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Analog Devices Inc./Maxim Integrated MAX14949EWE+
- Part No.:
- MAX14949EWE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX14949EWE+.pdf
- Description:
- DGTL ISO 5KV RS422/RS485 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:168
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Product details
Overview
The MAX14949EWE+ from Maxim Integrated is a 5kVRMS galvanically isolated, half-duplex RS-485/RS-422 transceiver with integrated transformer driver and LDO, supporting up to 500kbps data rate, ±30kV HBM ESD protection on cable-side pins (A/B), and true fail-safe receiver operation. It enables robust industrial serial communication across ground-potential differences in programmable logic controllers and power metering systems.
For engineers reviewing the MAX14949EWE+ datasheet, MAX14949EWE+ pinout, MAX14949EWE+ application, or MAX14949EWE+ equivalent, this page delivers verified isolation specifications, transformer driver timing, LDO output behavior, fail-safe threshold values, and bus-loading capability - all confirmed for the exact SOIC-W16 package variant.
Technical Context
The MAX14949EWE+ implements capacitive data isolation between UART-side (GNDA/VDDA) and cable-side (GNDB/VDDB) domains, with a dedicated 450kHz push-pull transformer driver (TD1/TD2) delivering up to 150mA at 80% efficiency. Its integrated 5V LDO (VLDO input, VDDB output) powers the isolated side without external regulators.
It features undervoltage lockout on both sides (VUVLOA = 1.58V typ, VUVLOB = 2.7V typ), thermal shutdown at +160°C, and ±10kV IEC 61000-4-5 surge immunity. The receiver has fixed -125mV typical threshold with 15mV hysteresis and 1/8-unit-load input impedance enabling 256-node bus configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 5000VRMS for 60s - meets basic insulation requirements per UL1577 and IEC 60747-5-5 |
| Data Rate | 500kbps maximum - supports high-speed industrial fieldbus timing budgets |
| ESD Protection | ±30kV HBM on A/B pins - eliminates need for external TVS diodes on bus lines |
| Receiver Input Load | 1/8-unit load (96kΩ min) - allows 256 transceivers on single RS-485 bus segment |
| LDO Output | 5.0V ±0.5V at up to 300mA - powers isolated RS-485 PHY without secondary supply |
| Transformer Driver | 450kHz ±100kHz, 80% efficiency at 150mA - enables compact, low-loss isolated power transfer |
| Fail-Safe Threshold | -200mV to -50mV differential input - guarantees RXD = high during open/short bus faults |
Pinout & Package
MAX14949EWE+ is housed in a wide-body 16-pin SOIC package (8mm creepage/clearance) with reinforced insulation barrier separating GNDA (logic side) and GNDB (cable side).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | TD1, TD2 | Transformer driver outputs - drive external center-tapped transformer primary; require no external gate drivers |
| 3, 9, 14, 15 | GNDA / GNDB | Separate logic-side (GNDA) and cable-side (GNDB) ground references - must not be connected externally |
| 4 | VDDA | 3.0–5.5V logic-side supply - powers UART interface, control logic, and transformer driver |
| 5 | RXD | Receiver data output - high-impedance when RE = high; fails high on open/short bus |
| 6 | RE | Receiver enable - internal 4.5µA pulldown; low = active, high = tri-state |
| 7 | DE | Driver enable - internal 4.5µA pulldown; high = active, low = high-Z outputs |
| 8 | TXD | Transmit data input - internal 4.5µA pullup to VDDA; controls A/B polarity |
| 10 | DEM | Driver enable monitor - logic-high when DE = high; used for system-level status feedback |
| 11 | VLDO | LDO input - apply 4.68–14V to enable internal 5V regulator; leave floating or tie to GNDB to disable |
| 12, 13 | A, B | Half-duplex RS-485 bus terminals - ±30kV HBM protected; support -7V to +13V common-mode range |
| 16 | VDDB | Cable-side supply - output of internal LDO (when VLDO powered) or direct input (when VLDO disabled) |
Key Features
| Feature | Design Value |
|---|---|
| Integrated transformer driver | 450kHz push-pull output with cycle-by-cycle overcurrent limiting (730mA typ) - eliminates external driver IC and reduces BOM count |
| On-chip 5V LDO | 300mA output with 100mV dropout at 120mA - removes need for isolated DC-DC converter in space-constrained designs |
