Product data

TDA8007BHL All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 9.1 — 18 June 2012 34 of 51
NXP Semiconductors
TDA8007BHL
Multiprotocol IC card interface
8.7 Deactivation sequence
When the session is completed, the microcontroller resets bit START at t
10
. The circuit
then executes an automatic deactivation sequence (see Figure 19
):
1. The card is reset by signal RST = low (t
11
).
2. Clock pulse CLK is stopped (t
12
).
3. Pins I/O, C4x and C8x fall to 0 V (t
13
).
4. Pin V
CC
falls to 0 V with typical 0.17 V/µs slew rate (t
14
).
5. The step-up converter is stopped (t
15
) and pins CLK, RST, V
CC
and I/O become low
impedance to ground, if both cards are inactive.
Thus:
t
11
=t
10
+
1
⁄
64
t
t
12
=t
11
+
1
⁄
2
t
t
13
=t
11
+t
t
14
=t
11
+
3
⁄
2
t
t
15
=t
11
+
7
⁄
2
t
t
de
= time that V
CC
needs to decrease to less than 0.4 V.
Fig 19. Deactivation sequence
START
V
UP
V
CC
I/O
CLK
RST
t
10
t
12
t
13
t
de
t
14
t
15
t
11
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