ncn6001 ON Semiconductor, ncn6001 Datasheet - Page 17

• Manufacturer Part Number: ncn6001
• Description: Compact Smart Card Interface Ic
• Manufacturer: ON Semiconductor

GENERAL PURPOSE CRD_C4 AND CRD_C8
address of a given interface (in the range $00 to $11), or as
a standard C4/C8 access to the smart card’s channels. Since
source to provide a logic one when the pin is left open. In this
case, care must be observed to avoid relative low impedance
to ground to make sure the pin is at a High logic level.
However, it is possible to connect the pin to V
supply) to force the logic input to a High level, regardless of
the input bias. Thanks to the CONTROL internal signal, the
system automatically adapts the mode of operation (chip
address or data communication) and, except the leakage, no
extra current is drawn from the battery to bias these pins
when the logic level is High.
1 mA typical sink current will be absorbed from the battery
supply.
These two pins can be used as a logic input to define the
The C4 and C8 pins are biased by an internal current
When any of these pins is connected to GND, a continuous
READ_C4
CONTROL
WRT_C4
V
CC
ADDRESS
U5
Figure 9. Typical CRD_C4 Output Drive and Logic Control
3
3
U8
U7
SHIFTER
LEVEL
V
1
2
1
2
max
U2
CC
(battery
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NCN6001
U1
17
U9
these pins can be directly connected to the V
supply, both output stages are built with switched
NMOS/PMOS totem pole as depicted in Figure 9.
positive going transient when the related pin is forced to the
High state during a data transfer. In the event of a low
impedance connected across C4 or C8 to ground, the current
flow is limited to 15 mA, according to the ISO7816−3
specification.
external microcontroller to the card and read back the logic
state, but none of these pins can read the data coming from
the external smart card. On the other hand, both C4 and C8
can read input logic, hence the physical address of a given
chip.
an extra protection structure Q3 has been implemented to
protect the MOS gates of the input circuit.
1
2
U6
V
CRD_VCC
The switched Totem Pole structure provides the fast
The two general purpose pins can transfer data from the
In order to sustain the 8 kV ESD specified for these pins,
CC
U3
U4
I = 1 A
3
Q2
GND
Q1
SWITCHED
ESD
BIAS
500 R
Q3
R1
GND
CRD_VCC
C4
CC
power