DS_8014R_012
73S8014R Data Sheet
3.4 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 on the 73S8014R is carried out by the digital input 5V/#V.
Choice of the VCC capacitor:
Depending on the application, the requirements in terms of both VCC minimum voltage and transient 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 of capacitor should be an X5R/X7R with ERS<100 mΩ.
3.5 On-Chip Oscillator and Card Clock
The 73S8014R 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 4 different division rates, defined by digital inputs CLKDIV 1
and CLKDIV 2, as per the following table:
CLKDIV1
CLKDIV2
CLK
Max XTALIN
27MHz
0
0
1
1
0
1
0
1
1/8 XTALIN
¼ XTALIN
XTALIN
27MHz
20MHz
½ XTALIN
27MHz
Rev. 1.0
17
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
