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Renesas 71256S45DB
- Part No.:
- 71256S45DB
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
71256S45DB.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,568
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Product details
Overview
71256S45DB from Renesas is a military-grade 256K (32K × 8-bit) CMOS static RAM with 45ns maximum address access time, TTL-compatible I/O, and full MIL-STD-883 Class B compliance for operation from –55°C to +125°C. It features low-power standby mode (20mA ISB), 5V ±10% supply, and ceramic DIP packaging - deployed in avionics data buffers, radar memory modules, and hardened telemetry systems.
For engineers reviewing the 71256S45DB datasheet, 71256S45DB pinout, 71256S45DB application, or 71256S45DB equivalent, key selection criteria include military temperature qualification, 45ns read/write timing under worst-case conditions, CS-controlled power-down behavior, and compatibility with legacy 28-pin DIP board layouts requiring high-reliability SRAM.
Technical Context
This device implements a fully decoded 15-bit address space (A0–A14) driving a 262,144-bit memory array with bidirectional 8-bit data bus (I/O0–I/O7). Its control architecture uses three independent active-low enables: CS (chip select), WE (write enable), and OE (output enable), supporting both CS- and WE-controlled write cycles per AC Table 12.
Power management relies on hierarchical standby: when CS goes HIGH, the device enters TTL-level standby (ISB = 20mA max); at CMOS-level CS deassertion (VHC), it achieves full standby (ISB1 = 20mA max). No battery backup function is implemented - that capability is exclusive to L-suffix variants (e.g., 71256L45DB).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144 bits), fixed parallel interface |
| Access Time (tAA) | 45ns max at –55°C to +125°C, defines minimum address hold before valid data |
| Supply Voltage | 5V ±10% (4.5V–5.5V), compatible with standard TTL logic rails |
| Operating Temperature | –55°C to +125°C, qualified per MIL-STD-883 Class B |
| Standby Current (ISB) | 20mA max at VCC max, enables system-level power gating via CS |
| Input/Output Compatibility | TTL-compatible inputs and outputs, eliminates level-shifting in mixed-logic systems |
| Package | 28-pin 600-mil ceramic DIP (CD28), through-hole mount with hermetic sealing |
Pinout & Package
71256S45DB is housed in a 28-pin 600-mil ceramic dual in-line package (CD28), featuring hermetic construction and lead finish suitable for high-reliability military assembly processes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit unidirectional address bus selecting one of 32K memory locations |
| I/O0–I/O7 | Data Input/Output | Bidirectional 8-bit data bus; high-impedance when CS=HIGH or OE=HIGH |
| CS | Chip Select | Active-low global enable; controls standby entry/exit and output driver state |
| WE | Write Enable | Active-low signal qualifying write cycles when CS=LOW; determines data latching edge |
| OE | Output Enable | Active-low control for output drivers only; does not affect internal memory state |
| VCC | Power Supply | +5V ±10% main supply; powers core logic and I/O buffers |
| GND | Ground | Reference return path for all signals and supply currents |
Key Features
| Feature | Design Value |
|---|---|
| MIL-STD-883 Class B compliance | Qualified for military applications including screening, burn-in, and environmental stress testing |
| 45ns military-grade timing | Guaranteed tAA ≤45ns across full –55°C to +125°C range, enabling deterministic real-time buffering |
| TTL-compatible I/O | Direct interface with 74LS/ALS logic families without external translators or pull-ups |
| CS-driven standby mode | Automatic transition to low-power state (ISB = 20mA) upon chip deselect, reducing system heat load |
| Hermetic ceramic DIP package | CD28 package provides moisture resistance and thermal stability for long-life field deployment |
Applications
| Avionics Data Buffering | Radar Signal Memory |
|---|---|
Use Scenario: Real-time buffering of ADC samples between analog front-end and DSP in airborne radar receivers. IC Role / Device Role / Timing Role: High-speed parallel SRAM providing zero-wait-state storage for burst-mode sampling at 10+ MSPS. Use Value: 45ns tAA ensures deterministic latency under extreme thermal cycling, meeting DO-254 timing closure requirements. |
Use Scenario: Storing intermediate FFT coefficients during pulse-Doppler processing in ground-based surveillance radar. IC Role / Device Role / Timing Role: Non-volatile buffer holding processed data frames prior to RF transmission or display rendering. Use Value: MIL-STD-883 qualification guarantees operation at +125°C ambient inside sealed radar cabinets. |
| Hardened Telemetry Systems | Tactical Radio Baseband Memory |
Use Scenario: Storing encrypted telemetry packets in satellite transponders exposed to radiation and thermal vacuum. IC Role / Device Role / Timing Role: Radiation-tolerant SRAM retaining integrity during single-event upsets due to CMOS process hardening. Use Value: Ceramic DIP package and Class B screening ensure >10-year operational life in LEO missions. |
Use Scenario: Frame buffering in software-defined radios operating in mobile battlefield environments. IC Role / Device Role / Timing Role: Low-latency memory for interleaving/deinterleaving of OFDM symbols in SDR baseband processors. Use Value: TTL compatibility simplifies integration with legacy FPGA I/O banks lacking voltage translation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-reliability SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 71256S45TDB | Same speed grade and military temp range, but 300-mil SOJ (SD28) package instead of 600-mil CDIP | Requires PCB redesign for surface-mount assembly; lacks hermetic seal of ceramic DIP | Select when board space constraints favor SOJ or reflow assembly is required |
| 71256S55DB | Slower 55ns access time, otherwise identical CD28 package, MIL-STD-883 Class B, and electrical specs | Suitable for less timing-critical subsystems where margin allows relaxed cycle timing | Select when system timing budget permits longer tAA and cost reduction is prioritized |
Compared with 71256S45DB, 71256S45TDB offers identical timing and qualification in a smaller SOJ footprint but sacrifices hermeticity and through-hole serviceability, while 71256S55DB trades 10ns performance for broader timing margin and potential cost savings in non-critical paths.
