DS8024-RJX+ Maxim Integrated Products, DS8024-RJX+ Datasheet - Page 7

• Manufacturer Part Number: DS8024-RJX+
• Description: IC INTERFACE SMART CARD 28-TSSOP
• Manufacturer: Maxim Integrated Products

Specifications of DS8024-RJX+

• Applications: Smart Card
• Interface: Analog
• Voltage - Supply: 2.7 V ~ 6 V
• Package / Case: 28-TSSOP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The DS8024 is an analog front-end for communicating
with 3V and 5V smart cards. Using an integrated
charge pump, the DS8024 can operate from a single
input voltage. The device translates all communication
lines to the correct voltage level and provides power for
smart card operation. It can operate from a wide input
voltage range (3.3V to 6.0V). The DS8024 is compatible
with the NXP TDA8024 and is provided in the same
packages. (Note that the PORADJ pin is not present in
the DS8024. Most applications do not make use of this
Figure 1. Functional Diagram
Figure 2. Voltage Supervisor Behavior
CMDVCC
CLKDIV1
CLKDIV2
AUX1IN
AUX2IN
XTAL1
XTAL2
5V/3V
RSTIN
I/OIN
GND
V
OFF
DD
(INTERNAL SIGNAL)
ALARM
POWER-SUPPLY
V
_______________________________________________________________________________________
DD
SUPERVISOR
GENERATION
CLOCK
Detailed Description
I/O TRANSCEIVER
SEQUENCER
CONTROL
DS8024
CARD VOLTAGE
CHARGE PUMP
TEMPERATURE
GENERATOR
MONITOR
AND
POWER ON
t
W
V
PGND
CP1
CP2
V
V
CGND
RST
CLK
PRES
PRES
I/O
AUX1
AUX2
DDA
UP
CC
input pin, instead using the DS8024’s default reset
threshold.)
The DS8024 can operate from a single supply or a dual
supply. The supply pins for the device are V
V
to 6.0V, 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
reaches V
nal power-on reset pulse, t
is executed when V
An internal charge pump and regulator generate the
3V or 5V card supply voltage (V
and regulator are supplied by V
should be connected to a minimum 3.3V (maximum
6.0V) supply and should be at a potential that is equal
to or higher than V
The charge pump operates in a 1x (voltage follower) or
2x (voltage doubler) mode depending on the input
V
The voltage supervisor monitors the V
220µs reset pulse (t
device inactive during power on or power off of the V
supply. See Figure 2.
DDA
DDA
• For 5V cards, the DS8024 operates in a 1x mode
• For 3V cards, the DS8024 operates in a 1x mode
Smart Card Interface
for V
for V
SUPPLY DROPOUT
, and PGND. V
and the selected card voltage (5V or 3V).
DDA
DDA
t
TH2
W
> 5.8V and in a 2x mode for V
> 4.1V and in a 2x mode for V
+ V
HYS2
DD
DD
DD
.
W
falls below V
) is used internally to keep the
and for the duration of the inter-
should be in the range of 2.7V
Voltage Supervisor
W
. A deactivation sequence
CC
DDA
Power Supply
). The charge pump
TH2
and PGND. V
POWER OFF
.
V
V
TH2
TH2
DD
+ V
DDA
DDA
HYS2
supply. A
DD
< 5.8V.
< 4.0V.
, GND,
DDA
DD
DD
7