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Analog Devices Inc./Maxim Integrated ADUM1254ASA+T
- Part No.:
- ADUM1254ASA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ADUM1254ASA+T.pdf
- Description:
- TWO CHANNEL, BIDIRECTIONAL I2C D
- Quantity:
- Payment:
- Shipping:
Inventory:1,382
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Product details
Overview
ADUM1254ASA+T from Analog Devices is a bidirectional I²C isolator with idle-bus hot-swap capability and regulated low VOL (0.69V on Side 1, 0.4V on Side 2), supporting 2.25V–5.5V dual supplies and 2MHz SCL operation across reinforced galvanic isolation. It enables isolated I²C communication between microcontrollers and sensors in battery management systems and PoE-powered equipment.
For engineers reviewing the ADUM1254ASA+T datasheet, ADUM1254ASA+T pinout, ADUM1254ASA+T application, or ADUM1254ASA+T equivalent, this page delivers verified specifications, side-specific current sinking (5mA Side 1 / 50mA Side 2), CMTI ≥100 kV/µs, VIOWM = 445 VRMS (narrow SOIC), and hot-swap timing parameters critical for robust bus integration.
Technical Context
The ADUM1254ASA+T implements two independent bidirectional open-drain channels using iCoupler® digital isolation technology, with asymmetric buffer design: Side 1 regulates logic-low voltage at 0.64V and enforces ΔVO/IT ≥45mV to prevent latch-up, while Side 2 uses conventional buffers with VIL2 = 0.3×VDD2 and VOL2 = 0.4V at 50mA sink.
Its hot-swap architecture precharges Side 2 bus pins (VPRECHG = 0.3×VDD2, RPRECHG = 140kΩ), then monitors for idle or STOP condition (tIDLE = 75μs after tHS_EN = 102ms) before enabling isolation, ensuring disturbance-free insertion into live I²C buses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage (VIOWM) | 445 VRMS continuous - meets reinforced insulation requirements for industrial mains-connected systems in narrow SOIC package. |
| Max Data Rate | 2 MHz SCL - supports standard- and fast-mode I²C without protocol modification or clock stretching limitations. |
| Side 1 VOL (max) | 0.69 V at 5 mA sink - ensures compatibility with legacy I²C devices requiring tight low-level voltage margins. |
| Side 2 VOL (max) | 0.4 V at 50 mA sink - enables lower pull-up resistor values (e.g., ≤1kΩ) for faster rise times and higher noise immunity. |
| CMTI | ≥100 kV/µs - guarantees reliable signal transmission under high dv/dt transients common in motor drives and SMPS environments. |
| Supply Range | 2.25 V to 5.5 V per side - allows level-shifting between 3.3 V MCU domains and 5 V peripherals without external translators. |
| Operating Temp | −40°C to +125°C ambient - qualified for under-hood automotive, industrial PLC, and high-temperature battery pack monitoring. |
Pinout & Package
ADUM1254ASA+T is supplied in an 8-pin narrow-body SOIC package (Outline 21-0041) with 4 mm creepage/clearance, RoHS-compliant, moisture sensitivity level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VDD1 | Side 1 power supply | Accepts 2.25–5.5 V; requires local 0.1 µF + 1 nF ceramic decoupling for stable I²C signaling and UVLO immunity. |
| 2 - SDA1 | Side 1 bidirectional data line | Open-drain I²C bus interface; logic-low regulated to ≤0.69 V to prevent bus contention with downstream devices. |
| 3 - SCL1 | Side 1 bidirectional clock line | Open-drain I²C clock interface; supports clock stretching from either side of isolation barrier. |
| 4 - GND1 | Side 1 ground reference | Return path for Side 1 circuitry; must be isolated from GND2 by ≥4 mm clearance/creepage. |
| 5 - GND2 | Side 2 ground reference | Return path for Side 2 circuitry; galvanically separated from GND1; enables floating bus domain operation. |
| 6 - SCL2 | Side 2 bidirectional clock line | Open-drain I²C clock interface; features enhanced hot-swap precharge and idle detection prior to connection. |
| 7 - SDA2 | Side 2 bidirectional data line | Open-drain I²C bus interface; sinks up to 50 mA to drive low-impedance pull-ups and reduce rise time. |
| 8 - VDD2 | Side 2 power supply | Accepts 2.25–5.5 V independently of VDD1; enables true level-shifting and fault containment between domains. |
Key Features
| Feature | Design Value |
|---|---|
| Idle-bus hot-swap on Side 2 | Prevents data corruption during live insertion by enforcing connection only after detecting bus IDLE or STOP condition (tIDLE = 75 μs). |
