Intel IXP43X manual Decoupling Capacitance Recommendations, VCC Decoupling, 14.3 VCC33 Decoupling

Page 54

Intel® IXP43X Product Line of Network Processors—Hardware Design Guidelines

 

Nominal

Description

Name

voltage

 

†

 

 

 

 

VCCPUSB

3.3V

3.3-V power supply input pins are used for USB IO.

 

 

 

VCCUSBCORE

1.3V

1.3-V power supply input pins are used for USB IO core.

 

 

 

 

 

1.3-V power supply input pins are used for internal logic of the analog phase lock-loop circuitry.

VCCA

1.3V

Requires special power filtering circuitry. See the Intel® IXP43X Product Line of Network

 

 

Processors Datasheet

 

 

 

3.14.1 Decoupling Capacitance Recommendations

It is common practice to place decoupling capacitors between the supply voltages and ground. Placement can be near the input supply pins and ground, with one 100-nF capacitor per pin. Additional decoupling capacitors can be place all over the board every 0.5" to 1.0". This ensures good return path for currents and reduce power surges and high-frequency noise.

It is also recommended that 4.7-µF to 10-µF capacitors be placed every 2" to 3".

3.14.2VCC Decoupling

Connect one 100-nF capacitor per each VCC pin. Placement should be as close as possible to the pin. It is also recommended to place a 4.7-µF capacitor near the device.

Use traces as thick as possible to eliminate voltage drops in the connection.

3.14.3VCC33 Decoupling

Connect one 100-nF capacitor per each Vcc33 pin. Placement should be as close as possible to the pin. It is also recommended to place a 4.7-µF capacitor near the device.

Use traces as thick as possible to eliminate voltage drops in the connection.

3.14.4VCCDDR Decoupling

Connect one 100-nF capacitor per each VCCDDR pin. Placement should be as close as possible to the pin. It is also recommended to place a 4.7-µF capacitor near the device.

Use traces as thick as possible to eliminate voltage drops in the connection.

3.14.5Power Sequence

Power sequence is crucial for proper functioning of the IXP43X network processors. For a complete description of power sequencing, see the Intel® IXP43X Product Line of Network Processors Datasheet.

3.14.6Reset Timing

Proper reset timing is also a crucial requirement for proper functioning of the IXP43X network processors. There are two reset signal PWRON_RESET_N and RESET_IN_N which required assertion sequence.

For a complete description of their functionality, see the Intel® IXP43X Product Line of Network Processors Datasheet and its section titled Reset Timings. PWRON_RESET_N is used as a Power Good and RESET_IN_N is used for resetting internal registers.

Intel® IXP43X Product Line of Network Processors

 

