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Analog Devices Inc./Maxim Integrated MAX14938GWE+T
- Part No.:
- MAX14938GWE+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MAX14938GWE+T.pdf
- Description:
- DGTL ISO 2750VRMS RS485 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
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Product details
Overview
The MAX14938GWE+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 A/B pins, 20Mbps data rate, and true fail-safe receiver. It enables robust industrial serial communication across ground-potential differences in PLC backplanes and fieldbus nodes.
For engineers reviewing the MAX14938GWE+T datasheet, MAX14938GWE+T pinout, MAX14938GWE+T application, or MAX14938GWE+T equivalent, key selection criteria include isolation voltage rating (2750VRMS/60s), cable-side power architecture (integrated LDO with VLDO input), differential driver output voltage (≥2.1V into 54Ω), receiver input impedance (¼-unit load), and thermal shutdown threshold (+160°C).
Technical Context
This device implements capacitive galvanic isolation between UART-side (GNDA/VDDA) and cable-side (GNDB/VDDB) domains, supporting bidirectional signal transmission without conductive coupling. The isolation barrier withstands 630VPEAK repetitive peak voltage and 445VRMS working voltage per IEC 60747-5-5.
It integrates a 5V LDO (typ) with 300mA current limit, powered via VLDO pin, enabling self-contained cable-side supply generation. The transceiver features undervoltage lockout on both sides (VUVLOA = 1.58V, VUVLOB = 2.7V), thermal shutdown at +160°C, and ±10kV IEC 61000-4-5 surge immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 2750VRMS for 60s - meets basic insulation requirements per UL1577 and CSA Bulletin 5A |
| Data Rate | 20Mbps - supports high-speed PROFIBUS-DP Class 3 and RS-485 fast-mode applications |
| Differential Output Voltage | ≥2.1V into 54Ω - ensures reliable signal integrity under worst-case bus loading |
| Receiver Input Load | ¼-unit load - allows up to 128 nodes on a single RS-485 bus segment |
| ESD Protection (A/B) | ±35kV HBM - eliminates need for external TVS diodes on bus lines |
| LDO Output | 5V ±0.5V, 300mA - powers cable-side circuitry and external termination resistors |
| Common-Mode Transient Immunity | 35kV/μs - maintains data integrity during fast ground-potential transients |
Pinout & Package
Package: 16-pin wide-body SOIC (W SOIC), creepage/clearance ≥8mm, rated for -40°C to +105°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDDA | UART-side power input | 1.71V–5.5V logic supply; bypass with 0.1µF + 1µF near pin |
| GNDA | UART-side ground reference | Reference for TXD, RXD, DE, RE, PV; must be isolated from GNDB |
| RXD | Receiver data output | Logic-level UART output; high-impedance when RE = high |
| RE | Receiver enable | Active-low; internal 4.5µA pull-down to GNDA |
| DE | Driver enable | Active-high; internal 4.5µA pull-down to GNDA |
| TXD | Driver input | Logic-level UART input; internal 4.5µA pull-up to VDDA |
| PV | Power valid input | Hold low during power-up; internal 4.5µA pull-up to VDDA |
| VLDO | LDO input voltage | 4.68V–14V input to enable internal 5V LDO; leave unconnected to disable LDO |
| VDDB | Cable-side power | 5V LDO output or external cable-side supply input; bypass with 0.1µF + 1µF |
| GNDB | Cable-side ground | Reference for A, B, DEM, VLDO; galvanically isolated from GNDA |
| A / B | RS-485 differential bus terminals | Driver outputs / receiver inputs; ±8V to +13V common-mode range |
| DEM | Driver enable monitor | Open-drain output high when DE = high; referenced to GNDB |
| N.C. | No connection | Pins 7 (MAX14939) and 14 are not internally connected |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5V LDO | Eliminates external regulator; powers VDDB and up to 10mA of external termination loads |
| True fail-safe receiver | Guarantees RXD = high when A/B are open, shorted, or bus is idle - prevents spurious framing errors |
| Undervoltage lockout (dual-rail) | Disables driver/receiver if VDDA < 1.58V or VDDB < 2.7V - prevents metastable logic states |
| Thermal shutdown | Forces driver outputs to high-Z at +160°C junction temperature - protects against sustained overloads |
| ±35kV HBM ESD on A/B | Meets IEC 61000-4-2 Level 4 without external protection - reduces BOM count and PCB area |
Applications
| Industrial PLC Backplane Interface | PROFIBUS-DP Field Node |
|---|---|
Use Scenario: Isolating CPU module UART from distributed I/O modules across a noisy 24V DC backplane with large ground potential differences. IC Role / Device Role / Timing Role: Half-duplex isolated transceiver bridging UART to RS-485 physical layer; handles 20Mbps burst traffic during cyclic data exchange. Use Value: Breaks ground loops that cause communication dropouts; ¼-unit load allows >100 I/O modules per segment without repeaters. | Use Scenario: Connecting sensor/actuator nodes to a PROFIBUS-DP master in factory automation, where cable runs exceed 100m and EMI is severe. IC Role / Device Role / Timing Role: Isolated PROFIBUS-DP physical layer transceiver; compliant with EN 50170 Part 2 timing and electrical specs. Use Value: ±35kV HBM ESD withstands handling damage; 2.1V min VOD into dual 220Ω terminations ensures signal margin at 12Mbps PROFIBUS Class 2 rates. |
| Smart Power Meter Communication | HVAC Building Management System |
