iru1160 International Rectifier Corp., iru1160 Datasheet - Page 5

• Manufacturer Part Number: iru1160
• Description: 6a Ultra Low Dropout Positive Adjustable Regulator -
• Manufacturer: International Rectifier Corp.

Stability
The IRU1160 requires the use of an output capacitor as
part of the frequency compensation in order to make the
regulator stable. Typical designs for the microproces-
sor applications use standard electrolytic capacitors with
typical ESR in the range of 50 to 100mV and an output
capacitance of 500 to 1000mF. Fortunately as the ca-
pacitance increases, the ESR decreases resulting in a
fixed RC time constant. The IRU1160 takes advantage
of this phenomena in making the overall regulator loop
stable.
For most applications a minimum of 100mF aluminum
electrolytic capacitor such as Sanyo, MVGX series,
Panasonic FA series as well as the Nichicon PL series
insures both stability and good transient response.
Thermal Design
The IRU1160 incorporates an internal thermal shutdown
that protects the device when the junction temperature
exceeds the allowable maximum junction temperature.
Although this device can operate with junction tempera-
tures in the range of 1508C, it is recommended that the
selected heat sink be chosen such that during maxi-
mum continuous load operation the junction tempera-
ture is kept below this number. The example below
shows the steps in selecting the proper surface mount
package.
Rev. 1.4
08/20/02
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: [phone]
www.irf.com
Data and specifications subject to change without notice. 02/01
Assuming, the following conditions:
Calculate the maximum power dissipation using the fol-
lowing equation:
Using table below select the proper package and the
amount of copper board needed.
Pkg
TO-263 1.4"X1.4"
TO-263 1.0"X1.0"
TO-263 0.7"X0.7"
TO-263 Pad Size
Note: Above table is based on the maximum junction
temperature of 1358C.
V
V
V
I
P
P
OUT
OUT
IN
CTRL
D
D
Visit us at www.irf.com for sales contact information
= I
= 13(3.3 - 2.8)+
= 3.3V
= 3A (DC Avg)
Copper
= 2.8V
Area
= 5V
OUT
3(V
IN
- V
JA
( C/W)
25
30
35
45
OUT
( )
)+
60
3
( )
I
OUT
60
3(5 - 2.8) = 1.61W
TAC Fax: [phone]
(
Max Pd
T
4.4W
3.7W
3.1W
2.4W
A
3(V
=25 C
IRU1160
CTRL
)
(
- V
Max Pd
T
A
=45 C
3.6W
3.0W
2.6W
2.0W
OUT
)
)
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