My Inquiry
My Account
Analog Devices Inc./Maxim Integrated ADUM1254ASA+
- Part No.:
- ADUM1254ASA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Digital Isolators
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ADUM1254ASA+.pdf
- Description:
- TWO CHANNEL, BIDIRECTIONAL I2C D
- Quantity:
- Payment:
- Shipping:
Inventory:4,446
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
ADUM1254ASA+ from Analog Devices is a bidirectional I²C isolator with idle-bus hot-swap capability and regulated low VOL (0.69 V on Side 1, 0.4 V on Side 2), supporting 2.25–5.5 V dual supplies and 2 MHz SCL operation across reinforced galvanic isolation. It enables isolated communication between microcontrollers and sensors in battery management systems and PoE-powered equipment.
For engineers reviewing the ADUM1254ASA+ datasheet, ADUM1254ASA+ pinout, ADUM1254ASA+ application, or ADUM1254ASA+ equivalent, this page delivers verified electrical specs, thermal derating data, safety certification status (UL 1577, IEC 60747-17 pending), and side-specific current sinking (5 mA Side 1 / 50 mA Side 2) critical for I²C bus timing and pull-up resistor selection.
Technical Context
The ADUM1254ASA+ implements two independent bidirectional open-drain channels using iCoupler® capacitive isolation, with asymmetric buffer architecture: Side 1 regulates logic-low voltage at 0.64 V and enforces ≥50 mV margin below VIH to prevent latch-up; Side 2 uses conventional buffers with 0.4 V VOL and VIL/VIL thresholds scaled to VDD2.
Its hot-swap logic precharges SDA2/SCL2 to 0.3×VDD2 via 140 kΩ Thevenin impedance, then waits ≥75 µs for bus idle or STOP condition before enabling cross-side connection-ensuring no data corruption during live insertion into powered I²C buses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 445 VRMS working voltage (8-lead narrow SOIC), 3000 VRMS for 1 min per UL 1577 - enables safe interface between 24 V industrial control and 3.3 V MCU domains |
| Supply Range | 2.25 V to 5.5 V on both VDD1 and VDD2 - supports level-shifting between 3.3 V and 5 V I²C subsystems without external translators |
| Max Data Rate | 2 MHz SCL frequency - meets high-speed I²C Fast-mode Plus requirements for real-time sensor polling |
| Side 1 VOL | 0.69 V max at 5 mA sink - ensures compatibility with legacy I²C devices requiring ≤0.7 V logic-low threshold |
| Side 2 VOL | 0.4 V max at 50 mA sink - allows use of lower-value pull-ups (e.g., 1.8 kΩ @ 3.3 V) for faster rise times and noise immunity |
| CMTI | 100 kV/µs common-mode transient immunity - maintains signal integrity in motor drive environments with fast-switching power stages |
| Operating Temp | −40°C to +125°C ambient - qualified for under-hood automotive BMS and industrial PLC backplanes |
Pinout & Package
ADUM1254ASA+ is housed 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 supply input | Power domain for primary MCU side; requires local 1 nF + 0.1 µF ceramic decoupling |
| 2 - SDA1 | Side 1 bidirectional I²C data | Open-drain output with regulated 0.64 V logic-low; connects directly to MCU SDA pin |
| 3 - SCL1 | Side 1 bidirectional I²C clock | Open-drain output with same regulation as SDA1; supports clock stretching from either side |
| 4 - GND1 | Side 1 ground reference | Return path for VDD1 and Side 1 I/Os; must be isolated from GND2 by ≥4 mm |
| 5 - GND2 | Side 2 ground reference | Return path for VDD2 and Side 2 I/Os; forms isolation barrier boundary with GND1 |
| 6 - SCL2 | Side 2 bidirectional I²C clock | Open-drain output with 0.4 V VOL; enables multi-controller topologies across isolation barrier |
| 7 - SDA2 | Side 2 bidirectional I²C data | Open-drain output with 50 mA sink capability; interfaces to isolated slave devices (e.g., temperature sensors) |
| 8 - VDD2 | Side 2 supply input | Power domain for isolated peripherals; independent of VDD1 for true galvanic separation |
Key Features
| Feature | Design Value |
|---|---|
| Idle-bus hot-swap | Precharges SDA2/SCL2 to 0.3×VDD2 and validates bus idle (≥75 µs) before connection - eliminates glitches during live insertion into powered systems |
| Asymmetric VOL regulation | Side 1 holds VOL at 0.64 V ±50 mV; Side 2 achieves 0.4 V at 50 mA - prevents bus contention while maximizing noise margin on both sides |
| Bidirectional clock channel | SCL1 ↔ SCL2 translation supports clock stretching by slaves on either side and multiple controllers - essential for complex I²C topologies |
| Reinforced isolation | VIOWM = 445 VRMS (narrow SOIC), VIORM = 630 VPEAK - certified per IEC 60747-17 for functional safety in industrial equipment |
| High CMTI | 100 kV/µs immunity - sustains error-free operation in presence of fast transients from MOSFET switching or relay bounce |
Applications
| Battery Management System (BMS) | Power over Ethernet (PoE) Controller Interface |
|---|---|
|
Use Scenario: Isolating cell monitor ICs (e.g., LTC68xx) from host MCU in 48 V EV battery packs where ground potential differences exceed 100 V. IC Role / Device Role / Timing Role: Bidirectional I²C isolator bridging high-side monitoring domain (VDD2 = 5 V) and low-side MCU domain (VDD1 = 3.3 V) with 2 MHz clock support. Use Value: Enables real-time voltage/temperature reporting without ground loops, while Side 2's 50 mA sink drives low-impedance bus stubs in dense PCB layouts. |
Use Scenario: Interfacing PoE PSE controller (e.g., MAX5984) to isolated PD detection circuitry in IEEE 802.3af/at systems. IC Role / Device Role / Timing Role: Hot-swap-capable isolator connecting PSE MCU (Side 1) to isolated 48 V PD signature resistors and classification circuitry (Side 2). Use Value: Prevents bus lockup during live insertion of PD modules; 0.4 V VOL on Side 2 ensures reliable detection of 25 kΩ signature resistors under worst-case VDD2 = 3.3 V. |
| Motor Drive Current Sensing | Industrial PLC I/O Module |
|
