LTC3622_15 Datasheet, PDF (14/24 Pages) Linear Technology – 17V, Dual 1A Synchronous Step-Down Regulator with Ultralow Quiescent Current

LTC3622/
LTC3622-2/LTC3622-23/5
Applications Information
ripple current and consequent output voltage ripple. Do
not allow the core to saturate!
Different core materials and shapes change the size/cur-
rent and price/current relationship of an inductor. Toroid
or shielded pot cores in ferrite or permalloy materials are
small and don’t radiate much energy, but generally cost
more than powdered iron core inductors with similar
characteristics. The choice of which style inductor to use
mainly depends on the price versus size requirements
and any radiated field/EMI requirements. New designs for
surface mount inductors are available from Toko, Vishay,
NEC/Tokin, Cooper, TDK and Würth Elektronik. Refer to
Table 2 for more details.
Checking Transient Response
The regulator loop response can be checked by looking
at the load transient response. Switching regulators take
several cycles to respond to a step in load current. When
a load step occurs, V_OUT immediately shifts by an amount
equal to the ΔI_LOAD • ESR, where ESR is the effective series
Table 2. Inductor Selection Table
INDUCTOR
INDUCTANCE
(μH)
IHLP-1616BZ-11 Series
1.0
2.2
4.7
IHLP-2020BZ-01 Series
1
2.2
3.3
4.7
5.6
6.8
FDV0620 Series
1
2.2
3.3
4.7
MPLC0525L Series
1
1.5
2.2
HCM0703 Series
1
1.5
2.2
3.3
4.7
RLF7030 Series
1
1.5
2.2
3.3
4.7
6.8
WE-TPC 4828 Series
1.2
1.8
2.2
2.7
3.3
3.9
4.7
XFL4020 Series
1.0
1.5
2.2
3.3
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
8.8
9.6
12
20
31
45
17
20
23
27
30
47
52
10.8
14.4
21.35
34.8
52.2
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
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
8
6.7
6.0
3.9
3.6
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 × 7.4
7 × 7.4
7 × 7.4
7 × 7.4
7 × 7.4
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
4×4
4×4
4×4
4×4
4×4
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
3.2
3.2
3.2
3.2
3.2
3.2
2.8
2.8
2.8
2.8
2.8
2.8
2.8
2
2
2
2
2
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
Coilcraft
www.coilcraft.com
3622fa
14
For more information www.linear.com/LTC3622