ICS1532 Datasheet, PDF (19/36 Pages) Integrated Device Technology – 110 MHZ TRIPLE 8-BIT ADC WITH CLOCK GENERATOR

ICS1532
110 MHZ TRIPLE 8-BIT ADC WITH CLOCK GENERATOR
Chapter 6 OSC Divider & OSCOUT
The ICS1532 accepts either a crystal across XIN and
XOUT or a single ended clock on the XIN input (with
XOUT left open). See Table 11-4 for crystal
requirements. This input (OSC) may be output to the
OSCOUT pin at the same input frequency, half the
input frequency, or divided by >2. This translates to
OSC, OSC/2 and the OSC Divider and is selected by
Register2C:5~4.
The OSC Divider works as follows, The period of the
OSC input becomes the high time of the OSC_OUT
signal and the low time is controlled by Register 7.
Table 6-1 OSC Divider Functionality
Parameter
Value
OSC Divider Frequency (Input Osc Frequency) *
[(Register 7: 6~0) + 2]
OSC High Time
Input OSC Period
OSC Low Time
[Reg7 + 1] *
Input OSC Period
Minimum OSC Divider 3 (Reg7:6~0 = 0000001)
Maximum OSC Divider 257 (Reg7 = 1111 1111)
RESERVED OSC Divider 0 (Reg7 = 0000 0000)
Chapter 7 Loop Filter
The ICS1532 contains an internal loop filter and also
supports the use of an external loop filter configured as
in Figure 7-1. Selection between these two filters is
controlled by Register 8:7. A 0 selects the external, a 1
selects the internal filter.
Figure 7-1 External Loop Filter
Implementing the external loop filter gives the system
engineer flexibility to add external filter functionality if
without having to alter the PCB.
Chapter 8 PLL Parameter Settings
Settings for all standard VESA video modes are pro-
vided by IDT as a starting point for the systems engi-
neer. These files are in human readable text files (*.ics
files) and come bundled within the ICS1532 Register
Editor Tool.
This tool directly drives the ICS1532EB Evaluation
Board and can be downloaded from www.idt.com.
While the internal loop filter works well for most
applications, IDT still recommends the implementation
of an external filter network on all designs.
MDS 1532 G
19
www.idt.com
Revision 060804