DATA SHEET • CX74038

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

101075I • Skyworks Proprietary and Confidential information • Products and product information are subject to change without notice • January 31, 2005

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Table 5. CX74038 Register Descriptions (1 of 2)

Symbol

Function

Description

Register Word Address 00

Address bits [1:0]

00

SC2

IF synthesizer charge-pump output current

[3:2]

Bits [3:2] select the IF synthesizer charge pump output current:

bit 3

bit 2

0

0

Selects 0.4 mA charge pump output current

0

1

Selects 0.8 mA charge pump output current

1

0

Selects 1.2 mA charge pump output current

1

1

Selects 1.6 mA charge pump output current

LD

Test mode [6:4]

Bits [6:4] set the test mode:

bit 6

bit 5 bit 4

0

0

0

multiplexes Ndiv output of IF SX to LD output

0

0

1

multiplexes Rdiv output of IF SX to LD output

0

1

0

multiplexes lock detect output of IF SX to LD output

0

1

1

multiplexes ANDed lock detect of both SX to LD output

1

0

0

multiplexes Ndiv output of RF SX to LD output

1

0

1

multiplexes Rdiv output of RF SX to LD output

1

1

0

multiplexes lock detect output of RF SX to LD output

1

1

1

Hi-Zs the charge-pump output of RF SX

R2

IF synthesizer reference divider [19:7]

Bits [19:7] set the IF synthesizer 13-bit reference divider ratio

RF synthesizer fractional-N mode selection

[21:20] (Note 1)

Bits [21:20] set the RF synthesizer fractional-N mode:

bit 21 bit 20

0

0

Reserved

0

1

Reserved

1

0

Fractional-N mode with dithering

1

1

Fractional-N mode without dithering

Register Word Address 01

Address bits [1:0]

01

SP1

RF synthesizer phase detector output

polarity [2]

Bit [2] sets the polarity of the RF synthesizer phase detector output:

0 Sets phase detector output for negative VCO gain

1 Sets phase detector output for positive VCO gain

SC1

RF synthesizer charge-pump output current

[4:3]

Bits [4:3] set the RF synthesizer charge pump output current:

bit 4

bit 3

0

0

Selects 120

µA charge pump output current

0

1

Selects 240

µA charge pump output current

1

0

Selects 360

µA charge pump output current

1

1

Selects 480

µA charge pump output current

PS

RF synthesizer prescaler selection [5]

Bit [5] selects the RF synthesizer prescaler:

0 Select 8/9 prescaler

1 Select 16/17 prescaler

R1

RF synthesizer reference divider [8:6]

Bits [8:6] set the RF synthesizer’s 3-bit reference divider ratio

ME

RF synthesizer modulo extender [21:9]

Bits [21:9] extend the RF synthesizer’s fractional modulo up to 2,097,152 (optional)