Power Integrity Probing

Power Integrity Measurement

Challenge

The core noise, IO noise, digital circuit noise, and PLL noise should be characterized before making high-volume production. Power noise measurement results are functions of power noise frequency, system circuit sensitivity, and input patterns.

As the system package gets smaller, such as package-on-package or multi-chip packages, the power noise becomes more important.

Power Noise  Measurement Tips

  1. System power noise should be set up to include different state transitions, such as reset, sleep/wakeup mode, read/write turn-around, and multiple IO switching mode.
  2. In additional to random noise, the data bus frequency should include power plane resonance frequency patterns that are usually about hundreds of megahertz.
  3. Use a bypass cap close to the ASIC on the backside of the board for power noise probing.
  4. The probe should have short ground leads to reduce the probing effect.
  5. Avoid ground lead since it may create AC voltage drop that can be included in the noise source, especially for high frequency power noise measurements.

 

Helpful links

  1. Power Integrity course by CEI
  2. Designing and modeling of PI
  3. Signal/Power integrity interactions

Good Practices

Power plane impedance measurement, including silicon, package, bypass capacitors, PCB and VRM, can affect power plane noise resonance frequency.

  1. A significant noise source can be observed if the system is excited close to the system resonance frequency.
  2. In order to measure power plane impedance, use a strong probe tips to probe the bypass capacitors.

 

Power Integrity Probing Demonstrations

Power Integrity Probing Demonstration

Power Integrity probing displayed on a PC

 Power Integrity Probing Demonstration 

Power Integrity probing with FP160 and RProbe

About PacketMicro

PacketMicro, based in Silicon Valley, provides a wide range of gigahertz probes, probe positioners, bench-top probe stations, and digital microscopes. In addition, PacketMicro offers wireless modules and engineering services in Bluetooth Smart, ZigBee, and wireless sensor networks. PacketMicro customers include many Fortune 100 companies.

Get in touch

PacketMicro, Inc.
1900 Wyatt Drive, Suite 9
Santa Clara, CA 95054
USA

+1 408 675 3900 (Main)

+1 408 580 0059

info@packetmicro.com