TDA8020 データシートの表示（PDF） - Philips Electronics

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TDA8020

Dual smart card interface

Philips Electronics 

Philips Semiconductors

Dual IC card interface

Product specification

TDA8020HL

DC-to-DC converter

VCC1 is the supply voltage for card 1 contacts and VCC2 is

the supply voltage for card 2 contacts. Card 1 and card 2

may be independently powered-down, powered at 5 V or

powered at 3 V. A capacitor type step-up converter is used

for generating these voltages. This step-up converter acts

either as a doubler, tripler or follower. An hysteresis of

100 mV is present on the different threshold voltages.

If VCC is the maximum value of VCC1 and VCC2, then there

are 5 possible situations:

• VDD < 3.4 V and VCC = 3 V: in this case, the DC-to-DC

converter acts as a doubler with a regulation of

approximately 4.0 V

• VDD < 3.4 V and VCC = 5 V: in this case, the DC-to-DC

converter acts as a tripler with a regulation of

approximately 5.5 V

• VDD > 3.5 V and VCC = 3 V: in this case, the DC-to-DC

converter acts as a follower: VDD is applied on VUP

• 5.8 V > VDD > 3.5 V and VCC = 5 V: in this case, the

DC-to-DC converter acts as a doubler with a regulation

of approximately 5.5 V

• VDD > 5.9 V and VCC = 5 V: in this case, the DC-to-DC

converter acts as a follower and VDD is applied on VUP.

The output voltage, VUP, is fed internally to the VCC

generators. VCC1, VCC2 and CGND1, CGND2 are used as

a reference for all other cards contacts.

The sum of ICC1 and ICC2 shall not exceed 80 mA, which

means that when a card is drawing its maximum current

(around 60 mA at VCC = 5 V, 55 mA at VCC = 3 V), the

other card should be set in low power consumption mode

(less than 20 or 25 mA). Note that during the card Advice

to Receive (ATR) process, the current may be maximum;

so, a card should only be activated if the other card draws

less than 20 or 25 mA. The DC-to-DC converter is supplied

via separate supply pins VDDA and AGND to allow

decoupling separate from the other supply pins.

During normal operation or activation, each card is allowed

to draw independently a current of up to 60 mA at

VCC = 5 V or up to 55 mA at VCC = 3 V, with a supply

voltage from 2.7 V up to 6.5 V provided the sum of

ICC1 and ICC2 does not exceed 80 mA.

If VDD > 3 V, for 5 V cards, then both cards can draw up to

60 mA at the same time.

If VDD > 3 V, for 3 V cards, then both cards can draw up to

55 mA at the same time.

I2C-bus

A 400 kHz I2C-bus slave interface is used for configuring

the device and reading the status.

I2C-BUS PROTOCOL

The I2C-bus is for 2-way, 2-line communication between

different ICs or modules. The serial bus consists of two

bidirectional lines; one for data (SDA), and one for the

clock (SCL).

Both the SDA and SCL lines must be connected to a

positive supply voltage via a pull-up resistor.

The following protocol has been defined:

• Data transfer may be initiated only when the bus is not

busy

• During data transfer, the data line must remain stable

whenever the clock line is HIGH. Changes in the data

line while the clock line is HIGH will be interpreted as

control signals.

BUS CONDITIONS

The following bus conditions have been defined:

• Bus not busy: both data and clock lines remain HIGH

• Start data transfer: a change in the state of the data line,

from HIGH-to-LOW, while the clock is HIGH, defines the

START condition

• Stop data transfer: a change in the state of the data line,

from LOW-to-HIGH, while the clock is HIGH, defines the

STOP condition

• Data valid: the state of the data line represents valid

data when, after a START condition, the data line is

stable for the duration of the HIGH period of the clock

signal. There is one clock pulse per data bit.

DATA TRANSFER

Each data transfer is initiated with a START condition and

terminated with a STOP condition.

Data transfer is unlimited in the read mode. The

information is transmitted in bytes and each receiver

acknowledges with a ninth bit.

The TDA8020HL operates in standard mode (100 kHz

clock rate) and fast mode (400 kHz clock rate) defined in

the I2C-bus specification.

By definition, a device that sends a signal is called a

transmitter, and the device which receives the signal is

called a receiver. The device which controls the signal is

2003 Nov 06

8

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