PDF C9851 Data sheet ( Hoja de datos )

Número de pieza	C9851
Descripción	Clock Generator
Fabricantes	Cypress Semiconductor
Logotipo
Hay una vista previa y un enlace de descarga de C9851 (archivo pdf) en la parte inferior de esta página. Total 14 Páginas
No Preview Available ! www.DataSheet4U.com PRELIMINARY C9851 Clock Generator for PentiumIII Server and Workstation Applications Product Features • Six pairs of current referenced differential clocks • Two 3V 180° displaced Mref clocks for DRCG • One 66.6 MHz reference output • One 14.318 MHz reference output • Select logic for Differential Swing Control, Test mode, Hi-Z, Power-down, Spread spectrum, and limited frequency select • Cypress Spread Spectrum for EMI reduction • 48 Pin SSOP Package Frequency Selection Table SEL 100/133 SELA SELB CPU(1:6), CPU#(1:6) 0 00 100 MHz 0 01 100 MHz 0 10 200 MHz 0 11 Hi-Z 1 0 0 133.3 MHz 1 01 25 MHz 1 10 200 MHz 1 11 REF/2 Block Diagram Product Description This device provides the necessary clocks for a differential host bus system in multi-processor servers and workstations. It also generates a 66.6MHz hub clock for interfacing with a complimentary part, the Cypress B9852. The 2 Mref clock outputs are 180 degrees out of phase and are used for interfacing with the Direct Rambus Clock Generator (DRCG), C9820, C9821, or C9822. This device integrates the Cypress spread spectrum technology for optimum EMI reduction. 3VMref, 3Vmref_b 50 MHz Low 50 MHz Hi-Z 66.67 MHz 50 MHz 66.7 MHz REF/4 Table 1 3V66 66.67 MHz Low 66.67 MHz Hi-Z 66.67 MHz 66.67 MHz 66.67 MHz REF Pin Configuration REF 14.318 MHz Low 14.318 MHz Hi-Z 14.318 MHz 14.318 MHz 14.318 MHz REF XIN OSC XOUT MultSel(0:1) Spread# SelA SelB SEL100/133 VCO PwrDwn# I Control VDDR REF VSSR VDDA I_Ref VSSI CPU (1:6) CPU (1:6)# VDDM 3VMRef 3VMRef_b VSSM VDDL 3V66 VSSL VSSR Ref VDDR XIN XOUT VSSR VDDM 3VMref 3VMref_b VSSM VDD VSS VDDL 3V66 VSSL SEL100/133 MultSel0 MultSel1 VDDA VSSA SelA SelB Spread# PwrDwn# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 48 VDD 47 VSS 46 VDDC 45 CPU1 44 CPU1# 43 VSSC 42 CPU2 41 CPU2# 40 VDDC 39 CPU3 38 CPU3# 37 VSSC 36 CPU4 35 CPU4# 34 VDDC 33 CPU5 32 CPU5# 31 VSSC 30 CPU6 29 CPU6# 28 VDDC 27 I_Ref 26 VSSA 25 VDDA Cypress Semiconductor Corporation 525 Los Coches St. Milpitas, CA 95035. Tel: 408-263-6300, Fax: 408-263-6571 http://www.cypress.com Document#: 38-07068 Rev. 05/04/2001 Page 1 of 14 1 page PRELIMINARY C9851 Clock Generator for PentiumIII Server and Workstation Applications Group Limits and Parameters (applicable to all settings: Sel133/100# = x) (Continued) Output name CPU[(1:6), (1:6)#] 3VMref, 3VMref_b REF 3V66 Table 2. Max Load Rs = 33.2Ω, Rp = 49.9Ω 30 pF 20 pF 30 pF Lumped Test Load Configurations The following shows lumped test load configurations for the differential Host Clock Outputs. (MULTsel1 = 0, MULTsel0 = 1) Rs 33.2ohm Rp 49.9ohm Rs 33.2ohm Rp 49.9ohm Test Nodes Fig.1A Cypress Semiconductor Corporation 525 Los Coches St. Milpitas, CA 95035. Tel: 408-263-6300, Fax: 408-263-6571 http://www.cypress.com Document#: 38-07068 Rev. 05/04/2001 Page 5 of 14 5 Page PRELIMINARY C9851 Clock Generator for PentiumIII Server and Workstation Applications Suggested Oscillator Crystal Parameters Characteristic Symbol Min Typ Max Units Conditions Frequency Fo 14.17 14.31818 14.46 MHz Tolerance TC - - +/-100 PPM Note 1 Frequency Stability TS - - +/- 100 PPM Stability (TA -10 to +60C) Note 1 Operating Mode -- - - Parallel Resonant, Note 1 Load Capacitance CXTAL - 20 - pF The crystal’s rated load. Note 1 Effective Series Resistance (ESR) RESR - 40 - Ohms Note 2 Note1: For best performance and accurate frequencies from this device, It is recommended but not mandatory that the chosen crystal meets or exceeds these specifications Note 2: Larger values may cause this device to exhibit oscillator startup problems To obtain the maximum accuracy, the total circuit loading capacitance should be equal to CXTAL. This loading capacitance is the effective capacitance across the crystal pins and includes the clock generating device pin capacitance (CFTG), any circuit trace capacitance (CPCB), and any onboard discrete load capacitance (CDISC). The following formula and schematic illustrates the application of the loading specification of a crystal (CXTAL)for a design. CL = (CXINPCB + CXINFTG + CXINDISC) X (CXOUTPCB + CXOUTFTG + CXOUTDISC) (CXINPCB + CXINFTG + CXINDISC) + (CXOUTPCB + CXOUTFTG + COUTDISC) Where: CXTAL CXOUTFTG CXOUTFTG CXINPCB CXOUTPCB CXINDISC CXOUTDISC = the load rating of the crystal = the clock generators XIN pin effective device internal capacitance to ground = the clock generators XOUT pin effective device internal capacitance to ground = the effective capacitance to ground of the crystal to device PCB trace = the effective capacitance to ground of the crystal to device PCB trace = any discrete capacitance that is placed between the XIN pin and ground = any discrete capacitance that is placed between the XOUT pin and ground CXINPCB CXINDISC XIN CXINFTG CXOUTPCB CXOUTDISC XOUT CXOUTFTG Clock Generator As an example, and using this formula for this datasheet’s device, a design that has no discrete loading capacitors (CDISC) and each of the crystal to device PCB traces has a capacitance (CPCB) to ground of 4pF (typical value) would calculate as: CL = (4pF + 36pF + 0pF) X (4pF + 36pF + 0pF) = 40 X 40 = 1600 = 20pF (4pF + 36pF + 0pF) + (4pF + 36pF + 0pF) 40 + 40 80 Therefore to obtain output frequencies that are as close to this data sheets specified values as possible, in this design example, you should specify a parallel cut crystal that is designed to work into a load of 20pF Cypress Semiconductor Corporation 525 Los Coches St. Milpitas, CA 95035. Tel: 408-263-6300, Fax: 408-263-6571 http://www.cypress.com Document#: 38-07068 Rev. ** 05/04/2001 Page 11 of 14 11 Page

Páginas	Total 14 Páginas
PDF Descargar	[ Datasheet C9851.PDF ]

Hoja de datos destacado

Número de pieza	Descripción	Fabricantes
C9851	Clock Generator	Cypress Semiconductor

Número de pieza	Descripción	Fabricantes
SLA6805M	High Voltage 3 phase Motor Driver IC.	Sanken
SDC1742	12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters.	Analog Devices

DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares,
permitiéndote verlos en linea o descargarlos en PDF.

DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar