DS8005 Maxim, DS8005 Datasheet - Page 9

• Manufacturer Part Number: DS8005
• Description: The DS8005 dual smart card interface is a low-cost, dual analog front-end for an IC card reader interface that needs to communicate with two smart cards in a mutually exclusive fashion
• Manufacturer: Maxim

The DS8005 is an analog front-end for communicating
with 1.8V, 3V, and 5V dual smart cards. It is a dual
input-voltage device, requiring one supply to match
that of a host microcontroller and a separate +5V sup-
ply for generating correct smart card supply voltages.
The device translates all communication lines to the
correct voltage level and provides power for smart card
operation. It is a low-power device, consuming very lit-
tle current in active-mode operation (during a smart
card communication session), and is suitable for use in
battery-powered devices such as laptops and PDAs,
consuming only 10nA in stop mode. The device is
designed for applications that do not require communi-
cation using the C4 and C8 card contacts (AUX1 and
AUX2). It is suitable for SIM/SAM interfacing, as well as
for applications where only the I/O line is used to com-
municate with a smart card.
Figure 1. Functional Diagram
_______________________________________________________________________________________
CMDVCC
CLKDIV1
CLKDIV2
SEL_AB
XTAL1
XTAL2
V
RSTIN
5V/3V
1_8V
OFF2
V
I/OIN
DDA2
OFF
DDA
Detailed Description
GENERATION
GENERATION
REGULATOR
SEQUENCER
INTERRUPT
CONTROL
CLOCK
XCVR
I/O
QSEL_AB
QSEL_AB
DETECTION
FAULT
The device has dual supplies. The supply pins for the
device are V
2.7V to 6.0V range, and is the supply for signals that
interface with the host controller. It should, therefore, be
the same supply as used by the host controller. All
smart card contacts remain inactive during power-on or
power-off. The internal circuits are kept in the reset
state until V
tion of the internal power-on reset pulse, t
vation sequence is executed when V
V
An internal regulator generates the 1.8V, 3V, or 5V card
supply voltage (V
plied separately by V
to a minimum 4.75V supply to provide the correct sup-
ply voltage for 5V smart cards.
TH2
Smart Card Interface
.
DD
INTERFACE A
INTERFACE B
DD
SUPPLY
POWER
CARD
CARD
reaches V
DS8005
, GND, and V
CC_
DDA
). The regulator should be sup-
TH2
. V
DDA
DDA
+ V
CGND
I/OA
V
RSTA
CLKA
PRESA
I/OB
V
RSTB
CLKB
PRESB
V
GND
Power Supply
. V
HYS2
CCA
CCB
DD
should be connected
DD
and for the dura-
should be in the
DD
W
falls below
. A deacti-
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