5.8 GHz One Antenna Reflective Tag
CHR2244
Design Recommendations
n
All of the different inputs (TR, Mod) and outputs (SB_out, DATA_out) should be properly isolated
(separated enough or with a ground path between them).
n
As TR port is the most sensitive one, a specific circuit (see on diagram) can be used for high level of
isolation.
n
n
Device slug should be connected to RF ground plane through multiples vias (>=9).
An external matching may be required to optimize RF performances on 50W impedance, versus
substrate height. A RF ground plane height of 0.008” (0.203mm) under the component (evaluation
board) provides the highest RF performances thanks to low RF ground inductance and low pin to pin
coupling.
Adjustment abilities:
Pin number Pin name Component
Description
Standby sensitivity adjust port :
7
SENS
Ga_SB
Ad
R3
R4
R5
R6
A value lower than 2.2MW decreases Standby chain
sensitivity.
Standby amplifiers Gain adjust port :
12
19
20
A value lower than 680kW increases Standby chain
sensitivity.
Downlink threshold adjust port :
A value lower than 6.8MW decreases Downlink chain
sensitivity.
Downlink amplifiers Gain adjust port :
Ga_WK
A value lower than 220 kW increases Downlink chain
sensitivity.
IMPORTANT NOTICE :
All this adjustments may cause non linear response of the performances versus resistors values. The
sensitivity is –1x(Minimum RF power for considered mode).
Ref. : DSCHR2244QDG5053 - 22 Feb 05
7/16
Specifications subject to change without notice
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UMS [ UNITED MONOLITHIC SEMICONDUCTORS ]
