s8024rn Maxim Integrated Products, Inc., s8024rn Datasheet - Page 9

• Manufacturer Part Number: s8024rn
• Description: 73s8024rn Low Cost Smart Card Interface
• Manufacturer: Maxim Integrated Products, Inc.

DS_8024RN_020
4 Card Power Supply
The card power supply is internally provided by the LDO regulator, and controlled by the digital
ISO-7816-3 sequencer. Card voltage selection is carried out by the digital input 5V/#V.
Choice of the V
Depending on the applications, the requirements in terms of both V
currents that the interface must be able to provide to the card are different. An external capacitor must be
connected between the VCC pin and to the card ground in order to guarantee stability of the LDO
regulator, and to handle the transient requirements. The type and value of this capacitor can be
optimized to meet the desired specification. Table 1 shows the recommended capacitors for each V
power supply configuration and applicable specification.
Note: Capacitor value for NDS implementation is also defined by the deactivation time requirement.
5 Over-Temperature Monitor
A built-in detector monitors die temperature. Upon an over-temperature condition, a card deactivation
sequence is initiated, and an error or fault condition is reported to the system controller.
6 On-Chip Oscillator and Card Clock
The 73S8024RN device has an on-chip oscillator that can generate the smart card clock using an
external crystal (connected between the pins XTALIN and XTALOUT) to set the oscillator frequency.
When the clock signal is available from another source, it can be connected to the pin XTALIN, and the
pin XTALOUT should be left unconnected.
The card clock frequency may be chosen between four different division rates, defined by digital inputs
CLKDIV 1 and CLKDIV 2, as per Table 2.
Card power down mode (card clock STOP) is supported and is controllable through the dedicated digital
inputs CLKSTOP and CLKLEV (not supported in the 20QFN package).
Rev. 1.9
EMV 4.0
ISO-7816-3
NDS
Specification
Specification Requirements
CC
Capacitor:
Transient Current
Min V
Allowed During
CC
4.6V
4.5V
4.6V
CLKDIV1
Voltage
Table 1: Choice of V
0
0
1
1
Table 2: Card Clock Frequency
Transient
CLKDIV2
Current
Charge
30nA.s
20nA.s
40nA.s
Max
0
1
0
1
CC
Pin Capacitor
Required
Min V
Supply
Power
4.75V
4.75V
4.85V
⅛ XTALIN
¼ XTALIN
½ XTALIN
XTALIN
CLK
PC
CC
System Requirements
minimum voltage and transient
Capacitor
X5R/X7R
100mΩ
ESR <
Type
w/
73S8024RN Data Sheet
Capacitor Value
3.3 µF
1 µF
1 µF
PC
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