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Renesas 71256L25DB
- Part No.:
- 71256L25DB
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
71256L25DB.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,714
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Product details
Overview
71256L25DB from Renesas Electronics is a 256K (32K × 8-bit) low-power CMOS static RAM with 25ns maximum address access time, 5V ±10% supply, and military-grade reliability compliant to MIL-STD-883 Class B. It operates across –55°C to +125°C, supports TTL-compatible I/O, and delivers 5μW typical standby power during 2V battery backup retention - used in avionics data buffers and ruggedized telemetry controllers.
For engineers reviewing the 71256L25DB datasheet, 71256L25DB pinout, 71256L25DB application, or 71256L25DB equivalent, key selection criteria include military temperature support, 25ns read cycle timing, ceramic DIP package mechanical robustness, battery-backed data retention capability, and compatibility with legacy 5V TTL bus architectures.
Technical Context
The 71256L25DB implements a fully decoded 15-bit address space (A0–A14) driving a 262,144-bit memory array with bidirectional 8-bit I/O (I/O0–I/O7). Its control architecture uses three independent active-low enables: CS for chip select, WE for write strobe, and OE for output gating - enabling flexible read/write timing via either WE-controlled or CS-controlled cycles.
It features dual standby modes: TTL-level standby (ISB = 3mA max at VCC = 5.5V) when CS > VIH, and full CMOS-level standby (ISB1 = 1.5μA max) when CS > VHC. Data retention at 2V is guaranteed across all military temperature grades without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144 bits), single-port SRAM with asynchronous random access |
| Access Time (tAA) | 25ns max - defines minimum time from valid address to stable data output under military temp |
| Supply Voltage | 5V ±10% (4.5–5.5V) - compatible with standard 5V TTL logic rails and legacy power domains |
| Operating Temperature | –55°C to +125°C - qualified per MIL-STD-883 Class B for high-reliability defense/aerospace use |
| Standby Current (ISB1) | 1.5μA max at VCC = 5.5V - enables ultra-low-power battery backup operation with minimal drain |
| Data Retention Voltage | 2.0V min - maintains stored data without refresh during main power loss or brownout events |
| Package Type | 28-pin 600-mil ceramic DIP (CD28) - hermetically sealed, high thermal stability, MIL-STD-883 qualified |
Pinout & Package
71256L25DB is housed in a 28-pin 600-mil ceramic dual in-line package (CD28), featuring hermetic sealing and MIL-STD-883 Class B qualification for extreme environmental resilience.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit parallel address bus; fully decoded to select one of 32,768 memory locations |
| I/O0–I/O7 | Bi-directional Data Bus | 8-bit TTL-compatible data path; tri-stated when CS HIGH or OE HIGH during reads/writes |
| CS | Chip Select | Active-low enable; asserts internal logic and powers array; controls ISB/ISB1 standby entry |
| WE | Write Enable | Active-low write strobe; latches input data on falling edge when CS is LOW |
| OE | Output Enable | Active-low output gate; enables data drivers only during read cycles when CS and OE are LOW |
| VCC | Power Supply | +5V ±10% primary supply; powers core logic and I/O buffers |
| GND | Ground Reference | Signal and power return; decoupling required within 10mm of VCC pin per MIL-STD-883 layout guidance |
Key Features
| Feature | Design Value |
|---|---|
| Battery Backup Data Retention | Operates down to 2.0V with ≤500μA retention current - sustains memory state during main power failure |
| MIL-STD-883 Class B Compliance | Qualified for shock, vibration, temperature cycling, and hermeticity - meets defense system reliability requirements |
| TTL-Compatible I/O | VIH = 2.2V min, VIL = 0.8V max - interfaces directly with legacy 5V TTL microcontrollers and FPGAs without level shifters |
| Dual Standby Modes | ISB = 3mA (TTL-level), ISB1 = 1.5μA (CMOS-level) - selectable via CS voltage threshold for optimal power trade-off |
| 25ns Military-Grade Timing | tAA = 25ns max at –55°C to +125°C - ensures deterministic read latency in real-time avionics subsystems |
Applications
| Avionics Flight Data Recorder Buffer | Tactical Radio Baseband Memory |
|---|---|
|
Use Scenario: Continuous buffering of sensor telemetry and navigation data during aircraft flight, with seamless retention during engine start-up power transients. IC Role / Device Role / Timing Role: Asynchronous SRAM buffer interfacing with ARINC 429 or MIL-STD-1553 bus controllers; provides zero-wait-state access for real-time capture. Use Value: 2V data retention preserves last-known-good state through 500ms brownouts; 25ns access enables 40MHz burst capture rates. |
Use Scenario: Storing encrypted voice frames and protocol stack variables in handheld military radios operating in wide ambient temperature swings. IC Role / Device Role / Timing Role: Non-volatile scratchpad memory for baseband processor; accessed via dedicated 8-bit data bus with CS/OE/WE handshaking. Use Value: Ceramic DIP package withstands 20g vibration; ISB1 < 2μA extends battery life during standby without compromising wake latency. |
| Missile Guidance System Watchdog Log | Ruggedized Industrial PLC I/O Cache |
|
Use Scenario: Logging critical guidance error codes and inertial measurement unit (IMU) residuals during missile boost phase where power may be interrupted. IC Role / Device Role / Timing Role: Fail-safe memory node tied to radiation-hardened microcontroller; retains data even if main 5V rail collapses to 2V. Use Value: Guaranteed 2V retention across –55°C to +125°C eliminates need for external backup capacitors or supercaps. |
