DAC39RF10 datasheet(206/232 Pages) TI2

206 / 232 page

An alternative is to use dividers and mixers to translate the APLL output to a new higher frequency. Figure 9-11

shows an example for a 10GHz clock synthesizer. This uses the same reference multiplier chain and APLL as

described above and adds a mixing stage to translate the DAC clock from 8 to 10GHz.

LMX1204

EP2C+

CMD275P4

MDB-24H+

PMA2-183LN+

10 GHz

1 GHz

Ref In

DRO

-2V

THS4031

SIM-153LH+

EP2C+

PMA2-183LN+

To DAC

Clock

Distribution

Reference Multiplier

8 GHz Analog PLL

8 to 10 GHz Mixing Stage

Figure 9-11. 10GHz Clock Synthesizer

The LMX1204 can operate as a buffer, multiplier or divider. In this case the LMX1204 is used to divide the

8GHz APLL output by 4, which is then mixed with the input to translate the clock to 10GHz. A bandpass filter

is required after mixing to remove the LO feedthrough and undesirable mixing products. Figure 9-12 shows the

input 8GHz scaled to 10GHz and resulting 10GHz after mixing.

As with the reference multiplier chain, special care must be taken selecting the components and operating points

for best phase noise. A slight improvement in noise floor was found by power combining two the of the LMX1204

outputs before feeding the IF input of the mixer.

Offset Frequency (Hz)

102

103

104

105

106

107

108

-170

-160

-150

-140

-130

-120

-110

-100

10 GHz Clock

8 GHz Clock (scaled to 10 GHz)

Figure 9-12. 8GHz and 10GHz Clock Phase Noise

9.2.5 Application Curves

The radar chip waveform used for testing is a non-linear frequency modulated (NLFM) pulse, lasting 4096

samples at the 250MSPS complex input rate. At baseband, the frequency ramps from -100MHz to + 100MHz,

following a frequency ramp curve developed by Price and shown in Equation 6 [Price R. Chebyshev Low Pulse

Compression Sidelobes via a Nonlinear FM. National Radio Science Meeting of URSI; PortSaid, Egypt: 1979.]

with T = 4096 samples, B = 0.8, Bl = 0.5611 and Bc = 0.238.

ff,Bl, Bc =B×t−T2T× Bl+ Bc

1−4t−T22T2

(6)

DAC39RF10-SP, DAC39RF10-SEP

DAC39RFS10-SP, DAC39RFS10-SEP

SBAS932A – MARCH 2024 – REVISED FEBRUARY 2026

www.ti.com

206

Submit Document Feedback

Product Folder Links: DAC39RF10-SP DAC39RF10-SEP DAC39RFS10-SP DAC39RFS10-SEP

DAC39RF10 Datasheet(PDF) 206 Page - Texas Instruments

DAC39RF10 Datasheet(HTML) 206 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL