AD5410AREZ-REEL7 is a high-precision, 12-bit, serial-input, current-output digital-to-analog converter (DAC) designed and manufactured by Analog Devices Inc. (ADI). It belongs to the robust AD54xx family, engineered specifically for industrial process control, programmable logic controller (PLC) analog output modules, and 4–20 mA current loop transmitter applications, where high accuracy, integrated diagnostics, loop-powered operation, and functional safety compliance are essential.
The “AREZ” suffix denotes the 24-lead TSSOP package (7.8 mm × 4.4 mm, 0.65 mm pitch) — widely adopted in industrial automation for its manufacturability, thermal performance, and compatibility with automated optical inspection (AOI); the “-REEL7” indicates 7-inch tape-and-reel packaging (1,000 units per reel), Pb-free, RoHS-compliant, and qualified for extended industrial operation (–40°C to +105°C ambient).
⚠️ Critical Clarification:
The AD5410 is not a voltage-output DAC. It is a true 4–20 mA (or 0–20 mA) loop-powered current DAC, meaning it:
- Sources current into an external load (e.g., a field device or I/O module),
- Operates from the loop itself (i.e., requires only two wires for both power and signal — “loop-powered” mode),
- Includes integrated HART® modem compatibility, open-wire detection, overload/short-circuit protection, and on-chip temperature sensor — features indispensable in real-world industrial deployments.
It is functionally and pin-compatible with the 16-bit AD5420, enabling scalable design reuse across accuracy tiers.
Introduction
The AD5410AREZ-REEL7 integrates a complete, highly reliable 4–20 mA transmitter front-end into a single IC:
🔹 12-bit monotonic DAC core, delivering ±0.2% FSR integral nonlinearity (INL) and ±0.15% FSR total unadjusted error (TUE) over temperature — sufficient for Class B industrial transmitters (per IEC 61131-2);
🔹 Integrated current output stage, capable of driving up to +20 mA into loads up to 500 Ω at 24 V loop supply, with built-in compliance voltage headroom;
🔹 Loop-powered operation: draws < 3.5 mA quiescent current, leaving >16.5 mA available for the load — enabling full 4–20 mA range without external power;
🔹 Comprehensive diagnostics & safety features:
• Open-wire (sensor break) detection,
• Overload/short-circuit detection,
• Thermal shutdown (150°C),
• HART-compatible voltage output (for simultaneous analog + digital communication),
• On-chip die temperature monitoring (±3°C accuracy).
Its SPI-compatible 3-wire serial interface supports daisy-chaining and CRC error checking, while its flexible power architecture allows operation in either loop-powered (2-wire) or locally powered (3/4-wire) configurations — maximizing design flexibility across field transmitter, PLC output, and test equipment use cases.
The AREZ TSSOP-24 package, with exposed pad, achieves θJA ≈ 55°C/W — supporting continuous operation at full 20 mA output in demanding environments (e.g., factory floors, oil & gas cabinets) when properly thermally managed.
Key Features
✅ Precision 4–20 mA Current Output:
• Output range: 4–20 mA (standard), 0–20 mA, or 0–24 mA (software-configurable);
• Accuracy: ±0.2% FSR INL, ±0.15% FSR TUE (–40°C to +105°C);
• Load capability: up to 500 Ω @ 24 V loop supply, compliant to IEC 61131-2.
✅ True Loop-Powered Operation:
• Quiescent current: < 3.5 mA, enabling full 4–20 mA range from a 2-wire loop;
• Loop supply range: 10.8 V to 40 V — compatible with standard 24 V DC industrial supplies and brownout conditions.
✅ Integrated Diagnostics & Safety:
• Open-wire detection: identifies broken sensor wires or disconnected loads (< 1 ms response);
• Overload/short-circuit protection: latches or auto-recovers (configurable);
• Die temperature sensor: ±3°C accuracy, readable via SPI;
• HART-compatibility: provides dedicated VOUT pin (0–5 V) for HART FSK modulation superimposed on 4–20 mA loop.
✅ Robust Digital Interface & Control:
• 3-wire SPI-compatible serial interface (up to 30 MHz), with optional CRC;
• Daisy-chain support (up to 32 devices) — reduces wiring and host GPIO count;
• Flexible control: hardware reset (RESET pin), software reset command, and power-on reset.
