2001 Oct 04 12
Philips Semiconductors Product specification
HITAG long range reader module
hardware
HTRM800 family
10 APPLICATION INFORMATION
10.1 Metallic environment and interferences
The communication range is impaired by metallic
environment and electromagnetic interferences
(e.g. monitors and keyboards). Therefore, you should
keep a distance of at least one time the antenna diameter
to metallic surfaces or loops as well as to electromagnetic
interferences. If this is not possible, you have to take
preventive measures such as using ferrites or shielding for
transponder and antenna.
The HTRM800 is able to suppress up to two harmonic
electromagnetic disturbances.
10.2 Distance between two antennas
In order to be able to operate two systems side by side
without negative influence on communication ranges, you
must place the antennas at a minimum distance. To keep
this distance low, magnetic shielding must be realized.
This topic is handled in detail in application note
“Antenna
Design for the HITAG Long Range System”
.
10.3 External power supply
Instead of a transformer type supply unit (see Fig.5),
a switching frequency power supply unit can be used
alternatively. The switching frequency must be in the
range from 165 to 210 kHz (overtemperature, load and
production).
handbook, full pagewidth
STANDARD
NET
FILTER
F1 F2
F3
A
B
C
D1
1N4001
D2
D4
D3
800 mA
(18 V)
800 mA
(18 V)
OPTIONAL
VOLTAGE
SELECTOR
MGU423
Fig.5 Transformer type power supply.
handbook, full pagewidth
7815
2200 µF
(40 V)
10 µF
(40 V)
10 µF
(40 V)
10 µF
(18 V)
10 µF
(18 V)
2200 µF
(40 V)
100
nF
100
nF
100
nF
100
nF
100
nF
1 kΩ
1 kΩ
100
nF
IN4001
IN4001
+15 V
−15 V
GNDC
MGU424
A
B
7915
72 µH 3A
72 µH 3A
F1 = depends on the type of transformer.
F2 = 800 mA delayed.
F3 = 800 mA delayed.
D1 = D2 = D3 = D4 = 4 x 1N4001.
