SKY74038 Datasheet, PDF (9/12 Pages) Skyworks Solutions Inc. – 2.6 GHz/800 MHz Dual Fractional-N/lnteger-N Frequency Synthesizer

DATA SHEET • SKY74038 FREQUENCY SYNTHESIZER
Table 5. SKY74038 Register Descriptions (1 of 2)
Symbol
Function
Register Word Address 00b
Address bits [1:0]
SC2
IF synthesizer charge-pump output current
[3:2]
LD
Test mode [6:4]
R2
IF synthesizer reference divider [19:7]
RF synthesizer fractional-N mode selection
[21:20] (Note 1)
Register Word Address 01b
Address bits [1:0]
SP1
RF synthesizer phase detector output
polarity [2]
SC1
RF synthesizer charge-pump output current
[4:3]
PS
RF synthesizer prescaler selection [5]
R1
RF synthesizer reference divider [8:6]
ME
RF synthesizer modulo extender [21:9]
Description
00b
Bits [3:2] select the IF synthesizer charge pump output current:
bit 3 bit 2
0 0 Select 0.4 mA charge pump output current
0 1 Select 0.8 mA charge pump output current
1 0 Select 1.2 mA charge pump output current
1 1 Select 1.6 mA charge pump output current
Bits [6:4] set the test mode:
bit 6 bit 5 bit 4
0 0 0 Multiplex Ndiv output of IF SX to LD output
0 0 1 Multiplex Rdiv output of IF SX to LD output
0 1 0 Multiplex lock detect output of IF SX to LD output
0 1 1 Multiplex ANDed lock detect of both SX to LD output
1 0 0 Multiplex Ndiv output of RF SX to LD output
1 0 1 Multiplex Rdiv output of RF SX to LD output
1 1 0 Multiplex lock detect output of RF SX to LD output
1 1 1 Hi-Z the charge pump output of RF SX
Bits [19:7] set the IF synthesizer 13-bit reference divider ratio
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
01b
Bit [2] sets the polarity of the RF synthesizer phase detector output:
0 = Set phase detector output for negative VCO gain
1 = Set phase detector output for positive VCO gain
Bits [4:3] set the RF synthesizer charge pump output current:
bit 4 bit 3
0 0 Select 120 µA charge pump output current
0 1 Select 240 µA charge pump output current
1 0 Select 360 µA charge pump output current
1 1 Select 480 µA charge pump output current
Bit [5] selects the RF synthesizer prescaler:
0 = Select 8/9 prescaler
1 = Select 16/17 prescaler
Bits [8:6] set the RF synthesizer’s three-bit reference divider ratio
Bits [21:9] extend the RF synthesizer’s fractional modulo up to 2,097,152 (optional)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
101075M • Skyworks Proprietary and Confidential information • Products and Product Information are Subject to Change Without Notice • June 4, 2007
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