EWIXP420ABBT Intel, EWIXP420ABBT Datasheet - Page 70
Manufacturer Part Number
Specifications of EWIXP420ABBT
Core Operating Frequency
Operating Temperature (max)
Operating Temperature (min)
Operating Temperature Classification
Lead Free Status / Rohs Status
Hardware Design Guidelines
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
Other important considerations are:
The purpose of bypass capacitors is to provide a regulated power and ground to the
circuits for the short time needed until the regular power supply can provide the
necessary current, when the circuits are switching and therefore they need quick
additional currents. The transient currents needed flow to and from the capacitors.
The IXP42X product line and IXC1100 control plane processors has two supply
voltages: VCC (processor voltage) and VCCP (I/O voltage).
Simulation is recommended to determine if using capacitors smaller than 0.1-µF
capacitors yield better impedance at higher frequencies in your application.
General Decoupling/Bypass Guidelines
Analysis of the complete decoupling circuit may be quite complex. The following
implementation — based on experience — is highly recommended:
• The “island” must be large enough to include the required power supply decoupling
• Minimize signal degradation, the gap between the supply island and the voltage
• Minimize the number of traces routed across the power plane gap, since each
• In general, tantalum capacitors are used
• In general, high-quality MLC capacitor may be used
• Bypassing every Vcc pin is not necessarily required.
• Use the right value capacitor
capacitance, and the necessary connection to the voltage source.
plane should be kept to a minimum: typical gap size is about 0.02 inches.
crossing introduces signal degradation due to the impedance discontinuity that
occurs at the gap. For traces that must cross the gap, route them on the side of the
board next to the ground plane to reduce or eliminate the signal degradation
caused by crossing the gap. When this is not possible, then route the trace to cross
the gap at a right angle (90°).
— Tantalum capacitors may have very low impedance, for example 100 µF, 10v
— However, the design may need to be guarded by specifying at least 2:1 voltage
— In systems where more power variations are designed in, for example local
— Such capacitors also have low impedance, for example, a 0.1-µF, 50-V
— Place one small capacitor per each fast IC (integrated circuit)
— Place one small capacitor for every two slow ICs.
— Place one small capacitor for every four power pins on BGA components
— Place one 1000-pF capacitor for each power pin on clock buffers and clock
— Use 10-pF ceramic SMT capacitors for decoupling clock signals for EMI control.
tantalum capacitor may have a resistance of 140 mΩ and inductance of 3 nH.
margin as such capacitors can explode.
power downs, additional voltage margin may be required
capacitor may have resistance of 50 mΩ and inductance of 0.8 nH.
IXP42X product line and IXC1100 control plane processors—General Layout and Routing
Document Number: 252817-008US