DRAM Testing

Reading time : 3 minutes
Published on 16 Jun 2020 - Updated on 05 Dec 2020

Electrical

DDR Side Power

VDDQ (DDR Power)

  • Ripple (Min and Max voltage)
  • Mean voltage

Criteria : Check DDR voltage

VRef_DQ

  • Ripple (Min and Max voltage)
  • Mean voltage

Criteria : Vmin = 0.49 _ VDDQ Mean / Vmax = 0.51_ VDDQ Mean

VRef_CA

  • Ripple (Min and Max voltage)
  • Mean voltage

Criteria : Vmin = 0.49 _ VDDQ Mean / Vmax = 0.51_ VDDQ Mean

VTT (Termination power)

  • Ripple (Min and Max voltage)
  • Mean voltage

CPU Side Power

VDDQ (DDR Power)

  • Ripple (Min and Max voltage)
  • Mean voltage

Criteria : Check CPU Datasheet

VRef_DQ

  • Ripple (Min and Max voltage)
  • Mean voltage

Criteria : Vmin = 0.49 _ VDDQ Mean / Vmax = 0.51_ VDDQ Mean

VRef_CA

  • Ripple (Min and Max voltage)
  • Mean voltage

Criteria : Vmin = 0.49 _ VDDQ Mean / Vmax = 0.51_ VDDQ Mean

Data signals

  • For each Data group, check for longest and shortest DQ signal length. Check Setup and Hold time vs DQS signal. Check Overshoot and Undershoot, Vmin, Vmax Rise time, fall time
  • For each Data group, check for longest and shortest DQ signal length. Check Setup and Hold time vs DQS signal.

Command and address signals

  • For following signals WE#, CAS#, RAS#, CS#, Longest address signal, Shortest address signal Check Setup and Hold time vs associated CLK for each CS# signal. Check Vmax, Vmin, T pulse, Rise time, fall time

Datastrobe signals

  • Check Tdss, Tdsh, TDQSS for each DQS signal vs CLK signal
  • Do clock classic test for DQS signals

Functional

For x86 platform :

  • 24h Memtest x86+

For ARM platform :

  • 24h Memtester under linux
  • 24h mtest under Uboot

For All platforms :

  • All RAM slots are functional with all DDR in the AVL list
  • Detected memory size is correct in Bios and OS ( for linux use cat/proc/meminfo)
  • Check memory bandwidth (Linux : steam)

2nd source

  • All first source tests
  • EMI
  • SRT

Testing tools

Uboot

  • Memory stress test : mtest

Linux

Testing

Document Category Item
Hardware RAM Power Vddq Min, Max, Mean voltages (ram side)
Hardware RAM Vrefdq Min, Max, Mean voltages (ram side)
Hardware RAM Vreca Min, Max, Mean voltages (ram side)
Hardware RAM Vtt Min, Max, Mean voltages (ram side)
Hardware RAM Power Vddq Min, Max, Mean voltages (CPU side)
Hardware RAM Vrefdq Min, Max, Mean voltages (CPU side)
Hardware RAM Vreca Min, Max, Mean voltages (CPU side)
Hardware RAM Vtt Min, Max, Mean voltages (CPU side)
Hardware RAM For each data group on longest and shortest DQ : Check Setup and Hold time vs DQS signal.
Hardware RAM For each data group on longest and shortest DQ : Check Overshoot and Undershoot, Vmin, Vmax Rise time, fall time
Hardware RAM For following signals WE#, CAS#, RAS#, CS#, Longest address signal, Shortest address signal Check Setup and Hold time vs associated CLK for each CS# signal. Check Vmax, Vmin, T pulse, Rise time, fall time
Hardware RAM Datastrobe : Check Tdss, Tdsh, TDQSS for each DQS signal vs CLK signal
Hardware RAM Do clock classic test for DQS signals
Functional RAM 24h Memtester under linux
Functional RAM 24h mtest under Uboot
Functional RAM Detected memory size is correct in Bios and OS ( for linux use cat/proc/meminfo)
Functional RAM Check memory bandwidth