Memory Buffer Self-Tester

Intelligent BIST Solution Integrating RCD, DB & Memory Controller for RDIMM/LRDIMM Verification

The Deep-I Memory Buffer Self-Tester is an integrated intelligent testing solution that combines our Si-proven RCD, Data Buffer (DB), and Memory Controller (MC) IP with advanced Built-In Self-Test (BIST) engines to provide end-to-end autonomous verification of RDIMM and LRDIMM memory modules. By embedding the tester logic on-chip, the self-tester eliminates the need for expensive external ATE equipment, enabling CK/CA path validation through the RCD, DQ/DQS path validation through the DB, full memory controller protocol exercising, and complete DIMM-level stress testing — all driven by on-chip BIST pattern generators and checkers with per-DQ, per-DQS, and per-CA granularity.

RCD+DB+MCIntegrated Test
On-Chip BISTNo External ATE
PRBS-31Pattern Generation
Per-DQ/DQSGranular Testing
Loop-BackData-Path Verify
BER <10⁻¹²Error Rate Target
Eye MarginVoltage & Timing
Si-ProvenProduction Ready
RCD+DB+MCIntegrated Test
On-Chip BISTNo External ATE
PRBS-31Pattern Generation
Per-DQ/DQSGranular Testing
Loop-BackData-Path Verify
BER <10⁻¹²Error Rate Target
Eye MarginVoltage & Timing
Si-ProvenProduction Ready

Self-Tester Architecture

Integrated RCD, DB, and Memory Controller BIST engines for autonomous RDIMM/LRDIMM verification
without external ATE — the tester is the chip itself.

RCD BIST Engine

CK/CA path self-test: exercises the full RCD signal chain including PLL lock verification, CA parity checking, DCS/DCA training mode validation, ALERT_n assertion testing, and per-subchannel loopback through the RCD. Validates fly-by routing integrity to every DRAM position.

CK/CA Path Test

DB BIST Engine

DQ/DQS path self-test: per-DQ and per-DQS PRBS pattern generation and self-checking through each Data Buffer. Validates bidirectional data flow, DQS regeneration, DFE equalization, ZQ calibration, and BCOM sideband protocol across all 10 DBs on LRDIMM.

DQ/DQS Path Test

Memory Controller BIST

Full MC protocol exerciser: generates JEDEC-compliant command sequences (ACT, RD, WR, PRE, REF, MRS) with correct timing, scheduler stress patterns, multi-rank interleaving, and power management mode transitions (self-refresh, power-down, DVFS) to stress the entire DIMM under realistic workloads.

Protocol Exerciser

Eye Margin & BER Analyzer

On-chip eye margin shmoo: sweeps voltage and timing across the data eye to generate 2D BER contour maps per DQ lane. DESTM-compatible real-time signal quality monitoring. Reports pass/fail with programmable BER threshold (target <10⁻¹²) and margin budgets for production screening.

Signal Quality Test

Self-Tester System Architecture

On-chip BIST replaces external ATE — autonomous verification from RCD through DB to DRAM

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Key Benefits

Eliminate external ATE cost, accelerate time-to-market, guarantee first-time-right modules

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Zero External ATE Cost

On-chip BIST engines eliminate the need for multi-million-dollar external ATE equipment. Self-test runs autonomously at power-on or on-demand via I3C sideband trigger, reducing test cost per module dramatically.

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Faster Time-to-Market

Parallel self-test of RCD CK/CA path + DB DQ/DQS path + MC protocol in a single power-on sequence. Complete DIMM-level validation in seconds instead of hours on external testers.

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Per-Lane Diagnostic Granularity

Per-DQ, per-DQS, and per-CA testing isolates failures to individual signal lanes. 2D BER eye contour maps per lane enable precise margin budgeting for production screening and debug.

Key Features

Comprehensive BIST coverage across every signal path on the DIMM

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PRBS Multi-Pattern Engine

Supports PRBS-7, PRBS-15, PRBS-23, PRBS-31 and custom user-defined patterns. Walking-1, walking-0, checkerboard, and worst-case SSO (simultaneous switching output) patterns for comprehensive SI/PI stress.

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Loop-Back Data-Path Verify

RCD loopback (CA pass-through), DB loopback (DQ internal loop), and MC-to-DRAM full-path loop-back modes. Each loop isolates a specific segment of the signal chain for targeted fault localization.

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Real-Time BER & Eye Monitor

On-chip voltage/timing shmoo generates 2D BER contour maps in real-time. DESTM-compatible diagnostics. Programmable BER threshold (10⁻⁹ to 10⁻¹⁵) with automatic pass/fail classification and margin reporting via I3C.

Self-Tester vs External ATE

Why on-chip BIST replaces traditional memory test equipment

Deep-I BIST vs Traditional ATE

Cost, speed, and coverage comparison

Parameter
Deep-I BIST
External ATE
Equipment Cost
On-chip (near zero)
$2M ~ $10M per tester
Test Time per DIMM
Seconds (autonomous)
Minutes ~ Hours
Test Parallelism
Every DIMM self-tests
Limited by tester slots
At-Speed Testing
Full speed (9600 MT/s)
Often speed-limited
In-System Test
Yes (field diagnostics)
No (lab only)
Per-DQ Granularity
✔ Per-DQ/DQS/CA
Depends on setup
Eye Margin Shmoo
✔ On-chip 2D BER
✔ With scope setup

Self-Test Sequence Flow

Autonomous power-on self-test validates every signal path on the DIMM in seconds.

Step 1

PLL Lock & RCD Initialization

BIST engine triggers PLL lock verification, RCD reset sequence via I2C/I3C, and initial control word configuration. Validates clock stability and duty-cycle correction before any data testing begins.

Step 2

CK/CA Path — RCD Loop-Back BIST

RCD enters DCS/DCA training mode. BIST generates CA test patterns on both clock edges (DDR mode), RCD loopback returns via ALERT_n or QLBD/QLBS feedback. Per-subchannel CA bit testing with parity verification. Validates fly-by routing to every DRAM position.

Step 3

DQ/DQS Path — DB Loop-Back BIST

Each of 10 DBs enters loopback mode via BCOM. BIST generates per-DQ PRBS patterns (PRBS-7/15/23/31) through host-side TX → DB internal loop → host-side RX. Per-DQ error counter and BER calculation. ZQ calibration verification per DB. Walking-1 and SSO patterns for SI/PI stress.

Step 4

Full-Path — MC-to-DRAM Stress Test

MC protocol exerciser sends full JEDEC command sequences (ACT/RD/WR/PRE/REF) through RCD to DRAM, data through DB to DRAM and back. Multi-rank interleaving, power-mode transitions, and 2D eye margin shmoo with BER contour mapping per DQ lane. Final pass/fail report via I3C.

See the Self-Tester in Action

Autonomous BIST replaces million-dollar ATE — watch the complete test sequence.

Ready to Eliminate External ATE?

Contact our team to discover how the Deep-I Memory Buffer Self-Tester can cut your DIMM qualification cost and time while improving test coverage and diagnostic granularity.