Cypress CY25818, CY25819 manual Level Digital Inputs, Modulation Rate, Maximum Ratings 1

Page 3

CY25818/19

3-Level Digital Inputs

S0 digital input is designed to sense three logic levels desig- nated as HIGH “1,” LOW “0,” and MIDDLE “M.” With this 3-Level digital input logic, the 3-Level logic is able to detect three different logic levels.

The S0 pin includes an on-chip 20K (10K/10K) resistor divider. No external application resistors are needed to implement 3-Level logic, as follows.

Logic Level “0”: 3-Level logic pin connected to GND.

Logic Level “M”: 3-Level logic pin left floating (no connection.)

Logic Level “1”: 3-Level logic pin connected to Vdd. Figure 1 illustrates how to implement 3-Level Logic.

LO G IC

LO G IC

LO G IC

LO W (0)

M ID D LE (M )

H IG H (H )

 

 

 

 

 

 

V D D

 

 

 

S 0

 

S0

 

 

S 0

 

 

to VSS

U N C O NN EC TED

to V DD

 

 

 

 

 

 

 

 

Modulation Rate

Spread Spectrum Clock Generators utilize frequency modulation (FM) to distribute energy over a specific band of frequencies. The maximum frequency of the clock (fmax) and minimum frequency of the clock (fmin) determine this band of frequencies. The time required to transition from fmin to fmax and back to fmin is the period of the Modulation Rate, Tmod. The Modulation Rates of SSCG clocks are generally referred to in terms of frequency, and fmod = 1/Tmod.

The input clock frequency, fin, and the internal divider determine the Modulation Rate.

In the case of CY25818/19 devices, the (Spread Spectrum) Modulation Rate, fmod, is given by the following formula:

fmod = fIN/DR

where fmod is the Modulation Rate, fIN is the Input Frequency, and DR is the Divider Ratio, as given in Table 3.

V S S

Figure 1. 3-Level Logic

Table 3. Modulation Rate Divider Ratios

Product

 

Input Frequency Range

 

 

 

Divider Ratio (DR)

 

 

CY25818

 

8–16 MHz

 

 

 

 

256

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CY25819

 

16–32 MHz

 

 

 

 

512

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Maximum Ratings[1, 2]

 

Input Voltage Relative to Vss:

 

Vss + 0.3V

Supply Voltage (Vdd):

+ 5.5V

Operating Temperature:

 

 

0°C to + 70°C

Storage Temperature:

 

 

–65°C to + 150°C

Input Voltage Relative to Vdd:

Vdd + 0.3V

 

 

 

 

 

 

 

 

 

 

Table 4. DC Electrical Characteristics Vdd = 3.3V ±10%, TA = 0°C to +70°C and CL = 15 pF (unless otherwise noted)

 

 

 

 

 

 

 

 

 

 

 

Parameter

Description

Conditions

 

 

Min.

Typ.

 

Max.

 

Unit

Vdd

Power Supply Range

 

 

2.97

3.3

 

3.63

 

V

 

 

 

 

 

 

 

 

 

 

VINH

Input HIGH Voltage

S0 Input

 

0.85 Vdd

Vdd

 

Vdd

 

V

VINM

Input MIDDLE Voltage

S0 Input

 

0.40 Vdd

0.50 Vdd

 

0.60 Vdd

 

V

VINL

Input LOW Voltage

S0 Input

 

0.0

0.0

 

0.15 Vdd

 

V

VOH1

Output HIGH Voltage

IOH = 4 ma, SSCLK and REFCLK

2.4

 

 

V

VOH2

Output HIGH Voltage

IOH = 6 ma, SSCLK and REFCLK

2.0

 

 

V

VOL1

Output LOW Voltage

IOL = 4 ma, SSCLK Output

 

 

0.4

 

V

VOL2

Output LOW Voltage

IOL = 10 ma, SSCLK Output

 

 

1.2

 

V

CIN1

Input Capacitance

XIN (Pin 1) and XOUT (Pin 8)

6.0

7.5

 

9.0

 

pF

CIN2

Input Capacitance

All Digital Inputs

 

3.5

4.5

 

6.0

 

pF

IDD1

Power Supply Current

FIN=8 MHz, no load

 

 

10.0

 

12.5

 

mA

IDD3

Power Supply Current

FIN=32 MHz, no load

 

 

19.0

 

23.0

 

mA

IDD4

Power Supply Current

PD# = Vss

 

 

150

 

250

 

mA

Document #: 38-07362 Rev. *B

Page 3 of 7

[+] Feedback

Image 3
Contents Applications FeaturesBlock Diagram Pin ConfigurationSpread% Selection Pin.DescriptionOverview Input Frequency Range and SelectionParameter Description Conditions Min Typ Max Unit Level Digital InputsModulation Rate Maximum Ratings 1Characteristics Curves ICLKFR1ICLKFR2 Application Schematic Sscg ProfilesXIN Lead-free Package Drawing and DimensionsOrdering Information Part Number Package Type Product FlowRBI Issue Orig. Description of Change DateDocument History OXC

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.