
Input Transformers
LL1531 and LL1532
LL1531 is a small size, high impedance line input transformer.
LL1532 is a small size medium impedance mic/line input transformer.
The transformers consists of two coils each with one primary and one secondary winding separated by a
electrostatic shield. The secondaries are serially connected internally. The core is a high permeability mu-metal
core.
Being a high impedance transformer, the LL1531 should normally be used with primaries connected in series.
The LL1532 can be used with primaries in series or in parallel.
The transformers are magnetically shielded by a mu-metal case.
Turns ratio: 1 + 1 : 2
Dims (Length x Width x Height above PCB (mm)): 28 x 17 x 15
Pin layout (viewed from component side) and winding schematics:
Spacing between pins: 3.81 mm (0.15")
Spacing between rows of pins: 20.32 mm (0.8")
Weight: 25 g
Rec. PCB hole diameter: 1.5 mm
LL1531 LL1532
Static resistance of each primary:
500Ω 70Ω
Static resistance of secondary:
1.3kΩ 180Ω
Distortion (primaries connected in series,
source impedance 600Ω ):
+ 10 dBU primary level, 50 Hz:
0.2 %
+ 0 dBU primary level, 50 Hz:
0.2 %
+ 20 dBU primary level, 50 Hz:
1 %
+ 10 dBU primary level, 50 Hz:
1 %
Self resonance point :
> 80 kHz > 200 kHz
Optimum termination for best square-wave
response (source imp. 600Ω ) :
8 kΩ in series with 1.2 nF 2 kΩ in series with 1.6 nF
Frequency response
(source and load as above)
10 Hz - 25 kHz +/- 0.3 dB 10 Hz - 50 kHz +/- 0.3 dB
Isolation between windings/ between windings and shield: 3 kV / 1.5 kV
R980618
4
3
2
1
8
6
5
5
2
1
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6
8
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
LL1531
(top view)