General description

The TDA8024 is a complete and cost-efficient analog interface for asynchronous 3 V or 5 V smart cards. It can be placed between the card and the microcontroller to perform all supply, protection and control functions. Very few external components are required. The TDA8024AT is a direct replacement for the TDA8004AT.

Features and benefits

■ IC card interface

■ 3 V or 5 V supply for the IC (VDD and GND)

■ Three specifically protected half-duplex bidirectional buffered I/O lines to card contacts C4, C7 and C8

■ DC-to-DC converter for VCC generation separately powered from a 5 V ± 20 supply (VDDP and PGND)

■ 3 V or 5 V ± 5 regulated card supply voltage (VCC) with appropriate decoupling has the following capabilities:

◆ ICC < 80 mA at VDDP = 4 V to 6.5 V

◆ Handles current spikes of 40 nAs up to 20 MHz

◆ Controls rise and fall times

◆ Filtered overload detection at approximately 120 mA

■ Thermal and short-circuit protection on all card contacts

■ Automatic activation and deactivation sequences; initiated by software or by hardware in the event of a short-circuit, card take-off, overheating, VDD or VDDP drop-out

■ Enhanced ESD protection on card side (>6 kV)

■ 26 MHz integrated crystal oscillator

■ Clock generation for cards up to 20 MHz (divided by 1, 2, 4 or 8 through CLKDIV1 and CLKDIV2 signals) with synchronous frequency changes

■ Non-inverted control of RST via pin RSTIN

■ ISO 7816, GSM11.11 and EMV (payment systems) compatibility

■ Supply supervisor for spike-killing during power-on and power-off and Power-on reset (threshold fixed internally or externally by a resistor bridge); not for TDA8024AT

■ Built-in debounce on card presence contacts

■ One multiplexed status signal OFF

Applications

■ IC card readers for banking

■ Electronic payment

■ Identification

■ Pay TV