ICS94206 Datasheet, PDF (1/18 Pages) Integrated Circuit Systems – Programmable System Frequency Generator for PII/III™

Integrated
Circuit
Systems, Inc.
ICS94206
Programmable System Frequency Generator for PII/III™
Recommended Application:
440BX - VIA Apollo Pro133 - ALI 1631 style chipset.
Output Features:
• 2 - CPUs @2.5V
• 1 - IOAPIC @ 2.5V
• 13 - SDRAM @ 3.3V
• 6 - PCI @3.3V,
• 1 - 48MHz, @3.3V
• 1 - 24MHz @ 3.3V
• 2 - REF @3.3V, 14.318MHz.
Features:
• Programmable ouput frequency.
• Programmable ouput rise/fall time.
• Programmable PCI_F and PCICLK skew.
• Spread spectrum for EMI control typically by 7dB to
8dB,
with programmable spread percentage.
• Watchdog timer technology to reset system
if over-clocking causes malfunction.
• Uses external 14.318MHz crystal.
• FS pins for frequency select
Key Specifications:
• CPU – CPU: <175ps
• SDRAM - SDRAM: <500ps
• PCI – PCI: <500ps
• CPU(early)-PCI: Min=1.0ns, Typ=2.0ns, Max=4.0ns
X1
X2
BUFFER IN
FS(3:0) ⁴
MODE
CLK_STOP#
PCI_STOP#
SDATA
SCLK
Block Diagram
PLL2
/2
XTAL
OSC
STOP
PLL1
Spread
Spectrum
LATCH
4
POR
Control
Logic
Config.
Reg.
STOP
STOP
PCI
CLOCK
DIVDER
STOP
48MHz
24MHz
IOAPIC
2 ^REF(1:0)
CPUCLK_F
CPUCLK 1
12 ^{SDRAM (11:0)}
SDRAM_F
PCICLK (4:0)
5
PCICLKF
VDD1
*PCI_STOP/REF0
GND
X1
X2
VDD2
*MODE/PCICLK_F
**FS3/PCICLK0
GND
PCICLK1
PCICLK2
PCICLK3
PCICLK4
VDD2
BUFFER IN
GND
SDRAM11
SDRAM10
VDD3
SDRAM9
SDRAM8
GND
SDATA
SCLK
Pin Configuration
1
48
VDDL1
2
47
IOAPIC
3
46
REF1/FS2*
4
45
GND
5
44
CPUCLK_F
6
43
CPUCLK1
7
42
VDDL2
8
41
CLK_STOP#*
9
40
SDRAM_F
10
39
GND
11
38
SDRAM0
12
37
SDRAM1
13
36
VDD3
14
35
SDRAM2
15
34
SDRAM3
16
33
GND
17
32
SDRAM4
18
31
SDRAM5
19
30
VDD3
20
29
SDRAM6
21
28
SDRAM7
22
27
VDD4
23
26
48MHz/FS0*
24
25
24MHz/FS1*
48-Pin 300mil SSOP
* Internal Pull-up Resistor of 120K to VDD
** Internal Pull-down resistor of 120K to GND
Functionality
FS3 FS2 FS1 FS0
0
0
0
0
0
0
0
1
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
1
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
CPU
(MHz)
80.00
75.00
83.31
66.82
103.00
112.01
68.01
100.23
120.00
114.99
109.99
105.00
140.00
150.00
124.00
132.99
PCICLK
(MHz)
40.00
37.50
41.65
33.41
34.33
37.34
34.01
33.41
40.00
38.33
36.66
35.00
35.00
37.50
31.00
33.25
94206 Rev B 04/26/01
ICS reserves the right to make changes in the device data identified in
this publication without further notice. ICS advises its customers to
obtain the latest version of all device data to verify that any
information being relied upon by the customer is current and accurate.