Generator. ICD2028 Datasheet

ICD2028 Datasheet PDF


Part

ICD2028

Description

PC Motherboard Clock Generator

Manufacture

Cypress Semiconductor

Page 12 Pages
Datasheet
Download ICD2028 Datasheet


ICD2028 Datasheet
fax id: 35071ICD2028
ICD2028
PC Motherboard Clock Generator
Features
Eight independent clock outputs handle all clocking re-
quirements for personal computer motherboards
CPU clock frequency range:
10 MHz to 100 MHz with user-defined duty cycle
Four user-configurable outputs
Skew-free CPU clock, CPU clock ÷2, and buffered CPU
clock options on configurable outputs
Ideally suited for desktop PCs
Phase-locked loop oscillator input derived from single
14.31818 MHz crystal
Sophisticated internal loop-filter requires no external
components
Battery input maintains 32.768 kHz clock during pow-
er-down
Three-state oscillator control disables outputs for test
purposes
5V operation
Low-power, high-speed CMOS technology
Available in 20-pin SOIC package configuration
Functional Description
A modern personal computer motherboard often requires as
many as seven different crystal can oscillators. The System
Logic family of frequency synthesis parts from Cypress/IC De-
signs replaces the large number of oscillators required to build
such multi-function motherboards. These parts synthesize all
the required frequencies in a single monolithic device, thus
lowering manufacturing costs and significantly reducing the
printed circuit board space required.
The ICD2028 is a second-generation PC Motherboard Clock
Generator built on the foundation of the industry-standard and
most widely-used ICD2023. The ICD2028 offers most of the
features of the ICD2023, as well as some important enhance-
ments:
• An additional VCO
• An additional clock output
• Four customer-configured outputs which can be configured
to have
• A skew-free divided-by-two CPU clock
• An additional skew-free CPU clock
• User-definable CPUCLK output duty cycle
Because today’s desktop PCs must support a myriad of new
requirements, and each company’s implementation tends to
be unique, the most important new feature of the ICD2028 is
its ability to tailor four of the outputs to the individual needs of
today’s system logic design engineer, and to configure the
CPUCLK duty cycle for special microprocessor needs.
The ICD2028 was specifically designed to support such de-
manding clock requirements as:
• 486 and Pentium™ microprocessors both with and without
clock doublers
• New single-chip system logic chip sets
• Super I/O combo chips
• New high-density floppy disk drive controllers
The ICD2028 consists of two crystal-controlled oscillators,
three phase-locked loops, and eight different outputs in a sin-
gle package. To sum up, the greatest asset of the ICD2028 lies
in its ability to serve as the single source of all clocking require-
ments in modern desktop PCs.
Pin Configuration
SOIC
Top View
32XOUT
32.768 kHz
CLKC
VDD
GND
XTALIN
XTALOUT
SYSBUS
CLKD
CPUCLK
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
32XIN
VBATT
OE
S2
AVDD
S1
S0
24.0MHz
CLKA
CLKB
ICD2028–1
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
June 1994 – Revised April 1995

ICD2028 Datasheet
Block Diagram
VBATT
32XIN
32XOUT
OSCILLATOR
(INPUT FROM
32.768 kHz
CRYSTAL)
S2
S1
S0
XTALIN
XTALOUT
(INPUT FROM
14.31818 MHz
CRYSTAL)
OSCILLATOR
CPUCLK
PLL
SYSCLK
PLL
96 MHz
UTILITY
PLL
GND VDD AVDD
ICD2028
32.768 kHz
SYSBUS
CPUCLK
24.0 MHz
4
USER-
CONFIGURABLE
LOGIC
DIVIDERS AND
MUX MATRIX
CLKA
CLKB
CLKC
CLKD
OE
ICD2028–2
2


Features Datasheet pdf fax id: 35071ICD2028 ICD2028 PC Mother board Clock Generator Features • Eig ht independent clock outputs handle all clocking requirements for personal com puter motherboards • CPU clock freque ncy range: 10 MHz to 100 MHz with user- defined duty cycle • Four user-config urable outputs • Skew-free CPU clock, CPU clock ÷2, and buffered CPU clock options on configurable outputs • Ide ally suited for desktop PCs • Phase-l ocked loop oscillator input derived fro m single 14.31818 MHz crystal • Sophi sticated internal loop-filter requires no external components • Battery inpu t maintains 32.768 kHz clock during pow er-down • Three-state oscillator cont rol disables outputs for test purposes • 5V operation • Low-power, high-sp eed CMOS technology • Available in 20 -pin SOIC package configuration Functio nal Description A modern personal compu ter motherboard often requires as many as seven different crystal can oscillat ors. The System Logic family of frequency synthesis parts from Cypress/IC Designs replac.
Keywords ICD2028, datasheet, pdf, Cypress Semiconductor, PC, Motherboard, Clock, Generator, CD2028, D2028, 2028, ICD202, ICD20, ICD2, stock, pinout, distributor, price, schematic, inventory, databook, Electronic, Components, Parameters, parts, cross reference, chip, Semiconductor, circuit, Electric, manual, substitute, Equivalent




@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site (Privacy Policy & Contact)