13 Safety Limiting Values

Safety limiting⁽¹⁾ intends to minimize 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	MAX	UNIT
DW-16 PACKAGE
I_S	Safety input, output, or supply current	R_θJA =94.4°C/W, V_I = 5.5 V, T_J = 150°C, T_A = 25°C	241	mA
		R_θJA = 94.4°C/W, V_I = 3.6 V, T_J = 150°C, T_A = 25°C	368
		R_θJA = 94.4°C/W, V_I = 2.75 V, T_J = 150°C, T_A = 25°C	482
P_S	Safety input, output, or total power	R_θJA = 94.4°C/W, T_J = 150°C, T_A = 25°C	1324	mW
T_S	Maximum safety temperature		150	°C
D-8 PACKAGE
I_S	Safety input, output, or supply current ⁽¹⁾	R_θJA =146.1°C/W, V_I = 5.5 V, T_J = 150°C, T_A = 25°C	156	mA
		R_θJA = 146.1°C/W, V_I = 3.6 V, T_J = 150°C, T_A = 25°C	238
		R_θJA = 146.1°C/W, V_I = 2.75 V, T_J = 150°C, T_A = 25°C	311
P_S	Safety input, output, or total power ⁽¹⁾	R_θJA = 146.1°C/W, T_J = 150°C, T_A = 25°C	856	mW
T_S	Maximum safety temperature ⁽¹⁾		150	°C

(1) The maximum safety temperature, T_S, has the same value as the maximum junction temperature, T_J, specified for the device. The I_S and P_S parameters represent the safety current and safety power respectively. The maximum limits of I_S and P_S should not be exceeded. These limits vary with the ambient temperature, T_A.

The junction-to-air thermal resistance, R_θJA, in the Section 9 table is that of a device installed on a high-K test board for leaded surface-mount packages. Use these equations to calculate the value for each parameter:
T_J = T_A + R_θJA × P, where P is the power dissipated in the device.
T_J(max)= T_S = T_A + R_θJA × P_S, where T_J(max) is the maximum allowed junction temperature.
P_S = I_S × V_I, where V_I is the maximum input voltage.