Datasheet

TDA8034T_TDA8034AT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 3.1 — 13 December 2012 5 of 30
NXP Semiconductors
TDA8034T; TDA8034AT
Smart card interface
[5] Uses an internal 20 k pull-up resistor connected to pin V
DD(INTF)
.
[6] Uses an internal 10 k pull-up resistor connected to pin V
DD(INTF)
.
8. Functional description
Remark: Throughout this document the ISO 7816 terminology conventions have been
adhered to and it is assumed that the reader is familiar with these.
8.1 Power supplies
The power supply voltage ranges are as follows:
• V
DDP
: 4.85 V to 5.5 V
• V
DD
: 2.7 V to 3.6 V
V
DD
should rise prior to V
DDP
or at the same time. V
DDP
should not rise before V
DD
.
All interface signals to the system controller are referenced to V
DD(INTF)
. All card contacts
remain inactive during power up or power down. After powering up the device, pin OFFN
remains LOW until pin CMDVCCN is set HIGH and pin PRESN is LOW. During power
down, pin OFFN goes LOW when V
DDP
falls below the falling threshold voltage (V
th
).
The internal oscillator frequency (f
osc(int)
) is only used during the activation sequences.
When the card is not activated (pin CMDVCCN is HIGH), the internal oscillator is in low
frequency mode to reduce power consumption.
This device has a Low Drop-Off (LDO) voltage regulator connected to pin V
CC
, and is
used instead of a DC-to-DC converter. It ensures a minimum V
CC
of 4.75 V and that the
power supply voltage on pin V
DDP
does not fall below 4.85 V for a maximum load current
of 65 mA.