Isolation Capacitor
VCC2VCC1
SDA2
or SCL2
SDA1
or SCL1
GND1
GND2
V
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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
ISO1540
,
ISO1541
SLLSEB6D –JULY 2012–REVISED DECEMBER 2016
ISO154x Low-Power Bidirectional I
2
C Isolators
1
1 Features
1
• 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 35-
mA 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-V
PK
Isolation per DIN V VDE V 0884-10
(VDE V 0884-10): 2006-12
– 2500-V
RMS
Isolation for 1 Minute per UL 1577
– CSA Component Acceptance Notice 5A, IEC
60950-1 and IEC 61010-1 End Equipment
Standards
– CQC Basic Insulation per GB4943.1-2011
2 Applications
• Isolated I
2
C Buses
• SMBus and PMBus Interfaces
• Open-Drain Networks
• Motor Control Systems
• Battery Management
• I
2
C Level Shifting
3 Description
The ISO1540 and ISO1541 devices are low-power,
bidirectional isolators that are compatible with I
2
C
interfaces. These devices have logic input and output
buffers that are separated by Texas Instruments
Capacitive Isolation technology using a silicon dioxide
(SiO
2
) barrier. When used with isolated power
supplies, these devices block high voltages, isolate
grounds, and prevent noise currents from entering the
local ground and interfering with or damaging
sensitive circuitry.
This isolation technology provides for function,
performance, size, and power consumption
advantages when compared to optocouplers. The
ISO1540 and ISO1541 devices enable a complete
isolated I
2
C interface to be implemented within a
small form factor.
The ISO1540 has two isolated bidirectional channels
for clock and data lines while the ISO1541 has a
bidirectional data and a unidirectional clock channel.
The ISO1541 is useful in applications that have a
single master while the ISO1540 is suitable for multi-
master applications. For applications where clock
stretching by the slave is possible, the ISO1540
device should be used.
Isolated bidirectional communication is accomplished
within these devices by offsetting the low-level output
voltage on side 1 to a value greater than the high-
level input voltage on side 1, thus preventing an
internal logic latch that otherwise would occur with
standard digital isolators.
Device Information
(1)
PART NUMBER PACKAGE BODY SIZE (NOM)
ISO1540
ISO1541
SOIC (8) 4.90 mm × 3.91 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
