LTC1756 Linear Technology, LTC1756 Datasheet - Page 10

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

LTC1756
APPLICATIONS
State Definitions
IDLE/DEACTIVATION
V
READY, DATA = Z
CARD = PRES
Once the LTC1756 enters the Idle/Deactivation state the
deactivation sequence begins. The deactivation sequence
will continue until V
An activation command (PWR = 0V) will only be acknowl-
edged once this occurs.
ALARM/DEACTIVATION
The only possible next state is Idle/Deactivation which is
achieved by disabling the LTC1756 via the PWR pin
(i.e., PWR = V
The alarm indication can be cleared by rapidly cycling the
PWR pin. However, a new activation cycle will not begin
until V
10
CC
, RST, CLK, I/O = L
CC
is or has dropped below approximately 1V.
IN
).
U
CC
is discharged to approximately 1V.
INFORMATION
U
POWER OFF
W
Figure 4. LTC1756 State Diagram
PWR = V
U
DEACTIVATION
DEACTIVATION
ALARM
IN
IDLE
PRES “0”
ACTIVE
V
RST = R
I/O, DATA = Ready for data (after READY becomes low)
CARD = PRES
FAULT TIMEOUT
Same as Active except:
The duration of a fault is being measured. If the fault
duration exceeds 5 s then the Alarm/Deactivation state
follows. If the fault duration is less than 5 s, then the
device is returned to the Active state.
FAULT > 5 s
PRES “0”
PWR = V
PWR = 0V
CC
or
= 3V or 5V (as determined by the 5V/3V pin)
IN
IN
, CLK = C
TIMEOUT
NO
FAULT
ACTIVE
FAULT
1756 F04
IN
FAULT