TDA8034HN All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2016. All rights reserved.
Product data sheet Rev. 3.4 — 29 June 2016 12 of 32
NXP Semiconductors
TDA8034HN
Low power smart card interface
Remark: The value of period T is 64 times the period interval of the internal oscillator (i.e.
25 s).
8.9 V
CC
regulator
The V
CC
buffer is able to continuously deliver up to 65 mA at V
CC
= 5V, 3V, or 1.8V.
The V
CC
buffer has an internal overload protection with a threshold value of approximately
120 mA. This detection is internally filtered, enabling spurious current pulses up to
200 mA with a duration of a few milliseconds to be drawn by the card without causing
deactivation. However, the average current value must stay below maximum; see Table 8
.
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
DDP
falling
• V
DD
falling
• V
DD(INTF)
falling
• Overheating
Fault detection monitors two different situations:
• Outside card sessions, pin CMDVCCN is HIGH: pin OFFN is LOW if the card is not in
the reader and HIGH if the card is in the reader. Any voltage drop on V
DD
is detected
by the voltage supervisor. This generates an internal power-on reset pulse but does
not act upon the pin OFFN signal. The card is not powered-up and short-circuits or
overheating are not detected.
OSCINT = internal oscillator.
Fig 8. Deactivation sequence
001aak995
RST
CLK
I/O
V
CC
XTAL1
OSCINT
CMDVCC
high frequency
t10 t11 t12 t13
t
deact
t14
low frequency
