cy2278a Cypress Semiconductor Corporation., cy2278a Datasheet - Page 3

• Manufacturer Part Number: cy2278a
• Description: Pentium Clock Synthesizer/driver Mobile With Intel 82430tx Sdram
• Manufacturer: Cypress Semiconductor Corporation.

Pin Summary
Function Table
Name
V
V
V
AV
V
XTALIN
XTALOUT
SEL2
SEL1
SEL0
PCI_RUN
USB_RUN
CPU_RUN
PWR_DWN
XCPUCLK[0:2]
XCPUCLK3_F
CPUCLK[0:2]
PCICLK[2:9]
PCICLK_F[0:1]
CLK8MHZ
IOAPIC
REF[0:1]
USBCLK/IRCLK
Note:
0
0
0
0
1
1
1
1
SEL2
3.
DDQ3
DDQ2
DDCPU
SS
DD
For best accuracy, use a parallel-resonant crystal, C
[3]
0
0
1
1
0
0
1
1
SEL1
[3]
0
1
0
1
0
1
0
1
SEL0
Pins
6, 14, 19, 22, 36
48
42
26
3, 9, 16, 25, 31, 33, 39, 45
4
5
30
32
34
27
28
29
46
44, 43, 41
40
38, 37, 35
10, 11, 12, 13, 15, 17, 18, 20 PCI clock outputs
7, 8
21
47
2, 1
23, 24
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
XTALIN
75.0 MHz
20.0 MHz
25 MHz
33.33 MHz
50.0 MHz
60.0 MHz
66.67 MHz
40.0 MHz
CPUCLK
LOAD
= 18 pF.
Description
3.3V Digital voltage supply
IOAPIC Digital voltage supply, 2.5V
CPU Digital voltage supply, 2.5V or 3.3V
Analog voltage supply, 3.3V
Ground
Reference crystal input
Reference crystal feedback
CPU clock frequency select input, bit 2
CPU clock frequency select input, bit 1
CPU clock frequency select input, bit 0
Control input, stops all PCI clocks except PCICLK_F when driven LOW
Control input, stops all USB/IR clocks when driven LOW
Control input, stops all CPU clocks except XCPUCLK_F when driven LOW
Power down input, shuts down device when driven LOW
2.5V or 3.3V CPU clock outputs
2.5V or 3.3V CPU clock output, free-running on CY2278A-1L only. This output
is not free-running on the -2L, -3L, -4L configurations.
3.3V CPU clock output
PCI clock outputs, free-running on CY2278A-1L, -3L, -4L only. This output is
not free-running on the -2L configuration
8-MHz Keyboard clock output
IOAPIC clock output
Reference clock outputs, 14.318 MHz. REF0 has high drive
USB or IR clock outputs, 48 MHz
37.5 MHz
10.0 MHz
12.5 MHz
16.67 MHz
25.0 MHz
30.0 MHz
33.33 MHz
20.0 MHz
3
PCICLK
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
IOAPIC
REF
48.0 MHz
48.0 MHz
48.0 MHz
48.0 MHz
48.0 MHz
48.0 MHz
48.0 MHz
48.0 MHz
USBCLK
IRCLK
CY2278A
8.0 MHz
8.0 MHz
8.0 MHz
8.0 MHz
8.0 MHz
8.0 MHz
8.0 MHz
8.0 MHz
CLK8MHZ