CY2254A Cypress Semiconductor, CY2254A Datasheet - Page 2

• Manufacturer Part Number: CY2254A
• Description: Pentium Processor Compatible Clock Synthesizer/Driver
• Manufacturer: Cypress Semiconductor

Pin Summary
Function Table
Document #: 38-07203 Rev. *A
V
XTALIN
XTALOUT
V
OE
CPUCLK0
CPUCLK1
V
CPUCLK2
CPUCLK3
V
S1
S0
V
PCICLK0
PCICLK1
V
PCICLK5
PCICLK4
V
PCICLK3
PCICLK2
V
IOCLK
KBDCLK
USBCLK
V
REF1
REF0
Notes:
1.
2.
Name
Option
1, 2
1, 2
1, 2
1, 2
1
2
DD
SS
DD
SS
DD
SS
DD
SS
DD
For best accuracy, use a parallel-resonant crystal, C
TCLK is a test clock on XTALIN (pin 2) during test mode.
[1]
[1]
0
1
1
1
1
1
OE
X
0
0
1
1
1
S0
X
0
1
0
1
1
S1
14.318 MHz High-Z
14.318 MHz 50.0 MHz
14.318 MHz 60.0 MHz
14.318 MHz 66.66 MHz
TCLK
14.318 MHz 55.0 MHz
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
XTALIN
1
[2]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
2
TCLK/2
CPUCLK
LOAD
Voltage supply
Reference crystal input
Reference crystal feedback
Ground
Output Enable, Active HIGH (internal pull-up resistor to V
CPU clock output
CPU clock output
Voltage supply
CPU clock output
CPU clock output
Ground
CPU clock select input, bit 1 (internal pull-up resistor to V
CPU clock select input, bit 0 (internal pull-up resistor to V
Voltage supply
PCI clock output
PCI clock output
Ground
PCI clock output
PCI clock output
Voltage supply
PCI clock output
PCI clock output
Ground
I/O clock output (24 MHz)
Keyboard controller clock output (12 MHz)
Universal Serial Bus clock output (48 MHz)
Voltage supply
Reference clock output (14.318 MHz)
Reference clock output (14.318 MHz)
Description
= 17 pF.
High-Z
25.0 MHz
30.0 MHz
33.33 MHz
TCLK/4
27.5 MHz
PCICLK
High-Z
14.318 MHz 24 MHz
14.318 MHz 24 MHz
14.318 MHz 24 MHz
TCLK
14.318 MHz 24 MHz
Ref. Clock
Output
High-Z
TCLK/4
IOCLK
High-Z
12 MHz
12 MHz
12 MHz
TCLK/8
KBDCLK
1 only
DD
DD
DD
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)
)
)
CY2254A
High-Z
48 MHz
48 MHz
48 MHz
48 MHz
USBCLK
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