10

FN6637.0

June 3, 2009

.

.

Typical Application Circuit

backplane common voltage of a TFT-LCD panel. Maintaining

performance. The ability of the ISL24021 to source/sink

driver. The ±1A short circuit current capability combined with

a large bandwidth and fast settling time give the ISL24021

for TFT-LCD applications.

Power Dissipation

With a 300mA maximum continuous output drive capability, it

is possible to exceed the rated +150°C maximum junction

temperature. It is important to calculate the maximum power

dissipation of the ISL24021 for the application. Proper load

conditions will ensure that the ISL24021 junction temperature

stays within a safe operating region.

The ISL24021 has a built-in thermal protection, which

automatically shuts the output OFF (high impedance) when

the die temperature reaches +165°C. This ensures safe

operation and prevents internal damage to the device. When

the die cools by +15°C the output will automatically turn ON.

The maximum power dissipation allowed in a package is

determined according to Equation 1:

where:

•

θ

The actual maximum power dissipation of the IC is the total

quiescent supply current, times the total power supply

voltage, plus the power dissipation in the IC caused by the

loading condition.

Sourcing:

Sinking:

Device overheating can be avoided by calculating the

curve, Figure 28, for further information.

ISL24021

INP

OUT

4.7µF

0.1µF

0.1µF

4.7µF

THERMAL PAD

INN

FIGURE 25. OUTPUT SNUBBER CIRCUIT

ISL24021

INP

OUT

4.7µF

0.1µF

0.1µF

4.7µF

THERMAL PAD

INN

FIGURE 26. OUTPUT SERIES RESISTOR CIRCUIT

INP

OUT

4.7µF

0.1µF

DEPENDING ON THE

APPLICATION

INN

PANEL

ISL24021

TFT-LCD

CAPACITANCE

VCOM

CALIBRATOR/

RESISTOR

LADDER

THERMAL PAD CONNECTED

-

+

+

0.1µF

P

DMAX

T

JMAX

T

AMAX

–

Θ

JA

---------------------------------------------

=

(EQ. 1)

P

DMAX

V

S

I

S

V

DD

V

I

LOAD

×

–

[]

+

×

=

(EQ. 2)

P

DMAX

V

S

I

S

V

OUT

V

I

LOAD

×

–

[]

+

×

=

(EQ. 3)

ISL24021