IMIC9835 Ver la hoja de datos (PDF) - Cypress Semiconductor

Número de pieza

componentes Descripción

Lista de partido

IMIC9835

Low-EMI Clock Generator for Intel® Mobile 133-MHz/3 SO-DIMM Chipset Systems

Cypress Semiconductor 

Test Measurement Condition

Output under Test

Probe

Load Cap

C9835

3.3V signals

tDC

-

-

3.3V

2.4V

1.5V

2.5V signals

tDC

-

-

2.0V

1.25V

2.5V

0.4V

0.4V

0V

0V

Tr

Tf

Table 12. Suggested Oscillator Crystal Parameters

Parameter

Description

Fo

Frequency

Figure 8.

Conditions

Tr

Tf

Min.

Typ.

14.17 14.31818

Max.

14.46

Units

MHz

TC

TS

CXTAL

RESR

Tolerance

Frequency Stability

Operating Mode

Load Capacitance

Effective Series Resistance (ESR)

Note 35

Stability (TA – 10 to +60C)[35]

Parallel Resonant[35]

The crystal’s rated load[35]

Note 36

±100

±100

PPM

PPM

20

pF

40

Ohms

To obtain the maximum accuracy, the total circuit loading

capacitance should be equal to CXTAL. This loading capaci-

tance is the effective capacitance across the crystal pins and

includes the clock generating device pin capacitance (CFTG),

any circuit trace capacitance (CPCB) and any onboard discrete

load capacitance (CDISC).

The following formula and schematic illustrates the application

of the loading specification of a crystal (CXTAL) for a design.

CL = (CXINPCB + CXINFTG + CXINDISC) X (CXOUTPCB + CXOUTFTG + CXOUTDISC)

Where:

CXTAL = the load rating of the crystal.

CXOUTFTG ....= the clock generators XIN pin effective device

internal capacitance to ground.

CXOUTFTG = the clock generators XOUT pin effective device

internal capacitance to ground.

CXINPCB = the effective capacitance to ground of the crystal

to device PCB trace.

As an example and using a formula for this datasheet’s device,

CXOUTPCB = the effective capacitance to ground of the crystal

to device PCB trace.

a design that has no disrete loading capacitors (CDISC) and

each of the crystal to device PCB traces has a capacitance

(CPCB) to ground of 4pF (typical value) would calculate as:

Notes:

CXINDISC = any discrete capacitance that is placed between

the XIN pin and ground.

CXOUTDISC= any discrete capacitance that is placed between

the XOUT pin and ground.

35. For best performance and accurate frequencies from this device, it is recommended but not mandatory that the chosen crystal meets or exceeds these

specifications.

36. Larger values may cause this device to to exhibit oscillator startup problems.

Document #: 38-07303 Rev. **

Page 15 of 18

Share Link: