DEVICE I/O SCHEMATICS

OUT

8 W

13 W

IN

750kW

500 W

Input

Output

IEC SAFETY LIMITING VALUES

ISO7220A, ISO7220B, ISO7220C, ISO7220M

ISO7221A, ISO7221B, ISO7221C, ISO7221M

Safety limiting intends to prevent potential damage to the isolation barrier upon failure of input or output circuitry.

A failure of the IO can allow low resistance to ground or the supply and, without current limiting, dissipate

sufficient power to overheat the die and damage the isolation barrier potentially leading to secondary system

failures.

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

θ

124

Safety input, output, or

SOIC-8

mA

supply current

θ

190

Maximum case temperature

SOIC-8

150

°C

The safety-limiting constraint is the absolute maximum junction temperature specified in the absolute maximum

ratings table. The power dissipation and junction-to-air thermal impedance of the device installed in the

application hardware determines the junction temperature. The assumed junction-to-air thermal resistance in the

Thermal Characteristics table is that of a device installed in the JESD51-3, Low Effective Thermal Conductivity

Test Board for Leaded Surface Mount Packages and is conservative. The power is the recommended maximum

input voltage times the current. The junction temperature is then the ambient temperature plus the power times

the junction-to-air thermal resistance.

Copyright © 2006–2008, Texas Instruments Incorporated

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Product Folder Link(s): ISO7220A ISO7220B ISO7220C ISO7220M ISO7221A ISO7221B ISO7221C ISO7221M