ISL59117 Datasheet, PDF (9/10 Pages) Intersil Corporation – Triple Channel Video Driver with LPF

ISL59117
Power Dissipation
With the high output drive capability of the ISL59117, it is
possible to exceed the +125°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 amplifier 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
T_AMAX = Maximum ambient temperature
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:
for sourcing:
PD_MAX
=
V_S
×
I_S
M
A
X
+
(
V_S
–
V_O
U
T
)
×
-^V----^O----^U----^T--
R_L
for sinking:
PD_MAX = V_S × I_SMAX + (V_OUT – V_S) × I_LOAD
Power Supply Bypassing Printed Circuit Board
Layout
As with any modern operational amplifier, a good printed
circuit board layout is necessary for optimum performance.
Lead lengths should be as short as possible. The power
supply pin must be well bypassed to reduce the risk of
oscillation. For normal single supply operation, a single
4.7µF tantalum capacitor in parallel with a 0.1µF ceramic
capacitor from V_S+ to GND will suffice.
Printed Circuit Board Layout
For good AC performance, parasitic capacitance should be
kept to minimum. Use of wire wound resistors should be
avoided because of their additional series inductance. Use
of sockets should also be avoided if possible. Sockets add
parasitic inductance and capacitance that can result in
compromised performance.
Where:
V_S = Supply voltage
I_SMAX = Maximum quiescent supply current
V_OUT = Maximum output voltage of the application
R_LOAD = Load resistance tied to ground
I_LOAD = Load current
9
FN6278.0
September 21, 2006