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Analog Devices Inc. AD261BND-3
- Part No.:
- AD261BND-3
- Manufacturer:
- Analog Devices Inc.
- Category:
- Digital Isolators
- Package:
- 22-DIP Module
- Datasheet:
-
AD261BND-3.pdf
- Description:
- DGTL ISO 3.5KV GEN PURP 22DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,247
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Product details
Overview
AD261BND-3 from Analog Devices is a high-speed logic isolator with 3.5 kVrms isolation rating, five unidirectional isolated channels configured as 3 inputs (S0–S2) and 2 outputs (F0–F1), 20 MHz bandwidth, 14 ns propagation delay, and ±1 ns edge symmetry - used in IGBT motor drive controls and PLC analog I/O cards to maintain signal integrity across noisy field/system boundaries.
For engineers reviewing the AD261BND-3 datasheet, AD261BND-3 pinout, AD261BND-3 application, or AD261BND-3 equivalent, this page delivers verified technical context, real-world design meaning for key specs, validated pin functions per configuration, and two confirmed alternative isolators with documented functional and application differences.
Technical Context
The AD261BND-3 implements capacitive isolation with a 3.5 kVrms tested barrier, supporting 10 kV/µs common-mode transient immunity and continuous output update via background input polling every ~5 µs. Its five HCMOS-compatible lines use Schmidt-trigger inputs and three-state outputs on both sides.
Each channel operates with 14 ns typical propagation delay, <±1 ns rising/falling edge symmetry error, and 25 ns minimum pulse width support. The device features dual enable pins (ENABLESYS and ENABLEFLD) that independently place all system-side or field-side outputs into high-impedance state without affecting input sampling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 3.5 kVrms test voltage (100% production tested); enables safe operation in industrial mains-referenced field interfaces up to 1.25 kVrms working voltage. |
| Logic Bandwidth | 20 MHz minimum; supports accurate PWM isolation and high-speed digital I/O up to 50 Mbps NRZ data rates. |
| Propagation Delay | 14 ns typical (tPHL/tPLH); ensures tight timing alignment between field and system domains in real-time control loops. |
| Edge Symmetry Error | ±1 ns max (tPHL vs tPLH); preserves duty cycle fidelity for time-critical signals like motor gate drivers. |
| Common-Mode Transient Immunity | 10 kV/µs minimum; prevents false triggering during fast transients in IGBT switching noise environments. |
| Supply Voltage Range | 4.0 V to 5.75 V per side; accommodates brown-out conditions while maintaining full logic-level compatibility. |
| Operating Temperature | –25°C to +85°C rated performance; validated for use in industrial PLC backplanes and motor drive cabinets. |
Pinout & Package
AD261BND-3 uses a 22-pin plastic DIP package (ND-22A) with 18 mm creepage distance between system and field sides, supporting CSA/IEC 750 V mains isolation compliance. Pin 1 is marked by notch; pins 9–14 are not present.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–3 (S0–S2) | System-side Inputs | Three dedicated transmit-only logic inputs from microcontroller or system domain; accept HCMOS levels with 0.9–4.2 V thresholds. |
| 4–5 (S3–S4) | Not Used (NC) | No internal connection; must be left unconnected or tied to valid logic level per design guidelines. |
| 6 | ENABLESYS | Active-high enable for all system-side outputs; drives them to high-Z when low, enabling multiplexing of multiple AD261BND-3 units. |
| 7 | +5 VdcSYS | System-side power supply input; requires local 0.01 µF bypass capacitor for stable 20 MHz operation. |
| 8 | 5 V RTNSYS | System-side ground reference; separate from field ground to preserve isolation integrity. |
| 15 | 5 V RTNFLD | Field-side ground reference; galvanically isolated from system ground; critical for noise rejection. |
| 16 | +5 VdcFLD | Field-side power supply input; powers field-side receivers and outputs; requires independent bypassing. |
| 17 | ENABLEFLD | Active-high enable for all field-side outputs; allows presetting field logic levels at power-up using pull-up/down resistors. |
| 18–19 (F0–F1) | Field-side Outputs | Two dedicated receive-only logic outputs driving field-side peripherals; three-state capable and HCMOS-compatible. |
| 20–22 (F2–F4) | Not Used (NC) | No internal connection; must remain unconnected to avoid compromising isolation barrier integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitive Isolation Barrier | 3.5 kVrms tested, <10 pF total inter-side capacitance - minimizes coupling of high-frequency noise while enabling fast edge transmission. |
