Cypress CY25819 Pin.Description, Overview, Input Frequency Range and Selection, Spread% Selection

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CY25818/19

Pin.Description

Pin

Name

Description

1

XIN/CLK

Clock, Crystal, or Ceramic Resonator Input Pin.

 

 

 

2

Vss

Power Supply Ground.

 

 

 

3

S0

Digital Spread% Control Pin. 3-Level input (H-M-L). Default = M.

 

 

 

4

SSCLK

Modulated Spread Spectrum Output Clock. The output frequency is referenced to input frequency. Refer

to Table 2 for the amount of modulation (Spread%).

 

 

5

REFCLK

Unmodulated Reference Clock Output. The unmodulated output frequency is the same as the input

frequency.

 

 

6

PD#

Power-Down Control Pin. Default = H (Vdd).

 

 

 

7

Vdd

Positive Power Supply.

 

 

 

8

XOUT

Clock, Crystal, or Ceramic Resonator Output Pin. Leave this pin unconnected if an external clock is used

at XIN pin.

 

 

Overview

The Cypress CY25818/19 products are Spread Spectrum Clock Generator (SSCG) ICs used for the purpose of reducing EMI found in today’s high-speed digital electronic systems. The devices use a Cypress proprietary phase-locked loop (PLL) and Spread Spectrum Clock (SSC) technology to synthesize and modulate the frequency of the input clock. By frequency modulating the clock, the measured EMI at the fundamental and harmonic frequencies is greatly reduced. This reduction in radiated energy can significantly reduce the cost of complying with regulatory agency requirements and improve time to market without degrading system perfor- mance.

The input frequency range is 8–16 MHz for the CY25818 and 16–32 MHz for the CY25819. Both products accept external clock, crystal, or ceramic resonator inputs.

The CY25818/19 provide separate modulated (SSCLK) and unmodulated reference (REFCLK) clock outputs which are the same frequency as the input clock frequency. Down spread frequency modulation can be selected by the user, based on three discrete values of Spread%. A separate power down function is also provided.

Table 2. Spread% Selection

The CY25818/19 products are available in an 8-pin SOIC (150-mil) package with a commercial operating temperature range of 0–70°C. Contact Cypress for availability of –40 to +85°C industrial temperature range operation or TSSOP package versions. Refer to the CY25568, CY25811, CY25812, and CY25814 products for other functions such as clock multiplication of 1×, 2×, or 4× to generate a wide range of Spread Spectrum output clocks from 4 to 128 MHz.

Input Frequency Range and Selection

CY25818/19 input frequency range is 8–32 MHz. This range is divided into two segments, as given in Table 1.

Table 1. Input and Output Frequency Selection

Product

Input/Output Frequency Range

CY25818

8–16 MHz

CY25819

16–32 MHz

Spread% Selection

CY25818/19 SSCG products provide Down-Spread frequency modulation. The amount of Spread% is selected by using 3-Level S0 digital input. Spread% values are given in Table 2.

XIN (MHz)

Product

S0 = 1

S0 = 0

S0 = M

 

 

Down (%)

Down (%)

Down (%)

8–10

CY25818

–3.0

–2.2

–0.7

10–12

CY25818

–2.7

–1.9

–0.6

12–14

CY25818

–2.5

–1.8

–0.6

14–16

CY25818

–2.3

–1.7

–0.5

16–20

CY25819

–3.0

–2.2

–0.7

20–24

CY25819

–2.7

–1.9

–0.6

24–28

CY25819

–2.5

–1.8

–0.6

28–32

CY25819

–2.3

–1.7

–0.5

Document #: 38-07362 Rev. *B

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Contents Pin Configuration FeaturesBlock Diagram ApplicationsInput Frequency Range and Selection Pin.DescriptionOverview Spread% SelectionMaximum Ratings 1 Level Digital InputsModulation Rate Parameter Description Conditions Min Typ Max UnitICLKFR2 Characteristics CurvesICLKFR1 XIN Application SchematicSscg Profiles Part Number Package Type Product Flow Package Drawing and DimensionsOrdering Information Lead-freeOXC Issue Orig. Description of Change DateDocument History RBI

CY25819, CY25818 specifications

Cypress Semiconductor, a renowned player in the embedded solutions market, has introduced two advanced clock generators: the CY25819 and CY25818. These devices stand out in the realm of high-performance clock management solutions, offering a variety of features that make them ideal for various applications such as telecommunications, consumer electronics, and computing systems.

The CY25819 and CY25818 utilize cutting-edge technology to provide users with exceptional flexibility and reliability. Both devices are designed to generate multiple clock outputs from a single reference clock input, which ultimately reduces component count and simplifies circuit design. This is especially valuable in modern electronic designs that prioritize space efficiency and power reduction.

One of the key features of the CY25819 is its ability to produce up to nine output clocks, while the CY25818 generates up to six. This capability allows designers to meet the diverse timing requirements of complex systems seamlessly. Additionally, both models support a wide range of output frequencies, which can be easily configured through I2C communication. This programmability ensures that designers can adapt the device to their specific needs, enhancing its versatility for different applications.

In terms of performance characteristics, both the CY25819 and CY25818 exhibit low phase noise and jitter, critical metrics for applications where timing precision is paramount. The low jitter performance is particularly important in high-speed data transfers and communication interfaces, as it helps maintain signal integrity and minimize errors.

Another notable feature includes power management capabilities. The CY25819 and CY25818 provide multiple power-saving modes, such as a low power sleep mode, which significantly reduces power consumption when the system is idle. This energy-efficient design is aligned with the growing demand for sustainable electronic solutions and extends battery life in portable applications.

Furthermore, these devices are built with robust engineering to ensure high reliability under various operating conditions. They offer a wide temperature range, making them suitable for industrial applications.

In summary, the Cypress CY25819 and CY25818 clock generators are exceptional solutions tailored for complex timing needs in a diverse array of industries. With their high output capabilities, superior performance, energy-efficient features, and reliability, they represent the forefront of clock management technology, enabling engineers to innovate and optimize their designs effectively.