![Page 1: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/1.jpg)
RF PLLs and Synthesizers: Key Parameters and SpecificationsTI Precision Labs – Clocks and Timing
Presented by Liam Keese
Prepared by Noel Fung
1
![Page 2: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/2.jpg)
Phase lock loop (PLL) overview
2
![Page 3: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/3.jpg)
Phase lock loop (PLL) overview
• Carefully design loop filter to meet phase noise, lock time and spurs requirement
• Key parameters and specifications for a design– Phase detector frequency
– Charge pump current
– VCO gain
– PLL and VCO noise
– Spurs
– Lock time
• Design tools– Clock Architect
– PLLatinum Sim
3
![Page 4: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/4.jpg)
PLL – Flicker noise and FOM
• Normalized PLL 1/f noise (Flicker noise)– Usually dominates at offset below 1 kHz
– Typical value better than -120 dBc/Hz
• Normalized PLL noise floor (FOM)– Determines phase noise at mid-range
offset
– Typical value better than -230 dBc/Hz
4
Offset (Hz)P
has
e n
ois
e (
dB
c/H
z)
-160
-140
-120
-100
-80
100 1k 10k 100k 1M 10M 100M
PLL FlickerPLL Flat
![Page 5: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/5.jpg)
PLL – N Divider noise
• Normalized PLL 1/f noise (Flicker noise)– Usually dominates at offset below 1 kHz
• Normalized PLL noise floor (FOM)– Determines phase noise at mid-range
offset
• N-counter– Added noise = 20log(N)
– e.g. added noise = 40 dB for N = 100
5
Offset (Hz)P
has
e n
ois
e (
dB
c/H
z)
-160
-140
-120
-100
-80
100 1k 10k 100k 1M 10M 100M
PLL FlickerPLL Flat + N
![Page 6: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/6.jpg)
PLL – Total PLL noise (in-band noise)
• Normalized PLL 1/f noise (Flicker noise)– Usually dominates at offset below 1 kHz
• Normalized PLL noise floor (FOM)– Determines phase noise at mid-range
offset
• N-counter– Added noise = 20log(N)
• Total noise determines PLL in-band noise
6
Offset (Hz)P
has
e n
ois
e (
dB
c/H
z)
-160
-140
-120
-100
-80
100 1k 10k 100k 1M 10M 100M
PLL FlickerPLL Flat + NTotal PLL Noise
![Page 7: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/7.jpg)
Phase detector frequency, fPD
• fPD = Reference clock frequency / R
• Rising edge of R-divider signal triggers phase comparison
• Max. fPD is usually less than 300 MHz
7
R
N
1 / fPD
time
![Page 8: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/8.jpg)
Charge pump current
• Constant current source
• Turn-on time is variable
• Current is configurable– 100 µA to a few mA per step
8
R
N
time
Current
![Page 9: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/9.jpg)
VCO gain, Kvco
• Use a varactor diode to change the oscillator frequency
• Tuning range is limited
• KVCO
– Changes in frequency against Vtune
– Varies across the whole VCO tuning range
– A few MHz/V to more than a 100 MHz/V
9
Vcc
Vtune
Load
A typical Colpitts oscillator
![Page 10: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/10.jpg)
VCO phase noise
• Determines closed-loop far-out phase noise
10
Poor phase noise
Good phase noise
![Page 11: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/11.jpg)
VCO phase noise
• Determines closed-loop far-out phase noise
• Phase noise– SSB power difference between the
carrier and an offset, normalized in 1 Hz
– Expressed in xx dBc/Hz@ yy Hz offset
– Carrier frequency specific
11
SSB
Offset
Pow
er
diffe
ren
ce
-121 dBc/Hz @ 100 kHz offset at 2.1 GHz carrier
![Page 12: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/12.jpg)
Spurs
• Phase detector spurs– Offset = fPD
• Fractional spurs– Offset = Nfrac x fPD
• Sub-fractional spurs– ½, ¼ of fractional spurs
• Crosstalk spurs– Crosstalk between
• Phase detector and VCO– Integer Boundary Spurs (IBS)
• Phase detector and output• Reference clock and output• Reference clock and VCO
12
Spurs
![Page 13: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/13.jpg)
Lock time
• Lock time is how long it takes to change one frequency to another and get within a certain frequency tolerance
• Wide loop bandwidth reduces lock time
• Lock time 4 / loop bandwidth
13
Time (s)F
req
uen
cy
(MH
z)-20 0 20 40 60 80 100
450
500
550
600
650
Loop bandwidth60 kHz40 kHz20k Hz
![Page 14: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/14.jpg)
Applying key parameters and specifications
14
![Page 15: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/15.jpg)
Phase detector frequency
15
fPD determines N-divider value
![Page 16: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/16.jpg)
Charge pump current
16
Charge pump gain
![Page 17: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/17.jpg)
VCO gain
17
VCO gain
![Page 18: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/18.jpg)
VCO phase noise
18
VCO noise
![Page 19: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/19.jpg)
PLL noise
19
PLL noise
![Page 20: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/20.jpg)
To find more technical resources and search products, visit ti.com/clocks
20
![Page 21: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/21.jpg)
Quiz
• True or false: VCO phase noise determines closed-loop close-in phase noise
• True or false: N-divider will increase PLL noise by 20log(N)
• True or false: Phase detector is triggered by the rising edge of the N-divider signal
• True or false: Turn-on time of the charge pump is proportional to the phase difference between the signals from R-divider and N-divider
• True or false: Phase detector spur frequency is not predictable
21
![Page 22: 3KDVH ORFN ORRS 3// RYHUYLHZ - TI Training...3UHVHQWHG E\ /LDP .HHVH 3UHSDUHG E\ 1RHO )XQJ 3KDVH ORFN ORRS 3// RYHUYLHZ 3KDVH ORFN ORRS 3// RYHUYLHZ &DUHIXOO\ GHVLJQ ORRS …](https://reader036.vdocuments.net/reader036/viewer/2022071506/61269b133e01df110d2eaac1/html5/thumbnails/22.jpg)
Quiz
• True or false: VCO phase noise determines closed-loop close-in phase noise
• True or false: N-divider will increase PLL noise by 20log(N)
• True or false: Phase detector is triggered by the rising edge of the N-divider signal
• True or false: Turn-on time of the charge pump is proportional to the phase difference between the signals from R-divider and N-divider
• True or false: Phase detector spur frequency is not predictable
22