Datasheet
MCP16321/2
DS22285A-page 20 © 2011 Microchip Technology Inc.
5.0.6 INDUCTOR SELECTION
The MCP16321/2 is designed to be used with small
surface mount inductors. Several specifications should
be considered prior to selecting an inductor. To
optimize system performance, low ESR inductors
should be used.
EQUATION 5-3: INDUCTOR CURRENT
RIPPLE
EXAMPLE 5-3: MCP16321 PEAK
INDUCTOR CURRENT
– 1A
An inductor saturation rating minimum of 1.255A is
recommended. A trade-off between size, cost and
efficiency is made to achieve the desired results.
EXAMPLE 5-4: MCP16322 PEAK
INDUCTOR CURRENT
– 2A
An inductor saturation rating minimum of 2.255A is
recommended. A trade-off between size, cost and
efficiency is made to achieve the desired results.
C
OUT
33 µF None
V
IN
=12V
V
OUT
=3.3V
I
OUT
=1A
L=4.7µH
Inductor ripple current = 509 mA
Inductor peak current = 1.255A
V
IN
=12V
V
OUT
=3.3V
I
OUT
=2A
L=4.7µH
Inductor ripple current = 509 mA
Inductor peak current = 2.255A
TABLE 5-1: CAPACITOR VALUE RANGE
Parameter Min Max
Δ
I
L
V
L
L
------t
ON
×
=
I
LPK
Δ
I
L
2
--------- I
OUT
+=
I
LPK
Δ
I
L
2
--------- I
OUT
+=
TABLE 5-2: MCP16321 RECOMMENDED
INDUCTORS
Part
Number
Value
(µH)
DCR
(Ω)
I
SAT
(A)
Size
WxLxH
(mm)
Coilcraft
®
1008PS 4.7 0.35 1.7 3.81x3.78x2.74
LPS4012 4.7 0.175 1.8 4.1x4.1x1.2
LPS4018 4.7 0.125 1.9 4.1x4.1x1.8
LPS5015 4.7 0.15 1.8 5x5x1.5
MSS5121 4.7 0.095 1.66 5.1x5.1x2.2
LPS5030 4.7 0.083 2 5x5x3
MSS6122 4.7 0.065 1.82 6.1x6.1x2.2
MOS6020 4.7 0.05 1.94 6.8x6x2.4
Wurth Elektronik
®
744042 4.7 0.07 1.65 4.8x4.8x1.8
744068 4.7 0.072 1.55 8x8x1.1
7448944 4.7 0.0545 4.2 8x8x3.8
EPCOS
®
LTF5022T 4.7 0.073 2 5.2x5x2.2
VLC5020T 4.7 0.097 2 5x5x2
VLC6020T 4.7 0.079 1.8 6x6x2
VLCF5020T 4.7 0.122 1.7 5x5x2
VLF5014ST 4.7 0.12 1.7 4.8x4.6x1.4
TABLE 5-3: MCP16322 RECOMMENDED
INDUCTORS
Part Number
Value
(µH)
DCR
(Ω)
I
SAT
(A)
Size
WxLxH
(mm)
Coilcraft
®
MSS6132-472 4.7 0.056 2.84 6.1x6.1x3.2
LPS6225-472 4.7 0.065 3.2 6.2x6.2x2.5
MSS7341-502 4.7 0.024 3.16 7.3x7.3x4.1
DO1813H-472 4.7 0.054 2.6 8.89x6.1x5.0
Wurth Elektronik
®
7447785004 4.7 0.06 2.5 5.9x6.2x3.3
7447786004 4.7 0.057 2.8 5.9x6.2x5.1
7447789004 4.7 0.033 3.9 7.3x3.2x1.5
EPCOS
®
B82464G2 4.7 0.033 3.1 10.4x10.4x3.0
B82464A2 4.7 0.03 4.5 10.4x10.4x3.0