EM4205-EM4305
Timing Characteristics
VDD = 2.0 V, VSS = 0 V, fCOIL1 = 125kHz square wave, VCOIL1 = 4VPP, TOP = 25°C,
Data rate fRF/32, Bi-phase unless otherwise specified
Parameter
Symbol
tMONO
tWEE
tPR
Conditions
Min.
20
Typ.
40
9.34
12.16
1.48
3.3
Max.
60
Unit
s
ms
ms
ms
ms
s
Data Extractor timeout
EEPROM programming time
Protection words update time
Power check time
Power-up initialization
Processing Pause
tPC
tPU
tPP
586
Table 4
Data Extractor timeout (tMONO
)
COIL1-COIL2
CLOCK
TIMEOUT
tMONO
FIELD STOP
Figure 2
Transceiver field is amplitude modulated (field stops) to transmit data to the EM4205/4305. Data extractor detects absence
of signal on coil terminals for period longer then TMONO. Please note that the field has to be stopped for a much longer
period of time than TMONO. In figure above magnetic field is stopped when modulator switch is OFF. Second signal shows
internal clock signal, which continues to be extracted up to the point where COIL1-COIL2 signal is lower then 1Vpp. Third
signal, Timeout, indicates to the chip logic that a magnetic field stop was detected. The field stop detection time is at least
TMONO after the last extracted clock from the coil voltage. The length of transceiver field stop depends on the Q factor of the
transponder. First field stop has to be longer (~18 - 20 RF cycles) since it is possible that it happens when chip modulator
switch is off.
Power-up initialization (tPU
)
tPU
Figure 3
After the supply voltage crosses the POR threshold, the logic reads configuration word and then enters in default read
mode. tPU is the time from turning on transmitter field to start of the default read mode.
3
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Copyright 2013, EM Microelectronic-Marin SA
4205-4305-DS-01.doc, Version 4.0, 22-Oct-13
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
