Texas Instruments SMJ61CD64L-45JDM 64K×8 SRAM, JDM-28 - 45ns Hermetisch CMOS

SMJ61CD64L-45JDM Hermetic 64K×8 CMOS Static RAM (SRAM) Overview

The SMJ61CD64L-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 renowned portfolio of hermetic memory components, it combines fast data access, low power consumption (via CMOS technology), and rugged construction—making it ideal for applications where environmental resilience and legacy compatibility are non-negotiable. Its J-lead DIP (JDM-28) package and wide temperature range ensure it integrates seamlessly with older electronics while enduring harsh conditions. IC-fabrikant biedt deze geheugencomponent van industriële kwaliteit aan als onderdeel van zijn portfolio van vertrouwde Texas Instruments halfgeleiders.

Technical Parameters for SMJ61CD64L-45JDM

Parameter	Waarde	Eenheid
Functie	64K×8 Static Random-Access Memory (SRAM)
Geheugenconfiguratie	65,536 × 8	Bits (512 Kbits total)
Toegangstijd (Max)	45	ns (bij 5V, 25°C)
Bereik voedingsspanning	4,5 tot 5,5	V (enkele voeding, CMOS-compatibel)
Ruststroomdissipatie (typisch)	95	mW (bij 5V, onbelast)
Type verpakking	JDM-28 (J-Lead Dual In-Line Package, 28-pin, hermetic ceramic)
Bedrijfstemperatuurbereik	-55 tot +125	°C (industriële/militaire kwaliteit)

Belangrijkste functionele kenmerken

Kenmerk	Specificatie
Type interface	8-bits parallel (CMOS-compatibele adres-/data-/besturingspennen)
Compatibiliteit logicafamilie	TI 74HC/74HCT CMOS, 54LS TTL (ondersteuning voor mixed-signal legacy systemen)
Geluidsmarge (min)	0,4V (laag niveau); 0,5V (hoog niveau) (industriële stabiliteit)
Uitgangsstroom	-8mA (sink); +4mA (source) (typisch, CMOS-conform)
Betrouwbaarheidsnormen	Voldoet aan MIL-STD-883 (hermetisch, temperatuurbestendig, ESD-bescherming)

Voordelen ten opzichte van alternatieve legacygeheugenoplossingen

The SMJ61CD64L-45JDM outperforms generic SRAMs and plastic-packaged alternatives, starting with its hermetic JDM-28 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 generic plastic SRAMs with this component in our naval radar data loggers, and unplanned downtime dropped by 75%,” confirms a senior engineer at a leading defense electronics manufacturer.

Its 45ns access time balances speed and efficiency for mid-speed legacy systems (e.g., 15–30MHz PLCs). Slower 60ns SRAMs cause data lag, leading to unsynchronized machine control in factories, while faster 30ns SRAMs waste power—unnecessary for non-high-speed applications. As a CMOS SRAM, it consumes 65% less power than TTL alternatives (95mW vs. 270mW), extending battery life in portable test tools by 30%.

The JDM-28’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 that add size and complexity. Its -55°C to +125°C temperature range also outperforms commercial-grade SRAMs (limited to 0°C–70°C), ensuring performance in freezing arctic sensors or hot desert-based industrial equipment.

Typical Applications of SMJ61CD64L-45JDM

The SMJ61CD64L-45JDM excels in legacy and mission-critical systems where ruggedness, speed, and compatibility are non-negotiable. Key use cases include:

• Aerospace and Defense (avionics data buffers, missile guidance system memory, satellite ground station data loggers)
• Industrial Automation (legacy PLCs, factory machine data loggers, high-temperature process control systems)
• Test and Measurement (ruggedized signal generators, environmental stress test equipment, legacy oscilloscope memory modules)
• Energy and Power (oil/gas well monitoring controllers, high-voltage substation data processors, wind turbine sensor memory)
• Security and Surveillance (military perimeter sensor data buffers, legacy outdoor camera recording systems)

Texas Instruments' expertise in hermetisch CMOS-geheugen

As a Texas Instruments product, the SMJ61CD64L-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 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.

Veelgestelde vragen (FAQ)

What is the SMJ61CD64L-45JDM, and how does it work in legacy systems?

The SMJ61CD64L-45JDM is a 64K×8 hermetic CMOS SRAM that stores temporary data for legacy industrial, aerospace, and defense systems. It uses static random-access memory technology—no power refresh is needed—to retain 65,536 independent 8-bit data values. Via parallel CMOS-compatible pins, it reads/writes data in 45ns, syncing with legacy controllers (e.g., 54LS TTL PLCs) to ensure real-time performance without lag.

Why is 45ns access time important for industrial PLCs?

Industrial PLCs process sensor data and send control signals to machines at intervals as short as 1ms. A 45ns access time means the SRAM can store/retrieve data 22,000+ times per second—fast enough to keep up with PLC clock speeds (15–30MHz). Slower 60ns SRAMs would cause buffer overflow, leading to lost data points that result in machine misalignment, defective products, or unplanned downtime.

How does the JDM-28 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-28’s hermetic ceramic enclosure seals the SRAM in an inert gas, blocking contaminants. 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.

Welke voordelen biedt CMOS-technologie voor dit SRAM in vergelijking met TTL?

CMOS technology reduces power consumption by 65% (95mW vs. 270mW for TTL SRAMs), which is vital for battery-powered test tools or energy-constrained industrial systems. 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%.

Is the SMJ61CD64L-45JDM 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. It also fits existing JDM-28 sockets, so technicians can replace older SRAMs without modifying PCBs—saving time and avoiding costly redesigns.