TDA8023 Datasheet, PDF(6/32 Page) NXP Semiconductors

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TDA8023 Datasheet, PDF (6/32 Pages) NXP Semiconductors – Low power IC card interface

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NXP Semiconductors

TDA8023

Low power IC card interface

8. Functional description

Remark: Throughout this document, it is assumed that the reader is familiar with

ISO 7816 and EMV 2000 terminology.

8.1 Power supplies

The supply pins for the TDA8023 are VDD and GND. VDD should be in the range from

2.7 V to 6.5 V. The supply voltages VDD, VDD(INTF) and VDD(DCDC) may be applied to the

TDA8023 in any time sequence.

All interface signals with the system controller are referenced to a separate supply voltage

VDD(INTF) on pin VDDI, that may be lower or higher than VDD.

For generating a supply voltage VCC of 5 V Â± 5 % or 3 V Â± 5 % used by the card, an

integrated DC-to-DC converter is incorporated. This DC-to-DC converter should be

separately supplied by VDD(DCDC) on pin VDDP and GNDP (from 2.7 V to 6.5 V).

The I2C-bus signals SDA and SCL may be externally referenced to a voltage higher than

VDD.

8.2 Voltage supervisor

8.2.1 Without external divider on pin PORADJ

The voltage supervisor surveys the VDD supply voltage. It is used as Power-On Reset

(POR) and as supply dropout detection during a card session. Supply dropout detection

ensures that a proper deactivation sequence is followed before the voltage is too low. A

reset pulse of duration tW (see Figure 4) is used internally for maintaining the TDA8023 in

the Inactive mode during powering up or powering down of VDD.

As long as VDD is less than Vth(POR)H the TDA8023 will remain inactive whatever the levels

on the command lines are. This also lasts for the duration of tW after VDD has reached a

level higher than Vth(POR)H. When VDD falls below Vth(POR)L an automatic deactivation

sequence of the contacts is performed.

In this case (no external resistor bridge) it is mandatory to connect pin PORADJ to GND.

TDA8023_1

Product data sheet

power on

VDD

shutdown mode

status read

INT

SDWN

bus unresponsive

Fig 4. Voltage supervisor and Shutdown mode

Rev. 01 â 16 July 2007

power off

Vth(POR)H

Vth(POR)L

Vhys(POR)

bus unresponsive

001aag339

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