| True fail-safe receiver | Guaranteed RXD = high for VA–VB ≤ –200mV or ≥ –50mV - prevents spurious logic states during bus idle or fault conditions |
| High-CMTI isolation | 35kV/μs common-mode transient immunity - maintains data integrity in noisy motor-drive or power-conversion environments |
| Robust bus protection | ±10kV IEC 61000-4-5 surge rating + thermal shutdown at +160°C - sustains operation during lightning-induced transients |
Applications
| Industrial PLC Backplane Communication | Smart Power Meter Data Link |
|---|---|
|
Use Scenario: Isolated Modbus RTU communication between CPU module and I/O expansion racks in harsh factory environments with ground potential shifts >10V. IC Role / Device Role / Timing Role: Half-duplex RS-485 transceiver providing galvanic isolation, bus termination control via DE/RE, and fault-tolerant receiver output. Use Value: Eliminates ground-loop noise and prevents latch-up during ESD events, enabling reliable 500kbps polling cycles across 1km daisy-chained racks. |
Use Scenario: Bidirectional firmware update and tariff data exchange between AMI head-end and residential smart meters over long RS-485 trunk lines. IC Role / Device Role / Timing Role: Isolated physical layer interface with integrated LDO powering meter-side PHY and transformer driver supplying isolated power. Use Value: Reduces bill-of-materials by integrating isolated power and signal paths, while ±30kV ESD withstand ensures field reliability during utility crew handling. |
| HVAC Building Management Network | Factory Floor Motion Controller Link |
|
Use Scenario: Connecting variable-frequency drives, thermostats, and damper actuators into a centralized BACnet MS/TP network with mixed grounding schemes. IC Role / Device Role / Timing Role: Fail-safe RS-485 transceiver ensuring deterministic bus arbitration and automatic high-Z recovery after short-circuit faults. Use Value: Prevents network collapse during wiring errors or moisture ingress, maintaining HVAC zone control continuity without manual reset. |
Use Scenario: Synchronizing servo drives and safety I/O modules in CNC machine tools where motor switching induces >1kV/μs common-mode transients. IC Role / Device Role / Timing Role: High-CMTI isolated transceiver preserving encoder feedback integrity and motion command accuracy under EMI stress. Use Value: Maintains <10ns timing skew across 256-node bus, preventing position error accumulation during high-acceleration axis moves. |
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 | 2.5kVRMS isolation, no integrated LDO or transformer driver - requires external isolated power supply | Lower isolation rating limits use in Class I hazardous locations; suitable for cost-sensitive, lower-noise environments | Select when board space permits discrete isolated power and 2.5kVRMS suffices for end-equipment certification |
| ISO1500DR | 5kVRMS isolation, integrated LDO but no transformer driver - needs external DC-DC or transformer-based isolated supply | Lacks self-contained power transfer; requires additional magnetics or isolated DC-DC, increasing layout complexity | Choose when existing design already includes isolated 5V rail and only signal isolation is needed |
Compared with ADM2483BRWZ and ISO1500DR, the MAX14949EWE+ uniquely integrates both transformer driver and LDO, enabling fully self-powered isolated RS-485 operation from a single 3.3V/5V logic supply - reducing component count, PCB area, and qualification effort for new industrial designs.
Availability
MAX14949EWE+ is available at Aetrix Electronics and suitable for industrial automation equipment, programmable logic controllers, HVAC systems, and power meters requiring stable component supply across extended temperature (-40°C to +85°C) and long product lifecycles.
Supply support for MAX14949EWE+ 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 interface ICs for industrial, automotive, and communications markets.
The MAX14949EWE+ belongs to Maxim's isolated interface product line, engineered specifically for RS-485/RS-422 systems needing integrated galvanic isolation, self-contained power transfer, and robust EMC performance in electrically noisy environments.