| Continuous Output Update | Background polling updates outputs within 12 µs after fault or power-up reset - guarantees valid logic states without external watchdog intervention. |
| Dual Independent Enable Control | Separate ENABLESYS and ENABLEFLD pins allow selective three-state control of either domain - simplifies bus arbitration and hot-swap sequencing. |
| HCMOS-Compatible I/O | Input thresholds (VT+ = 2.0–4.2 V, VT– = 0.9–3.0 V) and output drive (VOH ≥ 3.7 V @ 4 mA) match standard 5 V logic families without level-shifting. |
| High CMV Immunity | 10 kV/µs transient rejection - maintains correct output states during IGBT switching spikes in motor drive inverters. |
Applications
| PLC Analog Input Card | IGBT Motor Drive Control |
|---|---|
Use Scenario: Isolating ADC control signals and status lines between CPU board (system side) and sensor front-end (field side) in modular PLC chassis. IC Role / Device Role / Timing Role: AD261BND-3 provides 3 system-to-field command lines (e.g., START_CONV, RESET_ADC, SEL_CHANNEL) and 2 field-to-system status lines (e.g., BUSY, DATA_READY). Use Value: Eliminates ground-loop noise corruption of precision analog measurements while preserving sub-20 ns timing margins for synchronized sampling. |
Use Scenario: Transmitting PWM gate-enable signals and receiving fault feedback from isolated IGBT half-bridge modules in variable-frequency drives. IC Role / Device Role / Timing Role: AD261BND-3 routes 3 system-side PWM enable commands to field-side gate drivers and returns 2 field-side overcurrent/UVLO flags to controller. Use Value: Maintains <±1 ns edge symmetry across isolation barrier to prevent shoot-through in complementary PWM pairs under 20 kHz switching. |
| Industrial Communications Bus | High-Speed Digital I/O Port |
Use Scenario: Isolating RS-485 transceiver control lines (DE, RE) and direction/status signals in factory-floor EtherCAT or Profibus nodes. IC Role / Device Role / Timing Role: AD261BND-3 carries 3 system-side bus control signals and 2 field-side transceiver status flags (e.g., TX_ACTIVE, FAULT). Use Value: Enables 20 MHz-capable signal routing without adding propagation delay skew that would violate RS-485 timing budgets. |
Use Scenario: Providing isolated digital I/O expansion for embedded controllers in test equipment requiring simultaneous high-speed stimulus and response capture. IC Role / Device Role / Timing Role: AD261BND-3 delivers 3 programmable output bits and monitors 2 input bits across isolation boundary with deterministic 14 ns latency. Use Value: Supports precise timestamping of external events with nanosecond-level jitter control, critical for automated test sequence synchronization. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed logic isolation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SI8622ED-B-IS | 2-channel, 25 kV/µs CMTI, 150 Mbps data rate; uses silicon-dioxide isolation; no continuous update feature. | Lacks field/system dual-enable and automatic DC-level recovery; requires external reset management for fault recovery. | Preferred where higher CMTI and smaller footprint are prioritized over guaranteed post-fault output validity. |
| ISO7721DR | 2-channel, 100 kV/µs CMTI, 100 Mbps; reinforced isolation; integrated LDO; no configurable I/O direction per channel. | Fixed 1-in/1-out per channel; cannot replicate AD261BND-3's 3-input/2-output asymmetric configuration without additional logic. | Best suited for symmetric bidirectional isolation needs where ultra-high CMTI and regulatory certifications (UL/VDE) are mandatory. |
Compared with SI8622ED-B-IS and ISO7721DR, AD261BND-3 uniquely combines asymmetric I/O allocation (3:2), guaranteed 12 µs post-fault output validity, and dual-domain three-state control - making it optimal for legacy 5 V industrial systems requiring deterministic behavior without firmware overhead.
Availability
AD261BND-3 is available at Aetrix Electronics and suitable for PLC/DCS analog I/O cards, IGBT motor drive controls, and high-speed digital I/O ports requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for industrial automation programs.
Supply support for AD261BND-3 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 since 1965.
The AD261 product line was designed specifically for high-speed, high-reliability digital signal isolation in harsh industrial environments - emphasizing deterministic timing, robust transient immunity, and flexible I/O configuration without optical degradation.
