TDA8034T Philips Semiconductors, TDA8034T Datasheet - Page 6

• Manufacturer Part Number: TDA8034T
• Description: Smart Card Interface
• Manufacturer: Philips Semiconductors

NXP Semiconductors
TDA8034T_TDA8034AT_1
Product data sheet
8.3 Clock circuits
The voltage supervisor monitors the voltage of the V
Power-On Reset (POR) and supply drop-out detection during a card session. The
supervisor threshold voltages for V
than V
has reached a level higher than V
The output of the supervisor is sent to a digital controller in order to reset the
TDA8034T/TDA8034AT. This defined reset pulse of approximately 8 ms, i.e. (t
1
voltage power on; see
V
Remark: f
parameter.
The clock signal from pin CLK to the card is either supplied by an external clock signal
connected to pin XTAL1 or generated using a crystal connected between pins XTAL1 and
XTAL2. The TDA8034T/TDA8034AT automatically detects if an external clock is
connected to XTAL1, eliminating the need for a separate pin to select the clock source.
Automatic clock source detection is performed on each activation command (falling edge
of the signal on pin CMDVCCN). The presence of an external clock on pin XTAL1 is
checked during a time window defined by the internal oscillator. If a clock is detected, the
internal crystal oscillator is stopped. If a clock is not detected, the internal crystal oscillator
is started. When an external clock is used, it is mandatory that the clock is applied to pin
XTAL1 before the falling edge of the signal on pin CMDVCCN.
fosc(int)low
Fig 4.
DDP
(internal signal)
falls below V
th
+ V
V
ALARMN
Voltage supervisor waveforms
), is used internally to maintain the IC in the Shutdown mode during the supply
th
osc(int)low
+ V
hys
V
V
hys
DD
, the IC remains inactive irrespective of the command line levels. After V
th
th
is the low frequency (or inactive) mode of the defined f
.
Rev. 01 — 5 February 2010
Figure
power on
4. A deactivation sequence is performed when either V
th
DDP
+ V
t
w
and V
hys
TDA8034T; TDA8034AT
, the IC remains inactive for the duration of t
DD
are set internally. As long as V
supply dropout
DDP
and V
t
w
DD
supplies providing both
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Smart card interface
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osc(int)
power off
w
001aak993
DD
= 1024
is less
6 of 29
DD
w
DD
.
or