73S8010C Data Sheet
DS_8010C_024
3 Oscillator
The Teridian 73S8010C device has an on-chip oscillator that can generate the smart card clock using an
external crystal, connected between the XTALIN and XTALOUT pins, to set the oscillator frequency.
When the card clock signal is available from another source, it can be connected to the pin XTALIN, and
the pin XTALOUT should be left unconnected.
4 DC-DC Converter – Card Power Supply
An internal DC-DC converter provides the card power supply. This converter is able to provide either a
3 V or 5 V card voltage from the power supply applied on the VDD pin. The digital ISO-7816-3 sequencer
controls the converter. Bit 2 of the Control register selects the card voltage.
The circuit is an inductive step-up converter/regulator. The external components required are 2 filter
capacitors on the power-supply input VDD (100 nF + 10 µF, next to the LIN pin), an inductor, and an output
filter capacitor on the card power supply VCC. The circuit performs regulation by activating the step-up
operation when VCC is below a set point of 5.0 or 3.0 volts minus a comparator hysteresis voltage and the
input supply VDD is less than the set point for VCC. When VDD is greater than the set point for VCC (VDD
=
3.6 V, VCC = 3 V) the circuit operates as a linear regulator. Depending on the inductor values, the voltage
converter can provide current on VCC as high as 100 mA.
The circuit provides over-current protection and limits ICC to 150 mA. When an over-current condition is
sensed, the circuit initiates a deactivation sequence from the control logic and reports back to the host
controller a fault on the interrupt output INT.
Choice of the Inductor
The nominal inductor value is 10 µH, rated for 400 mA. The inductor is connected between pin LIN (pin 5
in the SO package, pin 2 in the QFN package) and the VDD voltage. The value of the inductor can be
optimized to meet a particular configuration (ICC_MAX). The inductor should be located on the PCB as
close as possible to the LIN pin of the IC.
Choice of the VCC Capacitor
Depending on the applications, the requirements in terms of both VCC minimum voltage and transient
currents that the interface must be able to provide to the card vary. Table 4 shows the recommended
capacitors for each VCC power supply configuration and applicable specification.
Table 4: Choice of Vcc Capacitor
Specification Requirement
Min VCC Voltage
Application
Max Transient
Specification
Allowed During
Capacitor Type Capacitor Value
Current Charge
Transient Current
EMV 4.0
4.6V
4.5V
30nA.s
20nA.s
3.3 µF
1 µF
X5R/X7R w/
ESR < 100 mΩ
ISO-7816-3
10
Rev. 1.5
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
