SMJ64C16S-70JDM Legacy Hermetic 16K×8 CMOS Static RAM (SRAM) Overview
The SMJ64C16S-70JDM 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 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-24) package, 70ns access time, and wide temperature range make it a staple for maintaining older electronics that demand consistent performance in harsh conditions. 集成电路制造商 提供这种工业级存储器件，作为其值得信赖的 Texas Instruments 半导体产品组合的一部分。
Technical Parameters for SMJ64C16S-70JDM Industrial SRAM
| 参数 | 价值 | 单位 |
|---|---|---|
| 功能 | 16K×8 静态随机存取存储器 (SRAM) | |
| 内存配置 | 16,384 × 8 | 比特（128 千比特/共 16 千字节） |
| 访问时间（最长） | 70 | 毫微秒（5V，25°C 时） |
| 电源电压范围 | 4.5 至 5.5 | V（单电源，CMOS 兼容） |
| 静态功耗（典型值） | 75 | 毫瓦（5V 时，无负载） |
| 包装类型 | JDM-24（J 引线双列直插式封装，24 引脚，密封陶瓷） | |
| 工作温度范围 | -55至+125 | °C（工业/军用级） |
主要功能特点
| 特征 | 规格 |
|---|---|
| 接口类型 | 8 位并行（与 CMOS 兼容的地址/数据/控制引脚） |
| 逻辑系列兼容性 | TI 74HC/74HCT CMOS、54LS TTL（支持混合信号传统系统） |
| 噪声裕量（最小值） | 0.4V（低电平）；0.5V（高电平）（工业级稳定性） |
| 输出驱动电流 | -8mA（灌电流）；+4mA（源电流）（典型值，符合 CMOS 标准） |
| 可靠性标准 | 符合 MIL-STD-883（密封性、温度循环、ESD 保护） |
与其他传统内存解决方案相比的优势
The SMJ64C16S-70JDM outperforms generic SRAMs, plastic-packaged alternatives, and faster but less efficient 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 90ns plastic SRAMs with this model in our 12MHz industrial PLCs, and memory-related downtime dropped by 75%,” confirms a senior engineer at a leading manufacturing automation firm.
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Its 70ns access time strikes a perfect balance for mid-speed legacy systems (8–15MHz controllers). Faster 40–50ns SRAMs waste power (consuming 35% more energy) for minimal speed gains, while slower 90ns SRAMs cause data lag that disrupts sensor-to-controller sync. For example, a factory sensor hub using a 90ns SRAM took 1.8ms to process 200 8-bit data points; switching to this 70ns model cut processing time to 1.4ms—fast enough to avoid delays without unnecessary power use.
As a CMOS SRAM, it uses 70% less power than TTL alternatives (75mW vs. 250mW), extending backup battery life in industrial systems by 25% during power outages. This is critical for safety-critical equipment like emergency shutdown controllers, where prolonged battery life prevents operational gaps in remote sites (e.g., oil rigs, rural factories).
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JDM-24 的 J 引线设计能产生比标准通孔引脚更强的焊点，从而减少汽车或航空航天系统中因振动引起的故障。与现代表面贴装 SRAM 不同，它适用于为 J 引线封装设计的传统 PCB，从而避免了昂贵的重新设计或增加尺寸和复杂性的适配器板。其 -55°C 至 +125°C 的温度范围也优于商用级 SRAM（仅限于 0°C-70°C），确保了在严寒的北极传感器站或炎热的沙漠工业设备中的性能。
Typical Applications of SMJ64C16S-70JDM
The SMJ64C16S-70JDM excels in legacy and mission-critical systems where ruggedness, balanced speed/power, and compatibility are non-negotiable. Key use cases include:
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- 航空航天与国防（航空电子设备数据缓冲器、导弹制导系统存储器、卫星地面站记录器）
- 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)
- 测试与测量（加固型信号发生器、环境压力测试设备、传统示波器存储器）
- 安全与监控（军用周边传感器数据缓冲器、传统室外摄像机记录模块）
德州仪器在全封闭 CMOS 存储器领域的专长
As a Texas Instruments product, the SMJ64C16S-70JDM leverages TI’s 70+ years of leadership in industrial and military-grade semiconductors. TI’s hermetic CMOS SRAMs are not just built for performance—they are engineered for longevity. Each unit undergoes rigorous testing to meet strict global standards: temperature cycling (-55°C to +125°C for 1,000 cycles), humidity resistance (85% RH at 85°C for 1,000 hours), and electrostatic discharge (ESD) protection (2kV human-body model, per MIL-STD-883 Method 3015).
This commitment to durability has made TI a trusted partner for industry leaders like Boeing (aerospace), Siemens (industrial automation), and Lockheed Martin (defense)—all of which rely on TI’s legacy memory components to maintain critical older systems that cannot be easily replaced. For businesses managing legacy infrastructure, TI’s components ensure continuity without sacrificing reliability or efficiency.
常见问题（FAQ）
What is the SMJ64C16S-70JDM, and how does it work in legacy systems?
The SMJ64C16S-70JDM 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 70ns, syncing with 8–15MHz legacy controllers (e.g., 54LS TTL PLCs) to ensure real-time performance without unnecessary power drain.
为什么 70ns 的访问时间是中速工业 PLC 的最佳平衡点？
Mid-speed PLCs (8–15MHz) process data at intervals of 67–125ns per cycle—fast enough for most factory tasks but not requiring ultra-fast memory. A 70ns access time matches these cycle times perfectly: it’s fast enough to avoid data lag, but not so fast that it wastes power (unlike 40ns SRAMs, which consume 35% more energy). This balance cuts operational costs and extends battery life in backup-powered systems.
JDM-24 包装如何提高易振动环境中的可靠性？
易振动的环境（如工厂机器人、风力涡轮机）通常会损坏标准通孔 SRAM 焊点。JDM-24 的 J 引线引脚折叠在封装下面，与印刷电路板形成更大的焊点区域，可以吸收振动。在测试中，J 引线焊点在高振动条件下的使用寿命是标准直引脚的 5 倍，从而减少了关键设备的意外停机时间。
与 TTL 相比，CMOS 技术为这种 SRAM 带来了哪些优势？
CMOS technology reduces power consumption by 70% (75mW vs. 250mW 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 minimizing unplanned downtime.
Is the SMJ64C16S-70JDM compatible with legacy mixed-signal systems?
是的，由于它与 TI 的 54LS TTL 和 74HC/74HCT CMOS 逻辑系列具有双重兼容性，因此可与混合信号传统系统（如与 CMOS 传感器配对的 TTL 控制器）无缝协作。其 CMOS 输入/输出电平和宽噪声裕度消除了对逻辑电平转换器的需求。它还适用于现有的 JDM-24 插座，因此技术人员无需修改 PCB 即可替换旧的 SRAM，从而节省了时间并避免了昂贵的重新设计。
