LTC3600_15 Datasheet, PDF (13/28 Pages) Linear Technology – 15V, 1.5A Synchronous Rail-to-Rail Single Resistor Step-Down Regulator

LTC3600
Applications Information
In most applications, the input capacitor is merely required
to supply high frequency bypassing, since the impedance to
the supply is very low. A 22µF ceramic capacitor is usually
enough for these conditions. Place this input capacitor as
close to V_IN pin as possible.
Inductor Selection
Given the desired input and output voltages, the inductor
value and operating frequency determine the ripple current:
∆I_L
=


V_{O U T}
f_SW • L


_1−
V_OUT 
V_IN 
Lower ripple current reduces core losses in the inductor,
ESR losses in the output capacitors, and output voltage
ripple. Highest efficiency operation is obtained at low
frequency with small ripple current. However, achieving
this requires a large inductor. There is a trade-off between
component size, efficiency and operating frequency.
A reasonable starting point is to choose a ripple current
that is about 40% of I_OUT(MAX). Note that the largest ripple
current occurs at the highest V_IN. To guarantee that ripple
current does not exceed a specified maximum, the induc-
tance should be chosen according to:
L
=


f_SW
V_{O U T}
• ∆I_L(M
A
X
)



^1−

V_{O U T}
V_{I N(M A}


X )
Table 1. Inductor Selection Table
INDUCTOR
IHLP-1616BZ-11 Series
IHLP-2020BZ-01 Series
FDV0620 Series
MPLC0525L Series
HCP0703 Series
RLF7030 Series
WE-TPC 4828 Series
INDUCTANCE
(µH)
1.0
2.2
4.7
1
2.2
3.3
4.7
5.6
6.8
1
2.2
3.3
4.7
1
1.5
2.2
1
1.5
2.2
3.3
4.7
6.8
8.2
1
1.5
2.2
3.3
4.7
6.8
1.2
1.8
2.2
2.7
3.3
3.9
4.7
DCR
(mΩ)
24
61
95
18.9
45.6
79.2
108
113
139
18
37
51
68
16
24
40
9
14
18
28
37
54
64
8.8
9.6
12
20
31
45
17
20
23
27
30
47
52
MAX CURRENT
(A)
4.5
3.25
1.7
7
4.2
3.3
2.8
2.5
2.4
5.7
4
3.2
2.8
6.4
5.2
4.1
11
9
8
6
5.5
4.5
4
6.4
6.1
5.4
4.1
3.4
2.8
3.1
2.7
2.5
2.35
2.15
1.72
1.55
DIMENSIONS
(mm)
4.3 × 4.7
4.3 × 4.7
4.3 × 4.7
5.4 × 5.7
5.4 × 5.7
5.4 × 5.7
5.4 × 5.7
5.4 × 5.7
5.4 × 5.7
6.7 × 7.4
6.7 × 7.4
6.7 × 7.4
6.7 × 7.4
6.2 × 5.4
6.2 × 5.4
6.2 × 5.4
7 × 7.3
7 × 7.3
7 × 7.3
7 × 7.3
7 × 7.3
7 × 7.3
7 × 7.3
6.9 × 7.3
6.9 × 7.3
6.9 × 7.3
6.9 × 7.3
6.9 × 7.3
6.9 × 7.3
4.8 × 4.8
4.8 × 4.8
4.8 × 4.8
4.8 × 4.8
4.8 × 4.8
4.8 × 4.8
4.8 × 4.8
HEIGHT
(mm)
2
2
2
2
2
2
2
2
2
2
2
2
2
2.5
2.5
2.5
3
3
3
3
3
3
3
3.2
3.2
3.2
3.2
3.2
3.2
2.8
2.8
2.8
2.8
2.8
2.8
2.8
MANUFACTURER
Vishay
www.vishay.com
Toko
www.toko.com
NEC/Tokin
www.nec-tokin.com
Cooper Bussmann
www.cooperbussmann.com
TDK
www.tdk.com
Würth Elektronik
www.we-online.com
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