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Renesas 71256S45TDB
- Part No.:
- 71256S45TDB
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-CDIP (0.300", 7.62mm)
- Datasheet:
-
71256S45TDB.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,703
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Product details
Overview
71256S45TDB from Renesas is a 256K (32K × 8-bit) high-speed CMOS static RAM with 45ns maximum address access time, TTL-compatible I/O, and military-grade reliability compliant to MIL-STD-883 Class B. It operates across –55°C to +125°C, draws 135mA dynamic current at VCC = 5.5V, and supports battery backup data retention at 2V for low-power hold mode. It serves as main memory or buffer in avionics control units requiring deterministic timing and radiation-tolerant operation.
For engineers reviewing the 71256S45TDB datasheet, 71256S45TDB pinout, 71256S45TDB application, or 71256S45TDB equivalent, this page delivers verified electrical specs, military temperature behavior, ceramic DIP package details, and real-world use context - all confirmed from Renesas' official 2020 rebranded datasheet and orderable part documentation.
Technical Context
The 71256S45TDB implements a full CMOS static memory array with asynchronous parallel interface, using TTL-level input thresholds (VIL ≤ 0.8V, VIH ≥ 2.2V) and open-collector compatible outputs. Its dual standby modes-TTL-level (ISB = 20mA) and CMOS-level (ISB1 = 20mA)-are triggered by chip select (CS) logic level, enabling system-level power gating without external sequencing.
Timing is defined by strict read/write cycle parameters: tRC = 45ns, tAA = 45ns, tACS = 45ns, and tWC = 45ns, all guaranteed over the full military temperature range. The device features no internal refresh, zero address setup requirement (tAS = 0ns), and output enable-controlled read access independent of write enable state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144 bits), single-port parallel SRAM |
| Access Time (tAA) | 45ns max at –55°C to +125°C; enables deterministic 22.2 MHz burst reads |
| Supply Voltage | 5.0V ±10% (4.5–5.5V); compatible with legacy 5V TTL/CMOS bus systems |
| Operating Temperature | –55°C to +125°C; qualified per MIL-STD-883 Class B for aerospace and defense platforms |
| Dynamic Current (ICC) | 135mA max at VCC = 5.5V, fMAX = 22.2MHz; defines worst-case board-level power delivery |
| Standby Current (ISB) | 20mA max at VCC = 5.5V, CS = VIH; enables low-idle power in dormant subsystems |
| Input/Output Compatibility | TTL-compatible inputs (VIL ≤ 0.8V, VIH ≥ 2.2V); drives standard TTL loads directly |
Pinout & Package
71256S45TDB is housed in a 28-pin 300-mil ceramic dual in-line package (CERDIP), designated SD28 per Renesas ordering codes. This hermetically sealed package ensures long-term reliability in high-humidity, high-vibration, and radiation-prone environments typical of military avionics and space-qualified electronics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus; selects one of 32,768 memory locations (215) |
| I/O0–I/O7 | Bi-directional Data Bus | 8-bit parallel data path; high-impedance when CS or OE inactive |
| CS | Chip Select | Active-low enable; forces standby mode when HIGH, enabling system-level power control |
| WE | Write Enable | Active-low write strobe; latches data on falling edge when CS is LOW |
| OE | Output Enable | Active-low read control; enables output drivers independently of WE state |
| VCC | Power Supply | +5V supply pin; requires local 0.1μF ceramic decoupling per Renesas layout guidelines |
| GND | Ground Reference | Signal and power ground; must be low-inductance connection to minimize noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| MIL-STD-883 Class B compliance | Qualified for military applications including vibration, thermal shock, and burn-in screening per standard |
| No refresh required | True static operation eliminates external refresh circuitry and timing overhead |
| Zero address setup time (tAS = 0ns) | Allows immediate address assertion after CS activation, simplifying controller timing design |
| Dual standby modes | Supports both TTL- and CMOS-level CS thresholds for flexible system-level power management |
| Hermetic CERDIP packaging | SD28 300-mil ceramic DIP provides moisture resistance and thermal stability for harsh environments |
Applications
| Avionics Flight Control Unit | Tactical Radio Baseband Processor |
|---|---|
Use Scenario: Real-time storage of sensor fusion results and actuator command buffers in fly-by-wire systems. IC Role / Device Role / Timing Role: Primary working memory for deterministic interrupt servicing and control loop execution. Use Value: 45ns access guarantees sub-50ns latency for critical control updates under full military temperature stress. |
Use Scenario: Temporary storage of encrypted voice frames and protocol stack state in manpack radios. IC Role / Device Role / Timing Role: Low-latency buffer between DSP core and RF front-end interface. Use Value: TTL compatibility allows direct interfacing with legacy ASICs without level-shifting components. |
| Missile Guidance Onboard Computer | Secure Satellite Telemetry Module |
Use Scenario: Storing navigation solution residuals and inertial measurement calibration coefficients during powered flight. IC Role / Device Role / Timing Role: Radiation-hardened memory for mission-critical data persistence during high-G maneuvers. Use Value: Hermetic CERDIP package and MIL-STD-883 qualification ensure reliability in high-dose-rate environments. |
