
Microphone Input Transformer
LL1636
LL1636 is an audio input transformer for applications where a high turn’s ratio is desired. The transformer is
built up from two coils, each with a secondary winding surrounded by shields and two primary windings. This
structure results in an excellent frequency response. All winding ends are available on the pins. Thus, the
transformer can be configured for a number of different turn’s ratios.
The LL1636 is made with amorphous core material. As this type of core does not store energy (unlike
conventional mu-metal cores) the low frequency resonance with external series capacitors is practically
eliminated.
Turns ratio: 1 + 1 + 1 + 1 : 10 + 10
Dims: (Length x Width x Height above PCB (mm)) 30 x 22.5 x 14.5
Pin Layout (viewed from pins side) and Windings Schematics:
Spacing between pins: 2.54 mm (0.1")
Spacing between rows of pins: 22.86 mm (0.9")
Weight: 27 g
Rec. PCB hole diameter: 1.5 mm
Static resistance of each primary (average): 10 Ω
Static resistance of each secondary (average): 415 Ω
Self resonance point :
> 250 kHz
Frequency response
(@ -10 dBU, all in series. Source 50
Ω
, load 100 k
Ω)
: 10 Hz -- 25 kHz +/- 1 dB
10 Hz -- 90 kHz +/- 1.5 dB
Distortion (primaries connected in series, source impedance 50
Ω
): < 0.5% @ -2 dBU, 50 Hz
Primary no load impedance @ 0 dBU, 50 Hz, all in series: 8 k
Ω
typically
Core / Can: Amorphous Strip Core / Mu-metal can
Isolation between windings / between windings and core: 3 kV / 1.5 kV
Turns ratio and possible use at different termination alternatives. Termination alternatives are shown on
the following page.
Termination
Alternative
Turns
ratio
Copper Resistance
prim/sec
Possible Use
A 1:5
40Ω / 790 Ω 400Ω / 10 kΩ
B 1:5
10Ω / 200 Ω
Not recommended
C 1:10
10Ω / 790 Ω 100Ω / 10kΩ
D 1:10
2.5Ω / 200 Ω
Not recommended
E 1:20
2.5Ω / 790 Ω 25Ω / 10kΩ
.
R980429
1
9
2
3
4
5
6
7
8
10
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14
15
16
1
2
3
4
13
14
16
15
9
10
8
7
6
5
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
Can + core 14