SD250

Document 130 -1
Base/Gate Driver Transformers
• Lower cost than toroidal equivalents
• Frequency range of 10 – 250 kHz and up
• Industry standard pin centers
• 3750 Vrms, one minute isolation (hipot) between
primary and secondary windings; 1500 Vrms, one
minute between secondaries
• UL1446 Class B (130°C) Insulation System
(UL File E83628)
Coilcraft Designer’s Kit No. P404 contains samples of four
standard driver transformers. To order, contact Coilcraft or
visit http://order.coilcraft.com to purchase on-line.
Turns ratio ±3% (pri : sec)
Primary winding
Inductance (min)1
Leakage inductance (max)1
DCR
Volt-time product
SD250-1L 1 : 1
SD250-2L 1 : 1.5
SD250-3L 1 : 1 : 1
SD250-4L
1 : 1.5 : 1.5
SD250-1 and 250-2
1.5 mH
1.5 mH
1.5 mH
1.5 mH
4.0 µH
4.0 µH
4.0 µH
4.0 µH
0.4 0.4 0.4 0.4 
375 V-µsec
375 V-µsec
375 V-µsec
375 V-µsec
Secondary winding(s)
Capacitance, pri to sec (max)
DCR, each section (max)
6
SD250-3 and 250-4
7
Sec 1
1
Pri
(drive)
6
10
5
1. Measured at 1 Vrms, 15.75 kHz.
2. Operating temperature range –40°C to +85°C.
3. Electrical specifications at 25°C.
Sec 2
9
Recommended
board layout
1
0.75
19,05
5
5
0.950
max
24,13
1.10
max
27,94
0.395
max
10,03
10
0.032
dia ref
0,813
Weight:
15.6 – 16.8 g
Termination: Tin-silver over tin over copper
Packaging:
49 per tray
9
1.10
max
27,94
7
6
1
0.62 ±0.015
15,75 ±0,38
6
0.15 ±0.030
3,81 ±0,762
Sec
5
50 pF
50 pF
50 pF
50 pF
0.75 2.5 0.75 2.5 
Notch
indicates
pin 1
10
1
Pri
(drive)
0.20
5,08
7
9
10
0.40
10,16
0.044
dia
1,12
0.80
20,32
Pins 7 and 9 are not present
on SD250-1 and SD250-2
Document 130-1 Revised 04/20/12
Document 130-2
Custom Version Specifications
In addition to the standard base/gate driver transformers shown here, Coilcraft can provide custom versions to meet
your specifications.
Our two basic structures are the 0.95″ high part shown and a 1.20″ high version. Both are available with either single
or double sections.
Turns Per Layer vs Wire Size*
36
ns
34
500
20
40
60
80
100 120
NP (turns)
140
160
* Applies to both double and single section bobbins.
s
bb
i
D
n
io
se
ct
28
le
5
0.9
bb
bo
e
bl
ou
b
26
ng
1000
h
hig
30
t
ec
Si
20
1500
ins
Wire size (AWG heavy insulation)
ns
bo
bb
i
h
ig
h
2000
n
io
32
bo
2500
bi
ob
ns
3000
1.
E-T (Volt-microseconds)
Volt-Time vs Primary Turns*
24
22
20
18
16
14
12
10
20
50
100
Nl (turns/layer)
* Applies to both 0.95 and 1.20 high bobbins.
Please use the information below to determine the performance characteristics available.
Core
0.95″ high bobbins
1.20″ high bobbins
Initial permeability
2000 µ2000 µ
Ae (core cross-sectional area) 0.40 cm2 0.80 cm2
le (mean magnetic path length)
4.90 cm
4.80 cm
Bobbin
Material
UL94V-0, 130°C
Number of terminals available
10
10
Number of wiring sections available
1 or 2
1 or 2
Document 130-2 Revised 04/20/12