1 Features
1• Highest Signaling Rate: 1 Mbps
• Low Power Consumption, Typical I CC per Channel
(3.3-V operation):
– ISO7420: 1.1 mA, ISO7421: 1.5 mA
• Low Propagation Delay – 9 ns Typical
• Low Skew – 300 ps Typical
• Wide TA Range: –40°C to 125°C (M-Grade)
• 50-kV/μs Transient Immunity, Typical
• Over 25-Year Isolation Integrity at Rated Voltage
• Operates From 3.3-V and 5-V Supply and Logic
Levels
• 3.3-V and 5-V Level Translation
• Narrow Body SOIC-8 Package
• Safety and Regulatory Approvals:
– 4242 VPK Isolation per DIN V VDE V 0884-10
and DIN EN 61010-1
– 2500 VRMS Isolation for 1 minute per UL 1577
– CSA Component Acceptance Notice 5A, IEC
60950-1 and IEC 61010-1 Standards
– CQC Certification per GB4943.1-2011

2 Applications
• Optocoupler Replacement in:
– Industrial Fieldbus
– Profibus
– Modbus
– DeviceNet™ Data Buses
– Servo Control Interface
– Motor Control
– Power Supplies
– Battery Packs

3 Description
The ISO7420, ISO7420M and ISO7421 provide
galvanic isolation up to 2500 VRMS for 1 minute per
UL. These digital isolators have two isolated
channels. Each isolation channel has a logic input
and output buffer separated by a silicon dioxide
(SiO2) insulation barrier. Used in conjunction with
isolated power supplies, these devices prevent noise currents on a data bus or other circuit from entering
the local ground and interfering with or damaging
sensitive circuitry. The suffix M indicates wide
temperature range (–40°C to 125°C).
These devices have TTL input thresholds and require
two supply voltages, 3.3 or 5 V, or any combination.
All inputs are 5-V tolerant when supplied from a 3.3-V supply.
Note: The ISO7420 and ISO7421 are specified for signaling rates up to 1 Mbps. Due to their fast
response time, under most cases, these devices will
also transmit data with much shorter pulse widths.
Designers should add external filtering to remove
spurious signals with input pulse duration <20 ns if
desired.