Skip to main content

We use cookies to understand how you use our site and improve your experience. See our Privacy Policy.

ISO1540D

Bidirectional I²C Isolator

The ISO1540D is a bidirectional i²c isolator from Texas Instruments. View the full ISO1540D datasheet below including key specifications, electrical characteristics, absolute maximum ratings.

ISO1540D shares its datasheet with ISO1540, whose page lists every part number it covers.

Official ISO1540D datasheet (PDF) — the source this page was extracted from.

Manufacturer

Texas Instruments

Package

SOIC-8

ISO1540D Key Specifications

ParameterValue
PackageSOIC-8 (D)
Isolation Rating4000 VPK / 2500 VRMS (1 min)
Clearance / Creepage4.8 mm / 4.3 mm
ESD Protection (HBM)4 kV all pins, 8 kV bus pins
Communication InterfaceI2C / SMBus / PMBus compatible (bidirectional SDA and SCL)
Maximum Capacitive Load40 pF (Side 1), 400 pF (Side 2)
Thermal Resistance (θJA)114.6 °C/W
Maximum Operating Frequency1 MHz
Operating Temperature Range-40°C to 125°C
Output Sink Current, Side 13.5 mA
Output Sink Current, Side 235 mA
Supply Voltage (VCC1, VCC2)3V to 5.5V
Common-Mode Transient Immunity±50 kV/µs (typical)
Supply Current Side 1 (3-3.6V, Low Input)2.4 mA typ
Supply Current Side 2 (3-3.6V, Low Input)1.7 mA typ

ISO1540D Overview

Part: ISO1540 / ISO1541 — Texas Instruments

Type: Low-Power Bidirectional I²C Digital Isolator

Description: 3–5.5 V, 1 MHz isolated bidirectional I²C isolator with open-drain outputs (3.5 mA side 1 / 35 mA side 2 sink), 2500 VRMS isolation (UL 1577) and ±50 kV/μs typical transient immunity.

Operating Conditions:

  • Supply voltage (VCC1, VCC2): 3–5.5 V
  • Operating temperature (ambient): -40 to 125 °C
  • Operating frequency: up to 1 MHz
  • Capacitive load: 40 pF max (side 1), 400 pF max (side 2)

Absolute Maximum Ratings:

  • Max supply voltage (VCC1, VCC2): 6 V
  • Output current: 20 mA (SDA1, SCL1); 100 mA (SDA2, SCL2)
  • Max junction temperature: 150 °C
  • Storage temperature: -65 to 150 °C

Key Specs:

  • Supply voltage: 3–5.5 V on both sides
  • Output sink current (recommended): 0.5–3.5 mA side 1, 0.5–35 mA side 2
  • Input thresholds side 1: VIL1 max 0.5 V, VIH1 min 0.7 × VCC1
  • Input thresholds side 2: VIL2 max 0.3 × VCC2, VIH2 min 0.7 × VCC2
  • Maximum operating frequency: 1 MHz
  • Thermal resistance RθJA: 114.6 °C/W (D, SOIC-8)
  • ESD HBM: ±8000 V (bus pins), ±4000 V (all pins); CDM ±1500 V
  • Recommended junction temperature: -40 to 136 °C; thermal shutdown 139–197 °C

Features:

  • Isolated bidirectional I²C-compatible communication
  • ISO1540: two bidirectional channels (SDA and SCL), suitable for multi-controller systems and clock stretching
  • ISO1541: bidirectional data and unidirectional clock channel, for single-controller systems
  • ±50 kV/μs typical transient immunity
  • 4242 VPK isolation per DIN EN IEC 60747-17 (VDE 0884-17)
  • 2500 VRMS isolation for 1 minute per UL 1577
  • CSA approval per IEC 62368-1; CQC basic insulation per GB4943.1-2011

Applications:

  • Isolated I²C buses
  • SMBus and PMBus interfaces
  • Open-drain networks
  • Motor control systems
  • Battery management
  • I²C level shifting

