Texas Instruments SMJ64C64S-45JDM 64K×8 SRAM, JDM-28 - 45ns Hermetic CMOS

SMJ64C64S-45JDM Legacy Hermetic 64K×8 CMOS Static RAM (SRAM) Overview

The SMJ64C64S-45JDM from Texas Instruments is a high-reliability 64K×8 static random-access memory (SRAM) engineered for legacy industrial, aerospace, and defense systems. Part of TI’s iconic CMOS SRAM portfolio, it provides fast, non-volatile temporary data storage—ideal for applications where low latency, environmental resilience, and legacy compatibility are non-negotiable. Its hermetic J-lead DIP (JDM-28) package, 45ns access time, and wide temperature range make it a staple for maintaining or upgrading older electronics that rely on consistent, rugged memory performance. Fabricant de circuits intégrés propose ce composant de mémoire de qualité industrielle dans le cadre de son portefeuille de semi-conducteurs Texas Instruments de confiance.

SMJ64C64S-45JDM Technical Parameters

Principales caractéristiques fonctionnelles

Avantages par rapport aux autres solutions de mémoire patrimoniale

The SMJ64C64S-45JDM outperforms generic SRAMs and plastic-packaged alternatives for legacy systems, starting with its hermetic JDM-28 package. Unlike plastic DIPs (which absorb moisture and degrade in 2–3 years), its ceramic enclosure and vacuum seal ensure 10+ years of reliability in harsh environments. “We replaced plastic SRAMs with this component in our offshore oil rig sensors—memory failures dropped from 22% to 0% annually,” confirms a senior engineer at a leading energy equipment manufacturer.

Its 45ns access time balances speed and power efficiency for mid-speed legacy systems (e.g., 15–30MHz PLCs). Slower SRAMs (60ns+) cause data lag, leading to unsynchronized machine control, while faster 30ns SRAMs waste power—unnecessary for non-high-speed applications. This sweet spot makes it ideal for most industrial data logging and test equipment use cases.

The JDM-28’s J-lead design offers better PCB solder joint reliability than standard through-hole DIPs, reducing vibration-induced failures in automotive or aerospace systems. Unlike modern surface-mount SRAMs, it retains compatibility with legacy PCBs designed for J-lead packages, avoiding costly redesigns or adapter boards.

As a CMOS SRAM, it consumes 70% less power than TTL SRAMs (e.g., 74LS series), extending battery life in portable test tools. Its -55°C to +125°C temperature range also outperforms commercial-grade SRAMs (0°C–70°C), ensuring performance in freezing arctic sensors or hot desert-based radar systems.

Typical Applications of SMJ64C64S-45JDM

The SMJ64C64S-45JDM excels in legacy and mission-critical systems where ruggedness, speed, and compatibility matter. Key use cases include:

• Aérospatiale et défense (tampons de données avioniques, mémoire de systèmes de guidage de missiles, enregistreurs de stations terrestres de satellites)
• Automatisation industrielle (automates programmables anciens, enregistreurs de données de machines industrielles, systèmes de contrôle de processus à haute température)
• Test et mesure (générateurs de signaux robustes, équipement de test de résistance à l'environnement, mémoire d'oscilloscope)
• Énergie et électricité (contrôleurs de surveillance de puits de pétrole/gaz, processeurs de données de postes à haute tension, mémoire de capteurs d'éoliennes)
• Sécurité et surveillance (tampons de données de capteurs périmétriques militaires, modules d'enregistrement de caméras extérieures)

L'expertise de Texas Instruments en matière de mémoire CMOS hermétique

As a Texas Instruments product, the SMJ64C64S-45JDM leverages TI’s 70+ years of leadership in industrial and military-grade semiconductors. TI’s hermetic CMOS SRAMs undergo rigorous testing to meet strict standards: temperature cycling (-55°C to +125°C), humidity resistance (85% RH, 85°C), and electrostatic discharge (ESD) protection (2kV human-body model). This commitment to durability has made TI a trusted partner for Boeing, Siemens, and Lockheed Martin, who rely on TI’s legacy memory components to maintain critical older systems that cannot be easily replaced.

Foire aux questions (FAQ)

What is a 64K×8 SRAM, and how does the SMJ64C64S-45JDM work?

A 64K×8 SRAM is a static random-access memory that stores 65,536 (64K) independent 8-bit data values (512 Kbits total) and allows fast read/write access without power refresh. The SMJ64C64S-45JDM uses CMOS technology and parallel pins: address pins select a memory location, data pins transfer 8-bit data, and control pins (chip enable, write enable) manage access. Its 45ns access time ensures data is processed quickly for real-time legacy systems.

Why is 45ns access time important for industrial data loggers?

Industrial data loggers capture sensor data at regular intervals (e.g., 1ms per sample) and need memory that can store data without lag. A 45ns access time means the SRAM can write one 8-bit sample in 45 billionths of a second—fast enough to keep up with 22,000+ samples per second. Slower 60ns SRAMs would cause buffer overflow, leading to lost data points—critical gaps in quality control or machine health monitoring.

How does the hermetic JDM-28 package improve reliability in coastal environments?

Coastal environments expose electronics to salt-laden air, which corrodes metal pins and degrades plastic packages. The JDM-28’s hermetic ceramic enclosure seals the SRAM in an inert gas, preventing salt ingress. Its J-lead solder joints also create a tighter seal with PCBs than standard through-hole pins, reducing corrosion. This ensures 10+ years of reliability vs. 2–3 years for plastic DIP SRAMs in coastal applications.

Quels sont les avantages de la technologie CMOS par rapport à la technologie TTL pour cette SRAM ?

CMOS technology reduces power consumption by 70% vs. TTL (100mW vs. 300mW for TTL SRAMs), which is critical for battery-powered test tools or energy-constrained industrial systems. CMOS also provides better noise margin (0.4V–0.5V vs. 0.3V for TTL), making the SMJ64C64S-45JDM more resistant to electrical interference in factory floors or radar systems—cutting data corruption errors by 40%.

Is the SMJ64C64S-45JDM compatible with legacy CMOS/TTL mixed-signal systems?

Yes. It is compatible with both TI’s 74HC/74HCT CMOS and 54LS TTL logic families, thanks to its CMOS-compatible input/output levels and wide noise margin. This makes it a drop-in replacement for older SRAMs in mixed-signal systems (e.g., TTL controllers paired with CMOS sensors), avoiding costly PCB redesigns or logic level translators. It also fits existing JDM-28 sockets, simplifying maintenance for legacy equipment.