900,000+ datasheet pdf search and download

Datasheet4U offers most rated semiconductors data sheet pdf




Cypress Semiconductor Electronic Components Datasheet

IMIFS794 Datasheet

(IMIFS791/92/94) Low EMI Spectrum Spread Clock

No Preview Available !

92/94
www.DataSheet4U.com
FS791/92/94
Features
• Spread Spectrum Clock Generator (SSCG) with 1x, 2x
and 4x outputs
• 80- to 140-MHz operating frequency range
• Modulates external clocks including crystals, crystal
oscillators, and ceramic resonators
• Programmable modulation with simple R-C external
loop filter (LF)
• Center spread modulation
• 3–5 Volt power supply
• TTL/CMOS compatible outputs
• Low short-term jitter
• Low Power Dissipation;
— 3.3 VDC = 73 mW—typical
— 5.0 VDC = 225 mW—typical
• Available in 8-pin SOIC package
.
Low EMI Spectrum Spread Clock
Applications
• Desktop/Notebook computers
• VGA, XGA, and SXGA LCD displays
• High-speed printers and copiers
• CD-ROM, VCD, and DVD
• Embedded systems
• Networking, LAN/WAN
• Modems
Benefits
• Programmable EMI reduction
• Fast time-to-market
• Lower cost of compliance
• No degradation in Rise/Fall time
• Lower component and PCB layer count
Block Diagram
Xin
1
10 pF.
Xout
2
10 pF.
VDD
8
Power Contol
Logic
Reference
Divider
Modulation
Control
Input Control
Loop Filter 4
Phase
Detector
10 pF.
VCO
VCO / N
Counter
and
Mux
5
VSS
37
S1 S0
Pin Configuration
Xin
Xout
S1
LF
18
2 FS79x 7
36
45
VDD
S0
FSOUT
VSS
FSOUT
6
www.DataSheet4U.com
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
Document #: 38-07343 Rev *A
Revised December 28, 2002


Cypress Semiconductor Electronic Components Datasheet

IMIFS794 Datasheet

(IMIFS791/92/94) Low EMI Spectrum Spread Clock

No Preview Available !

www.DataSheet4U.com
FS791/92/94
.
Pin Description
Pin Name
1,2 Xin/Xout
3,7 S1/S0
4 LF
5 VSS
6 FSOUT
8 VDD
I/O Type
Description
I/O analog Pins form an on-chip reference oscillator when connected to terminals of an
external parallel resonant crystal. XIN may be connected to TTL/CMOS ex-
ternal clock other than crystal, leave XOUT (pin 2) unconnected.
I CMOS/TTL Digital control inputs used to select the input frequency range and output
frequency scaling. Refer Table 1 for selection.
S1 has internal pull-up(1) and S0 has internal pull-down(0).
I Analog Loop filter. Single ended three-state output of the phase detector. A sin-
gle-pole low-pass filter is connected to the loop filter (LF).
P Power Power Supply Ground.
O CMOS/TTL Modulated Clock Output. The output frequency is centered on and a multiple
of the input (Xin) as follows:
FS791 = 1X; FS792 = 2X; FS794 = 4X
P Power Positive Power Supply.
Table 1. Output Frequency Selection FSOUT SSCG (Modulated Output Clock) Product Selection
Product Number
FS791
FS792
FS794
FSOUT Frequency Scaling
1X
2X
4X
Description
1X Modulated Frequency of Input Clock
2X Modulated Frequency of Input Clock
4X Modulated Frequency of Input Clock
General Description
The Cypress FS791/2/4 are Spread Spectrum Clock Genera-
tor ICs (SSCG) designed for the purpose of reducing Electro
Magnetic Interference (EMI) found in todays high-speed digi-
tal systems.
The FS791/2/4 SSCG clocks use an Cypress proprietary tech-
nology to modulate the input clock frequency, FSOUT, by mod-
ulating the frequency of the digital clock. By modulating the
reference clock the measured EMI at the fundamental and har-
monic frequencies of FSOUT is greatly reduced. This reduc-
tion in radiated energy can significantly reduce the cost of
complying with regulatory requirements without degrading dig-
ital waveforms.
The FS791/2/4 are designed to operate over a very wide range
of input frequencies and provide 1x, 2x, and 4x modulated
clock outputs.
The bandwidth of the frequency spread at FSOUT is deter-
mined by the values of the loop filter components. The modu-
lation rate is determined internally by the input frequency and
the selected input frequency range.
The bandwidth of these products can be programmed from as
little as 0.6% up to as much as 4.0% by selecting the proper
loop filter value. Refer to the Loop Filter Selection chart on
page 4 for recommended values. Due to a wide range of ap-
plication requirements, an external loop filter (LF) is used on
the FS79x products.
The user can select the exact amount of frequency modulation
suitable for the application. Using a fixed internal loop filter
would severely limit the use of a wide range of modulation
bandwidths (Spread%) to a few discrete values.
The Cypress FS791/2/4 Spread Spectrum Clock Generator
(SSCG) products are versatile devices to use in a wide range
of applications.
Refer to FS781/2/4 products for applications requiring a 6 to
82 MHz frequency range.
www.DataSheet4U.com
Document #: 38-07343 Rev *A
Page 2 of 9


Part Number IMIFS794
Description (IMIFS791/92/94) Low EMI Spectrum Spread Clock
Maker Cypress Semiconductor
Total Page 9 Pages
PDF Download

IMIFS794 Datasheet PDF

View PDF for Mobile








Similar Datasheet

1 IMIFS791 (IMIFS791/92/94) Low EMI Spectrum Spread Clock
Cypress Semiconductor
2 IMIFS792 (IMIFS791/92/94) Low EMI Spectrum Spread Clock
Cypress Semiconductor
3 IMIFS794 (IMIFS791/92/94) Low EMI Spectrum Spread Clock
Cypress Semiconductor





Part Number Start With

0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z

Site map

Webmaste! click here

Contact us

Buy Components

Privacy Policy