HDG

April 2007

54

Document Number: 316844; Revision: 001US

Page 53 Page 55
Image 54
Page 53 Page 55
Contents Intel IXP43X Product Line of Network Processors Hardware Design GuidelinesIntel IXP43X Product Line of Network Processors HDGApril Contents Figures Tables Document Number 316844 Revision 001US § § Date Revision Description001 Initial release HDG Content Overview Chapter Name DescriptionList of Acronyms and Abbreviations Sheet 1 Related DocumentationAcronyms Term ExplanationOverview List of Acronyms and Abbreviations Sheet 2HDG Intel IXP435 Network Processor Block Diagram Typical Applications System Architecture Description System Memory MapIntel IXP43X Product Soft Fusible Features Sheet 1 Soft Fusible FeaturesSignal Type Definitions Symbol DescriptionDDRII/I Sdram Interface Soft Fusible Features Sheet 2USB Host Each USB can be Enable separately EthernetType Signal InterfaceDDRII/I Sdram Interface Pin Description Sheet 1 Name Device-Pin Connection Terminatio Description FieldDDRII/I Sdram Initialization DDRII/I Sdram Interface Pin Description Sheet 2Expansion Bus Signal Recommendations Sheet 1 Expansion BusType Pull Name Recommendations Field Down Boot/Reset Strapping Configuration Sheet 1 Reset Configuration StrapsExpansion Bus Signal Recommendations Sheet 2 Name Type Pull Recommendations Field DownBoot/Reset Strapping Configuration Sheet 2 Intel XScale Processor Cfg0 Cfg1 Cfgenn Actual Core Speed Setting Intel XScale Processor Operation Speed3 8-Bit Device Interface MHz4 16-Bit Device Interface Flash Interface 16-Bit Device InterfaceUart Interface Flash Interface ExampleUart Signal Recommendations MII Interface Uart Interface ExampleSignal Interface MII MII NPE a Signal RecommendationsMII NPE C Signal Recommendations Sheet 1 MII NPE C Signal Recommendations Sheet 2 MAC Management Signal Recommendations NPE a and NPE CDevice Connection, MII Gpio Interface MII Interface ExampleGpio Signal Recommendations USB InterfaceDesign Notes USB Host Signal Recommendations Name Type Pull Description Field DownCommon Mode Choke Host Device Utopia Level 2 Interface Utopia Level 2/MIIAType Pull Name Description Field Down UTPOPADDR40 UTPOPDATA4UTPOPDATA75 UtpopfciUtpipsoc ClavUtpipfci ETHARXDATA30 EtharxclkUTPIPDATA7 UTPIPDATA5UTPIPDATA6 UTPIPADDR40HSS Interface Device ConnectionHSSTXCLK0 High-Speed, Serial InterfaceHSSTXDATA0 HSSRXDATA0SSP Interface HSS Interface ExampleSynchronous Serial Peripheral Port Interface PCI Interface Serial Flash and SSP Port SPI Interface ExamplePCI Controller Sheet 1 Pciintan PCI Interface Block DiagramPCI Controller Sheet 2 PciclkinPCI Host/Option Interface Pin Description Sheet 1 Connect signal to same pin between PCI Parity Two devicesPCI Option Interface Type Option Description Name Device-Pin Connection FieldPCI Host/Option Interface Pin Description Sheet 2 On the Option device, these signals are notSignal PCIREQN0 to one PCIREQN30 inputs to the Host Type Option Name Device-Pin Connection Description FieldJtag Interface PCI Host/Option Interface Pin Description Sheet 3Input System Clock Clock SignalsClock Signals Clock OscillatorRecommendations for Crystal Selection Power Power SupplyNominal Name Voltage Description Decoupling Capacitance Recommendations Power SequenceReset Timing VCC Decoupling§ § General Recommendations Component PlacementPCB Overview Component SelectionComponent Placement on a PCB Stack-Up SelectionControlled-impedance traces Low-impedance power distribution Layer Stackup General Layout and Routing Guide General Layout GuidelinesSignal Changing Reference Planes General Component SpacingGood Design Practice for VIA Hole Placement Clock Signal Considerations Pad-to-Pad Clearance of Passive Components to a PGA or BGAMII Signal Considerations USB V2.0 ConsiderationsCrosstalk Power and Ground Plane EMI Design ConsiderationsTrace Impedance § § @33 MHz Electrical InterfaceTopology Tcyc = 30 nSec Tval = 11 nSec Tprop = 10 nSecClock Distribution PCI Address/Data Routing GuidelinesParameter Routing Guidelines Trace Length Limits PCI Clock Routing GuidelinesSignal Loading Routing GuidelinesDdrii / Ddri Sdram IntroductionDrasn / Ddrrasn DDRII/I Signal GroupsGroup Signal Name Description Dcasn / DdrcasnDDR Sdram Supported Ddri 16-bit Sdram Configurations Supported Ddri 32-bit Sdram ConfigurationsSupported Ddrii 32-bit Sdram Configurations SizeaAddress Size Leaf Select Total Supported Ddrii 16-bit Sdram ConfigurationsDDRII/DDRI Rcomp and Slew Resistances Pin Requirements Technology Arrangement BanksDDR-II Symbol Parameter Units Min Max Ddrii OCD Pin RequirementsDDR Clock Timings DDR Sdram Write Timings DDRII-400 MHz Interface -- Signal Timings Symbol Parameter Minimum Nominal Maximum UnitsTiming Relationships DDR II/I Sdram Interface -- Signal TimingsSymbol Parameter Minimum Nom Maximum Units Printed Circuit Board Layer StackupSignal Package Lengths Sheet 1 Group Signal Name Length milTiming Relationships Signal Package Lengths Sheet 2 Signal Package Lengths Sheet 3 Clock GroupData and Control Groups Parameter DefinitionDdrii Data and Control Signal Group Routing Guidelines DCB70/DDRCB70, DDQ310 / DDRDQ310Ddrii Command Signal Group Routing Guidelines Signal Group Members§ §
Top Page Image Contents