ADP2302-EVALZ Analog Devices Inc, ADP2302-EVALZ Datasheet - Page 18

• Manufacturer Part Number: ADP2302-EVALZ
• Description: Nonsynchronous Step-Down Regulator Eval. Board
• Manufacturer: Analog Devices Inc

Specifications of ADP2302-EVALZ

• Silicon Manufacturer: Analog Devices
• Application Sub Type: Step Down DC/DC Converter
• Kit Application Type: Power Management - Voltage Regulator
• Silicon Core Number: ADP2302
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

response and efficiency. Therefore, the inductor value is calculated
using the following equation:
where I
The inductor peak current is calculated using the following
equation:
The minimum current rating of the inductor must be greater
than the inductor peak current. For ferrite core inductors with a
quick saturation characteristic, the inductor saturation current
rating should be higher than the switch current limit threshold
to prevent the inductor from reaching its saturation point. Be
sure to validate the worst-case condition, in which there is a
shorted output, over the intended temperature range.
Inductor conduction loss is caused by the flow of current
through internal dc resistance (DCR). Larger sized inductors
have smaller DCR of the inductor and, therefore, may reduce
inductor conduction losses. Inductor core loss is related to the
core material and the ac flux swing, which are affected by the
peak-to-peak inductor ripple current. Because the ADP2302/
ADP2303 are high frequency switching regulators, shielded fer-
rite core materials are recommended for their low core losses
and low EMI. Some recommended inductors are shown in
Table 8.
Table 8. Recommended Inductors
Vendor
Sumida
Coilcraft
Toko
TDK
ADP2302/ADP2303
L
I
PEAK
=
LOAD(max)
0
3 .
=
×
(
V
I
I
LOAD
IN
is the maximum load current.
LOAD
Value (μH)
2.5
3.8
5.2
7
10
2.5
3.8
5.2
7
10
2.8
3.7
4.7
6.4
10
2.2
3.3
4.7
6.8
10
−
(max)
V
(max)
OUT
+
×
)
Δ
f
sw
I
RIPPLE
2
×
⎛
⎜
⎜
⎝
V
V
Part No.
CDRH104RNP-2R5N
CDRH104RNP-3R8N
CDRH104RNP-5R2N
CDRH104RNP-7R0N
CDRH104RNP-100N
MSS1038-252NL
MSS1038-382NL
MSS1038-522NL
MSS1038-702NL
MSS1038103NL
#919AS-2R8M
#919AS-3R7M
#919AS-4R7M
#919AS-6R4M
#919AS-100M
VLF10040T-2R2N7R1
VLF10040T-3R3N6R2
VLF10040T-4R7N5R4
VLF10040T-6R8N4R5
VLF10040T-100M3R8
OUT
IN
+
+
V
V
D
D
⎞
⎟
⎟
⎠
Rev. 0 | Page 18 of 28
DCR (mΩ)
7.8
9.6
16
20
26
10
13
22
27
35
10.7
14.2
16.2
22.9
26.5
7.9
10.5
12.7
19.8
28
CATCH DIODE
The catch diode conducts the inductor current during the off
time of the internal MOSFET. The average current of the diode
in normal operation is, therefore, dependent on the duty cycle
of the regulator as well as the output load current.
where V
The only reason to select a diode with a higher current rating
than necessary in normal operation is for the worst-case condi-
tion, in which there is a shorted output. In this case, the diode
current increases up to the typical peak current limit threshold.
Be sure to consult the diode data sheet to ensure that the diode
can operate well within the thermal and electrical limits.
The reverse breakdown voltage rating of the diode must be higher
than the highest input voltage and allow an appropriate margin
for the ringing that may be present on the SW node. A Schottky
diode is recommended for the best efficiency because it has a
low forward voltage drop and fast switching speed. Table 7
provides a list of recommended Schottky diodes.
Table 7. Recommended Schottky Diodes
Vendor
Vishay
ON Semiconductor
Diodes Inc.
I
DIODE
D
is the diode forward drop.
I
7.5
6
5.5
4.8
4.4
7.62
6.5
5.28
4.74
3.9
8.3
7
6.1
5.2
4.3
8.2
6.7
5.4
4.6
3.8
(
AVG
SAT
(A)
)
=
⎛
⎜
⎜
⎝
1
−
V
V
Dimensions L × W × H (mm)
10.5 × 10.3 × 3.8
10.5 × 10.3 × 3.8
10.5 × 10.3 × 3.8
10.5 × 10.3 × 3.8
10.5 × 10.3 × 3.8
10 × 10.2 × 3.8
10 × 10.2 × 3.8
10 × 10.2 × 3.8
10 × 10.2 × 3.8
10 × 10.2 × 3.8
10.3 × 10.3 × 4.5
10.3 × 10.3 × 4.5
10.3 × 10.3 × 4.5
10.3 × 10.3 × 4.5
10.3 × 10.3 × 4.5
10 × 9.7 × 4.0
10 × 9.7 × 4.0
10 × 9.7 × 4.0
10 × 9.7 × 4.0
10 × 9.7 × 4.0
OUT
Part No.
SSB43L
SSA33L
MBRS330T3
B330B
IN
+
+
V
V
D
D
⎞
× ⎟ ⎟
⎠
I
LOAD
V
30
30
30
30
(max)
RRM
(V)
I
4
3
3
3
AVG
(A)