ST8034T datasheet(30/39 Pages) STMICROELECTRONICS

No. de pieza	ST8034T

Descripción Electrónicos	16-pin smartcard interfaces

PDF	39 Pages

Scroll/Zoom	100%

Fabricante Electrónico	STMICROELECTRONICS [STMicroelectronics]

Página de inicio	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)

ST8034T Datasheet(PDF) 30 Page - STMicroelectronics