1 Features

• 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 T_A 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 V_PK Isolation per DIN V VDE V 0884-10 and DIN EN 61010-1
  • 2500 V_RMS 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 V_RMS 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.

1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Schematic

V_CCI and GNDI are supply and ground connections respectively for the input channels.

V_CCO and GNDO are supply and ground connections respectively for the output channels.