ata5551 ATMEL Corporation, ata5551 Datasheet - Page 8

• Manufacturer Part Number: ata5551
• Description: Standard Read/write Id Transponder With Anti-collision
• Manufacturer: ATMEL Corporation

Figure 10-1. Ideal and Real Behavior Signals
11. Operating Distance
11.1
8
Anti-collision Mode by Password Request (AOR = Answer-On-Request)
Atmel ATA5551 Preliminary
Gap detect
voltage
Coil
RF level reduces to zero immediately
Ideal behavior
Measured write-time frames of the IDIC demo kit software are:
Antennas with a high Q-factor require longer times for t
The maximum distance between the base station and the Atmel
the reader station, the coil geometries and the modulation options chosen (see “U2270B
Antenna Design Hints” and the “U2270B” datasheet). Under laboratory conditions, a distance of
up to 9cm can be reached. When using the Atmel RFID demo kit ATA2270-EK1, the typical
distances in the range of 0cm to 5cm can be achieved.
The AOR mode is an anti-collision procedure for transponders to read, e.g., ten transponders in
the field during 500ms (RF/32, maxblock 2). The number of transponders and the time to read
out are dependent on the application.
If the AOR mode has been configured by AOR bit at block 0, the transponder remains in sleep
mode while putting it into the field. If the specified AOR wake-up command is sent, the dedicated
transponder generates an internal RESET (see section “OP Code Formats” in the Atmel e5551
datasheet). Due to the RESET the transponder is woken up. That means, the transponder is
able to modulate the field (read mode). The AOR wake-up command consists of the OP code
and the 32-bit password. The time duration to send the AOR wake-up sequence is between
8.7ms and 27.5ms according to
mum/maximum values of the measured write-time frames and the content of the password.
To select another transponder in the field, it is necessary to send the stop OP code to stop the
modulation of the transponder.
t
1
1
t
t
t
t
gap
0
1
gap
= 180µs to 400µs
= 50µs to 130µs
= 270µs to 390µs
t
0
0
1
Figure
voltage
Gap detect
Coil
10-1. The time duration is dependent on the mini-
RF level decreases exponentially
Actual behavior
t
1 internal
1
t
1
gap
t
and shorter time values for t
gap
t
0
t
0
0 internal
®
ATA5551 depends mainly on
1
9211A–RFID–10/10
0
and t
1
.