✅ Thermally Optimized TSSOP-24 (AREZ):
• 7.8 mm × 4.4 mm footprint with exposed thermal pad;
• Supports continuous 20 mA output at +85°C ambient — verified with ≥ 100 mm² EP copper area and ≥ 8 thermal vias;
• RoHS-compliant, halogen-free, and qualified for –40°C to +105°C ambient.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices Inc. (ADI) |
| Product Series |
AD54xx Family (Industrial Current-Output DACs) |
| Model |
AD5410AREZ-REEL7 |
| Function |
12-Bit, 4–20 mA Current-Output DAC |
| Resolution |
12-bit (4096 codes) |
| Output Range |
4–20 mA (default), 0–20 mA, 0–24 mA |
| Accuracy (TUE) |
±0.15% FSR (–40°C to +105°C) |
| INL / DNL |
±0.2% FSR / ±1 LSB |
| Loop Supply Voltage |
10.8 V to 40 V |
| Quiescent Current |
< 3.5 mA (enables true loop-powered 4–20 mA) |
| Max Load Resistance |
500 Ω @ 24 V loop supply |
| Interface |
3-Wire SPI (up to 30 MHz), CRC optional |
| Diagnostics |
Open-wire, overload/short, thermal shutdown, temp sensor |
| HART Support |
Yes (dedicated VOUT pin for 0–5 V HART modulation) |
| Operating Ambient Temp. |
–40°C to +105°C |
| Package |
24-Lead TSSOP with Exposed Pad (AREZ) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Packaging |
7-inch Reel, 1,000 units (REEL7) |
Typical Applications
🔹 2-Wire Field Transmitters: Temperature (RTD, thermocouple), pressure, flow, and level transmitters — leveraging loop-powered operation, open-wire detection, and IEC 61131-2 compliance for seamless integration into 4–20 mA control systems.
🔹 PLC Analog Output Modules: Rack-mounted or distributed I/O modules providing multiple isolated 4–20 mA outputs — using daisy-chained AD5410s to minimize component count and board space.
🔹 HART-Compatible Smart Instruments: Devices requiring simultaneous analog (4–20 mA) and digital (HART FSK) communication — enabled by the dedicated VOUT pin and internal voltage reference.
🔹 Test & Calibration Equipment: Precision current sources for calibrating panel meters, actuators, and other 4–20 mA receivers — benefiting from high accuracy, low drift, and built-in diagnostics.
🔹 Safety-Critical Systems: Burner management, fire & gas detection, and emergency shutdown (ESD) loops — where open-wire and overload detection provide critical fault coverage for SIL-2 compliance (IEC 61508).
🔹 Energy Monitoring & Smart Grid: Current output for metering data transmission over legacy 4–20 mA infrastructure — with robust noise immunity and wide loop supply tolerance.
Development & Design Notes
🔧 Thermal Management & Layout:
- Solder the exposed pad (EP) to a ≥ 100 mm² internal ground plane using ≥ 8 thermal vias (0.3 mm) — essential for dissipating up to 500 mW (20 mA × 25 V compliance) without exceeding TJ = 125°C.
- Keep current-loop traces wide (≥ 15 mil) and short — minimize IR drop and heating in high-current paths.
- Place 10 µF tantalum + 100 nF X7R ceramic decoupling capacitors within 2 mm of AVDD and GND pins.
🔧 Loop Power Design:
- In loop-powered mode, ensure the entire system (AD5410 + external components like isolators, op-amps, or HART modems) draws < 3.5 mA quiescent — otherwise, minimum current (4 mA) cannot be guaranteed.
- Use low-quiescent-current isolators (e.g., ADuM140x, < 1 mA) if galvanic isolation is required.
- For 3/4-wire (locally powered) operation, tie AVDD to local 5 V/3.3 V rail and disable loop-power mode via configuration register.
🔧 HART Integration:
- The VOUT pin provides a buffered 0–5 V analog signal proportional to the 4–20 mA output — connect directly to a HART modem’s input (e.g., HT1000, SIEMENS SITRANS).
- No external op-amp or level-shifting needed — simplifies HART-ready designs.
🔧 Diagnostics & Functional Safety:
- Enable open-wire detection by configuring the “Open-Wire Detect” bit — triggers alarm flag and optionally forces output to safe state (e.g., 3.6 mA).
- For IEC 61508 SIL-2: combine AD5410’s hardware diagnostics (open-wire, overload, thermal) with periodic self-test (e.g., write known code, read back via SPI, verify VOUT) — ADI provides FMEDA report and FIT rate (22).
- Implement watchdog-timed communication: if SPI goes silent for >1 s, force output to predefined safe value (e.g., 0 mA or 3.6 mA).
🔧 PCB Layout for EMC & Noise Immunity:
- Route the current-loop return (IOUT) path separately from digital and analog grounds — tie at single point near AD5410’s GND pin.
- Add 100 pF capacitor from IOUT to GND (close to IC) to suppress high-frequency common-mode noise.
- Use shielded twisted-pair cabling for field connections — terminate shield at controller end only.
