This website requires the use of JavaScript!
X2Y® Amplifier Decoupling
  • Test #1 uses an AD8221 instrumentation amplifier
  • Pin pattern is amenable to X2Y® circuit 1” use
  • +V / -V power pins are on the same side of the device
X2Y AD8221X2Y AD8221 schematic
  • Test #2 uses an INA121 instrumentation amplifier
  • Pin pattern is amenable to X2Y® ”circuit 2” use
  • +V / -V power pins are on the opposite sides of the device
X2Y INA121X2Y INA121 schematic
Compare Bypass Conventional MLCC vs. X2Y

Test #1

  • Compares external noise rejection of power bypass networks
    – Single X2Y® 330nF rated part, versus four total MLCCs
  • Noise voltage measured directly across IC pins

DUT Configurations

PCB Configuration

Test #1

  • Two layer 1.5mm PCB
  • Single X2Y® 330nF rated part, versus four total MLCCs
  • Noise voltage probed directly across IC pins at IC body

PCB Configuration

PCB Configuration

Test #1

  • Equalized layout parasitics
  • Ground attachment matched between set-ups
  • Capacitor set-backs matched between set-ups

Ground and Capacitor Terminal set-back matched

Noise Injection
  • 200ps edges
    – Comparable to memory
  • 100MHz pulse rate
    – Isolate any cavity / capacitor ringing
  • 400mV on 15V power
    – Alternate tests:
    +15V / -15V
  • – 2.7% pp
Noise Injection +15V Set-upNoise Injection -15V Set-up
VCC_15V+

VCC 15V+

  • X2Y® 3.7mV pp, conventional 5.6mV pp
  • Conventional noise 151% greater than X2Y®
VCC_15V-

VCC 15V-

  • X2Y® 5.3mV pp, conventional 8.9mV pp
  • Conventional noise 168% greater than X2Y®
Compare Bypass Conventional MLCC vs. X2Y

Test #2

  • Amplifier power pin pattern amenable to X2Y® “circuit 2” use
    – the +/- power pins are on the same side of the device
  • Compares single X2Y® 100nF rated (200nF total) per pin vs. a single MLCC 220nF per pin

DUT Configurations

PCB Configuration

Test #2

  • Ground attachment is matched between set-ups
  • Capacitor set-backs are matched between set-ups
  • Compares single X2Y® 100nF rated (200nF total) per pin vs. a single MLCC 220nF per pin

Ground and capacitor set-back are matched

VCC_15V-

VCC 15V- 3.6mV

  • X2Y® 3.6mV pp, conventional 10.1mV pp
  • Conventional noise 280% greater than X2Y®
VCC_15V+

VCC 15V+ 4.9mV

  • X2Y® 4.9mV pp, conventional 17.3mV pp
  • Conventional noise 353% greater than X2Y®
Summary

Test #1

  • Conventional filter using two capacitor values per power pin, four capacitors total results in >= 150% voltage noise compared to just one X2Y® used for both power pins.

Test #2

  • – Conventional filter using one capacitor value per power pin, two capacitors total results in >= 280% voltage noise compared to one X2Y® used for each power pin.
  • Benefits: smaller space, fewer parts, better economy and performance when using X2Y® components.