TDA8020HL Datasheet, PDF (7/24 Pages) NXP Semiconductors – Dual smart card interface

Philips Semiconductors
Dual smart card interface
Product specification
TDA8020HL
FUNCTIONAL DESCRIPTION
Throughout this specification, it is assumed that the reader
is familiar with ISO 7816 norm terminology.
Supply
The TDA8020HL operates with a supply voltage from
2.5 to 6.5 V. An integrated voltage supervisor ensures that
no spike appears on cards contacts during power-on or off.
The supervisor also initializes the device, and forces an
automatic emergency deactivation of the contacts in the
event of a supply drop-out.
As long as the supply voltage is below the threshold
voltage V_th1, the capacitor C_DEL remains uncharged. When
the supply voltage reaches V_th1 and V_hys1, then C_DEL is
charged with a small current source of approximately 2 µA.
When the voltage on C_DEL reaches V_th2, then the
supervisor is no longer active. As long as the supervisor is
active (pin IRQ is LOW), bit SUPL in the status register is
set. When pin IRQ goes HIGH the supervisor becomes
inactive (see Fig.3).
Separate supply pins are used for the DC/DC converter,
allowing specific decoupling for counteracting the noise
the switching transistors may induce on the supply.
A specific reference supply voltage, V_DDI, is used for the
interface signals CLKIN1, CLKIN2, I/O1uC, I/O2uC,
SAD0, SAD1, SCL, SDA and IRQ, which can be lower
than V_DD (minimum 1.5 V), thus allowing direct control with
a low voltage supplied device.
Pins SCL, SDA and IRQ are open-drain outputs, and may
be externally pulled up to a voltage higher than V_DD.
I²C-bus
A 400 kHz I²C-bus slave interface is used for configuring
the device and reading the status. The bus has
2 addresses, one for each card. 4 devices may be used in
parallel due to the address selection pins SAD0 and SAD1
(see Table 1).
Table 1 Proposed addresses
PIN SAD1
LOW
LOW
HIGH
HIGH
PIN SAD0
LOW
HIGH
LOW
HIGH
CARD 1
40H
42H
44H
46H
CARD 2
48H
4AH
4CH
4EH
handbook, full pagewidth
VDD
Vth1 + Vhys1
Vth1
Vth2
VCDEL
IRQ
2001 Aug 15
tw
BUS NOT RESPONDING
tw
status read
after event
BUS OK
BUS NOT
RESPONDING
BUS OK
BUS NOT
RESPONDING
FCE835
Fig.3 Supply supervisor.
7