Availability
71256S45DB is available at Aetrix Electronics and suitable for avionics data buffering, radar signal memory, and hardened telemetry systems requiring stable component supply across extended military lifecycle programs.
Supply support for 71256S45DB 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 specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and aerospace markets.
The 71256S series belongs to Renesas' legacy high-reliability SRAM product line, designed specifically for military and aerospace applications demanding guaranteed timing, extended temperature operation, and MIL-STD-883 qualification.
FAQ
What is the maximum operating temperature range for the 71256S45DB?
The 71256S45DB is rated for continuous operation from –55°C to +125°C and is fully qualified to MIL-STD-883 Class B, including temperature cycling, mechanical shock, and steady-state bias testing across this full military temperature range. This specification is explicitly confirmed in the Absolute Maximum Ratings and Recommended Operating Conditions tables of the Renesas datasheet revision Aug.06.20.
Does the 71256S45DB support battery backup or data retention below 5V?
No, the 71256S45DB does not support battery backup or low-voltage data retention. That functionality is exclusive to L-suffix variants such as 71256L45DB, which specify 2V data retention and microamp-level standby current. The 71256S45DB is a standard-power part with ISB = 20mA minimum and requires stable 5V ±10% supply for all operational modes, including standby.
Is the 71256S45DB pin-compatible with other members of the 71256S family?
Yes, all 71256S variants - including 71256S25DB, 71256S35DB, and 71256S45DB - share identical pinout, package footprint (CD28), and functional interface. Differences are limited to guaranteed access time (tAA), power consumption profiles, and associated AC timing parameters; no PCB layout change is required when upgrading or downgrading speed grades within the S-series.
What package type does the 71256S45DB use, and is it RoHS-compliant?
The 71256S45DB uses a 28-pin 600-mil ceramic dual in-line package (CD28), designated in Renesas ordering information as "DB". Per the Aug.06.20 datasheet, green (lead-free/RoHS-compliant) versions are available - see ordering code suffix "Y" variants (e.g., 71256S45DBY) for RoHS-compliant manufacturing, though base 71256S45DB remains standard-lead unless explicitly ordered with green suffix.
Can the 71256S45DB be used in commercial or industrial temperature applications?
No - the 71256S45DB is exclusively specified and screened for military temperature range (–55°C to +125°C) and MIL-STD-883 Class B compliance. Commercial and industrial variants exist (e.g., 71256S25YG for industrial), but they carry different orderable part numbers, package codes, and qualification documentation. Using 71256S45DB outside its rated military range voids guaranteed specifications and reliability warranties.
71256S45DB 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:
- 45ns
- Access Time:
- 45 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
71256S45DB FAQ
1.How can I place an order for 71256S45DB through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256S45DB 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 71256S45DB reliable?
The price and inventory of 71256S45DB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256S45DB is usually 5 days.
3.What payment methods are accepted for 71256S45DB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256S45DB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256S45DB?
71256S45DB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256S45DB 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 71256S45DB?
For technical support, including 71256S45DB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256S45DB requirements.
6.How does Aetrix verify that 71256S45DB is sourced from the original manufacturer or authorized distributors?
All 71256S45DB 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 71256S45DB meets industry standards.
7.What is the process for return or replacement of 71256S45DB?
All 71256S45DB units undergo pre-shipment inspection (PSI). If there is an issue with 71256S45DB, 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 71256S45DB part is unused and in its original packaging.
Return procedure for 71256S45DB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71256S45DB Tags
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