HSSR711X Datasheet, PDF (11/12 Pages) Agilent(Hewlett-Packard) – 90 V/1.0 W, Hermetically Sealed, Power MOSFET Optocoupler

11
V_IN
5.5 V
R_IN
200 Ω
HSSR-7110
1
8
2
7
3
6
4
5
Figure 20. Burn-In Circuit.
R_OUT
1.0 Ω
V_O (SEE NOTE)
R_OUT
1.0 Ω
NOTE:
IN ORDER TO DETERMINE V_OUT CORRECTLY, THE CASE TO AMBIENT THERMAL IMPEDANCE MUST
BE MEASURED FOR THE BURN-IN BOARDS TO BE USED. THEN, KNOWING θ_CA, DETERMINE THE
CORRECT OUTPUT CURRENT PER FIGURES 2 AND 4 TO INSURE THAT THE DEVICE MEETS THE
DERATING REQUIREMENTS AS SHOWN.
T_je
T_jf1
T_jd
T_jf2
104
15
15
15
T_C
θ_CA
T_A
T_je = LED JUNCTION TEMPERATURE
T_jf1 = FET 1 JUNCTION TEMPERATURE
T_jf2 = FET 2 JUNCTION TEMPERATURE
T_jd = FET DRIVER JUNCTION TEMPERATURE
T_C = CASE TEMPERATURE (MEASURED AT CENTER
OF PACKAGE BOTTOM)
T_A = AMBIENT TEMPERATURE (MEASURED 6" AWAY
FROM THE PACKAGE)
θ_CA = CASE-TO-AMBIENT THERMAL RESISTANCE
ALL THERMAL RESISTANCE VALUES ARE IN °C/W
Figure 21. Thermal Model.
Applications Information
Thermal Model
The steady state thermal model
for the HSSR-7110 is shown in
Figure 21. The thermal resistance
values given in this model can be
used to calculate the temperatures
at each node for a given operating
condition. The thermal resistances
between the LED and other
internal nodes are very large in
comparison with the other terms
and are omitted for simplicity.
The components do, however,
interact indirectly through θ_CA,
the case-to-ambient thermal
resistance. All heat generated
flows through θ_CA, which raises
the case temperature T_C accord-
ingly. The value of θ_CA depends on
the conditions of the board design
and is, therefore, determined by
the designer.
The maximum value for each out-
put MOSFET junction-to-case
thermal resistance is specified as
15°C/W. The thermal resistance
from FET driver junction-to-case
is also 15°C/W. The power
dissipation in the FET driver,
however, is negligible in compar-
ison to the MOSFETs.
On-Resistance and Rating
Curves
The output on-resistance, R_ON,
specified in this data sheet, is the
resistance measured across the
output contact when a pulsed
current signal (I_O = 800 mA) is
applied to the output pins. The use
of a pulsed signal (≤ 30 ms)
implies that each junction
temperature is equal to the ambient
and case temperatures. The steady-
state resistance, R_SS, on the other
hand, is the value of the resistance
measured across the output contact
when a DC current signal is applied
to the output pins for a duration
sufficient to reach thermal
equilibrium. R_SS includes the effects
of the temperature rise of each
element in the thermal model.
Rating curves are shown in Figures
2 and 4. Figure 2 specifies the
maximum average output current
allowable for a given ambient
temperature. Figure 4 specifies the
output power dissipation allowable
for a given ambient temperature.
Above 55°C (for θ_CA = 80°C/W) and
107°C (for θ_CA = 40°C/W), the
maximum allowable output current
and power dissipation are related
by the expression R_SS = P_O(max)/
(I_O(max))² from which R_SS can be
calculated. Staying within the safe
area assures that the steady-state
junction temperatures remain less
than 150°C. As an example, for T_A
= 95°C and θ_CA = 80°C/W, Figure 2
shows that the output current
should be limited to less than