LTC1756 Linear Technology, LTC1756 Datasheet - Page 9

• Manufacturer Part Number: LTC1756
• Description: Smart Card Interface
• Manufacturer: Linear Technology

APPLICATIONS
Self-Start Mode
By connecting the CARD pin to the PWR pin the LTC1756
can be made to start up automatically when a Smart Card
is detected (Figure 2). In this mode, the READY pin
becomes an interrupt signal indicating to the microcon-
troller that a Smart Card is present and that V
pump voltage, is at its final value. The Smart Card remains
powered as long as it is detected by the PRES pin. When
the Smart Card is removed the LTC1756 will automatically
be deactivated by the fault detection circuitry.
Figure 2. Self-Start Mode
U
CARD
INFORMATION
U
READY
PWR
W
1756 F02
TO
MICROCONTROLLER
CC
, the charge
U
Deactivation Sequence
For maximum flexibility the Smart Card can be deactivated
either manually or automatically. In manual mode the
deactivation is controlled by explicitly manipulating the
LTC1756 input and control pins (DATA, RIN and CIN
followed by PWR). In automatic mode the PWR pin is used
to perform the built-in deactivation sequence. Once PWR
is brought high the built-in deactivation sequence occurs
as follows:
In the event of a fault, the LTC1756 automatically
implements the built-in deactivation sequence.
RST
CLK
V
I/O
CC
I/O = DATA
RST = R
CLK = C
Figure 3. Deactivation Sequence
DEACTIVATION DIRECTIVE
IN
IN
LTC1756
1755 F03
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