TDA8025 Datasheet, PDF (19/38 Pages) NXP Semiconductors – IC card interface

NXP Semiconductors
TDA8025
IC card interface
CMDVCCN
RST
CLK
I/O
V_CC
XTAL1
OSCINT
high frequency
t10 t11
t12
t13
t14
t_deact
low frequency
001aai970
Fig 13. Deactivation sequence with an external clock connected to pin XTAL1
8.9 V_CC regulator
Table 5. Selection of V_CC using pins VCC_SEL1 and VCC_SEL2
VCC_SEL1
VCC_SEL2
V_CC
0
0
3V
0
1
1.8 V
1
0
1.2 V
1
1
1.2 V
The V_CC buffer is able to continuously deliver up to:
• 65 mA at 3 V
• 65 mA at 1.8 V
• 30 mA at 1.2 V
The V_CC buffer has an internal overload protection with a threshold value of ±135 mA.
This detection is filtered, enabling spurious current pulses up to 200 mA with a duration of
up to 200 ns to be drawn by the card without causing deactivation. However, the average
current value must be below maximum.
To enhance V_CC stability, one 470 nF capacitor should be tied to pin CGND near pin 18
and one 220 nF capacitor should be tied to pin CGND near the C1 contact. Both
capacitors should have an ESR < 100 mΩ.
8.10 Fault detection
The following conditions are monitored by the fault detection circuit:
• Short-circuit or high current on pin V_CC
• Card removal during transaction
• V_DD(INTREGD) falling
TDA8025_1
Product data sheet
Rev. 01 — 6 April 2009
© NXP B.V. 2009. All rights reserved.
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