IRU1010CY International Rectifier, IRU1010CY Datasheet - Page 5

• Manufacturer Part Number: IRU1010CY
• Description: IC REG LDO ADJ 1.0A SOT-223
• Manufacturer: International Rectifier

Specifications of IRU1010CY

• Regulator Topology: Positive Adjustable
• Voltage - Output: 2.5 ~ 3.6 V
• Voltage - Input: Up to 7V
• Voltage - Dropout (typical): 1.1V @ 1A
• Number Of Regulators: 1
• Current - Output: 1A
• Current - Limit (min): 1.1A
• Operating Temperature: 0°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *IRU1010CY; IRU1010-CY; IRU1010-CY

Assuming the following specifications:
Where: V
shown in Figure 5.
The steps for selecting the right package with proper
board area for heatsinking to keep the junction tempera-
ture below 135 C is given as:
1) Calculate the maximum power dissipation using:
2) Calculate the maximum
3) Select a package from the datasheet with lower
Rev. 1.7
than the one calculated in the previous step.
Selecting TO-252 (D-Pak) with at least 0.5" square
of 0.062" FR4 board using 1 oz. copper has 70 C/W
which is lower than the calculated number.
V
V
V
I
T
P
P
θ
OUT(MAX)
JA(MAX)
A
IN
F
OUT
D
D
= 35 C
= 0.5V
= I
= 0.8 × (5 - 0.5 - 2.85) = 1.32W
= 5V
= 2.85V
F
OUT
is the forward voltage drop of the D1 diode as
=
= 0.8A
× (V
T
J
P
- T
D
IN
A
- V
=
135 - 35
F
1.32
- V
JA
OUT
allowed for our example:
)
= 75.6 C/W
www.irf.com
JA
To set the output DC voltage, we need to select R1 and
R2:
4) Assuming R1 = 121Ω, 1%:
Layout Consideration
The output capacitors must be located as close to the
V
mended to use a section of a layer of the PC board as a
plane to connect the V
prevent any high frequency oscillation that may result
due to excessive trace inductance.
5V
OUT
R
Select R2 = 154Ω, 1%.
terminal of the device as possible. It is recom-
2
10uF
=
Figure 5 - Final Schematic for half of the
D1
C1
(
V
V
OUT
REF
GTL+ termination regulator.
-1
V
IN
)
×R
IRU1010
OUT
Adj
1
=
pin to the output capacitors to
(
IRU1010(PbF)
2.85
1.25
V
OUT
-1
)
×121 = 154.8Ω
R1
121
1%
R2
154
1%
C2
22uF
2.85V
5