TSOP17..UU1

Vishay Telefunken

3 (8)

Rev. 10, 02-Apr 01

www.vishay.com

Document Number 82043

Suitable Data Format

The circuit of the TSOP17..UU1 is designed in that

way that unexpected output pulses due to noise or

disturbance signals are avoided. A bandpassfilter, an

integrator stage and an automatic gain control are

used to suppress such disturbances.

The distinguishing mark between data signal and

disturbance signal are carrier frequency, burst length

and duty cycle.

The data signal should fullfill the following condition:

• Carrier frequency should be close to center

frequency of the bandpass (e.g. 38kHz).

• Burst length should be 10 cycles/burst or longer.

• After each burst which is between 10 cycles and 70

cycles a gap time of at least 14 cycles is neccessary.

• For each burst which is longer than 1.8ms a

corresponding gap time is necessary at some time in

the data stream. This gap time should have at least

same length as the burst.

• Up to 1400 short bursts per second can be received

continuously.

Some examples for suitable data format are:

NEC Code, Toshiba Micom Format, Sharp Code, RC5

Code, RC6 Code, R–2000 Code, Sony Format

(SIRCS).

When a disturbance signal is applied to the

TSOP17..UU1 it can still receive the data signal.

However the sensitivity is reduced to that level that no

unexpected pulses will occure.

Some examples for such disturbance signals which

are suppressed by the TSOP17..UU1 are:

• DC light (e.g. from tungsten bulb or sunlight)

• Continuous signal at 38kHz or at any other

frequency

• Signals from fluorescent lamps with electronic

ballast (an example of the signal modulation is in the

figure below).

0

5

10

15

20

time [ms]

IR Signal from Fluorescent Lamp with low Modulation