Document 117-1
Surface Mount Wide Band RF Transformers
Available in a variety of impedance versions, Coilcraft’s
WBT Series chip transformers provide wide band pass
performance in a small surface mount package.
The transformers are built on an 1812 size ferrite body
with a ceramic base. They feature 50 V isolation and a
1/4 Watt RF power rating. The top is a high temperature
material that creates a flat surface for auto insertion. The
parts are packaged in tape and reel for easy dispensing.
Applications include impedance matching, voltage or
current transformation, DC isolation, balanced/unbal-
anced mixing, matching, power splitting, coupling and
signal inversion.
1:1 Transformers
Part
number
1812WBT-1
1812WBT-2
1812WBT-3
1812WBT-4
1812WBT-5
L per
winding
(µH)
14
5.3
1.25
0.220
0.090
Test
frequency
(MHz)
10
10
50
50
50
Imp.
ratio
pri:sec
1:1
1:1
1:1
1:1
1:1
DCR
max
(Ohms)
4.8
1.8
0.7
0.3
0.15
I
DC
(mA)
200
400
500
700
700
Isolation
(Vrms)
50
50
50
50
50
Insertion
loss (dB)
<1
<1
<1
<1
<1.5
Bandwidth
(MHz)
0.340-22
0.800-60
4-200
11-480
48-645
Color
dot
Yellow
Green
White
Orange
Red
1.5:1 Transformers
Part
number
1812WBT1.5-1
1812WBT1.5-2
1812WBT1.5-3
1812WBT1.5-4
L per winding
Test
(µH)
frequency
pri
sec
(MHz)
5.0
2.5
1.0
0.144
3.3
1.6
0.6
0.090
10
10
10
10
Imp.
ratio
pri:sec
1.5:1
1.5:1
1.5:1
1.5:1
DCR max
(Ohms)
pri
sec
1.05
0.74
0.43
0.18
0.87
0.58
0.34
0.14
I
DC
(mA)
400
500
500
700
Isolation
(Vrms)
50
50
50
50
Insertion
loss (dB)
0.5
0.5
0.75
2.25
Bandwidth
(MHz)
1.3-100
2.75-135
7.2-200
38-535
Color
dot
Red
Orange
Yellow
Green
2:1 Transformers
Part
number
1812WBT2-1
1812WBT2-2
1812WBT2-3
1812WBT2-4
L per winding
Test
(µH)
frequency
pri
sec
(MHz)
13.80
5.850
2.60
0.910
6.90
2.925
1.30
0.455
10
10
10
50
Imp.
ratio
pri:sec
2:1
2:1
2:1
2:1
DCR max
(Ohms)
pri
sec
4.6
1.25
0.52
0.27
3.2
0.95
0.42
0.23
I
DC
(mA)
200
400
600
700
Isolation
(Vrms)
50
50
50
50
Insertion
loss (dB)
<1.5
<1.5
<1.5
<1.5
Bandwidth
(MHz)
0.800-23
2.2-65
4-105
11-200
Color
dot
Brown
Red
Orange
Yellow
Operating temperature range
−40°C
to +85°C.
Electrical specifications at 25°C.
Specifications subject to change without notice.
Document 117-1
Revised 11/20/02
Document 117-2
0.150 max
3,81
4
1
0.135
max
3,43
0.070 ref
1,78
Recommended
Land Pattern
0.015
0,38
0.057
1,45
Top View
1
4
Pri
2
Sec
3
0.195 max
4,95
0.178 ±0.003
4,52 ±0,08
3
2
Pad
Detail
0.020
0,51
0.015
ref
0,38
Color dot
over
primary
0.020
0,51
0.115
2,92
0.100 ±0.003
2,54 ±0,008
0.040 min
1,02
0.030 ±0.002
0,76 ±0,05
0.048
1,22
0.018
0,46
Parts/reel: 7″ 600; 13″ 2,200 Tape width: 12 mm
For packaging data see Tape and Reel Specificationssection.
Attenuation (dB, Re: 50 Ohms)
Typical Frequency Attenuation
1:1 Transformers
0
1
2
3
4
5
-1
6
7
8
0.1
1
10
100
1000
-2
-3
-4
-5
Frequency (MHz)
Attenuation (dB, Re: 50 Ohms)
Typical Frequency Attenuation
1.5:1 Transformers
0
1
2
3
4
5
-1
6
7
8
0.1
1
10
100
1000
-2
-3
-4
Frequency (MHz)
Attenuation (dB, Re: 50 Ohms)
Typical Frequency Attenuation
2:1 Transformers
0
1
2
3
4
5
-1
6
7
8
0.1
1
10
100
1000
-2
-3
-4
Frequency (MHz)
Specifications subject to change without notice.
Document 117-2
Revised 02/14/03