ISO1540D - 2.5kVrms I2C Digital Isolator | Texas Instruments
料号： ISO1540D ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.47 | $34.70 |
| 100 | $2.95 | $295.00 |
| 500 | $2.55 | $1,275.00 |
| 1,000 | $2.2 | $2,200.00 |
ISO1540D 概述
A digital isolator transfers digital signals across an isolation barrier, preventing DC and ground-loop current flow while allowing data to pass. Digital isolators are core building blocks in power management hierarchies, replacing optocouplers with higher speed, better reliability, longer life, and smaller footprint. The ISO1540D specifically addresses I2C buses, whose open-drain, bidirectional clock and data lines require specialized direction-handling logic that general-purpose digital isolators cannot provide.
Key features include bidirectional SCL and SDA channels that isolate the I2C bus without external direction control, 1-MHz (fast-mode) operation, and 25kV/us common-mode transient immunity (CMTI) for robust operation in noisy power environments. The open-drain outputs integrate directly into standard I2C topologies with external pull-up resistors on both sides of the barrier.
Technically, the ISO1540D uses TI capacitive isolation technology with a silicon dioxide (SiO2) barrier, delivering high isolation robustness and long-term reliability with a typical propagation delay of 67ns, preserving I2C timing margins. The wide 3V to 5.5V supply range allows 3.3V-to-5V logic domain crossing across the barrier.
Typical applications include isolated I2C sensor interfaces in industrial automation, battery management systems (BMS), power supplies, motor drives, and medical monitoring equipment, where the ISO1540D separates control electronics from high-voltage or noisy power stages.
Design tip: size pull-up resistors on both sides according to bus capacitance and the 1-Mbps data rate, and place 0.1uF decoupling capacitors close to both supply pins, as current pricing of roughly $2 to $4 per unit (as of 2026-08-29) makes it cost-effective to use one isolator per isolated bus segment.
直接替换替代料： ISO1540D ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： ISO1540D （相同外形与封装尺寸） ——差异在于 Number of Channels, Data Rate, Supply Voltage Range, Package, Propagation Delay.
快速对比工具——选择替代料号进行并排对比：
ISO1541D
✅ 直接替换📋 参考替代料（不在目录中）
ISO1540QDQ1
✅ 直接替换📋 参考替代料（不在目录中）
ISO1540DR
✅ 直接替换📋 参考替代料（不在目录中）
ADUM1250ARZ
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$1.85 / 个
查看数据手册 →ADUM1251ARZ
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$4.23 / 个
查看数据手册 →ISO1540D 规格参数
| Isolation Type | Bidirectional I2C isolator |
| Number of Channels | 2 (SCL, SDA) |
| Isolation Voltage | 2500 Vrms |
| 数据速率 | 1 Mbps (1 MHz I2C fast-mode) |
| CMTI | 25 kV/us |
| Supply Voltage Range | 3 V to 5.5 V |
| Propagation Delay | 67 ns (typical) |
| Side 1 Sink Current | 3.5 mA |
| Side 2 Sink Current | 35 mA |
| 输出类型 | Open-drain |
| 工作温度 | -40C to +125C |
| 封装 | 8-SOIC (0.154in, 3.90mm width) |
| 安装类型 | Surface Mount |
| Isolation Technology | Capacitive, SiO2 barrier |
| RoHS 状态 | Compliant |
ISO1540D 引脚配置
| 引脚 1 | VCC1 — Side 1 supply, 3V to 5.5V |
| 引脚 2 | GND1 — Side 1 ground reference |
| 引脚 3 | SCL1 — Side 1 serial clock, open-drain, bidirectional |
| 引脚 4 | SDA1 — Side 1 serial data, open-drain, bidirectional |
| 引脚 5 | SDA2 — Side 2 serial data, open-drain, bidirectional |
| 引脚 6 | SCL2 — Side 2 serial clock, open-drain, bidirectional |
| 引脚 7 | GND2 — Side 2 ground reference (isolated) |
| 引脚 8 | VCC2 — Side 2 supply, 3V to 5.5V (isolated) |
典型应用
ISO1540D 适用于 6 应用s: Battery Management Systems (BMS), Industrial Automation Sensor Interfaces, Isolated Power Supply Telemetry, Motor Drive Control, Medical Monitoring Equipment, 3.3V to 5V I2C Logic Domain Crossing.
Battery Management Systems (BMS)
The ISO1540D isolates the I2C bus between battery cell monitors and the system controller in battery management systems. Its 2500Vrms isolation blocks pack-level voltages, and 25kV/us CMTI tolerates switching transients from adjacent power converters. Placed between the BQ769x0 monitor I2C bus and the MCU with 1k to 4.7k pull-ups on both sides, it transfers SCL and SDA bidirectionally without direction control. The -40C to +125C range supports automotive and industrial pack environments, and the 3V to 5.5V supply range allows 3.3V MCU domains to communicate with 5V monitoring domains across the barrier.
