TDA8034T Datasheet, PDF (5/29 Pages) NXP Semiconductors – Smart card interface

NXP Semiconductors
TDA8034T; TDA8034AT
Smart card interface
[5] Uses an internal 20 kΩ pull-up resistor connected to pin V_DD(INTF).
[6] Uses an internal 10 kΩ 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
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.
8.2 Voltage supervisor
V_DD(INTF)
V_DD
V_DD
REFERENCE
VOLTAGE
V_DDP
5 V or 3 V
TDA8034T_TDA8034AT
Product data sheet
Fig 3. Voltage supervisor circuit
All information provided in this document is subject to legal disclaimers.
Rev. 2.0. — 12 November 2010
001aak991
© NXP B.V. 2010. All rights reserved.
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