VISHAY
TSOP62..
Document Number 82177
Rev. 3, 23-Jun-03
Vishay Semiconductors
www.vishay.com
5
Suitable Data Format
The circuit of the TSOP62.. is designed in that way
that unexpected output pulses due to noise or distur-
bance signals are avoided. A bandpass filter, an inte-
grator stage and an automatic gain control are used
to suppress such disturbances.
The distinguishing mark between data signal and dis-
turbance signal are carrier frequency, burst length
and duty cycle.
The data signal should fulfill the following conditions:
• Carrier frequency should be close to center fre-
quency of the bandpass (e.g. 38 kHz).
• 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 necessary.
• For each burst which is longer than 1.8 ms a corre-
sponding gap time is necessary at some time in the
data stream. This gap time should be at least 4 times
longer than the burst.
• Up to 800 short bursts per second can be received
continuously.
Some examples for suitable data format are: NEC
Code (repetitive pulse), NEC Code (repetitive data),
Toshiba Micom Format, Sharp Code, RC5 Code,
RC6 Code, R-2000 Code, Sony Code.
When a disturbance signal is applied to the TSOP62..
it can still receive the data signal. However the sensi-
tivity is reduced to that level that no unexpected
pulses will occur.
Some examples for such disturbance signals which
are suppressed by the TSOP62.. are:
• DC light (e.g. from tungsten bulb or sunlight)
• Continuous signal at 38 kHz or at any other fre-
quency
• Signals from fluorescent lamps with electronic bal-
last with high or low modulation
(see Figure 13 or Figure 14).
Figure 13. IR Signal from Fluorescent Lamp with low Modulation
Figure 14. IR Signal from Fluorescent Lamp with high Modulation
0
5
10
15
20
Time ( ms )
16920
IR Signal
IR Signal from fluorescent
lamp with low modulation
0
5
10
15
20
Time ( ms )
16921
IR Signal
IR Signal from fluorescent
lamp with high modulation