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Número de pieza | ICS9148-20 | |
Descripción | Frequency Generator & Integrated Buffers | |
Fabricantes | Integrated Circuit Systems | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de ICS9148-20 (archivo pdf) en la parte inferior de esta página. Total 11 Páginas | ||
No Preview Available ! Integrated
Circuit
Systems, Inc.
ICS9148-20
Pentium/ProTM System Clock Chip
General Description
The ICS9148-20 is a Clock Synthesizer chip for Pentium and
PentiumPro CPU based Desktop/Notebook systems that will
provide all necessary clock timing.
Features include four CPU and eight PCI clocks. Three
reference outputs are available equal to the crystal frequency.
Additionally, the device meets the Pentium power-up
stabilization requirement, assuring that CPU and PCI clocks
are stable within 2ms after power-up.
PD# pin enables low power mode by stopping crystal OSC
and PLL stages. Other power management features include
CPU_STOP#, which stops CPU (0:3) clocks, and PCI_STOP#,
which stops PCICLK (0:6) clocks.
High drive CPUCLK outputs typically provide greater than 1
V/ns slew rate into 20pF loads. PCICLK outputs typically
provide better than 1V/ns slew rate into 30pF loads while
maintaining 50±5% duty cycle. The REF clock outputs
typically provide better than 0.5V/ns slew rates.
The ICS9148-20 accepts a 14.318MHz reference crystal or
clock as its input and runs on a 3.3V core supply.
Block Diagram
Features
Generates system clocks for CPU, IOAPIC, PCI, plus
14.314 MHz REF (0:2), USB, and Super I/O
Supports single or dual processor systems
Supports Spread Spectrum modulation for CPU & PCI
clocks, down spread -0.5%
Skew from CPU (earlier) to PCI clock (rising edges for
100/33.3MHz) 1.5 to 4ns
Two fixed outputs at 48MHz.
Separate 2.5V and 3.3V supply pins
2.5V or 3.3V output: CPU, IOAPIC
3.3V outputs: PCI, REF, 48MHz
No power supply sequence requirements
Uses external 14.318MHz crystal, no external load cap
required for CL=18pF crystal
48 pin 300 mil SSOP
Pin Configuration
48-Pin SSOP
Power Groups
VDD = Supply for PLL core
VDD1 = REF (0:2), X1, X2
VDD2 = PCICLK_F, PCICLK (0:6)
VDD3 = 48MHz0, 48MHz1
VDDL1 = IOAPIC (0:1)
VDDL2 = CPUCLK (0:3)
9148-20 Rev C 03/28/98
Ground Groups
GND = Ground for PLL core
GND1 = REF (0:2), X1, X2
GND2 = PCICLK_F, PCICLK (0:6)
GND3 = 48MHz0, 48MHz1
GNDL1 = IOAPIC (0:1)
GNDL2 = CPUCLK (0:3)
Pentium is a trademark on Intel Corporation.
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.
1 page ICS9148-20
CPU_STOP# Timing Diagram
CPUSTOP# is an asychronous input to the clock synthesizer. It is used to turn off the CPUCLKs for low power operation.
CPU_STOP# is synchronized by the ICS9148-20. The minimum that the CPUCLK is enabled (CPU_STOP# high pulse) is 100
CPUCLKs.All other clocks will continue to run while the CPUCLKs are disabled. The CPUCLKs will always be stopped in a low
state and start in such a manner that guarantees the high pulse width is a full pulse. CPUCLK on latency is less than 4 CPUCLKs
and CPUCLK off latency is less than 4 CPUCLKs.
Notes:
1. All timing is referenced to the internal CPUCLK.
2. CPU_STOP# is an asynchronous input and metastable conditions may exist.
This signal is synchronized to the CPUCLKs inside the ICS9148-20.
3. All other clocks continue to run undisturbed.
4. PD# and PCI_STOP# are shown in a high (true) state.
PCI_STOP# Timing Diagram
PCI_STOP# is an asynchronous input to the ICS9148-20. It is used to turn off the PCICLK (0:6) clocks for low power operation.
PCI_STOP# is synchronized by the ICS9148-20 internally. The minimum that the PCICLK (0:6) clocks are enabled (PCI_STOP#
high pulse) is at least 10 PCICLK (0:6) clocks. PCICLK (0:6) clocks are stopped in a low state and started with a full high pulse
width guaranteed. PCICLK (0:6) clock on latency cycles are only one rising PCICLK. Clock off latency is one PCICLK clock.
Notes:
1. All timing is referenced to the Internal CPUCLK (defined as inside the ICS9148 device.)
2. PCI_STOP# is an asynchronous input, and metastable conditions may exist. This signal is required to be synchronized
inside the ICS9148-20.
3. All other clocks continue to run undisturbed.
4. PD# and CPU_STOP# are shown in a high (true) state.
5
5 Page ICS9148-20
SYMBOL
A
A1
A2
B
C
D
E
e
H
h
L
N
∝
X
SSOP Package
COMMON DIMENSIONS
MIN.
NOM.
MAX.
.095 .101
.110
.008 .012
.016
.088 .090
.092
.008 .010
.0135
.005 .006
.0085
See Variations
.292 .296
.299
0.025 BSC
.400 .406
.410
.010 .013
.016
.024 .032
.040
See Variations
0° 5°
8°
.085 .093
.100
VARIATIONS
AC
AD
Ordering Information
ICS9148F-20
Example:
ICS XXXX F - PPP
MIN.
.620
.720
D
NOM.
.625
.725
MAX.
.630
.730
N
48
56
This table in inches
Pattern Number (2 or 3 digit number for parts with ROM code patterns)
Package Type
F=SSOP
Device Type (consists of 3 or 4 digit numbers)
Prefix
ICS, AV = Standard Device
ICS reserves the right to make changes in the device data identified in this
11 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.
11 Page |
Páginas | Total 11 Páginas | |
PDF Descargar | [ Datasheet ICS9148-20.PDF ] |
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