CK00 (100/133 MHz) spread spectrum
differential system clock generator
Product data
File under Integrated Circuits, ICL03
2001 Oct 11
Philips SemiconductorsProduct data
CK00 (100/133 MHz) spread spectrum
differential system clock generator
FEA TURES
•3.3 V operation
•Six differential CPU clock pairs
•Two PCI clocks at 33 MHz and one 3V66 clock
•Two 48 MHz clocks at 3.3 V
•One 14.318 MHz reference clock
•Power management control pins
•Host clock jitter less than 200 ps cycle-to-cycle
•Host clock skew less than 150 ps pin-to-pin
•Spread Spectrum capability
•Optimized frequency and spread spectrum performance
DESCRIPTION
The PCK2021 is a clock synthesizer/driver for a Pentium III and
other similar processors.
The PCK2021 has six differential pair CPU current source outputs,
two 33 MHz outputs, one 3V66 output, and two 48 MHz clocks
which can be disabled on power-up, and one 3.3 V reference clock
at 14.318 MHz which can also be disabled on power-up.
The part possesses a dedicated power-down input pin for power
management control. This input is synchronized on chip, and
ensures glitch-free output transitions. In addition, the part can be
configured to disable the 48 MHz outputs for lower power operation
and an increase in the performance of the functioning outputs. The
REF and PCI outputs can also be disabled for the highest
performance of the Host outputs.
19REF3.3 V fixed 14.318 MHz output
20SPREADEnables spread spectrum mode when held LOW on differential host outputs, 3V66 and PCI clocks.
22XINCrystal input
23XOUTCrystal output
26I
29, 30MULTSEL0
41PWRDWNDevice enters power-down mode when held LOW. Asserts LOW .
45SEL133/100Select input pin for enabling 133 MHz or 100 MHz CPU outputs
5, 7, 15,
21, 27, 28,
34, 46
43V
42V
V
DD
48M_1/SELB
HCLKB0
HCLKB1
HCLKB2
PCI1
HCLKB3
HCLKB4
HCLKB5
REF
MULTSEL1
V
SS
DDA
SSA
3.3 V power supply
Pins 9, 12, and 18 supply host output pairs 0, 1, and 2.
Pins 37 and 40 supply host output pairs 3, 4, and 5.
3.3 V fixed 48 MHz clock outputs. During power-up pins function as latched inputs that enable SELA and
SELB prior to the pins being used for output of 3 V at 48 MHz. Part must be clocked to latch data in.
Host output pair 0
Host output pair 1
Host output pair 2
33 MHz clocks: 33 MHz reference clocks
Host output pair 3
Host output pair 4
Host output pair 5
Asserts LOW.
This pin controls the reference current for the host pairs. This pin requires a fixed precision resistor tied to
ground in order to establish the correct current.
Select input pin used to control the scaling of the HCLK and HCLKB output current.
Ground
3.3 V power supply for analog circuits
Ground for analog circuits
2001 Oct 1 1
3
Philips SemiconductorsProduct data
CK00 (100/133 MHz) spread spectrum differential
system clock generator