LTC3331_15 Datasheet, PDF (25/34 Pages) Linear Technology – Nanopower Buck-Boost DC/DC with Energy Harvesting Battery Charger

LTC3331
APPLICATIONS INFORMATION
Inductor Selection
The buck is optimized to work with a 22µH inductor in
typical applications. A larger inductor will benefit high
voltage applications by increasing the on-time of the PMOS
switch and improving efficiency by reducing gate charge
loss. Choose an inductor with a DC current rating greater
than 500mA. The DCR of the inductor can have an impact
on efficiency as it is a source of loss. Tradeoffs between
price, size, and DCR should be evaluated.
The buck-boost is optimized to work with a minimum
inductor of 22μH for the 250mA I_{PEAK_BB} setting. For the
other seven I_{PEAK_BB} settings the inductor value should
increase as the I_{PEAK_BB} selection decreases to maintain the
same I_{PEAK_BB} • L product. The minimum inductor values for
the buck-boost for each I_{PEAK_BB} setting are listed in Table 3.
Larger inductors may increase efficiency. Choose an
inductor with an I_SAT rating at least 50% greater than the
selected I_PEAK value. Table 6 lists several inductors that
work well with both the buck and the buck-boost.
Table 6. Recommended Inductors for the LTC3331
PART NUMBER
744043102
LPS5030-105ML
LPS4018-105ML
LPS3314-105ML
B82442T1105K050
744043471
LPS4018-474ML
LPS3314-474ML
B82442T147K050
744042331
LPS4018-334ML
LPS3314-334ML
B82442T1334K050
744042221
LPS4018-224ML
LPS3314-224ML
B82442T1224K050
744031101
LPS4018-104ML
LPS3314-104ML
B82442T1104K050
744031470
LPS4018-473ML
LPS3314-473ML
B82442T1473K050
744031330
LPS4018-333ML
LPS3314-333ML
1070BS-330ML
B82442T1333K050
744031220
LPS5030-223ML
LPS4018-223ML
LPS3314-223ML
1070AS-220M
B82442T1223K050
744029220
1069BS-220M
L(µH)
1000
470
330
220
100
47
33
22
22
MANUFACTURER
Würth Elektronik
Coilcraft
Coilcraft
Coilcraft
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
Toko
EPCOS
Würth Elektronik
Coilcraft
Coilcraft
Coilcraft
Toko
EPCOS
Würth Elektronik
Toko
SIZE (mm) (L × W × H)
4.8 × 4.8 × 2.8
5.51 × 5.51 × 2.9
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
5.6 × 5 × 5
4.8 × 4.8 × 2.8
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
5.6 × 5 × 5
4.8 × 4.8 × 1.8
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
5.6 × 5 × 5
4.8 × 4.8 × 1.8
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
5.6 × 5 × 5
3.8 × 3.8 × 1.65
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
5.6 × 5 × 5
3.8 × 3.8 × 1.65
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
5.6 × 5 × 5
3.8 × 3.8 × 1.65
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
3.2 × 3.2 × 2
5.6 × 5 × 5
3.8 × 3.8 × 1.65
5.51 × 5.51 × 2.9
3.9 × 3.9 × 1.7
3.3 × 3.3 × 1.3
3.2 × 3.2 × 2
5.6 × 5 × 5
2.8 × 2.8 × 1.35
3.2 × 3.2 × 1.8
MAX IDC
(mA)
80
110
98
99
150
125
160
110
240
130
190
110
280
160
260
160
330
180
360
230
510
250
550
330
700
320
640
380
230
840
360
750
800
450
410
1040
300
290
MAX DCR
(Ω)
7
5.1
18
31
9.5
2.6
7.8
12
4.73
4.5
5.9
9.3
3.29
3.2
3.7
6
2.2
2.4
1.4
2.75
0.99
1
0.65
1.4
0.519
0.66
0.42
0.92
0.61
0.36
0.45
0.19
0.36
0.72
0.64
0.238
0.97
0.495
For more information www.linear.com/LTC3331
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