TDA8007B datasheet(21/36 Pages) PHILIPS

21 / 36 page

2000 Nov 09

Philips Semiconductors

Product speciﬁcation

Double multiprotocol IC card interface

TDA8007B

Step-up converter

Except for the VCC generator and the other cards contacts

buffers, the whole circuit is powered by VDD, and VDDA.

If the supply voltage is 2.5 V, then a higher voltage is

needed for the ISO contacts supply. When a card session

is requested by the microcontroller, the sequencer first

enables the step-up converter (a switched capacitors type)

which is clocked by an internal oscillator at a frequency of

approximately 2.5 MHz.

Suppose that VCC is the maximum of VCC1 and VCC2, then

there are four possible situations:

1. VDD = 3 V and VCC = 3 V: in this case the step-up

converter acts as a doubler with a regulation of

approximately 4.0 V.

2. VDD = 3 V and VCC = 5 V: in this case the step-up

converter acts as a tripler with a regulation of

approximately 5.5 V.

3. VDD = 5 V and VCC = 3 V: in this case the step-up

converter acts as a follower: VDD is applied to VUP.

4. VDD = 5 V and VCC = 5 V: in this case the step-up

converter acts as a doubler with a regulation of

approximately 5.5 V.

The recognition of the supply voltage is done by the

TDA8007B at approximately 3.5 V.

The output voltage VUP is fed to the VCC generators. VCC

and GND are used as a reference for all other card

contacts.

ISO 7816 security

The correct sequence during activation and deactivation of

the cards is ensured by two specific sequencers, clocked

by a division ratio of the internal oscillator.

Activation (START bit HIGH in PCR1 or PCR2) is only

possible if the card is present (PRES active HIGH with an

internal current source to GND) and if the supply voltage is

correct (supervisor not active).

The presence of the cards is signalled to the

microcontroller by the Hardware Status Register (HSR).

Bits PR1 or PR2 (in the USR) are set if card 1 or card 2 is

present. PRL1 or PRL2 are set if PR1 or PR2 has toggled.

During a session, the sequencer performs an automatic

emergency deactivation on one card in the event of card

take-off, or short-circuit. Both cards are automatically

deactivated in the event of a supply voltage drop, or

overheating. The hardware status register is updated and

the INT line falls, so that the system microcontroller is

aware of what happened.

Activation sequence

When the cards are inactive, VCC, CLK, RST, C4, C8

and I/O are LOW, with low-impedance with respect to

GND. The step-up converter is stopped.

When everything is satisfactory (voltage supply, card

present and no hardware problems), the system

microcontroller may initiate an activation sequence on a

present card.

After selecting the card and leaving the UART reset mode,

and then configuring the necessary parameters for the

counters and the UART, the START bit can be set within

the PCR (t0) (see Fig.8):

• The step-up converter is started (t1); if one card was

already active, then the step-up converter was already

on and nothing more occurs at this step

• VCC starts rising (t2) from 0 to 5 V or 3 V with a

controlled rise time of 0.17 V/

µs (typ.)

• I/O rises to VCC (t3); C4 and C8 also rise if bits

C4 and C8 within the PCR have been set to logic 1

(integrated 10 k

Ω pull-up resistors to VCC)

• The CLK is sent to the card and RST is enabled (t4).

After a number of CLK pulses that can be counted with the

time-out counter, bit RSTIN may be set by software: RST

will then rise to VCC.

The sequencer is clocked by 1

⁄64fint which leads to a time

interval of t = 25

µs (typ.). Thus t1 =0to 1⁄64t, t2 =t1 + 3⁄2t,

t3 =t1 + 7⁄2t and t4 =t1 + 4t.

Deactivation sequence

When the session is completed, the microcontroller resets

START HIGH (t10). The circuit then executes an automatic

deactivation sequence (see Fig.9):

• The card is reset (RST falls LOW) (t11)

• The CLK is stopped (t12)

• I/O, C4 and C8 fall to 0 V (t13)

• VCC falls to 0 V with typical 0.17 V/µs slew rate (t14)

• The step-up converter is stopped and CLK, RST, VCC

and I/O become low-impedance to GND (t15) (if both

cards are inactive).

t11 =t10 + 1⁄64t, t12 =t11 + 1⁄2t, t13 =t11 +t,t14 =t11 + 3⁄2t

and t15 =t11 + 7⁄2t.

tde = time that VCC needs to decrease to less than 0.4 V.

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