Use Scenario: Isolating shunt-based current sense amplifiers (e.g., INA240) from FPGA-based motor control logic in servo drives. IC Role / Device Role / Timing Role: I²C isolator relaying real-time current readings from isolated analog front-end to control FPGA operating at −40°C to +125°C. Use Value: −40°C to +125°C rating ensures operation near heatsinks; 100 kV/µs CMTI rejects noise from IGBT gate drivers switching at >20 kHz. |
Use Scenario: Connecting isolated digital I/O expander (e.g., PCA9555) to main PLC CPU across 2500 V isolation barrier in factory automation cabinets. IC Role / Device Role / Timing Role: Dual-channel isolator handling both SDA and SCL lines between 24 V isolated I/O domain and 5 V CPU domain. Use Value: 4 mm creepage/clearance meets IEC 61000-4-5 surge immunity requirements; Side 1's 0.69 V VOL guarantees compatibility with legacy 5 V I²C peripherals. |
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 | Narrow SOIC-8, same 445 VRMS isolation, but lacks idle-bus hot-swap and has higher Side 1 VOL (0.8 V) | Not suitable for live-insertion scenarios; requires external bus arbitration during power-up | Select ADUM1254ASA+ when hot-plug capability or tighter VOL compliance is required for legacy I²C slaves |
| SI8602ED-B-IS | Si86xx family; 5000 VRMS wide SOIC option, but only unidirectional SCL and bidirectional SDA - no clock stretching support | Cannot support multi-controller I²C topologies or slave-initiated clock stretch across isolation | Choose ADUM1254ASA+ for full bidirectional clock/data channels essential in advanced BMS and PoE designs |
Compared with ADUM1250ARZ and SI8602ED-B-IS, ADUM1254ASA+ uniquely combines idle-bus hot-swap, regulated low VOL on both sides, and fully bidirectional SCL-enabling robust, glitch-free I²C communication in live-insertion and multi-master industrial systems.
Availability
ADUM1254ASA+ is available at Aetrix Electronics and suitable for battery management systems, Power over Ethernet (PoE) controllers, and motor control systems requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for ADUM1254ASA+ 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 ADUM1254ASA+ belongs to the iCoupler® digital isolation product line, engineered specifically for robust, low-latency, and safety-certified galvanic isolation of serial interfaces-including I²C, SMBus, and PMBus-in harsh electromagnetic environments.
FAQ
What is the maximum continuous isolation voltage rating for ADUM1254ASA+?
The ADUM1254ASA+ is rated for 445 VRMS maximum working isolation voltage (VIOWM) in its 8-lead narrow SOIC package, with 3000 VRMS withstand voltage for 1 minute per UL 1577. This rating applies to continuous operation under pollution degree 2 conditions and is validated for material group I case construction per CSA standards.
Does ADUM1254ASA+ support clock stretching across the isolation barrier?
Yes, ADUM1254ASA+ fully supports clock stretching in both directions: SCL1 ↔ SCL2 translation allows a slave device on Side 2 to hold SCL2 low, which propagates to SCL1 and stalls the master on Side 1. This behavior is enabled by its bidirectional clock channel architecture and confirmed in the functional diagram and timing specifications.
What are the recommended decoupling capacitors for ADUM1254ASA+?
Per the Pin Description section, ADUM1254ASA+ requires a 1 nF ceramic capacitor and a 0.1 µF ceramic capacitor placed as close as possible to each supply pin (VDD1 and VDD2). These values minimize high-frequency noise and ensure stable operation during fast I²C transitions and hot-swap precharge events.
Can ADUM1254ASA+ operate with different supply voltages on Side 1 and Side 2?
Yes, ADUM1254ASA+ supports independent 2.25 V to 5.5 V supplies on VDD1 and VDD2, enabling level shifting between 3.3 V MCU domains and 5 V peripheral domains. Electrical characteristics-including VOL, VIH, and propagation delay-are specified across the full voltage range for each side, with no interdependence.
Is hot-swap functionality active on both SDA and SCL pins of ADUM1254ASA+?
Yes, hot-swap logic is applied independently to both SDA2 and SCL2 pins. The device precharges both lines to 0.3×VDD2 and monitors each for idle or STOP condition before enabling connection. This dual-line validation prevents partial bus activation that could corrupt ongoing I²C transactions.
ADUM1254ASA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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+ FAQ
1.How can I place an order for ADUM1254ASA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for ADUM1254ASA+ 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+ reliable?
The price and inventory of ADUM1254ASA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADUM1254ASA+ is usually 5 days.
3.What payment methods are accepted for ADUM1254ASA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADUM1254ASA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADUM1254ASA+?
ADUM1254ASA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADUM1254ASA+ 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+?
For technical support, including ADUM1254ASA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADUM1254ASA+ requirements.
6.How does Aetrix verify that ADUM1254ASA+ is sourced from the original manufacturer or authorized distributors?
All ADUM1254ASA+ 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+ meets industry standards.
7.What is the process for return or replacement of ADUM1254ASA+?
All ADUM1254ASA+ units undergo pre-shipment inspection (PSI). If there is an issue with ADUM1254ASA+, 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+ part is unused and in its original packaging.
Return procedure for ADUM1254ASA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ADUM1254ASA+ 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
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
