Ambient Temperature (qC)

0

50

100

150

200

0

100

200

300

400

500

600

D014

Ambient Temperature (qC)

0

50

100

150

200

0

200

400

600

800

1000

1200

1400

1600

D015

Power

21

ISO7821, ISO7821F

www.ti.com

SLLSEM2F – NOVEMBER 2014 – REVISED MARCH 2016

Product Folder Links: ISO7821 ISO7821F

Submit Documentation Feedback

Copyright © 2014–2016, Texas Instruments Incorporated

8.3.1.2 Safety Limiting Values

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

the I/O 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.

Table 5. Safety Limiting

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

Safety input, output, or supply

current for DW-16 package

and DWW-16 Packages

268

mA

410

537

Safety input, output, or total

power

1476

mW

Maximum safety temperature

150

°C

The maximum safety temperature is the maximum junction temperature specified for the device. 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

Information is that of a device installed on a High-K test board for Leaded Surface Mount Packages. 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.

Figure 13. Thermal Derating Curve for Safety Limiting

Current per VDE

Figure 14. Thermal Derating Curve for Safety Limiting

Power per VDE