Clkref Filter Implementation - Intel Pentium III Processor 512K Design Manual

4.2.1

CLKREF Filter Implementation

When using single-ended clocking mode, the BCLK#/CLKREF signal on the LV Intel Pentium
processor 512K serves as a reference voltage to the clock input. To provide a steady reference
voltage, a filter circuit must be implemented and attached to this pin. Figure 14 shows the
recommended CLKREF filter implementation. The CLKREF filter should be placed as close as
possible (less that 1.0 inch) to the processor's CLKREF pin.
Figure 14. CLKREF Filter Implementation
Table 16. CLKREF Component Values
Reference
R1
R2
C1
Design Guide
®
LV Intel Pentium
Vcc2.5
R1
R2
Value
150 Ω
150 Ω
4.7 µF
®
III Processor 512K Dual Processor Platform
Processor
PGA370
CLKREF
Y33
C1
1% Tolerance
1% Tolerance
III
Notes
27