ICS1531 Datasheet, PDF (57/76 Pages) Integrated Circuit Systems – Triple 8-bit MSPS A/D Converters with Line-Locked Clock Generator

ICS1531 Data Sheet - Preliminary
7.3.2 Programming Flow for Modifying Settings for Spread Spectrum
Chapter 7 Programming
Figure 7-4. ICS1531 Flow for PNLCLK and MCLK PLL Spread-Spectrum Settings
Disable Spread
Spectrum Mode
PNLCLK Reg 25:1 = 0
MCLK Reg 2B:1 = 0
No Change Yes
PLL Freq.
?
Set M, N, PFD Gain,
and Output Scaler
PNLCLK Regs 20, 21, 24
MCLK Regs 26, 27, 2A
No
Change
Spread
Spectrum
Mode?
Yes
Set Spread Sepctrum
Counter and Gain
PNLCLK Regs 22, 23, 24
MCLK Regs 28, 29, 2A
PLL Software
Reset
Wait ~ 1ms
PNLCLK and MCLK
Reg 2D
No
Done
Yes
Enable Spread Spectrum Mode
PNLCLK Reg 25:1 = 1
MCLK Reg 2B:1 = 1
ICS1531 Rev N 12/1/99
Copyright © 1999, Integrated Circuit Systems, Inc.
All rights reserved.
57
December, 1999