| Asymmetric VOL regulation | Side 1 VOL ≤0.69 V (5 mA) and Side 2 VOL ≤0.4 V (50 mA) ensure interoperability across mixed-voltage I²C nodes. |
| Bidirectional clock channel | Enables multiple controllers on opposite sides of isolation barrier and full support for clock stretching by any target device. |
| High CMTI (≥100 kV/µs) | Rejects fast common-mode transients in noisy industrial environments without signal degradation or false triggering. |
| Reinforced isolation (VIOWM = 445 VRMS) | Meets IEC 60747-17 and UL 1577 requirements for safety-critical applications with single-fault tolerance. |
Applications
| Isolated Battery Management | Industrial PoE Endpoint |
|---|---|
Use Scenario: Monitoring cell voltages and temperatures in high-voltage EV battery packs where MCU (Side 1) operates at low voltage and sensors (Side 2) reside near 400–800 V bus. IC Role / Device Role / Timing Role: ADUM1254ASA+T provides galvanically isolated I²C communication between MCU and isolated ADC/sensor ICs, preserving timing integrity at 2 MHz while blocking hazardous potentials. Use Value: Enables safe, real-time telemetry without optocoupler latency or discrete level-shifter complexity; 125°C rating supports under-pack thermal conditions. |
Use Scenario: Isolating I²C configuration and status interfaces between PoE PD controller (Side 1) and powered subsystems (Side 2) in network switches or IP cameras. IC Role / Device Role / Timing Role: ADUM1254ASA+T bridges I²C control lines across isolation barrier created by PoE transformer, maintaining SCL timing and supporting hot-plug of powered modules. Use Value: Prevents ground loop currents and ESD coupling into sensitive control logic; Side 2 hot-swap avoids bus lockup during module replacement. |
| Motor Drive Feedback Interface | Medical Isolated Sensor Hub |
Use Scenario: Connecting isolated position encoders and current sensors to main controller in servo drives where PWM noise exceeds 100 kV/µs. IC Role / Device Role / Timing Role: ADUM1254ASA+T serves as bidirectional I²C isolator for encoder calibration and fault reporting, with CMTI ≥100 kV/µs ensuring immunity to switching transients. Use Value: Eliminates need for separate clock/data isolators; bidirectional SCL allows host-initiated recalibration and sensor-initiated alarm signaling over same pair. |
Use Scenario: Interfacing isolated temperature, pressure, and ECG front-end sensors to central MCU in patient-connected medical devices requiring 2× MOPP. IC Role / Device Role / Timing Role: ADUM1254ASA+T provides reinforced I²C isolation between sensor ASICs (Side 2) and diagnostic processor (Side 1), meeting IEC 62368-1 basic insulation requirements. Use Value: Achieves 445 VRMS working voltage and 4 mm creepage in compact SOIC package-reducing board area vs. discrete isolator solutions while maintaining safety certification paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional I²C isolation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ADUM1250ARZ | Same pinout, identical electrical specs, but in 8-lead wide-body SOIC (VIOWM = 848 VRMS, 8 mm creepage). | Suitable for higher-isolation applications (e.g., AC mains interfacing) where 445 VRMS is insufficient. | Select ADUM1250ARZ when >445 VRMS working voltage or >4 mm creepage is mandated by system safety standards. |
| SI8602ED-B-IS | Si86xx-based isolator; 2-channel bidirectional I²C; VIOWM = 500 VRMS; no idle-bus hot-swap; VOL = 0.4 V (Side 2 only). | Lacks precharge/idle-detection logic; requires external hot-swap sequencing or bus reset recovery. | Choose SI8602ED-B-IS only if hot-swap is not required and higher CMTI (>150 kV/µs) is prioritized over bus robustness. |
Compared with ADUM1254ASA+T, ADUM1250ARZ offers higher isolation ratings in wider package, while SI8602ED-B-IS trades hot-swap reliability for marginally better transient immunity-making ADUM1254ASA+T optimal for field-serviceable I²C systems.
Availability
ADUM1254ASA+T is available at Aetrix Electronics and suitable for battery management systems, Power over Ethernet endpoints, and motor control feedback interfaces requiring stable component supply, long-term industrial lifecycle support, and guaranteed RoHS compliance.