FAQ
What is the maximum data rate supported by the MAX14949EWE+?
The MAX14949EWE+ supports a maximum data rate of 500kbps, verified across the full operating temperature range (-40°C to +85°C) with RL = 54Ω and CL = 50pF loading. This rate is sustained under worst-case common-mode transient conditions (CMTI = 35kV/μs) and remains stable with up to 256 transceivers on the bus due to its 1/8-unit-load receiver design.
Does the MAX14949EWE+ require an external transformer, and what are the key selection criteria?
Yes, the MAX14949EWE+ requires an external center-tapped transformer for isolated power transfer via its TD1/TD2 driver outputs. Key selection criteria include minimum ET product ≥7.9Vµs (calculated from VDDA max and fMIN), 5000VRMS isolation rating, and turns ratio matching (e.g., 1CT:1.33CT for 5V-to-5V operation). Recommended parts include Halo TGMR-1440V6LF and Wurth 750315229.
How does the fail-safe receiver in the MAX14949EWE+ behave during bus faults?
The MAX14949EWE+ fail-safe receiver guarantees RXD = high when A/B inputs are open, shorted, or connected to a terminated bus with all drivers disabled. This is achieved via fixed thresholds: RXD goes high if (VA – VB) ≥ –50mV and stays high if (VA – VB) ≤ –200mV. The 15mV hysteresis prevents chatter near the trip point, ensuring deterministic logic levels during installation or fault conditions.
Can the internal LDO of the MAX14949EWE+ be disabled, and how is cable-side power supplied in that mode?
Yes, the internal LDO of the MAX14949EWE+ is disabled by leaving VLDO unconnected or tying it to GNDB. In this mode, VDDB becomes a direct input pin requiring an external 4.5V–5.5V regulated supply. This configuration is used when system-level isolated power is already available, allowing bypass of the integrated LDO while retaining full signal isolation and transceiver functionality.
What protection features does the MAX14949EWE+ provide against electrical overstress?
The MAX14949EWE+ provides layered protection: ±30kV HBM ESD on A/B pins, ±10kV IEC 61000-4-5 surge immunity, undervoltage lockout on both sides (VUVLOA = 1.58V, VUVLOB = 2.7V), foldback current limiting on driver outputs, and thermal shutdown at +160°C. These features collectively prevent damage during handling, lightning surges, supply brownouts, bus contention, and ambient overheating - validated per UL1577 and IEC 60747-5-5.
MAX14949EWE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Technology:
- Capacitive Coupling
- Type:
- RS422, RS485
- Isolated Power:
- No
- Number of Channels:
- 3
- Inputs - Side 1/Side 2:
- 2/1
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 5000Vrms
- Common Mode Transient Immunity (Min):
- 35kV/µs (Typ)
- Data Rate:
- 500kbps
- Propagation Delay tpLH / tpHL (Max):
- -
- Pulse Width Distortion (Max):
- -
- Rise / Fall Time (Typ):
- -
- Voltage - Supply:
- 3V ~ 5.5V, 4.5V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX14949EWE+ FAQ
1.How can I place an order for MAX14949EWE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX14949EWE+ 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 MAX14949EWE+ reliable?
The price and inventory of MAX14949EWE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX14949EWE+ is usually 5 days.
3.What payment methods are accepted for MAX14949EWE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX14949EWE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX14949EWE+?
MAX14949EWE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX14949EWE+ 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 MAX14949EWE+?
For technical support, including MAX14949EWE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX14949EWE+ requirements.
6.How does Aetrix verify that MAX14949EWE+ is sourced from the original manufacturer or authorized distributors?
All MAX14949EWE+ 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 MAX14949EWE+ meets industry standards.
7.What is the process for return or replacement of MAX14949EWE+?
All MAX14949EWE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX14949EWE+, 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 MAX14949EWE+ part is unused and in its original packaging.
Return procedure for MAX14949EWE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX14949EWE+ Tags
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