AV9108
Integrated
Circuit
Systems, Inc.
CPU Frequency Generator
General Description
The AV9108 offers a tiny footprint solution for generating two simultaneous clocks. One clock, the REFCLK, is a fixed output frequency which is the same as the input reference crystal (or clock). The other clock, CLK1, can vary between 2 and 120 MHz, with up to 16 selectable preprogrammed frequencies stored in internal ROM.
The ICS9108 is ideal for use in a 3.3V system. It can generate a 66.66 MHz clock at 3.3V. In addition, the ICS9108 provides a symmetrical wave form with a worst case duty cycle of 45/55. The ICS9108 has very tight edge control between the CPU clock and 2XCPU clock outputs, with a worst case skew of 250ps.
The device has advanced features which include on-chip loop filters, tristate outputs, and power-down capability. A minimum of external components - two decoupling capacitors and an optional ferrite bead - are all that are required for jitter-free operation. Standard versions for computer motherboard applications are the AV9108-03, AV9108-05 and the ICS9108-10. Custom masked versions, with customized frequencies and features, are available in 6-8 weeks for a small NRE fee.
Features
∙Runs up to 80 MHz at 3.3V
∙50/50 typical duty cycle at 5V
∙±250ps absolute jitter
∙Generates frequencies from 2 to 140 MHz
∙2 to 32 MHz input reference frequency
∙Up to 16 frequencies stored internally
∙Patented on-chip Phase Locked Loop with VCO for clock generation
∙Provides reference clock and synthesized clock
∙On-chip loop filter
∙Low power 0.8μ CMOS technology
∙8-pin or 14-pin DIP or SOIC package
Block Diagram
AV 9108 RevB032195
AV9108
Pin Configuration
FS0 |
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1 |
8 |
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REFCLK |
FS1 |
1 |
14 |
FS0 |
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GND |
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2 |
7 |
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VDD |
FS2 |
2 |
13 |
REFCLK |
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FS3 |
3 |
12 |
VDD |
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AGND |
4 |
11 |
CLK1 |
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X1/ICLK |
3 |
6 |
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CLK1 |
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GND |
5 |
10 |
OE (CLK1) |
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X2 |
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4 |
5 |
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FS1 |
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6 |
9 |
OE (REFCLK) |
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PD |
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AV9108-05/-10 |
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X1/ICLK |
7 |
8 |
X2 |
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8-Pin DIP, SOIC |
AV9108-03/-11 |
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14-Pin DIP, SOIC |
Pin Descriptions for AV9108-03, AV9108-05 and AV9108-10
PIN NUMBER |
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PIN |
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NAME |
TYPE |
DESCRIPTION |
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-05/-10/-13 |
-03 |
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1 |
14 |
FS0 |
Input |
Frequency Select 0 for CLK1 (-03 has pull-up). |
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5 |
1 |
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FS1 |
Input |
Frequency Select 1 for CLK1 (-03 has pull-up). |
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2 |
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FS2 |
Input |
Frequency Select 2 for CLK1 (-03 has pull-up). |
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3 |
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FS3 |
Input |
Frequency Select 3 for CLK1 (-03 has pull-up). |
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4 |
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AGND |
- |
Analog GROUND. |
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2 |
5 |
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GMD |
- |
Digital GROUND. |
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6 |
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Input |
POWER-DOWN. Shuts off chip when low. Internal pull-up. |
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PD |
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3 |
7 |
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X1/ICLK |
Input |
CRYSTAL OUTPUT or INPUT CLOCK frequency. Typically 14.318 MHz |
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system clock. |
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4 |
8 |
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X2 |
Output |
CRYSTAL OUTPUT (No Connect when clock used.). |
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9 |
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OE(REFCLK) |
Input |
OUTPUT ENABLE. Tristates REFCLK when low. Pull-up. |
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10 |
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OE(CLK1) |
Input |
OUTPUT ENABLE. Tristates CLK1 when low. Pull-up. |
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6 |
11 |
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CLK1 |
Output |
CLOCK1 Output (see decoding tables). |
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7 |
12 |
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VDD |
- |
Digital power supply (+3V DC). |
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8 |
13 |
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REFCLK |
Output |
REFERENCE CLOCK output. Produces a buffered version of the input clock or |
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crystal frequency (typically 14.318 MHz). |
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2
AV9108
Actual Frequencies
Decoding Table for AV9108-05, 14.318 input
FS1 |
FS0 |
CLK1 |
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0 |
0 |
40.01 MHz |
0 |
1 |
50.11 MHz |
1 |
0 |
66.61 MHz |
1 |
1 |
80.01 MHz |
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Decoding Table for AV9108-03, 14.318 input
FS3 |
FS2 |
FS1 |
FS0 |
CLK1 |
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0 |
0 |
0 |
0 |
16.00 MHz |
0 |
0 |
0 |
1 |
39.99 MHz |
0 |
0 |
1 |
0 |
50.11 MHz |
1 |
0 |
1 |
1 |
80.01 MHz |
0 |
1 |
0 |
0 |
66.58 MHz |
0 |
1 |
0 |
1 |
100.23 MHz |
0 |
1 |
1 |
0 |
8.02 MHz |
0 |
1 |
1 |
1 |
4.01 MHz |
1 |
0 |
0 |
0 |
8.02 MHz |
1 |
0 |
0 |
1 |
20.00 MHz |
1 |
0 |
1 |
0 |
25.06 MHz |
1 |
0 |
1 |
1 |
40.01 MHz |
1 |
1 |
0 |
0 |
33.29 MHz |
1 |
1 |
0 |
1 |
50.11 MHz |
1 |
1 |
1 |
0 |
4.01 MHz |
1 |
1 |
1 |
1 |
2.05 MHz |
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Decoding Table for AV9108-10, 14.318 input
FS1 |
FS0 |
CLK1 |
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0 |
0 |
25.057 MHz |
0 |
1 |
33.289 MHz |
1 |
0 |
40.006 MHz |
1 |
1 |
50.113 MHz |
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Decoding Table for AV9108-11 (in MHz)
FS3 |
FS2 |
FS1 |
FS0 |
CLK1 |
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0 |
0 |
0 |
0 |
16.00 MHz |
0 |
0 |
0 |
1 |
33.39 MHz |
0 |
0 |
1 |
0 |
50.11 MHz |
1 |
0 |
1 |
1 |
80.01 MHz |
0 |
1 |
0 |
0 |
66.58 MHz |
0 |
1 |
0 |
1 |
100.23 MHz |
0 |
1 |
1 |
0 |
60.00 MHz |
0 |
1 |
1 |
1 |
4.01 MHz |
1 |
0 |
0 |
0 |
8.02 MHz |
1 |
0 |
0 |
1 |
20.05 MHz |
1 |
0 |
1 |
0 |
25.06 MHz |
1 |
0 |
1 |
1 |
39.99 MHz |
1 |
1 |
0 |
0 |
33.25 MHz |
1 |
1 |
0 |
1 |
50.11 MHz |
1 |
1 |
1 |
0 |
30.00 MHz |
1 |
1 |
1 |
1 |
4.01 MHz |
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Note: The dash number following ICS9108 must be included when ordering product since it specifies the frequency decoding table being ordered. Decoding options can be created by a simple metal mask change.
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