Texas Instruments SMJ68CE16L-70JDM 128K×8 SRAM, JDM-32 - 70ns CMOS ermetico

SMJ68CE16L-70JDM Legacy Hermetic 128K×8 CMOS Static RAM (SRAM) Overview

The SMJ68CE16L-70JDM from Texas Instruments is a high-reliability 128K×8 static random-access memory (SRAM) engineered for legacy industrial, aerospace, and defense systems. Part of TI’s trusted portfolio of hermetic memory components, it delivers non-refresh temporary data storage—ideal for applications where environmental resilience, legacy compatibility, and balanced speed/power efficiency are non-negotiable. Its J-lead DIP (JDM-32) package, 70ns access time, and wide temperature range make it a staple for maintaining older electronics that demand consistent performance in harsh conditions. Produttore di circuiti integrati offre questo componente di memoria di livello industriale come parte del suo portafoglio di semiconduttori di fiducia di Texas Instruments.

Technical Parameters for SMJ68CE16L-70JDM Industrial SRAM

Parametro	Valore	Unità
Funzione	Memoria statica ad accesso casuale (SRAM) 128K×8
Configurazione della memoria	131,072 × 8	Bits (1024 Kbits / 128 Kbytes total)
Tempo di accesso (max)	70	ns (a 5V, 25°C)
Intervallo di tensione di alimentazione	Da 4,5 a 5,5	V (alimentazione singola, compatibile CMOS)
Dissipazione di potenza a riposo (tipica)	82	mW (a 5 V, senza carico)
Tipo di confezione	JDM-32 (confezione J-Lead Dual In-Line, 32 pin, ceramica ermetica)
Intervallo di temperatura operativa	Da -55 a +125	°C (grado industriale/militare)

Caratteristiche funzionali chiave

Caratteristica	Specifiche
Tipo di interfaccia	Parallelo a 8 bit (pin di indirizzo/dati/controllo compatibili CMOS)
Compatibilità delle famiglie logiche	TI 74HC/74HCT CMOS, 54LS TTL (supporto per sistemi legacy a segnale misto)
Margine di rumore (min)	0,4V (livello basso); 0,5V (livello alto) (stabilità di livello industriale)
Corrente di pilotaggio in uscita	-8mA (sink); +4mA (source) (tipico, conforme a CMOS)
Standard di affidabilità	Conforme a MIL-STD-883 (ermeticità, cicli di temperatura, protezione ESD)

Vantaggi rispetto alle soluzioni alternative di memoria legacy

The SMJ68CE16L-70JDM outperforms generic SRAMs, plastic-packaged alternatives, and faster but inefficient memory options—starting with its hermetic JDM-32 package. Unlike plastic DIPs (which degrade in 2–3 years due to moisture or corrosion), its ceramic enclosure and vacuum seal ensure 10+ years of reliability. “We replaced 90ns plastic SRAMs with this model in our 12MHz industrial PLCs, and memory failures dropped from 16% to 0% annually,” confirms a senior engineer at a leading manufacturing automation firm.

Its 70ns access time strikes a perfect balance for mid-speed legacy systems (8–15MHz controllers). Faster 40–50ns SRAMs waste 30% more power for minimal speed gains, while slower 90ns SRAMs cause data lag. For example, a factory sensor hub using a 90ns SRAM took 1.8ms to process 300 8-bit data points; switching to this 70ns model cut time to 1.4ms—fast enough for real-time control without unnecessary energy use.

As a CMOS SRAM, it uses 65% less power than TTL alternatives (82mW vs. 235mW), extending backup battery life by 22% in industrial systems. This is critical for emergency shutdown controllers, where longer battery life prevents operational gaps in remote sites like offshore oil rigs.

The JDM-32’s J-lead design creates 2x stronger solder joints than standard through-hole pins, reducing vibration failures in factory robots or aircraft. Unlike modern surface-mount SRAMs, it fits legacy JDM-32 sockets—avoiding costly PCB redesigns. Its -55°C to +125°C range also outperforms commercial SRAMs (0°C–70°C), working reliably in freezing arctic sensors or hot desert-based equipment.

Typical Applications of SMJ68CE16L-70JDM

The SMJ68CE16L-70JDM excels in legacy and mission-critical systems where ruggedness, balanced efficiency, and compatibility matter. Key use cases include:

• Aerospaziale e Difesa (buffer di dati avionici, memoria del sistema di guida missilistica, logger di stazioni terrestri satellitari)
• Industrial Automation (8–15MHz legacy PLCs, factory machine data loggers, emergency backup control systems)
• Energy and Power (oil/gas well monitoring controllers, wind turbine sensor memory, high-voltage substation backup processors)
• Test e misurazioni (generatori di segnale resistenti, apparecchiature per test di stress ambientale, memoria per oscilloscopi legacy)
• Sicurezza e sorveglianza (buffer di dati per sensori perimetrali militari, moduli di registrazione di telecamere esterne legacy)

L'esperienza di Texas Instruments nella memoria CMOS ermetica

As a Texas Instruments product, the SMJ68CE16L-70JDM leverages TI’s 70+ years of leadership in industrial and military-grade semiconductors. TI’s hermetic CMOS SRAMs undergo rigorous testing: temperature cycling (-55°C to +125°C for 1,000 cycles), humidity resistance (85% RH at 85°C for 1,000 hours), and ESD protection (2kV human-body model, per MIL-STD-883).

This durability makes TI a trusted partner for Boeing (aerospace), Siemens (industrial automation), and Lockheed Martin (defense)—all rely on TI’s legacy memory to maintain critical older systems. For businesses managing legacy infrastructure, TI’s components ensure continuity without sacrificing reliability or efficiency.

Domande frequenti (FAQ)

What is the SMJ68CE16L-70JDM, and how does it support legacy systems?

The SMJ68CE16L-70JDM is a 128K×8 hermetic CMOS SRAM for legacy industrial/aerospace systems. It stores 131,072 independent 8-bit values without power refresh. Via CMOS-compatible parallel pins, it reads/writes in 70ns, syncing with 8–15MHz controllers (e.g., 54LS TTL PLCs) to deliver real-time performance without wasted power.

Why is 70ns access time ideal for 8–15MHz industrial PLCs?

8–15MHz PLCs operate on 67–125ns cycles. A 70ns access time matches this range: fast enough to avoid data lag, but not so fast that it wastes power (unlike 40ns SRAMs, which use 30% more energy). This balance cuts operational costs and extends backup battery life for critical systems.

How does the JDM-32 package improve reliability in harsh environments?

The JDM-32’s hermetic ceramic enclosure seals the SRAM in inert gas, blocking salt, dust, or chemicals that degrade plastic DIPs. Its J-lead pins form larger solder joints, resisting vibration. This design ensures 10+ years of use vs. 2–3 years for plastic SRAMs in coastal/factory environments.

Quali vantaggi offre la tecnologia CMOS rispetto alla TTL per questa SRAM?

CMOS cuts power use by 65% (82mW vs. 235mW for TTL), extending battery life in backups. It also has a wider noise margin (0.4V–0.5V vs. TTL’s 0.3V), making it more resistant to electrical interference from factory motors—reducing data corruption errors by 40%.

Is the SMJ68CE16L-70JDM compatible with mixed-signal legacy systems?

Yes. It works with TI 54LS TTL controllers and 74HC/74HCT CMOS sensors—no logic translators needed, thanks to TTL-compatible CMOS I/O levels. It fits existing JDM-32 sockets, letting technicians replace older SRAMs without PCB modifications—saving time and avoiding costly redesigns.