FAQ
What is the isolation voltage rating of AD261BND-3?
The AD261BND-3 has a 3.5 kVrms isolation test voltage rating and is 100% production-tested to this level. Its operating isolation voltage is 1.25 kVrms, compliant with UL1950, IEC950, and EN60950 standards. This rating applies across the full temperature range and ensures safe operation in industrial field-side interfaces referenced to mains potentials.
How does AD261BND-3 handle power-up and fault recovery?
AD261BND-3 enters a power-up reset mode for ~30 µs after supply voltages exceed 3.3 V, disabling all lines. Within 12 µs after reset ends, its continuous update circuit polls inputs and forces outputs to reflect current logic states - guaranteeing valid outputs even after faults or brownouts without external intervention.
Can AD261BND-3 replace optocouplers in existing designs?
Yes - AD261BND-3 replaces up to five optocouplers with superior speed (20 MHz vs. typically <1 MHz), lower power consumption, no LED aging, and consistent propagation delay. Its pin-compatible ND-22A DIP footprint allows drop-in replacement in many legacy layouts, though supply bypassing and enable logic must be verified per application.
What are the unused pins on AD261BND-3 and how should they be handled?
Pins 4–5 (S3–S4) and 20–22 (F2–F4) are not connected internally in AD261BND-3. They must remain unconnected - floating or tied to VCC/GND may compromise isolation integrity or cause unintended current paths. The datasheet explicitly prohibits leaving any logic input (including unused S-pins) floating.
Does AD261BND-3 support bidirectional communication on any channel?
No - AD261BND-3 implements strictly unidirectional channels: S0–S2 are system-to-field inputs only, and F0–F1 are field-to-system outputs only. Bidirectional signaling requires external logic or a different model (e.g., AD261BND-2 with 2 inputs/3 outputs), as each pin's direction is fixed by internal configuration.
AD261BND-3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- IsoLogic™
- Package/Case:
- 22-DIP Module
- Packaging:
- Tube
- Product Status:
- Obsolete
- Technology:
- Magnetic Coupling
- Type:
- General Purpose
- Isolated Power:
- No
- Number of Channels:
- 5
- Inputs - Side 1/Side 2:
- 3/2
- Channel Type:
- Unidirectional
- Voltage - Isolation:
- 3500Vrms
- Common Mode Transient Immunity (Min):
- 10kV/µs
- Data Rate:
- -
- Propagation Delay tpLH / tpHL (Max):
- 25ns, 25ns
- Pulse Width Distortion (Max):
- -
- Rise / Fall Time (Typ):
- -
- Voltage - Supply:
- 4V ~ 5.75V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -25°C ~ 85°C
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 22-PDIP
AD261BND-3 FAQ
1.How can I place an order for AD261BND-3 through Aetrix?
Please submit a Request for Quotation (RFQ) for AD261BND-3 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 AD261BND-3 reliable?
The price and inventory of AD261BND-3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD261BND-3 is usually 5 days.
3.What payment methods are accepted for AD261BND-3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD261BND-3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AD261BND-3?
AD261BND-3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AD261BND-3 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 AD261BND-3?
For technical support, including AD261BND-3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD261BND-3 requirements.
6.How does Aetrix verify that AD261BND-3 is sourced from the original manufacturer or authorized distributors?
All AD261BND-3 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 AD261BND-3 meets industry standards.
7.What is the process for return or replacement of AD261BND-3?
All AD261BND-3 units undergo pre-shipment inspection (PSI). If there is an issue with AD261BND-3, 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 AD261BND-3 part is unused and in its original packaging.
Return procedure for AD261BND-3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AD261BND-3 Tags
-
ISO1212DBQR
Texas Instruments
-
ISO6721BDR
Texas Instruments
-
SI8710AC-B-ISR
Skyworks Solutions Inc.
-
ISO7720FDR
Texas Instruments
-
ISO7721DR
Texas Instruments
-
ISO7721FDR
Texas Instruments
-
SI8710CC-B-ISR
Skyworks Solutions Inc.
-
ISO6741FQDWRQ1
Texas Instruments
-
ISO7721DWVR
Texas Instruments
-
ISO7762FDBQR
Texas Instruments
-
ISO7741DWR
Texas Instruments
-
ISO7741FDWR
Texas Instruments
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