DS8005 データシートの表示（PDF） - Maxim Integrated

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DS8005

Smart Card Interface

Maxim Integrated 

DS8005

Smart Card Interface

1_8V

5V/3V

VDDA

VDDA2

CLKDIV1

CLKDIV2

XTAL1

XTAL2

RSTIN

I/OIN

SEL_AB

CMDVCC

OFF

OFF2

REGULATOR

CLOCK

GENERATION

I/O

XCVR

CONTROL QSEL_AB

SEQUENCER

QSEL_AB

INTERRUPT

GENERATION

FAULT

DETECTION

CARD

INTERFACE A

CARD

INTERFACE B

DS8005

POWER

SUPPLY

CGND

I/OA

VCCA

RSTA

CLKA

PRESA

I/OB

VCCB

RSTB

CLKB

PRESB

VDD

GND

Figure 1. Functional Diagram

Detailed Description

The DS8005 is an analog front-end for communicat-

ing with 1.8V, 3V, and 5V dual smart cards. It is a dual

input-voltage device, requiring one supply to match that

of a host microcontroller and a separate +5V supply for

generating correct smart card supply voltages. The device

translates all communication lines to the correct voltage

level and provides power for smart card operation. It

is a low-power device, consuming very little current in

active-mode operation (during a smart card communica-

tion session), and is suitable for use in battery-powered

devices such as laptops and PDAs, consuming only 10nA

in stop mode. The device is designed for applications that

do not require communication using the C4 and C8 card

contacts (AUX1 and AUX2). It is suitable for SIM/SAM

interfacing, as well as for applications where only the I/O

line is used to communicate with a smart card.

Power Supply

The device has dual supplies. The supply pins for the

device are VDD, GND, and VDDA. VDD should be in the

2.7V to 6.0V range, and is the supply for signals that inter-

face with the host controller. It should, therefore, be the

same supply as used by the host controller. All smart card

contacts remain inactive during power-on or power-off.

The internal circuits are kept in the reset state until VDD

reaches VTH2 + VHYS2 and for the duration of the inter-

nal power-on reset pulse, tW. A deactivation sequence is

executed when VDD falls below VTH2.

An internal regulator generates the 1.8V, 3V, or 5V card

supply voltage (VCC_). The regulator should be supplied

separately by VDDA. VDDA should be connected to a

minimum 4.75V supply to provide the correct supply volt-

age for 5V smart cards.

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