Package:

  • SOIC (8), D package, 4.90 mm × 3.91 mm

ISO1540D Features

  • Isolated bidirectional, I 2 C compatible, communication
  • Supports up to 1-MHz operation
  • 3-V to 5.5-V supply range
  • Open-drain outputs With 3.5-mA Side 1 and 35mA Side 2 sink current capability
  • -40°C to +125°C operating temperature
  • ±50-kV/μs transient immunity (Typical)
  • HBM ESD protection of 4 kV on all pins; 8 kV on bus pins
  • Safety-related certifications:
  • -4242-VPK isolation per DIN EN IEC 60747-17 (VDE 0884-17)
  • -2500-VRMS isolation for 1 minute per UL 1577
  • -CSA approval per IEC 62368-1 end equipment standard
  • -CQC basic insulation per GB4943.1-2011

ISO1540D Applications

  • Isolated I 2 C buses
  • SMBus and PMBus interfaces
  • Open-drain networks
  • Motor control systems
  • Battery management
  • I 2 C level shifting

ISO1540D Pin Configuration

Figure 5-1. ISO1540 D Package 8-Pin SOIC Top View

Table 5-1. Pin Functions-ISO1540

PIN - NAMEPIN - NO.I/ODESCRIPTION
GND14-Ground, side 1
GND25-Ground, side 2
SCL13I/OSerial clock input / output, side 1
SCL26I/OSerial clock input / output, side 2
SDA12I/OSerial data input / output, side 1
SDA27I/OSerial data input / output, side 2
VCC11-Supply voltage, side 1
VCC28-Supply voltage, side 2

Table 5-1. Pin Functions-ISO1540

Figure 5-2. ISO1541 D Package 8-Pin SOIC Top View

Table 5-2. Pin Functions-ISO1541

PIN - NAMEPIN - NO.I/ODESCRIPTION
GND14-Ground, side 1
GND25-Ground, side 2
SCL13ISerial clock input, side 1
SCL26OSerial clock output, side 2
SDA12I/OSerial data input / output, side 1
SDA27I/OSerial data input / output, side 2
VCC11-Supply voltage, side 1
VCC28-Supply voltage, side 2

ISO1540D Electrical Characteristics

over recommended operating conditions, unless otherwise noted

PARAMETERPARAMETERTEST CONDITIONSMINTYPMAXUNIT
SIDE 1 (ONLY)SIDE 1 (ONLY)SIDE 1 (ONLY)SIDE 1 (ONLY)SIDE 1 (ONLY)SIDE 1 (ONLY)SIDE 1 (ONLY)
V ILT1Voltage input threshold low, SDA1 and SCL1480550660mV
V IHT1Voltage input threshold high, SDA1 and SCL1520610700mV
V HYST1Voltage input hysteresisV IHT1 -V ILT14060mV
V OL1Low-level output voltage, SDA1 and SCL1 (1)0.5 mA ≤ (I SDA1 and I SCL1 ) ≤ 3.5 mA570800mV
ΔV OIT1Low-level output voltage to high- level input voltage threshold difference, SDA1 and SCL1 (1) (2)0.5 mA ≤ (I SDA1 and I SCL1 ) ≤ 3.5 mA50mV
SIDE 2 (ONLY)SIDE 2 (ONLY)SIDE 2 (ONLY)SIDE 2 (ONLY)SIDE 2 (ONLY)SIDE 2 (ONLY)SIDE 2 (ONLY)
V ILT2Voltage input threshold low, SDA2 and SCL20.3 × VCC20.4 × VCC2V
V IHT2Voltage input threshold high, SDA2 and SCL20.4 × VCC20.5 × VCC2V
V HYST2Voltage input hysteresisV IHT2 - V ILT20.05 × VCC2V
V OL2Low-level output voltage, SDA2 and SCL20.5 mA ≤ (I SDA2 and I SCL2 ) ≤ 35 mA0.4V
BOTH SIDESBOTH SIDESBOTH SIDESBOTH SIDESBOTH SIDESBOTH SIDESBOTH SIDES
|I I |Input leakage currents, SDA1, SCL1, SDA2, and SCL2V SDA1 , V SCL1 = VCC1; V SDA2 , V SCL2 = VCC20.0110μA
C IInput capacitance to local ground, SDA1, SCL1, SDA2, and SCL2V I = 0.4 × sin(2E6πt) + 2.5 V7pF
CMTICommon-mode transient immunitySee Figure 7-32550kV/μs
V CCUVVCC undervoltage lockout threshold (3)1.72.52.9V

