esp32 SI5351A controller

easy SI5351A CLOCK GENERATOR setup

Mouse and swipe friendly.

CLK 0 ON

1 MHz FREQUENCY	2 mA OUTPUT DRIVE	OFF INVERT
A PLL	0 deg. PHASE DELAY

Frequency calculations

The output frequency can be calculated with the following 2 formula's:

With formula 1 we can set the internal VCO frequency between 600 and 900 MHz. With formula 2 we set the output frequency. The table below shows the calculated values:

Output frequency (Fout)=			.. MHz
Input clock frequency (Fclk_in)=			.. MHz
a1=		a2=
b1=		b2=
c1=		c2=
a1+b1/c1=		a2+b2/c2=

..	.		.
..	.	..	.
..	.	..	.
..	.	..	.

Once we have calculated the above values we can then fill the registers of the SI5351a according to the datasheet and application note 619

Spread Spectrum calculations

The output frequency can be calculated with the following 2 formula's:

With formula 1 we can set the internal VCO frequency between 600 and 900 MHz. With formula 2 we set the output frequency. The table below shows the calculated values:

spread spectrum amplitude= 1.5%
SSUDP=		SSUP=		SSDN=

Once we have calculated the above values we can then fill the registers of the SI5351a according to the datasheet and application note 619

The output frequency can be calculated with the following 2 formula's:

Reg. nr.	Value			Function
	Dec.	Hex.	Binary
3				Output enable control
15				PLL input source: xtal or ClkIn
16				CLK0 control
17				CLK1 control
18				CLK2 control
22				Integer/Fractional mode selection PLL A loop
23				Integer/Fractional mode selection PLL B loop
26				PLL A, VCO A setting
27
28
29
30
31
32
33
34				PLL B, VCO B setting
35
36
37
38
39
40
41
42				CLK0 divider
43
44
45
46
47
48
49
50				CLK1 divider
51
52
53
54
55
56
57
58				CLK2 divider
59
60
61
62
63
64
65
149				Spread spectrum settings
150
151
152
153
154
155
156
157
158
159
160
161
149				CLK 0 phase
166				CLK 1 phase
167				CLK 2 phase
183				Load capacitance

Once we have calculated the above values we can then fill the registers of the SI5351a according to the datasheet and application note 619

CLK 1 ON

2 MHz FREQUENCY	2 mA OUTPUT DRIVE	OFF INVERT
A PLL	0 deg. PHASE DELAY

Frequency calculations

The output frequency can be calculated with the following 2 formula's:

With formula 1 we can set the internal VCO frequency between 600 and 900 MHz. With formula 2 we set the output frequency. The table below shows the calculated values:

Output frequency (Fout)=			.. MHz
Input clock frequency (Fclk_in)=			.. MHz
a1=		a2=
b1=		b2=
c1=		c2=
a1+b1/c1=		a2+b2/c2=

..	.		.
..	.	..	.
..	.	..	.
..	.	..	.

Once we have calculated the above values we can then fill the registers of the SI5351a according to the datasheet and application note 619

CLK 2 ON

3 MHz FREQUENCY	2 mA OUTPUT DRIVE	OFF INVERT
A PLL	0 deg. PHASE DELAY

Frequency calculations

The output frequency can be calculated with the following 2 formula's:

With formula 1 we can set the internal VCO frequency between 600 and 900 MHz. With formula 2 we set the output frequency. The table below shows the calculated values:

Output frequency (Fout)=			.. MHz
Input clock frequency (Fclk_in)=			.. MHz
a1=		a2=
b1=		b2=
c1=		c2=
a1+b1/c1=		a2+b2/c2=

..	.		.
..	.	..	.
..	.	..	.
..	.	..	.

Once we have calculated the above values we can then fill the registers of the SI5351a according to the datasheet and application note 619

SYSTEM STATUS

PLL A	locked	✔	voltage	4.3V	✔
PLL B	locked	✔	current	45 mA	✔
Input Clock	running	✔	Internet	connected	✔

SYSTEM SETTINGS

OUTPUT LEVEL

INPUT CLOCK

0 % center

SPREAD SPECTRUM