ST8034AT datasheet(30/39 Pages) STMICROELECTRONICS

Teilenummer	ST8034AT

Bauteilbeschribung	16-pin smartcard interfaces

PDF	39 Pages

Scroll/Zoom	100%

Hersteller	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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30 / 39 page

DocID024587 Rev 4

31/40

ST8034T, ST8034AT, ST8034P, ST8034C

Functional description

6.10

Card supply voltage (VCC) selection

6.10.1

Automatic determining of card supply voltage (VCC) - all versions

except ST8034P

The supply voltage (VCC) that the card requires is determined automatically by monitoring

the duration of the high state on the CMDVCC pin before the activation command CMDVCC

falling edge occurs. If the CMDVCC pin stays high for more than 30 ms (tW_VCC), the

activation is done with VCC = 5 V. If the CMDVCC pin stays high for less than 15 ms, the

activation is done with VCC = 3 V.

To activate the card at VCC = 5 V, the CMDVCC pin must stay high for tW_VCC > 30 ms

before going low:

Figure 16. Card activation to VCC = 5 V (tW_VCC > 30 ms)

To activate the card at VCC = 3 V, the CMDVCC pin must stay high for tW_VCC < 15 ms

before going low:

Figure 17. Card activation to VCC = 3 V (tW_VCC < 15 ms)

ST8034AT Datenblatt(PDF) 30 Page - STMicroelectronics