Use Scenario: Enabling secure, noise-immune RS-485 communication between utility-grade meters and concentrators in electric substations with high dv/dt transients. IC Role / Device Role / Timing Role: Galvanically isolated RS-485 interface with 2750VRMS withstand; supports DLMS/COSEM protocol stacks. Use Value: 35kV/μs CMTI rejects switching noise from nearby breakers; thermal shutdown prevents latch-up during fault conditions. | Use Scenario: Interfacing HVAC controllers, VAV boxes, and chillers over long RS-485 daisy chains in commercial buildings with mixed grounding systems. IC Role / Device Role / Timing Role: Robust half-duplex transceiver with integrated LDO powering bus termination and local sensors. Use Value: VLDO input simplifies power design - one 12V rail powers both logic side (via VDDA) and bus side (via VLDO → VDDB); 128-node capacity scales system size. |
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 (1s), no integrated LDO, requires external 5V supply for isolated side | Needs additional regulator and layout space; lower ESD rating (±15kV HBM) | Choose when existing isolated 5V rail is available and cost sensitivity outweighs integration benefit |
| ISO1540DR | 1000VRMS isolation, I²C interface (not RS-485), no PROFIBUS support | Not functionally equivalent - targets different protocol stack and isolation class | Not suitable as direct alternative; only consider for non-RS-485, low-isolation-voltage designs |
Compared with ADM2483BRWZ, the MAX14938GWE+T delivers higher isolation endurance (2750VRMS/60s vs. 2500VRMS/1s) and eliminates external LDO design effort; compared with ISO1540DR, it provides full RS-485/PROFIBUS compliance, 20Mbps capability, and industrial-grade ESD robustness - making it the only viable functional alternative among listed options.
Availability
MAX14938GWE+T is available at Aetrix Electronics and suitable for industrial automation equipment, programmable logic controllers, and power metering systems requiring stable component supply, long-term lifecycle assurance, and certified isolation performance.
Supply support for MAX14938GWE+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 MAX14938GWE+T belongs to Maxim's isolated interface product line, engineered specifically for noise-immune fieldbus communication in harsh industrial environments where ground loop elimination and long-term reliability are critical.
FAQ
What isolation standard certifications does the MAX14938GWE+T meet?
The MAX14938GWE+T is certified to UL1577 and CSA Bulletin 5A for 2750VRMS isolation (60s), with VIORM = 630VPEAK and VIOWM = 445VRMS per IEC 60747-5-5. It also meets IEC 61000-4-5 Level 4 surge immunity (±10kV) and has 35kV/μs common-mode transient immunity - all verified in the official Maxim datasheet for MAX14938GWE+T.
Can the MAX14938GWE+T operate without using its integrated LDO?
Yes, the MAX14938GWE+T can operate without the integrated LDO: leave VLDO unconnected or tie it to GNDB, then apply a regulated 4.5V–5.5V supply directly to VDDB. This configuration bypasses the LDO while retaining full transceiver functionality, isolation, and protection features - confirmed in the MAX14938GWE+T datasheet's "Integrated LDO" section and Pin Description table.
What is the maximum number of MAX14938GWE+T devices supported on a single RS-485 bus?
The MAX14938GWE+T features a ¼-unit-load receiver input impedance, allowing up to 128 devices on a single RS-485 bus segment. This is explicitly stated in the "General Description" and "Applications Information" sections of the MAX14938GWE+T datasheet, and verified by its RIN = 48kΩ specification (vs. standard 12kΩ for 1-unit load).
Does the MAX14938GWE+T support PROFIBUS-DP Class 3 timing requirements?
Yes, the MAX14938GWE+T supports PROFIBUS-DP Class 3 with its 20Mbps maximum data rate, ≤68ns propagation delay (tDPLH/tDPHL), and ≤6ns output skew - all measured under PROFIBUS-equivalent load conditions. These parameters meet EN 50170 Part 2 Class 3 timing budgets, as confirmed in the MAX14938GWE+T switching characteristics tables and typical operating curves.
How does the true fail-safe feature of the MAX14938GWE+T prevent communication errors?
When A/B inputs are open, shorted, or the bus is idle (all drivers disabled), the MAX14938GWE+T's receiver guarantees RXD = high due to fixed thresholds (VTH = –200mV to –50mV). This prevents false start bits and framing errors during bus arbitration - a behavior validated in the "True Fail-Safe" subsection and Function Tables of the MAX14938GWE+T datasheet.
MAX14938GWE+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
MAX14938GWE+T FAQ
1.How can I place an order for MAX14938GWE+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX14938GWE+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 MAX14938GWE+T reliable?
The price and inventory of MAX14938GWE+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX14938GWE+T is usually 5 days.
3.What payment methods are accepted for MAX14938GWE+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX14938GWE+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX14938GWE+T?
MAX14938GWE+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX14938GWE+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 MAX14938GWE+T?
For technical support, including MAX14938GWE+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX14938GWE+T requirements.
6.How does Aetrix verify that MAX14938GWE+T is sourced from the original manufacturer or authorized distributors?
All MAX14938GWE+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 MAX14938GWE+T meets industry standards.
7.What is the process for return or replacement of MAX14938GWE+T?
All MAX14938GWE+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX14938GWE+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 MAX14938GWE+T part is unused and in its original packaging.
Return procedure for MAX14938GWE+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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