering a regulated 5V ±5% output at VDDB. It provides up to 10mA of load current and features 300mA current limiting, 0.19mV/mA load regulation, and 0.12mV/V line regulation. When unused, VLDO can be tied to GNDB and VDDB driven externally with 4.5–5.5V.
How does the MAX14939GWE+T implement true fail-safe receiver operation?
The MAX14939GWE+T guarantees RXD = high when (VA–VB) ≥ –50mV - covering open-circuit, shorted, or terminated-idle bus conditions. Its fixed receiver threshold (–200mV to –50mV) ensures deterministic logic-high output during faults, preventing undefined states in safety-critical PLC or motion control systems where bus integrity cannot be assumed.
What is the maximum number of nodes supported on an RS-485 bus using the MAX14939GWE+T?
The MAX14939GWE+T features a ¼-unit load receiver (≥48kΩ input resistance), allowing up to 128 transceivers on a single RS-485 bus segment. This complies with the RS-485 standard's 32-unit-load limit when combined with other ¼-unit-load devices, enabling large-scale distributed I/O without repeaters in HVAC or power monitoring systems.
What ESD protection level does the MAX14939GWE+T provide on its A and B pins?
The MAX14939GWE+T provides ±35kV ESD protection on A and B pins to GNDB per Human Body Model (HBM), ±12kV per IEC 61000-4-2 air-gap discharge, and ±10kV per contact discharge. This exceeds industrial immunity requirements and eliminates need for external TVS diodes in most field-wiring scenarios.
MAX14939GWE+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Capacitive Coupling
- Type:
- RS485
- Isolated Power:
- No
- Number of Channels:
- 3
- Inputs - Side 1/Side 2:
- 2/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 2750Vrms
- Common Mode Transient Immunity (Min):
- 35kV/µs (Typ)
- Data Rate:
- 20Mbps
- Propagation Delay tpLH / tpHL (Max):
- 68ns, 68ns
- Pulse Width Distortion (Max):
- -
- Rise / Fall Time (Typ):
- 15ns, 15ns (Max)
- Voltage - Supply:
- 1.71V ~ 5.5V, 4.5V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 105°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX14939GWE+T FAQ
1.How can I place an order for MAX14939GWE+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX14939GWE+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 MAX14939GWE+T reliable?
The price and inventory of MAX14939GWE+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX14939GWE+T is usually 5 days.
3.What payment methods are accepted for MAX14939GWE+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX14939GWE+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX14939GWE+T?
MAX14939GWE+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX14939GWE+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 MAX14939GWE+T?
For technical support, including MAX14939GWE+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX14939GWE+T requirements.
6.How does Aetrix verify that MAX14939GWE+T is sourced from the original manufacturer or authorized distributors?
All MAX14939GWE+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 MAX14939GWE+T meets industry standards.
7.What is the process for return or replacement of MAX14939GWE+T?
All MAX14939GWE+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX14939GWE+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 MAX14939GWE+T part is unused and in its original packaging.
Return procedure for MAX14939GWE+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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