TDA8034T(2010) データシートの表示（PDF） - NXP Semiconductors.

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TDA8034T
(Rev.:2010)

Smart card interface

NXP Semiconductors. 

NXP Semiconductors

TDA8034T; TDA8034AT

Smart card interface

The voltage supervisor monitors the voltage of the VDDP and VDD supplies providing both

Power-On Reset (POR) and supply drop-out detection during a card session. The

supervisor threshold voltages for VDDP and VDD are set internally. As long as VDD is less

than Vth + Vhys, the IC remains inactive irrespective of the command line levels. After VDD

has reached a level higher than Vth + Vhys, the IC remains inactive for the duration of tw.

The output of the supervisor is sent to a digital controller in order to reset the

TDA8034T/TDA8034AT. This defined reset pulse of approximately 8 ms, i.e. (tw = 1024 ×

1∨fosc(int)low), is used internally to maintain the IC in the Shutdown mode during the supply

voltage power on; see Figure 4. A deactivation sequence is performed when either VDD or

VDDP falls below Vth.

Remark: fosc(int)low is the low frequency (or inactive) mode of the defined fosc(int)

parameter.

Vth + Vhys

Vth

VDD

ALARMN

(internal signal)

tw

power on

Fig 4. Voltage supervisor waveforms

tw

supply dropout

power off

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8.3 Clock circuits

The clock signal from pin CLK to the card is either supplied by an external clock signal

connected to pin XTAL1 or generated using a crystal connected between pins XTAL1 and

XTAL2. The TDA8034T/TDA8034AT automatically detects if an external clock is

connected to XTAL1, eliminating the need for a separate pin to select the clock source.

Automatic clock source detection is performed on each activation command (falling edge

of the signal on pin CMDVCCN). The presence of an external clock on pin XTAL1 is

checked during a time window defined by the internal oscillator. If a clock is detected, the

internal crystal oscillator is stopped. If a clock is not detected, the internal crystal oscillator

is started. When an external clock is used, it is mandatory that the clock is applied to pin

XTAL1 before the falling edge of the signal on pin CMDVCCN.

TDA8034T_TDA8034AT

Product data sheet

All information provided in this document is subject to legal disclaimers.

Rev. 2.0. — 12 November 2010

© NXP B.V. 2010. All rights reserved.

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