推荐
Industrial Automation Sensor Interfaces
In industrial automation, I2C sensors and ADCs often sit near motors, relays, and high-voltage rails that inject ground noise. The ISO1540D provides a 2500Vrms galvanic barrier with 25kV/us CMTI so transients on the factory floor do not corrupt data or damage the controller. Its 67ns propagation delay keeps I2C timing margins intact at 400kHz and 1MHz fast-mode operation. The open-drain outputs integrate directly into standard I2C topologies with pull-ups on each side, allowing isolated sensor clusters to share one controller without ground loops between equipment chassis.
推荐
Isolated Power Supply Telemetry
Switching power supplies and DC-DC modules use I2C power monitors for telemetry, but the controller must remain isolated from the primary or hot-swap domain. The ISO1540D bridges the barrier with 2500Vrms isolation and 1Mbps speed, fast enough for periodic polling of voltage, current, and temperature registers on INA-class monitors. Its 25kV/us CMTI withstands the high dv/dt of power stages, and the 3V to 5.5V supply range lets both sides run at their native rails. Two 0.1uF decoupling capacitors, one per side, plus appropriately sized pull-ups complete the design.
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Motor Drive Control
Motor drives place gate drivers and current-sensing circuitry at high common-mode potentials that swing rapidly during PWM switching. The ISO1540D isolates the I2C configuration and status bus between the controller and drive electronics, with 25kV/us CMTI preventing PWM dv/dt transients from toggling the data lines. The 2500Vrms working barrier covers typical 400V-class drive isolation budgets, and the -40C to +125C operating range suits drive enclosures. Its bidirectional channels let the controller both configure registers and read fault flags over the same two-wire bus without extra direction signals.
推荐
Medical Monitoring Equipment
Medical monitoring equipment requires patient-isolation barriers on all interfaces touching sensor front ends. The ISO1540D provides 2500Vrms galvanic isolation for I2C connections between isolated analog front ends and the main processor board, helping designs meet isolation requirements while keeping the digital interface simple. Its capacitive SiO2 barrier avoids optocoupler aging and LED degradation, supporting long service life in clinical devices. The 3V to 5.5V supply range and low-power operation suit battery-powered portable monitors, while 1Mbps operation keeps sampling-control loops responsive.
推荐
3.3V to 5V I2C Logic Domain Crossing
Many mixed-rail systems must connect a 3.3V microcontroller I2C bus to a 5V peripheral domain. The ISO1540D solves this natively: each side is powered independently from 3V to 5.5V, so Side 1 at 3.3V can communicate with Side 2 at 5V without separate level shifters. The open-drain outputs pull to each side's local rail, preserving valid logic levels on both buses. Compared with passive level-shift schemes, it simultaneously provides the 2500Vrms isolation and 25kV/us CMTI needed when the peripheral domain sits on a noisy or floating ground.
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推荐产品汇总
工程参考数据： ISO1540D ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | ISO1541D | ISO1540QDQ1 | ADuM1250ARZ |
|---|---|---|---|---|
| Package | 8-SOIC (0.154in, 3.90mm) | 8-SOIC (0.154in, 3.90mm) - same | 8-SOIC (0.154in, 3.90mm) - same | 8-SOIC - verify pinout |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices |
| Isolation Voltage | 2500 Vrms | 2500 Vrms | 2500 Vrms | 2500 Vrms |
| Clock Channel Direction | Bidirectional | Unidirectional | Bidirectional | Bidirectional |
| Data Rate | 1 Mbps | 1 Mbps | 1 Mbps | 1 Mbps |
| Automotive Grade | No | No | Yes (AEC-Q100) | No |
| Supply Range | 3 V to 5.5 V | 3 V to 5.5 V | 3 V to 5.5 V | 3.0 V to 5.5 V |
关键差异点
- Bidirectional clock channel for multi-master and clock-stretching I2C （对比 ISO1541D)
- Automotive-grade variant available on identical footprint （对比 ISO1540QDQ1)
- TI capacitive SiO2 isolation with verified 25kV/us CMTI （对比 ADuM1250ARZ)
设计说明
Both SCL and SDA on each side of the ISO1540D require external pull-up resistors because the outputs are open-drain (3.5mA sink on Side 1, 35mA on Side 2). For 400kHz to 1MHz buses, use 1k to 2.2k pull-ups on both sides; for slower or higher-capacitance buses, 4.7k to 10k reduces static current. Refer to the TI ISO154x datasheet application section for pull-up sizing versus bus capacitance.
VCC1 and VCC2 are on separate, isolated domains and must each be decoupled with a 0.1uF ceramic capacitor placed within 2mm of the corresponding supply pin, plus a bulk capacitor if the local rail is shared with noisy loads. If one side is unpowered, the ISO1540D presents a high-impedance default state on that side, which supports hot-swap and multi-master I2C topologies.
Do not substitute the ISO1541D for the ISO1540D on multi-master buses or where clock stretching is used - the ISO1541D's unidirectional clock channel will lock up the bus. Also keep the isolated Side 2 ground return away from high dv/dt power-stage traces; although CMTI is 25kV/us, coupling into long isolated traces degrades signal integrity at 1MHz operation.
合规信息
RoHS compliant per distributor listings. AEC-Q100 qualification applies only to the ISO1540QDQ1 variant; the standard ISO1540D is not automotive qualified. Other compliance details not stated in provided data.
