ncn6804 ON Semiconductor, ncn6804 Datasheet - Page 14

• Manufacturer Part Number: ncn6804
• Description: Dual Smart Card Interface Ic With Spi Programming Interface
• Manufacturer: ON Semiconductor

Powerup Sequence
signals are Low during the CRD_VCCA/B positive going
slope. These lines are validated when CRD_VCCA/B is
above the minimum voltage specified by the EMV standard
depending upon the programmed CRD_VCC A or B value
(see CRD_VCC Power Supply section on page NO TAG).
CRD_VCC
CRD_RST
CRD_CLK
The Powerup Sequence makes sure all the card related
CRD_C4
CRD_C8
CRD_IO
Figure 4. Measured Typical Startup CRD_VCC
CS
Figure 3. Startup CRD_VCC Sequence
Sequence
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ATR
NCN6804
14
upon the current capability of the DC/DC converter
associated with the external inductor L and the reservoir
capacitor connected across CRD_VCCA or B and
GROUND. During this sequence, the average input current
is 300 mA typical (see Figure 4), assuming the system is
fully loaded during the start up.
sequence is under the control and responsibility of the
application software.
depends upon the external reservoir capacitor and the peak
current absorbed by the internal NMOS transistor built
across CRD_VCCA/B and Ground. These behaviors are
depicted Figure 5.
upon the external constraints, the designer must take care of
these limits if the t
not meet his requirements.
At powerup, the CRD_VCCA/B turn-on time depends
Even if enabled by the built-in sequencer the activation
On the other hand, at turn off, the CRD_VCCA/B fall time
Since these parameters have finite values, depending
Figure 5. CRD_VCC Typical Turn-on and Turn-off
ON
or t
OFF
Times
provided by the datasheet does