Document 621-2
Coupled Inductors for SEPIC Applications – MSD7342 Series
Inductance
2
Part number
1
MSD7342-252ML_
MSD7342-332ML_
MSD7342-472ML_
MSD7342-562ML_
MSD7342-682ML_
MSD7342-822ML_
MSD7342-103ML_
MSD7342-123ML_
MSD7342-153ML_
MSD7342-183ML_
MSD7342-223ML_
MSD7342-273ML_
MSD7342-333ML_
MSD7342-393ML_
MSD7342-473ML_
MSD7342-563ML_
MSD7342-683ML_
MSD7342-823ML_
MSD7342-104ML_
MSD7342-124ML_
MSD7342-154ML_
MSD7342-184ML_
MSD7342-224ML_
MSD7342-274ML_
MSD7342-334ML_
MSD7342-394ML_
MSD7342-474ML_
MSD7342-564ML_
MSD7342-684ML_
MSD7342-824ML_
MSD7342-105ML_
DCR max
3
(Ohms)
0.033
0.037
0.051
0.063
0.070
0.075
0.100
0.120
0.130
0.170
0.220
0.250
0.270
0.380
0.420
0.460
0.600
0.680
0.770
1.03
1.35
1.52
1.72
2.41
2.70
3.05
4.00
4.43
5.00
6.80
7.80
SRF typ
4
(MHz)
55
43
35
32
30
27
22
20
18
15
13.5
12.0
11.0
10.0
9.5
8.7
7.3
6.2
5.5
4.5
4.0
3.8
3.5
3.3
3.0
2.8
2.6
2.5
2.3
2.2
2.0
±20% (µH)
2.5
3.3
4.7
5.6
6.8
8.2
10
12
15
18
22
27
33
39
47
56
68
82
100
120
150
180
220
270
330
390
470
560
680
820
1000
Isat
(A)
5
10% drop 20% drop 30% drop
6.0
5.2
4.1
3.9
3.7
3.3
2.8
2.5
2.2
2.0
1.9
1.7
1.5
1.3
1.2
1.1
1.0
0.90
0.80
0.70
0.65
0.62
0.59
0.55
0.49
0.45
0.41
0.38
0.36
0.30
0.27
6.2
5.3
4.3
4.1
3.8
3.4
2.9
2.6
2.3
2.2
2.0
1.8
1.6
1.4
1.3
1.2
1.1
1.00
0.92
0.80
0.76
0.66
0.62
0.57
0.52
0.47
0.43
0.40
0.37
0.32
0.29
6.3
5.4
4.6
4.2
3.9
3.5
3.0
2.7
2.4
2.3
2.1
1.9
1.7
1.5
1.4
1.3
1.2
1.1
0.98
0.90
0.80
0.73
0.66
0.60
0.54
0.50
0.46
0.42
0.38
0.35
0.31
Irms
(A)
both
one
windings
6
winding
7
2.17
2.05
1.74
1.57
1.49
1.44
1.24
1.14
1.09
0.95
0.84
0.79
0.76
0.64
0.61
0.58
0.51
0.48
0.45
0.39
0.34
0.32
0.30
0.25
0.24
0.23
0.20
0.19
0.18
0.15
0.14
3.06
2.89
2.46
2.22
2.10
2.03
1.76
1.61
1.54
1.35
1.19
1.11
1.07
0.90
0.86
0.82
0.72
0.67
0.63
0.55
0.48
0.45
0.42
0.36
0.34
0.32
0.28
0.26
0.25
0.21
0.20
1. Please specify
termination
and
packaging
codes:
MSD7342-105MLC
Termination: L
= RoHS compliant matte tin over nickel over phos bronze.
Special order:
T
= RoHS tin-silver-copper (95.5/4/0.5)
or
S
= non-RoHS tin-lead (63/37).
Packaging: C
= 7″ machine-ready reel. EIA-481 embossed plastic
tape (250 parts per full reel).
B
= Less than full reel. In tape, but not machine ready. To
have a leader and trailer added ($25 charge), use
code letter C instead.
D
= 13″ machine-ready reel. EIA-481 embossed plastic
tape. Factory order only, not stocked (1000 parts per
full reel).
2. Inductance shown for each winding, measured at 100 kHz, 0.1 Vrms, 0
Adc on an Agilent/HP 4284A LCR meter or equivalent. When leads are
connected in parallel, inductance is the same value. When leads are
connected in series, inductance is four times the value.
3. DCR is for each winding. When leads are connected in parallel, DCR is
half the value. When leads are connected in series, DCR is twice the
value.
4. SRF measured using an Agilent/HP 4191A or equivalent. When leads
are connected in parallel, SRF is the same value.
5. DC current, at which the inductance drops the specified amount from its
value without current. It is the sum of the current flowing in both windings.
6. Equal current when applied to each winding simultaneously that causes
a 40°C temperature rise from 25°C ambient. See temperature rise
calculation.
7. Maximum current when applied to one winding that causes a 40°C
temperature rise from 25°C ambient. See temperature rise calculation.
8. Electrical specifications at 25°C.
Refer to Doc 639 “Selecting Coupled Inductors for SEPIC Applications.”
Refer to Doc 362 “Soldering Surface Mount Components” before soldering.
Temperature rise calculation based on specified
Irms
Winding power loss = (
I
L12
+
I
L22
) × DCR in Watts (W)
129°C
Temperature rise (
Δ
t) = Winding power loss ×
W
129°C
Δt
= (
I
L12
+
I
L22
) × DCR ×
W
Example 1.
MSD7342-123ML (Equal current in each winding)
Winding power loss = (1.14
2
+ 1.14
2
) × 0.120 = 0.312 W
129°C
= 40°C
Δ
t = 0.312 W ×
W
Example 2.
MSD7342-123ML (
I
L1
= 1.4 A,
I
L2
= 0.6 A)
Winding power loss = (1.4
2
+ 0.6
2
) × 0.120 = 0.278 W
Δ
t = 0.278 W ×
129°C
= 36°C
W
Coupled Inductor Core and Winding Loss Calculator
This web-based utility allows you to enter frequency, peak-to-peak (ripple)
current, and
Irms
current to predict temperature rise and overall losses,
including core loss. Visit www.coilcraft.com/coupledloss.
Specifications subject to change without notice.
Please check our website for latest information.
Document 621-2
Revised 11/10/09
© Coilcraft, Inc. 2010
COILCRAFT [ Coilcraft lnc. ]