Supply support for ADUM1254ASA+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
Analog Devices, Inc. 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 ADuM1254 product line delivers reinforced digital isolation for bidirectional serial buses, specifically engineered for robust I²C/SMBus communication in harsh environments where ground separation, hot-swap reliability, and extended temperature operation are mandatory.
FAQ
What is the maximum SCL frequency supported by the ADUM1254ASA+T?
The ADUM1254ASA+T supports I²C clock frequencies up to 2 MHz, enabling fast-mode Plus (Fm+) operation. This is validated across the full supply range (2.25 V–5.5 V) and temperature range (−40°C to +125°C), with propagation delays (tPLH12/tPHL12) specified at ≤133.3 ns and pulse-width distortion ≤94.2 ns to maintain timing margins.
Does the ADUM1254ASA+T require external direction-control signals for bidirectional I²C operation?
No, the ADUM1254ASA+T does not require external direction-control signals. Its internal architecture automatically detects data flow direction on both SDA and SCL lines using proprietary encoding/decoding logic, enabling true transparent bidirectional communication-identical to native I²C bus behavior without added control overhead.
How does the ADUM1254ASA+T implement idle-bus hot-swap on Side 2?
The ADUM1254ASA+T implements idle-bus hot-swap by first precharging SDA2/SCL2 to 0.3×VDD2 via 140 kΩ Thevenin impedance, then monitoring bus state for ≥75 μs after 102 ms enable delay. Connection occurs only upon detecting either bus IDLE (both lines high) or a valid STOP condition-preventing arbitration loss or data corruption during live insertion.
What are the isolation ratings for the ADUM1254ASA+T package?
The ADUM1254ASA+T uses an 8-pin narrow-body SOIC package rated for 445 VRMS maximum working isolation voltage (VIOWM), 630 VPEAK repetitive isolation voltage (VIORM), and 3000 VRMS withstand voltage (VISO) for 60 seconds. It achieves 4 mm creepage and clearance, meeting IEC 60747-17 and UL 1577 reinforced insulation requirements.
Can the ADUM1254ASA+T operate with different supply voltages on Side 1 and Side 2?
Yes, the ADUM1254ASA+T supports independent 2.25 V–5.5 V supplies on VDD1 and VDD2, enabling seamless level-shifting between 3.3 V microcontrollers and 5 V peripherals. This eliminates external level translators and maintains full 2 MHz I²C functionality regardless of voltage mismatch, with side-specific VOL and VIH thresholds optimized for each domain.
ADUM1254ASA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Magnetic Coupling
- Type:
- CAN, I2C
- Isolated Power:
- Yes
- Number of Channels:
- 2
- Inputs - Side 1/Side 2:
- 2/2
- Channel Type:
- Bidirectional
- Voltage - Isolation:
- 3000Vrms
- Common Mode Transient Immunity (Min):
- 100kV/µs
- Data Rate:
- 2MHz
- Propagation Delay tpLH / tpHL (Max):
- 95.8ns, 128.4ns
- Pulse Width Distortion (Max):
- 94.2ns
- Rise / Fall Time (Typ):
- -, 20.3ns
- Voltage - Supply:
- 2.25V ~ 5.5V
- Grade:
- -
- Qualification:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
ADUM1254ASA+T FAQ
1.How can I place an order for ADUM1254ASA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for ADUM1254ASA+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 ADUM1254ASA+T reliable?
The price and inventory of ADUM1254ASA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADUM1254ASA+T is usually 5 days.
3.What payment methods are accepted for ADUM1254ASA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADUM1254ASA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADUM1254ASA+T?
ADUM1254ASA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADUM1254ASA+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 ADUM1254ASA+T?
For technical support, including ADUM1254ASA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADUM1254ASA+T requirements.
6.How does Aetrix verify that ADUM1254ASA+T is sourced from the original manufacturer or authorized distributors?
All ADUM1254ASA+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 ADUM1254ASA+T meets industry standards.
7.What is the process for return or replacement of ADUM1254ASA+T?
All ADUM1254ASA+T units undergo pre-shipment inspection (PSI). If there is an issue with ADUM1254ASA+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 ADUM1254ASA+T part is unused and in its original packaging.
Return procedure for ADUM1254ASA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ADUM1254ASA+T Tags
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