Case Temperature − C

°

0

20

40

60

80

100

120

140

160

180

0

50

100

150

200

VCC1, VCC2 at 3.6 V

VCC1, VCC2 at 5.5 V

10

100

0

250

500

750

1000

V

– Working Voltage – V

IORM

PK

880

120

V

at 566 V

IORM

28 Years

G001

ISO7420E, ISO7420FE, ISO7421E, ISO7421FE

www.ti.com

SLLSE45F – DECEMBER 2010 – REVISED JULY 2015

8.3.4 Life Expectancy vs Working Voltage

Figure 20. Life Expectancy vs Working Voltage

8.3.5 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.

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

θJA = 212°C/W, VI = 5.5 V, TJ = 150°C, TA = 25°C

107

Safety input, output, or supply

IS

mA

current

θJA = 212°C/W, VI = 3.6 V, TJ = 150°C, TA = 25°C

164

TS

Maximum safety temperature

150

°C

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

Ratings(1) 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 Information 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.

Figure 21.

θJC Thermal Derating Curve per VDE

(1)

Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings

only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating

conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

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