Rainbow-electronics DS8314 Manual de usuario descargar pdf (Pagina 16)

DS8313/DS8314

Smart Card Interface

16 ______________________________________________________________________________________

Applications Information

Performance can be affected by the layout of the appli-

cation. For example, an additional cross-capacitance of

1pF between card reader contacts C2 (RST) and C3

(CLK) or C2 (RST) and C7 (I/O) can cause contact C2

to be polluted with high-frequency noise from C3 (or

C7). In this case, include a 100pF capacitor between

contacts C2 and CGND.

Application recommendations include the following:

• Ensure there is ample ground area around the

DS8313/DS8314 and the connector; place the

DS8313/DS8314 very near to the connector; decou-

ple the V

and V

DDA

lines separately. These lines

are best positioned under the connector.

• The device and the host microcontroller must use

the same V

supply. Pins CLKDIV1, CLKDIV2,

RSTIN, PRES, I/OIN, 5V/3V, 1_8V, CMDVCC, and

OFF are referenced to V

; if pin XTAL1 is to be

driven by an external clock, also reference this pin

to V

• Trace C3 (CLK) should be placed as far as possi-

ble from the other traces.

• The trace connecting CGND to C5 (GND) should

be straight (the two capacitors on C1 (V

) should

be connected to this ground trace).

• Avoid ground loops between CGND and GND.

• Decouple V

DDA

and V

separately. If two sup-

plies are the same in the application, they should

be connected in a star on the main trace

With all these layout precautions, noise should be kept to

an acceptable level and jitter on C3 (CLK) should be less

than 100ps. Reference layouts are available on request.

Technical Support

For technical support, go to https://support.maxim-

ic.com/micro.

Selector Guide

Note: Contact the factory for availability of other variants and package options.

Denotes a lead(Pb)-free/RoHS-compliant package.

Future product—contact factory for availability.

PART

LOW STOP-MODE

POWER

LOW ACTIVE-

MODE POWER

PRES POLARITY V

DDA

INPUTS PIN-PACKAGE

DS8313-RJX+ Yes Yes Positive 2 28 TSSOP

DS8313-RRX+ Yes Yes Positive 2 28 SO

DS8313L-RJX+* Yes Yes Negative 2 28 TSSOP

DS8313L-RRX+* Yes Yes Negative 2 28 SO

DS8314-RJX+* Yes Yes Positive 1 28 TSSOP

DS8314-RRX+* Yes Yes Positive 1 28 SO

DS8314L-RJX+* Yes Yes Negative 1 28 TSSOP

DS8314L-RRX+* Yes Yes Negative 1 28 SO

1 2 ... 11 12 13 14 15 16 17

DS8313/DS8314 1
Smart Card Interface 1

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Rainbow-electronics DS8314 Manual de usuario Pagina 16

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