73S8024C Maxim, 73S8024C Datasheet - Page 7

• Manufacturer Part Number: 73S8024C
• Description: The 73S8024C is a single smart card interface IC, compliant to the electrical requirements of ISO 7816-3 and EMV 4
• Manufacturer: Maxim

DS_8024C_023
4 DC-DC Converter – Card Power Supply
An internal DC-DC converter provides the card power supply. This converter is able to provide either 3 V
or 5 V card voltage from the power supply applied on the V
controls the converter. Card voltage selection is carried out by the digital input 5V/#V.
The circuit is an inductive step-up converter/regulator. The external components required are 2 filter
capacitors on the power-supply input V
output filter capacitor on the card power supply V
step-up operation when V
and the input supply V
(V
Depending on the inductor values, the voltage converter can provide current on V
The circuit provides over-current protection and limits I
sensed, the circuit initiates a deactivation sequence from the control logic and reports back to the host
controller a fault on the interrupt output OFF.
Choice of the inductor
The nominal inductor value is 10 µH, rated for 400 mA. The inductor is connected between LIN (pin 5 in
the SO package, pin 2 in the QFN package) and the V
meet a particular configuration (I
to the LIN pin of the IC.
Choice of the V
Depending on the applications, the requirements in terms of both the V
transient currents that the interface must provide to the card are different.
recommended capacitors for each V
5 Over-temperature Monitor
A built-in detector monitors die temperature. When an over-temperature condition occurs, a card
deactivation sequence is initiated, and an error or fault condition is reported to the system controller.
Rev. 1.3
DD
= 3.6 V, V
EMV 4.0
ISO-7816-3
Specification
CC
CC
=3 V) the circuit operates as a linear regulator.
capacitor
DD
Specification Requirement
is less than the set point for V
CC
Transient Current
Min V
Allowed During
is below a set point of 5.0 or 3.0 volts minus a comparator hysteresis voltage
CC_MAX
Table 1: Choice of VCC Pin Capacitor
Table 1: Choice of VCC Pin Capacitor
4.6 V
4.5 V
CC
CC
Voltage
). The inductor should be located on the PCB as close as possible
DD
power supply configuration and applicable specification.
(next to the LIN pin, 100 nF + 10 µF), an inductor, and an
Current Charge
CC
Max Transient
. The circuit performs regulation by activating the
30 nAs
20 nAs
DD
CC
CC
voltage. The inductor value can be optimized to
. When V
to 150 mA. When an over-current condition is
DD
pin. The digital ISO-7816-3 sequencer
DD
ESR < 100 mΩ
X5R/X7R w/
is greater than the set point for V
Capacitor
CC
Type
minimum voltage and the
Table 1
Application
CC
shows the
73S8024C Data Sheet
as high as 100 mA.
Capacitor
3.3 µF
Value
1 µF
CC
7