
Hybrid Transformer
LL6702
LL6702 is a hybrid transformer for telephone applications. It is built using a C-core, and meets requirements for
high isolation between windings.
The LL6702 has an extremely low leakage inductance and thus a flat frequency response curve. This makes it
easy to design the balancing network for good transhybrid loss in the entire frequency range.
Turns ratio: 1.5 , 1.5 : 1 + 1
Dims (Length x Width x Height above PCB (mm)): 47 x 31 x 15
Pin layout (viewed from component side) and winding schematics:
Spacing between pins: 5.08 mm (0.2")
Spacing between rows of pins: 30.48 mm (1.2")
Weight: 70 g
Rec. PCB hole diameter: 1.5 mm
Static resistance of primary (pins 1 - 4 ): 50Ω
Static resistance of balance (pins 2 - 5 ): 45Ω
Static resistance of each secondary (pins 6 - 7, 9 - 10 ): 36Ω
Max. DC current: 60 mA
Transhybrid loss (laboratory conditions): 50 dB, 10 Hz - 10 kHz
Isolation between primary and balance windings/ between
primary and secondary windings: 2 kV / 4 kV
Typical application: Telephone hybrid using two LL6702:
Balancing network ZB: Select ZB for minimum crosstalk which occurs when ZB
equals actual line impedance.
In applications, this is often accomplished with a combination of a potentiometer and a series of capacitors
Line termination: If RI = RO, the termination impedance, ZT , as seen from the two-wire side is:
ZT (AC) = 170 Ω + RI + RD. Thus, ZT is independent of ZB.
ZT (DC) = 100 Ω + RD. RD is an optional resistor used to reduce the line DC current
.
4
2
1
10
9
8
7
6
5
6
97
2-wire telephone
line
6
4
5
5
ZB
RO
RI
RD
2
2
4
1
1
4-wire input
4-wire output
10 97
R980626
64
7
1
5
210
9
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
LL6702
2 x LL6702
(To
view)