ST8034C datasheet(21/39 Pages) STMICROELECTRONICS

21 / 39 page

Functional description

ST8034T, ST8034AT, ST8034P, ST8034C

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DocID024587 Rev 4

Functional description

Throughout this document it is assumed that the reader is familiar with ISO7816

terminology.

6.1

Power supplies

All interface signals to the host microcontroller are referenced to VDD(INTF). All card contacts

remain inactive during power-up or power-down. After powering-up the device, OFF output

remains low until CMDVCC input is set high and PRES input is low. During power-down,

OFF output goes low when VDDP falls below the VDDP falling threshold voltage. The internal

oscillator clock frequency fOSC(INT) is used only during the activation sequence. When the

card is not activated (CMDVCC input is high), the internal oscillator is in low frequency

mode to reduce power consumption.

Power-on sequence: supply voltages may be applied to the ST8034 in any sequence.

6.2

Voltage supervisor

6.2.1

Voltage supervisor ST8034T and ST8034AT

Figure 8. Voltage supervisor - ST8034T and ST8034AT

ST8034C Datasheet(PDF) 21 Page - STMicroelectronics