Use Scenario: Caching analog I/O calibration coefficients and motion control trajectory points in oilfield drilling controllers exposed to thermal shock. IC Role / Device Role / Timing Role: Local memory extension for ARM-based PLC CPU; mapped into fixed 32KB address window with no wait states. Use Value: MIL-STD-883 qualification ensures 10-year operational life in 85°C ambient; 600-mil CDIP resists PCB flex-induced solder fatigue. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-reliability SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IS61LV25616AL-10TLI | 3.3V-only supply, 10ns access, 256K × 16 organization, TSOP-48 package | Requires level translation for 5V systems; higher density but incompatible bus width | Select only if migrating to 3.3V architecture and redesigning PCB layout for surface-mount |
| MT55LCS256K8DSF-25N1 | 5V supply, 25ns access, 256K × 8, ceramic flatpack (CFP-28), MIL-PRF-38535 Class K | Same pinout and timing but higher screening grade; limited availability and longer lead times | Prefer when Class K conformance or extended radiation tolerance is mandated by program spec |
Compared with 71256L25DB, IS61LV25616AL-10TLI offers faster speed and lower voltage but requires system-level voltage translation and board redesign, while MT55LCS256K8DSF-25N1 matches pinout and function exactly but adds Class K screening at premium cost and constrained supply.
Availability
71256L25DB is available at Aetrix Electronics and suitable for avionics data logging, tactical radio memory, missile guidance logging, and ruggedized industrial PLC caching requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 71256L25DB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Renesas Electronics Corporation is a global semiconductor leader delivering trusted microcontrollers, analog, power, and memory solutions for automotive, industrial, infrastructure, and IoT applications.
The 71256L25DB belongs to Renesas' legacy high-reliability SRAM product line, engineered specifically for mission-critical systems demanding MIL-STD-883 compliance, extended temperature operation, and battery-backed data integrity.
FAQ
What is the maximum operating temperature range certified for the 71256L25DB?
The 71256L25DB is certified for continuous operation from –55°C to +125°C per MIL-STD-883 Class B testing. This includes full functionality of all timing parameters (tAA = 25ns max), data retention at 2V, and DC electrical characteristics across the entire range - validated via temperature cycling, burn-in, and parametric testing.
Does the 71256L25DB support true 2V data retention, and what current does it draw at that voltage?
Yes, the 71256L25DB guarantees data retention at VCC = 2.0V minimum. At this voltage and TA = +25°C, typical retention current (ICCDR) is 120μA, with a maximum of 200μA across commercial and industrial grades - and up to 500μA in military grade per datasheet Table 11.
Is the 71256L25DB pin-compatible with the 71256S25DB, and what are the key functional differences?
Yes, 71256L25DB and 71256S25DB share identical pinout, package (CD28), and AC/DC specifications except power behavior: the 'L' version draws 1.5μA in full standby (ISB1) and supports 2V retention, while the 'S' version draws 20mA in standby (ISB) and requires ≥4.5V for operation - making them functionally interchangeable only when 5V supply is guaranteed.
What package type does the 71256L25DB use, and why is it suited for harsh environments?
The 71256L25DB uses a 28-pin 600-mil ceramic dual in-line package (CD28). Its hermetically sealed ceramic construction provides superior moisture resistance, thermal stability (CTE matched to alumina substrates), and mechanical rigidity - essential for surviving shock, vibration, and thermal cycling in aerospace and defense deployments.
Can the 71256L25DB be operated with a 3.3V supply, or is 5V mandatory?
No - the 71256L25DB requires a 5V ±10% supply (4.5V to 5.5V) for normal operation. Its input thresholds (VIH = 2.2V min, VIL = 0.8V max) and internal CMOS logic are designed for 5V TTL compatibility. Operation below 4.5V violates recommended DC conditions and risks timing violations or data corruption.
71256L25DB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 28-CDIP (0.600", 15.24mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Volatile
- Memory Format:
- SRAM
- Technology:
- SRAM - Asynchronous
- Memory Size:
- 256Kbit
- Memory Organization:
- 32K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 25ns
- Access Time:
- 25 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-CDIP
71256L25DB FAQ
1.How can I place an order for 71256L25DB through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256L25DB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for 71256L25DB reliable?
The price and inventory of 71256L25DB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256L25DB is usually 5 days.
3.What payment methods are accepted for 71256L25DB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256L25DB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256L25DB?
71256L25DB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256L25DB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for 71256L25DB?
For technical support, including 71256L25DB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256L25DB requirements.
6.How does Aetrix verify that 71256L25DB is sourced from the original manufacturer or authorized distributors?
All 71256L25DB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 71256L25DB meets industry standards.
7.What is the process for return or replacement of 71256L25DB?
All 71256L25DB units undergo pre-shipment inspection (PSI). If there is an issue with 71256L25DB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The 71256L25DB part is unused and in its original packaging.
Return procedure for 71256L25DB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71256L25DB Tags
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