ISO1540D Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted) (1) (2)

MINMAXUNIT
VoltageVCC1, VCC2-0.56V
SDA1, SCL1-0.5VCC1 + 0.5 (3)V
SDA2, SCL2-0.5VCC2 + 0.5 (3)V
I OOutput current SDA1, SCL1020mA
SDA2, SCL20100mA
T J(MAX)Maximum junction temperature150°C
T stgStorage temperature-65150°C
  • (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions . Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
  • (2) All voltage values here within are with respect to the local ground pin (GND1 or GND2) and are peak voltage values.
  • (3) Maximum voltage must not exceed 6 V.
MINMAXUNIT
VCC1, VCC2Supply voltage35.5V
V SDA1 , V SCL1Input and output signal voltages, side 10VCC1V
V SDA2 , V SCL2Input and output signal voltages, side 20VCC2V
V IL1Low-level input voltage, side 100.5V
V IH1High-level input voltage, side 10.7 × VCC1VCC1V
V IL2Low-level input voltage, side 200.3 × VCC2V
V IH2High-level input voltage, side 20.7 × VCC2VCC2V
I OL1Output current, side 10.53.5mA
I OL2Output current, side 20.535mA
C1Capacitive load, side 140pF
C2Capacitive load, side 2400pF
f MAXOperating frequency (1)1MHz
T AAmbient temperature-40125°C
T JJunction temperature-40136°C
T SDThermal shutdown139197°C

ISO1540D Thermal Information

THERMAL METRIC(1)ISO154x D (SOIC) PINS - 8UNIT
R θJAJunction-to-ambient thermal resistance114.6°C/W
R θJC(top)Junction-to-case (top) thermal resistance69.6°C/W
R θJBJunction-to-board thermal resistance55.3°C/W
ψ JTJunction-to-top characterization parameter27.2°C/W
ψ JBJunction-to-board characterization parameter54.7°C/W
R θJC(bot)Junction-to-case (bottom) thermal resistanceN/A°C/W

ISO1540D Typical Application

In Figure 8-4, the ultra low-power microcontroller, MSP430G2132, controls the I 2 C data traffic of configuration data and conversion results for the analog inputs and outputs. Low-power data converters build the analog

Variants on the same datasheet

These parts have exact links to the same datasheet. They are candidates to compare, not verified drop-in replacements; check package, pinout and electrical limits.

Part NumberManufacturerPackage
ISO1540Texas InstrumentsSOIC-8
ISO1540DRTexas Instruments8-SOIC (0.154", 3.90mm Width)
ISO1541Texas InstrumentsSOIC-8

Other Integrated Circuits

All Integrated Circuits datasheetsAll Texas Instruments datasheets (2,442)

Data on this page is extracted from publicly available manufacturer datasheets using automated tools including AI. It may contain errors or omissions. Always verify specifications against the official manufacturer datasheet before making design or purchasing decisions. See our Terms of Service. Rights holders can submit a takedown request.

Ask your AI agent about the ISO1540D

Connect SheetsData to Claude, Cursor, Codex or any MCP client and your agent reads this datasheet for you: pinout, limits, register maps and design checks, with the numbers taken from the PDF.

claude mcp add --transport http sheetsdata https://mcp.sheetsdata.com/mcp

Then ask: "Can the ISO1540D run from my 12 V rail? Check it against the datasheet limits."

Create a free account $2 of usage every month, no card needed.