CHR2244-QDG_15 Datasheet, PDF (7/14 Pages) United Monolithic Semiconductors – 5.8 GHz One Antenna Reflective Transponder for Tag

5.8 GHz One Antenna Reflective Tag
CHR2244-QDG
Adjustment abilities characterization
Typical performance, Tamb = +25°C, Vcc = 3.1V
STANDBY sensitivity
The maximum value of R3 resistor is 2.2MΩ. It could be used in order to reduce the Standby
sensitivity. The R4 resistor should be used to set the Standby sensitivity higher or lower. The
following table gives the typical relation between R3, R4 and the Standby sensitivity.
R3 (MΩ)
>2.2
2.2
2.2
2.2
2.2 (*)
2.2
2.2
2.2
2.2
1.5
R4 (kΩ)
indifferently
100
220
390
680 (*)
1200
3300
6800
No Resistor
No Resistor
Sensitivity (dB)
Non guaranteed functionality
S + 1.5 dB
S + 1 dB
S + 0.5 dB
S (*)
S - 0.5 dB
S - 1.5 dB
S - 3 dB
S - 4 dB
S - 5 dB
(*) S is the sensitivity of a given chip in the recommended environment.
In the full operating range and the recommended environment, -|S| < -38 dBm in accordance with
the electrical characteristics.
DOWNLINK sensitivity
R5 could be used in order to reduce the Downlink sensitivity or to set the compromise between
sensitivity and unwanted data, when no RF signal, due to noise or parasitic coupling. The R6
resistor should be used to set the Downlink sensitivity higher or lower. The following table gives the
typical relation between R5, R6 and the Downlink sensitivity.
R5 (MΩ)
No Resistor
No Resistor
No Resistor
No Resistor
6.8 (*)
4.7
3.3
2.2
1.5
1
R6 (kΩ)
10
47
220
No Resistor
No Resistor (*)
No Resistor
No Resistor
No Resistor
No Resistor
No Resistor
Sensitivity (dB)
S + 2 dB
S + 1.5 dB
S + 1 dB
S + 0.5 dB
S (*) (1)
S - 1 dB
S - 2 dB
S - 3 dB
S - 4 dB
S - 5 dB
(*) S is the sensitivity of a given chip in the recommended environment.
In the full operating range and the recommended environment, -|S| < -38 dBm in accordance with
the electrical characteristics.
(1) A higher sensitivity than in recommended configuration may cause significant density of unwanted
data when RF is not modulated.
These data are random because of the component noise floor proximity, or can be sensitive to an
environment perturbation.
Ref. :DSCHR2244-QDG9030 - 30 Jan 09
7/14
Specifications subject to change without notice
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