TDA8023 datasheet(13/32 Pages) NXP

13 / 32 page

TDA8023_1

Product data sheet

Rev. 01 — 16 July 2007

13 of 32

NXP Semiconductors

TDA8023

Low power IC card interface

• Doubler:

– If VCC = 5 V and VDD(DCDC) = 4 V to 5.8 V

– If VCC = 3 V and VDD(DCDC) < 4 V

• Tripler:

– If VCC = 5 V and VDD(DCDC) < 4 V

8.4.2 Inductive conﬁguration

The external components are a diode, a coil of 6.8

µH and a capacitor of 4.7 µF (see

Figure 2). In this conﬁguration the DC-to-DC converter acts as follows.

• If VCC = 5 V then VVUP is regulated at 5.5 V

• If VCC = 3 V then VVUP is regulated at 4 V

• If VCC = 1.8 V then the DC-to-DC converter acts as a follower

8.5 VCC buffer

In all modes (follower, doubler, tripler), the DC-to-DC converter is able to deliver 60 mA

over the whole VDD range (2.7 V to 6.5 V) or 90 mA if VDD > 3 V.

The current on the VCC buffer has an internal limitation of around 90 mA. When this limit is

reached, an automatic deactivation sequence is performed.

The VCC voltage should be decoupled with a low-ESR capacitor between 100 nF and

168 nF. If the card socket is not very close to the TDA8023, one capacitor should be

placed near the TDA8023, and a second one near the card contacts.

8.6 Sequencer and clock counter

The sequencer takes care of ensuring activation and deactivation sequences according to

ISO 7816 and EMV 2000, even in case of emergency (card removal during transaction,

supply dropout or hardware problem).

The sequencer is clocked with an internal oscillator.

The activation of a card is initiated by setting bit START in the Command register, which is

only possible if the card is present and if the voltage supervisor is not active. The

activation sequence is described in Section 8.6.1.

The deactivation is initiated either by the system controller or automatically in case of a

hardware problem or a supply dropout. The deactivation sequence is described in

Section 8.6.2.

Outside a session, card contacts are forced low-impedance with respect to pin GNDC.

8.6.1 Activation sequence

When the card is inactive, pins VCC, CLK, RST and I/O are LOW, which is low-impedance

with respect to pin GNDC. The DC-to-DC converter is stopped.

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