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CDCE937-Q1, CDCEL937-Q1

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SCAS892C – FEBRUARY 2010 – REVISED DECEMBER 2016

Product Folder Links: CDCE937-Q1 CDCEL937-Q1

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Copyright © 2010–2016, Texas Instruments Incorporated

(1)

Center/Down-Spread, Frequency0/1 and State0/1 are user-definable in PLLx Configuration Register;

(2)

Frequency0 and Frequency1 can be any frequency within the specified fVCO range.

(3)

State0/1 selection is valid for both outputs of the corresponding PLL module and can be power down,

3-state, low or active

Table 2. PLLx Setting (Can Be Selected For Each PLL Individual)(1)

SSC SELECTION (CENTER/DOWN)

SSCx [3-BITS]

CENTER

DOWN

0

0

0

0% (off)

0% (off)

0

0

1

±0.25%

–0.25%

0

1

0

±0.5%

–0.5%

0

1

1

±0.75%

–0.75%

1

0

0

±1.0%

–1.0%

1

0

1

±1.25%

–1.25%

1

1

0

±1.5%

–1.5%

1

1

1

±2.0%

–2.0%

FREQUENCY SELECTION(2)

FSx

FUNCTION

0

Frequency0

1

Frequency1

OUTPUT SELECTION(3) (Y2 ... Y7)

YxYx

FUNCTION

0

State0

1

State1

(1)

State0 and State1 are user definable in Generic Configuration

Register and can be power down, 3-state, low, or active.

Table 3. Y1 Setting(1)

Y1 SELECTION

Y1

FUNCTION

0

State 0

1

State 1

S1/SDA and S2/SCL pins of the CDCEx937-Q1 are dual function pins. In default configuration they are defined

as SDA and SCL for the serial interface. They can be programmed as control-pins (S1/S2) by setting the relevant

bits in the EEPROM. Note that the changes to the Control register (Bit [6] of Byte [02]) have no effect until they

are written into the EEPROM.

Once they are set as control pins, the serial programming interface is no longer available. However, if VDDOUT is

forced to GND, the two control-pins, S1 and S2, temporally act as serial programming pins (SDA and SCL).

S0 is not a multi-use pin, it is a control pin only.

10.3.2 Default Device Setting

The internal EEPROM of CDCEx937-Q1 is preconfigured as shown in Figure 6. The input frequency is passed

through to the output as a default. This allows the device to operate in default mode without the extra production

step of program it. The default setting appears after power is supplied or after power-down or power-up

sequence until it is re-programmed by the user to a different application configuration. A new register setting is

programmed through the serial SDA and SCL interface.