DS8005 데이터 시트보기 (PDF) - Maxim Integrated
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DS8005 Datasheet PDF : 20 Pages
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DS8005
Smart Card Interface
Smart Card Power Select
The device supports three smart card VCC voltages: 1.8V,
3V, and 5V. The power select is controlled by the 1_8V
and 5V/3V signals as shown in Table 3. The 1_8V signal
has priority over 5V/3V. When 1_8V is asserted high,
1.8V is applied to VCC when the smart card is active.
When 1_8V is deasserted, 5V/3V dictates VCC power
range. VCC is 5V if 5V/3V is asserted to a logic-high state,
and VCC is 3V if 5V/3V is pulled to a logic-low state. Care
must be exercised when switching from one VCC power
selection to the other. If both 1_8V and 5V/3V are high
with CMDVCC high at the same time, the device enters
stop mode. To avoid accidental entry into stop mode, the
state of 1_8V and 5V/3V must not be changed simulta-
neously. A minimum delay of 100ns should be observed
between changing the states of 1_8V and 5V/3V. See
Figure 9 for the recommended sequence of changing the
VCC range.
Table 3. VCC Select and Operation Mode
1_8V
5V/3V
CMDVCC
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
VCC SELECT (V)
3
3
5
5
1.8
1.8
1.8
1.8
CARD INTERFACE STATUS
Activated
Inactivated
Activated
Inactivated
Activated
Inactivated
Reserved (Activated)
Not Applicable—Stop Mode
VCC SELECT
1.8V
CMDVCC
1_8V
5V/3V
Figure 9. Smart Card Power Select
3V
5V
3V
1.8V
STOP MODE
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