Si5351 Oscillator Breakout Board

Features

• I2C Daisy-chain connector
• 3 outputs
• 25 or 27 MHz crystal (Rev 1)
• 27 MHz TCXO (Rev 3)
• Can be used as a heat shrinked assembly with cables

Pinout

J1 - Daisy-chained I2C

1. SCL
2. SDA
3. +3.3V
4. GND

J2 - VFO Outputs

• VFO out / GND Pairs

1. VFO0
2. VFO1
3. VFO2

Test Setup

Test Hardware

• Arduino Pro Mini
  • 3.3V/8MHz
• Rotary Encoder/Breakout Board
• 128x32 OLED
• Breadboard Power Supply
  • 3.3V operation

Test Software

• I2C-VFO3 Arduino Code on GitHub

Measurements

• 10 MHz FFT
  • Square wave has high odd harmonic content

Revision History

Rev 3

• TXCO
• Fixed solder mask clearance
• Tested
  • Correction factor less than +10 Hz at 10 MHz
    • 1ppm (spec 2.5ppm)

Rev 2

• TXCO instead of crystal
• Insufficient solder mask (too big a clearance)

Rev 1

• Used crystal

Assembly Sheet - Rev 3

Qty	Value	RefDes		Qty	Value	RefDes
2	0.1uF	C1,C2		1	Header, Right Angle, 2x3	J2
2	2.2K	R1,R2		1	Header, Right Angle, 2x4	J1
1	TCXO, 27 MHz FOX924B-27	U2
1	Si5351A	U1