P4022 EM Microelectronic, P4022 Datasheet - Page 4

• Manufacturer Part Number: P4022
• Description: Multi Frequency Contactless Identification Device
• Manufacturer: EM Microelectronic

Current Consumption
The total typical current consumption from the
storage capacitor CP in various modes is shown in
Table 4 below.
The total current consumption in conjunction with
the size of
determines the maximum time that transistor Q2
can be turned on and Q1 turned off, before the
supply voltage drops below 1 V, thereby resulting
in the power-on reset block resetting the chip.
This in turn determines the minimum data bit rate
and maximum range. Similarly the total storage
capacitance and total current determine the
maximum unpowered SWITCHED-OFF state time.
The second column shows the current drawn in
FREE-RUNNING mode. The third column shows
the current drawn for the bi-directional protocols,
which includes the current drawn by the GAP
input pull-up. The fourth column shows the total
current drawn in SWITCHED-OFF state.
mode both the GAP input and the shunt regulator
draws current from the storage capacitor.
Table 5 below shows the theoretical storage
capacitance required for various applications.
For free-running applications, the capacitance
required is determined by the data bit rate and
encoding method.
oscillator
applications. For the bi-directional protocols, the
GAP input pull-up also draws current during
modulation.
Supply
(V)
1.0
1.2
1.5
2.0
3.0
Current
(Free)
draw
( A)
1.8
2.6
3.8
11
6
the power
EM MICROELECTRONIC-MARIN SA
current
(Bi-directional)
Only the Logic, PON and
Current
( A)
2.2
3.6
6.3
13
31
storage
in
(SWTICHED-
capacitance
Free-running
OFF state)
Current
( A)
2.8
4.6
8.3
16
51
Table 4
In this
For counting applications (SWITCH-OFF BTG-
Supertag) the required unpowered time in the
SWITCHED-OFF state determines the size of the
capacitor. In applications where the chip can be
guaranteed to stay powered, the capacitor size is
determined by the data bit rate.
It should be noted that the on-chip capacitance is
sufficient for free-running applications at 64 kbit/s,
while inductive applications at 4 kbit/s require a
few nanofarad externally.
applications will require more than 20 F to
achieve
SWITCHED-OFF state.
Data bit
(kbit/s)
rate
64
64
4
4
coding
Glitch
Glitch
1 second unpowered
Man
Man
En-
running
Free-
2700
(pF)
670
170
40
Unpowered counting
Bi-direc-
P4022
PRELIMINARY
tional
3600
(pF)
900
240
80
time
Counting
( F)
Table 5
20
20
20
20
in
the
4