ST8024LTR STMicroelectronics, ST8024LTR Datasheet - Page 18

• Manufacturer Part Number: ST8024LTR
• Description: Interface - Specialized Smart card interface 3V or 5V 26 MHz
• Manufacturer: STMicroelectronics

Specifications of ST8024LTR

• Product Category: Interface - Specialized
• Rohs: yes
• Product Type: Smart Card Interface
• Operating Supply Voltage: 2.7 V to 6.5 V
• Supply Current: 1.2 mA
• Maximum Power Dissipation: 0.56 W
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-20
• Minimum Operating Temperature: - 25 C

Functional description
6
6.1
6.2
6.2.1
18/35
Functional description
Throughout this document it is assumed that the reader is familiar with ISO7816
terminology.
Power supply
The supply pins for the ST8024L are V
6.5 V. All signals interfacing with the system controller are referred to V
should also supply the system controller. All card reader contacts remain inactive during
power-on or power-off.
The internal circuits are kept in the reset state until V
duration of the internal power-on reset pulse, t
an automatic deactivation of the contacts is performed.
A step-up converter is incorporated to generate the 1.8 V (for those devices with the
1.8V pin), 3 V, or 5 V card supply voltage (V
separately by V
100 nF capacitors of the step-up converter should be located as near as possible to the
ST8024L and have an ESR less than 350 mΩ .
During power-up, the V
or at the same time
After powering the device, OFF remains low until CMDVCC is set high.
During power-off, OFF falls low when V
Voltage supervisor
Without external divider on pin PORADJ
The voltage supervisor surveys the V
(t
supply (see
As long as V
levels on the command lines. This state also lasts for the duration of t
reached a level higher than V
sequence of the contacts is performed.
W
) is used internally to keep the ST8024L inactive during power-on or power-off of the V
Figure
DD
DDP
is less than V
4).
and PGND. Due to the possibility of large transient currents, the two
DD
supply voltage must be applied prior to the V
th2
th2
Doc ID 17709 Rev 5
+ V
+ V
HYS2
HYS2
DD
DD
DD
supply. A defined reset pulse of approximately 8 ms
, the ST8024L remains inactive regardless of the
. When V
and GND. V
is below the falling threshold voltage.
CC
W
). The step-up converter should be supplied
(see
DD
DD
falls below V
Figure
DD
reaches V
should be in the range of 2.7 to
4). When V
th2
th2
, a deactivation
W
+V
DD
DDP
after V
DD
HYS2
, therefore V
falls below V
supply voltage
and for the
DD
has
ST8024L
DD
th2
DD
,