Kemo 1208 filter modules are 8 pole filter modules, in a 50 x 50 mm (2 x 2 ") package. The 1208 filter modules use 4 external resistors to set the cut off frequency.
   1200 Filter Module pdf data sheet (43 kB) file.

When designing circuits to around all the Kemo filter modules it is important to follow these guidelines:-
Clean stable noise free power rails
Decouple power rails close to the filter
Connect 'trim' pin to trim circuit or ground
Use large ground tracks and ground planes if possible
High speed digital signals and analogue circuits do not always mix well
Use stable low noise frequency setting resistors close to the filter module
Beware DC-DC converters (see our DC-DC page)

Specification 1208 (typical values in passband)

Dimensions            50 x 50 x 15 mm (2 x 2 x 0.6")
Weight                   35 gms (1.3 oz)
Connectors            Sockets suitable for 
                             0.6mm square pins 5mm long
                             (0.025" x 0.2")
Input impedance     1MΩ
Output impedance   47 Ω
Output current        8 mA (max)
Supply voltage        +/- 7 V to +/- 16 V DC
Supply current        50 mA
Gain                      - 1 dB (trim adjusts to 0 dB)
DC Offset             < +/- 60 mV (trim adjusts)
DC Offset drift       100 μV/°C at 25 °C
Signal level             within +/- 2.5 Volts of supply
Phase matching     +/- 2° (usually < +/- 1°)
Amplitude matching depends on filter response
Noise and THD       < 0.003%

NOTE - these are general figures, signal level, filter response, and frequency are all factors which influence filter performance. We manufacture filter modules from the best components we can obtain, and usually produce well matched batches of filter modules.
Contact us if you have a specific question.

Typical Circuit

Below is the typical circuit that we recommend for use with the 1208 filter modules. If the trim circuit is not used the trim pin should be connected to 0 Volts. 

Pin layout 

Labelling and Setting Frequency
1208 filter modules are labelled as follows:- 
1208/FF/RR PP
FF = base frequency (F_b)
RR = filter response
PP = Lowpass (LP) or Highpass (HP)
eg: 1208/200/01/ LP
is a 200 base frequency, response 01 (Anti-aliasing) Lowpass filter.

To set the cut of frequency the 4 R_fc resistors are calculated as follows
F_b = required cut off frequency   
R_fc = 795 kΩ  x F_b / F_c 
Example: 5 kHz cut-off from a 200 Hz base frerquency filter module
R_fc = 795 kΩ  x 200 / 5000    
R_fc = 31.8 kΩ OR 31.6 kΩ nearest E96 value.

Any questions please contact us.
   1200 Filter Module pdf data sheet (43 kB) file.