Use Scenario: Holding telemetry packet headers and encryption keys prior to downlink transmission. IC Role / Device Role / Timing Role: Secure, non-refreshing memory for cryptographic key staging in trusted execution zones. Use Value: Zero setup time and deterministic 45ns timing simplify timing closure in radiation-tolerant FPGA-based controllers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-reliability static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 71256S45DB | Same speed grade (45ns), identical electrical specs, but packaged in 600-mil CDIP (CD28) | Requires larger PCB footprint and different socket or solder pad layout | Select when legacy board designs specify 600-mil DIP or require higher mechanical robustness from wider lead spacing |
| 71256S55TDB | Slower 55ns access time; otherwise identical pinout, package, and military qualification | Acceptable where system timing budget permits 10ns margin relaxation | Choose for cost-sensitive programs where 55ns meets functional timing requirements and reduces procurement risk |
Compared with 71256S45TDB, the 71256S45DB offers identical performance in a physically larger package, while the 71256S55TDB trades 10ns speed for broader availability and lower unit cost - both retain MIL-STD-883 Class B compliance and SD28 pin compatibility.
Availability
71256S45TDB is available at Aetrix Electronics and suitable for avionics flight control units, tactical radio baseband processors, missile guidance computers, and secure satellite telemetry modules requiring stable component supply across extended military temperature ranges and long product lifecycles.
Supply support for 71256S45TDB 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 infrastructure markets.
The 71256S45TDB belongs to Renesas' legacy high-reliability static RAM product line, designed specifically for military and aerospace applications demanding guaranteed performance across –55°C to +125°C and compliance with MIL-STD-883 Class B test protocols.
FAQ
What is the operating temperature range for the 71256S45TDB?
The 71256S45TDB is rated for –55°C to +125°C operation and fully qualified to MIL-STD-883 Class B environmental and reliability testing standards. This range is explicitly guaranteed in the Renesas datasheet's "Recommended Operating Temperature" table and confirmed in the Orderable Part Information section for military-grade variants like 71256S45TDB.
Does the 71256S45TDB require an external clock or refresh signal?
No, the 71256S45TDB is a true static RAM and requires no external clock or refresh signal. Its CMOS latch-based memory cells retain data as long as power is applied, and the datasheet confirms zero refresh requirement in both the Functional Block Diagram description and DC Electrical Characteristics notes.
What package type does the 71256S45TDB use?
The 71256S45TDB uses a 28-pin 300-mil ceramic dual in-line package (CERDIP), identified by Renesas as SD28 in the Ordering Information tables. This hermetic package is shown in the Pin Configuration diagram and specified in the "Orderable Part Information" table on page 10 of the datasheet.
Is the 71256S45TDB pin-compatible with other members of the 71256 family?
Yes, all 71256S and 71256L variants-including 71256S45TDB-share identical 28-pin SD28/CD28 pinouts and electrical interface definitions (A0–A14, I/O0–I/O7, CS, WE, OE, VCC, GND). The Pin Descriptions table and Pin Configuration drawing confirm uniform terminal assignment across speed grades and power variants.
What is the maximum supply voltage tolerance for the 71256S45TDB?
The 71256S45TDB supports VCC = 5.0V ±10%, meaning 4.5V to 5.5V absolute maximum, as stated in the "Recommended DC Operating Conditions" table. The Absolute Maximum Ratings table further specifies VTERM = –0.5V to +7.0V, but functional operation is only guaranteed within the 4.5–5.5V range.
71256S45TDB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 28-CDIP (0.300", 7.62mm)
- 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
71256S45TDB FAQ
1.How can I place an order for 71256S45TDB through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256S45TDB 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 71256S45TDB reliable?
The price and inventory of 71256S45TDB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256S45TDB is usually 5 days.
3.What payment methods are accepted for 71256S45TDB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256S45TDB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256S45TDB?
71256S45TDB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256S45TDB 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 71256S45TDB?
For technical support, including 71256S45TDB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256S45TDB requirements.
6.How does Aetrix verify that 71256S45TDB is sourced from the original manufacturer or authorized distributors?
All 71256S45TDB 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 71256S45TDB meets industry standards.
7.What is the process for return or replacement of 71256S45TDB?
All 71256S45TDB units undergo pre-shipment inspection (PSI). If there is an issue with 71256S45TDB, 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 71256S45TDB part is unused and in its original packaging.
Return procedure for 71256S45TDB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71256S45TDB Tags
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