73S8023C-IM データシートの表示（PDF） - Teridian Semiconductor Corporation

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73S8023C-IM

Smart Card Interface

Teridian Semiconductor Corporation 

73S8023C Data Sheet

DS_8023C_019

6 Power Down

A power down function is provided via the PWRDN pin (active high). When activated, the Power Down

(PD) mode disables all the internal analog functions, including the card analog interface, the oscillators

and the DC-DC converter, to put the 73S8023C in its lowest power consumption mode. PD mode is only

allowed in the deactivated condition (out of a card session, when the CMDVCC signal is driven high from

the host controller).

The host controller invokes the power down state when it is desirable to save power. The signals PRES

and PRES remain functional in PD mode such that a card insertion sets OFF high. The micro-controller

must then set PWRDN low and wait for the internal stabilization time prior to starting any card session

(prior to turning CMDVCC low).

Resumption of the normal mode occurs approximately 10 ms (stabilization of the internal oscillators and

reset of the circuitry) after PWRDN is set low. No card activation should be invoked during this 10 ms

time period. If a card is present, OFF can be used as an indication that the circuit has completed its

recovery from power-down state. OFF will go high at the end of the stabilization period. Should

CMDVCC go low during PWRDN = 1, or within the 10 ms internal stabilization / reset time, it will not be

taken into account and the card interface will remain inactive. Since CMDVCC is taken into account on

its edges, it should be toggled high and low again after the 10 ms to activate a card.

Figure 2 illustrates the sequencing of the PD and Normal modes. PWRDN must be connected to GND if

the power down function is not used.

PRES

OFF

PWRDN

Internal RC OSC

CMDVCC

OFF follows PRES regardless of PWRDN

PWRDN during a card

session has no effect

PWRDN has effect when

the cardi s deactivated

~10ms

After setting PWRDN = 0,

the controller must wait at

least 10ms before setting

CMDVCC=0

EMV / ISO deactivation

time ~= 100 uS

Figure 2: Power Down Mode Operation: CS = high

7 Over-temperature Monitor

A built-in detector monitors die temperature. When an over-temperature condition occurs, a card

deactivation sequence is initiated, and an error or fault condition is reported to the system controller.

10

Rev. 1.5

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