ISL59531 Datasheet, PDF (19/21 Pages) Intersil Corporation – 16x16 Video Crosspoint with Differential Inputs

ISL59531
Linear Operating Region
In addition to bandwidth, one must also be very careful with
operating the device at its linear operating region. Figure 50
shows differential gain curve. The ISL59534 is a single
supply 5V device with its linear region is between 0.1 and
2V.
FIGURE 48. ENGINEERING EVALUATION BOARD
FIGURE 49. CUSTOMER DEMOBOARD
To prove that the parasitic capacitance is the largest
contributor to the difference in bandwidth of the two boards,
we added 2.7pF at the output of the demoboard. Figure 50
shows the similarity in frequency response of the
engineering evaluation board alongside the demoboard
piggybacked with 2.7pF.
FIGURE 50. DIFFERENTIAL GAIN RESPONSE
Power Dissipation and Thermal Resistance
With a large number of switches, it is possible to exceed the
150°C absolute maximum junction temperature under
certain load current conditions. Therefore, it is important to
calculate the maximum junction temperature for an
application to determine if load conditions or package types
need to be modified to assure operation of the crosspoint
switch in a safe operating area.
The maximum power dissipation allowed in a package is
determined according to:
PD_MAX
=
T_{----J---M-----A----X-----–-----}T_{----A---M-----A----X--}
Θ_JA
Where:
• T_JMAX = Maximum junction temperature = 125°C
• T_AMAX = Maximum ambient temperature = 85°C
• θ_JA = Thermal resistance of the package
The maximum power dissipation actually produced by an IC
is the total quiescent supply current times the total power
supply voltage, plus the power in the IC due to the load, or:
n
∑ ^{P D} M A X
=
V_S
×
I_SMAX
+
i
=
(V_S
1
–
V_OUTi)
×
V_{-----O----U----T----i}
R_Li
19