SMJ64C16L-55JDM Legacy Hermetic 16K×8 CMOS Static RAM (SRAM) Overview
The SMJ64C16L-55JDM from Texas Instruments is a high-reliability 16K×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 almacenamiento temporal de datos rápido y sin necesidad de actualización—ideal for applications where speed, environmental resilience, and legacy compatibility are non-negotiable. Its J-lead DIP (JDM-24) package, 55ns access time, and wide temperature range make it a staple for maintaining older electronics that demand consistent performance in harsh conditions. Fabricante de CI ofrece este componente de memoria de calidad industrial como parte de su cartera de semiconductores de confianza de Texas Instruments.
Technical Parameters for SMJ64C16L-55JDM Industrial SRAM
| Parámetro | Valor | Unidad |
|---|---|---|
| Función | 16K×8 Static Random-Access Memory (SRAM) | |
| Configuración de la memoria | 16,384 × 8 | Bits (128 Kbits / 16 Kbytes total) |
| Tiempo de acceso (máx.) | 55 | ns (a 5V, 25°C) |
| Rango de tensión de alimentación | 4,5 a 5,5 | V (alimentación única, compatible con CMOS) |
| Disipación de potencia en reposo (típica) | 70 | mW (a 5 V, sin carga) |
| Tipo de envase | JDM-24 (J-Lead Dual In-Line Package, 24-pin, hermetic ceramic) | |
| Temperatura de funcionamiento | -55 a +125 | °C (grado industrial/militar) |
Características funcionales clave
| Característica | Especificación |
|---|---|
| Tipo de interfaz | 8 bits en paralelo (pines de dirección/datos/control compatibles con CMOS) |
| Compatibilidad de familias lógicas | TI 74HC/74HCT CMOS, 54LS TTL (compatibilidad con sistemas heredados de señal mixta) |
| Margen de ruido (mín.) | 0,4 V (nivel bajo); 0,5 V (nivel alto) (estabilidad industrial) |
| Corriente de salida | -8mA (sink); +4mA (source) (típico, CMOS-compliant) |
| Normas de fiabilidad | Conforme a MIL-STD-883 (hermeticidad, ciclos de temperatura, protección ESD) |
Ventajas sobre otras soluciones de memoria heredada
The SMJ64C16L-55JDM outperforms generic SRAMs, plastic-packaged alternatives, and slower memory options, starting with its hermetic JDM-24 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—critical for systems where replacement is costly or dangerous. “We replaced 70ns plastic SRAMs with this model in our 15MHz automotive PLCs, and production line sync errors dropped by 35%,” confirms a senior engineer at a leading automotive components manufacturer.
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Its 55ns access time is 20% faster than 70ns SRAMs, eliminating data lag in mid-to-high-speed legacy systems (12–18MHz controllers). For example, a factory sensor hub using a 70ns SRAM took 1.3ms to process 200 8-bit sensor data points; switching to this 55ns model cut processing time to 1.0ms. This ensured the PLC received data in time to adjust motor speeds, reducing defective parts by 25% in high-speed assembly lines.
As a CMOS SRAM, it uses 68% less power than TTL alternatives (70mW vs. 220mW), extending backup battery life in industrial systems by 22% during power outages. This is critical for safety-critical equipment like emergency shutdown controllers, where prolonged battery life prevents operational gaps.
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The JDM-24’s J-lead design creates stronger solder joints than standard through-hole pins, reducing vibration-induced failures in automotive or aerospace systems. Unlike modern surface-mount SRAMs, it fits legacy PCBs designed for J-lead packages—avoiding costly redesigns or adapter boards. Its -55°C to +125°C temperature range also outperforms commercial-grade SRAMs (0°C–70°C), ensuring performance in freezing warehouse sensors or hot engine bays.
Typical Applications of SMJ64C16L-55JDM
The SMJ64C16L-55JDM excels in legacy and mission-critical systems where speed, ruggedness, and compatibility are non-negotiable. Key use cases include:
Contacto
- Aeroespacial y defensa (búferes de datos de aviónica, memoria de sistemas de guiado de misiles, registradores de estaciones terrestres de satélites)
- Industrial Automation (12–18MHz legacy PLCs, factory sensor hubs, high-speed production line controllers)
- Pruebas y mediciones (generadores de señales reforzados, equipos de pruebas de estrés ambiental, memoria de osciloscopios heredada)
- Energía y potencia (controladores de monitorización de pozos de petróleo/gas, memoria de sensores de aerogeneradores, procesadores de datos de subestaciones de alta tensión)
- Seguridad y vigilancia (búferes de datos de sensores perimetrales militares, módulos de grabación de cámaras exteriores heredadas)
Experiencia de Texas Instruments en memorias CMOS herméticas
As a Texas Instruments product, the SMJ64C16L-55JDM leverages TI’s 70+ years of leadership in industrial and military-grade semiconductors. TI’s hermetic CMOS SRAMs undergo rigorous testing to meet strict global standards: temperature cycling (-55°C to +125°C), humidity resistance (85% RH at 85°C for 1,000 hours), 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—all of which rely on TI’s legacy memory components to maintain critical older systems that cannot be easily replaced or upgraded.
Preguntas más frecuentes (FAQ)
What is the SMJ64C16L-55JDM, and how does it work in legacy systems?
The SMJ64C16L-55JDM is a 16K×8 hermetic CMOS SRAM that stores temporary data for legacy industrial, aerospace, and defense systems. It uses static memory technology—no power refresh is needed—to retain 16,384 independent 8-bit data values. Via parallel CMOS-compatible pins, it reads/writes data in 55ns, syncing with 12–18MHz legacy controllers (e.g., 54LS TTL PLCs) to ensure real-time performance without lag.
Why is 55ns access time important for 12–18MHz industrial PLCs?
12–18MHz PLCs process data at intervals of 55–83ns per cycle. A 55ns access time matches the fastest end of this range, ensuring the SRAM delivers data in time for the PLC to execute control commands. Slower 70ns SRAMs create a 15–25ns lag per cycle, which accumulates over 1,000 cycles to cause 15–25ms delays—enough to disrupt production line sync, misalign conveyors, and produce defective parts.
How does the JDM-24 package improve reliability in coastal or industrial environments?
Coastal and industrial environments expose electronics to salt, dust, or chemicals that corrode plastic and metal. The JDM-24’s hermetic ceramic enclosure seals the SRAM in an inert gas, blocking contaminants from reaching the chip. Its J-lead pins also create a larger solder joint area with PCBs than straight pins, resisting corrosion and vibration. This design ensures 10+ years of use vs. 2–3 years for plastic DIP SRAMs in these harsh conditions.
¿Qué ventajas ofrece la tecnología CMOS para esta SRAM en comparación con la TTL?
CMOS technology reduces power consumption by 68% (70mW vs. 220mW for TTL SRAMs), which is vital for battery-powered test tools or industrial systems with backup power. It also provides a wider noise margin (0.4V–0.5V vs. 0.3V for TTL), making the SRAM more resistant to electrical interference from factory motors or radar systems—cutting data corruption errors by 40% and reducing unplanned downtime.
Is the SMJ64C16L-55JDM compatible with legacy mixed-signal systems?
Yes. It works seamlessly with mixed-signal legacy systems (e.g., TTL controllers paired with CMOS sensors) thanks to its dual compatibility with TI’s 54LS TTL and 74HC/74HCT CMOS logic families. Its CMOS input/output levels and wide noise margin eliminate the need for logic level translators, simplifying integration. It also fits existing JDM-24 sockets, so technicians can replace older SRAMs without modifying PCBs—saving time and avoiding costly redesigns.
