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CY2291
Three-PLL General Purpose EPROM
Programmable Clock Generator
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 38-07189 Rev. *I Revised December 10, 2014
Three-PLL Genera l Purpose EPROM Programmable Clock Generator
Features
■ Three integrated phase-locked loops
■ EPROM programmability
■ Factory-programmable (CY2291) or field-programmable
(CY2291F) device options
■ Low-skew, low-jitter, high-accuracy outputs
■ Power-management options (Shutdown, OE, Suspend)
■ Frequency select option
■ Smooth slewing on CPUCLK
■ Configurable 3.3 V or 5 V operation
■ 20-pin SOIC Package
Functional Description
The CY2291 is a third-generation family of clock generators. The
CY2291 is upwardly compatible with the industry standard
ICD2023 and ICD2028 and continues their tradition by providing
a high level of customizable features to meet the diverse clock
synchoronous systems.
All parts provide a highly configurable set of close for PC
motherboard applications. Each of four configurable clock
outputs (CLKA-CLKD) can be assigned 1 of 30 frequencies in
any combination. Multiple outputs configured for the same or
related[3] frequencies have low (<500 ps) skew, in effect
providing on-chip buffering for heavily loaded signals.
The CY2291 can be configured for either 5 V or 3.3 V operation.
The internal ROM tables use EPROM technology, allowing full
customization of output frequencies. The reference oscillator has
been designed for 10 MHz to 25 MHz crystals, providing
additional flexibility. No external components are required with
this crystal. Alternatively, an external reference clock of
frequency between 1 MHZ to 30 MHz can be used. Customers
using the 32 kHz oscillator must connect a 10-M resistor in
parallel with the 32 kHz crystal.
For a complete list of related documentation, click here.
Selection Guide
Part Number Outputs Input Frequency Range Output Frequency Range Specifics
CY2291 8 10 MHz–25 MHz (external crystal)
1 MHz–30 MHz (reference clock)
76.923 kHz–100 MHz (5 V)
76.923 kHz–80 MHz (3.3 V)
Factory programmable
Commercial temperature
CY2291I 8 10 MHz–25 MHz (external crystal)
1 MHz–30 MHz (reference clock)
76.923 kHz–90 MHz (5 V)
76.923 kHz–66.6 MHz (3.3 V)
Factory programmable
Industrial temperature
CY2291F 8 10 MHz–25 MHz (external crystal)
1 MHz–30 MHz (reference clock)
76.923 kHz–90 MHz (5 V)
76.923 kHz–66.6 MHz (3.3 V)
Field programmable
Commercial temperature
CY2291FI 8 10 MHz–25 MHz (external crystal)
1 MHz–30 MHz (reference clock)
76.923 kHz–80 MHz (5 V)
76.923 kHz–60.0 MHz (3.3 V)
Field programmable
Industrial temperature
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