AK8140A Datasheet, PDF (11/45 Pages) Asahi Kasei Microsystems – Programmable Clock Generator

AK8140A
Example1) input 27MHz, output 123.75MHz
1. fVCO1
VCO1 frequency:
247.5MHz
ODIV = 2
2. fcmp1
Phase comparison frequency1: 9MHz
MDIV = 3
27MHz / 3 = 9MHz
3. NDIV1
Feedback dividing value:
27.5
INT = 28d, FRAC =-131072d
INT = round (247.5 / 9) = round(27.5) = 28d
FRAC = round (( 27.5 – 28 ) x 2¹⁸ ) = -131072d
Output frequency error: 0ppm
Example2) input 16MHz, output 24.576MHz
1. fVCO1
VCO frequency:
294.912MHz
ODIV = 12
2. fcmp1
Phase comparison frequency:
8MHz
MDIV = 2
16MHz / 2 = 8MHz
3. NDIV1
Feedback dividing value:
36.864
INT = 37d, FRAC = -35652d
INT = round (294.912/ 8 ) = round(36.864) = 37d
FRAC = round (( 36.864 – 37 ) x 2¹⁸ ) = -35652d
Output frequency error: 0.043ppm (1.06Hz)
draft-E-06
- 11 -
Sep -12