ncn6024 ON Semiconductor, ncn6024 Datasheet - Page 12

• Manufacturer Part Number: ncn6024
• Description: Compact And Low Cost Smart Card Interface Ic
• Manufacturer: ON Semiconductor

POWER-DOWN
NCN6024 runs a deactivation sequence by setting High
CMDVCC. The below power down sequence is executed:
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FAULT DETECTION
card, the NCN6024 provides security features to prevent
failures or damages as depicted here after.
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Interrupt Pin Management:
Low.
High position. INT is Low if no card is present in the card
connector (Normally open or normally closed type). INT is
High if a card is present. If a card is inserted (INT = High)
and if VDD drops below the UVLO threshold then INT pin
drops Low immediately. It turns back High when VDD
increases again over the UVLO limit (including hysteresis),
a card being still present.
goes Low when a fault is detected. In that case a deactivation
When the communication session is completed the
In order to protect both the interface and the external smart
A card session is opened by toggling CMDVCC High to
Before a card session, CMDVCC is supposed to be in a
During a card session, CMDVCC is Low and INT pin
CRD_RST is forced to Low
Card extraction detection
VDD under voltage detection
Short-circuit or overload on CRD_VCC
CRD_PRES
CRD_VCC
CMDVCC
CRD_VCC
CRD_RST
CRD_CLK
CMDVCC
INT
CRD_IO
Debounce
Figure 7. Fault Detection and Interrupt Management
Powerdown Resulting of
Card Extraction
Figure 6. Deactivation Sequence
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is immediately and automatically performed (see Figure 6).
When the microcontroller resets CMDVCC to High it can
sense the INT level again after having got completed the
deactivation.
of 8 ms typical duration. When a card is inserted, output INT
goes High only at the end of the debounce time. When the
card is removed a deactivation sequence is automatically
and immediately performed and INT goes Low.
ESD PROTECTION
the ESD spikes voltages. To cope with the different ESD
deact
As illustrated by Figure 7 the device has a debounce timer
The NCN6024 includes devices to protect the pins against
CRD_CLK is set Low 12 ms after CRD_RST.
CRD_IO, CRD_AUX1 and CRD_AUX2 are pulled Low
Finally CRD_VCC supply can be shut-off.
Card pin current limitation: in the case of a short circuit
to ground. No feedback is provided to the external MPU.
DC/DC operation: the internal circuit continuously
senses the CRD_VCC voltage (in the case of either
over or under voltage situation).
DC/DC operation: under-voltage detection on VDDP or
overload on VUP
Overheating
Powerdown Caused by
Debounce
Short−Circuit