Document 528-1
Coupled Inductors–MSD1260
For SEPIC and other
Applications
The excellent coupling coefficient (k
≥
0.94) makes the
MSD1260 series of coupled inductors ideal for use in
SEPIC applications. In SEPIC topologies, the required
inductance for each winding in a coupled inductor is half
the value needed for two separate inductors, allowing
selection of a part with lower DCR and higher current
handling.
These parts provide high inductance, high efficiency
and excellent current handling in a rugged, low cost
part. They are also well suited for use as a VRM
inductors in high-current DC-DC converters and VRM/
VRD controllers.
They can also be used as two single inductors con-
nected in series or parallel, as a common mode choke
or as a 1 : 1 transformer.
0.484
max
12,3
D1
+
L1
C1
Dot indicates pin1
Dash number
Internal code
Parts manufactured
prior to Sept. 2007
were marked with
only the dash number.
+
+
V
OUT
0.484
max
12,3
123
X
V
IN
Q1
L2
C2
Load
–
–
Typical SEPIC schematic
0.236 ±0.008
6,0 ±0,2
Refer to Application Note, Document 639,
“Selecting Coupled Inductors for SEPIC Applications”
Recommended
Land Pattern
0.197
5,0
0.138
3,5
0.157
4,0
2
3
1
4
0.217
5,5
0.197
5,0
3
2
4
1
0.177
4,5
0.059
1,5
0.079
2,0
Dimensions are in
inches
mm
1
L1
3
2
L2
4
Core material
Ferrite
Terminations
RoHS compliant matte tin over nickel over phos
bronze. Other terminations available at additional cost.
Weight:
2.8 – 3.2 g
Ambient temperature
–40°C to +85°C with
Irms
current, +85°C to
+125°C with derated current
Storage temperature
Component: –40°C to +125°C.
Packaging: –40°C to +80°C
Winding to winding isolation
500 Vrms
Resistance to soldering heat
Max three 40 second reflows at
+260°C, parts cooled to room temperature between cycles
Moisture Sensitivity Level (MSL)
1 (unlimited floor life at <30°C /
85% relative humidity)
Failures in Time (FIT) / Mean Time Between Failures (MTBF)
38 per billion hours / 26,315,789 hours, calculated per Telcordia SR-332
Packaging
500/13″ reel; Plastic tape: 24 mm wide, 0.35 mm thick,
16 mm pocket spacing, 6.6 mm pocket depth
PCB washing
Only pure water or alcohol recommended
Specifications subject to change without notice.
Please check our website for latest information.
Document 528-1
Revised 12/05/08
© Coilcraft, Inc. 2010
Document 528-2
Coupled Inductors for SEPIC – MSD1260 Series
Irms
(A)
Part
number
1
MSD1260-472ML_
MSD1260-562ML_
MSD1260-682ML_
MSD1260-822ML_
MSD1260-103ML_
MSD1260-123ML_
MSD1260-153ML_
MSD1260-183ML_
MSD1260-223ML_
MSD1260-273ML_
MSD1260-333ML_
MSD1260-393ML_
MSD1260-473ML_
MSD1260-563ML_
MSD1260-683ML_
MSD1260-823ML_
MSD1260-104ML_
MSD1260-124KL_
MSD1260-154KL_
MSD1260-184KL_
MSD1260-224KL_
MSD1260-274KL_
MSD1260-334KL_
MSD1260-394KL_
MSD1260-474KL_
MSD1260-564KL_
MSD1260-684KL_
MSD1260-824KL_
MSD1260-105KL_
Inductance
2
(µH)
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
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±20%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
DCR max
3
(Ohms)
0.036
0.040
0.048
0.052
0.060
0.074
0.085
0.097
0.116
0.124
0.134
0.142
0.174
0.198
0.216
0.274
0.322
0.418
0.476
0.536
0.691
0.806
1.09
1.20
1.59
1.81
2.06
2.65
3.06
SRF typ
4
(MHz)
32.0
31.0
28.0
25.0
22.0
21.0
17.6
17.0
15.0
13.6
12.7
11.7
8.7
7.6
6.1
5.3
5.0
4.4
4.0
3.6
3.2
2.8
2.5
2.3
2.1
2.0
1.8
1.5
1.2
Isat
5
(A)
10.3
9.66
9.21
8.55
7.40
6.86
6.09
5.30
5.01
4.66
4.22
3.80
3.25
3.07
2.83
2.55
2.20
2.05
1.82
1.60
1.51
1.41
1.28
1.16
1.00
0.95
0.88
0.79
0.69
both
windings
6
3.16
3.00
2.75
2.63
2.45
2.21
2.06
1.93
1.76
1.70
1.64
1.59
1.44
1.35
1.29
1.15
1.06
0.93
0.87
0.82
0.72
0.67
0.57
0.55
0.48
0.45
0.42
0.37
0.34
one
winding
7
4.47
4.24
3.88
3.72
3.46
3.12
2.92
2.73
2.49
2.41
2.32
2.25
2.03
1.91
1.83
1.62
1.50
1.31
1.23
1.16
1.02
0.95
0.81
0.77
0.67
0.63
0.59
0.52
0.49
1. When ordering, please specify
termination
and
packaging
codes:
MSD1260-105KLD
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: D
= 13″ machine-ready reel. EIA-481 embossed plastic
tape (500 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 D instead.
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 30% (typ) 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
Temperature rise (
Δ
t) = Winding power loss ×
55.6°C
Δt
= (
I
L12
+
I
L22
) × DCR ×
W
55.6°C
W
Example 1.
MSD1260-153ML (Equal current in each winding)
Winding power loss = (2.06
2
+ 2.06
2
) × 0.085 = 0.721 W
55.6°C
= 40°C
Δ
t = 0.721 W ×
W
Example 2.
MSD1260-153ML (
I
L1
= 2.4 A,
I
L2
= 1.3 A)
Winding power loss = (2.4
2
+ 1.3
2
) × 0.085 = 0.633 W
Δ
t = 0.633 W ×
55.6°C
= 35.2°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 528-2
Revised 12/05/08
© Coilcraft, Inc. 2010