5.8 GHz One Antenna Reflective Tag

CHR2244

Ref. : DSCHR2244QDG5053 - 22 Feb 05

7/16

Specifications subject to change without notice

Route Départementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE

Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09

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

Device slug should be connected to RF ground plane through multiples vias (>=9).

n

An external matching may be required to optimize RF performances on 50

Ω 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

7

SENS

R3

Standby sensitivity adjust port :

A value lower than 2.2M

Ω decreases Standby chain

sensitivity.

12

Ga_SB

R4

Standby amplifiers Gain adjust port :

A value lower than 680k

Ω increases Standby chain

sensitivity.

19

Ad

R5

Downlink threshold adjust port :

A value lower than 6.8M

Ω decreases Downlink chain

sensitivity.

20

Ga_WK

R6

Downlink amplifiers Gain adjust port :

A value lower than 220 k

Ω 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).