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Renesas 71256S70DB
- Part No.:
- 71256S70DB
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
71256S70DB.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,475
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Product details
Overview
71256S70DB from Renesas is a 256K-bit (32K × 8) high-speed CMOS static RAM with military-grade reliability, 70 ns maximum access time, 5 V ±10% supply, and –55°C to +125°C operating range. It features TTL-compatible I/O, battery-backed data retention (2 V), and automatic low-power standby mode triggered by chip select. Used in avionics, radar signal buffering, and hardened embedded controllers.
For engineers reviewing the 71256S70DB datasheet, 71256S70DB pinout, 71256S70DB application, or 71256S70DB equivalent, key selection criteria include military temperature compliance (MIL-STD-883 Class B), ceramic DIP package mechanical robustness, CS-controlled power-down behavior, and verified 70 ns read/write timing under full military thermal stress.
Technical Context
This device implements a fully decoded 15-bit address space (A0–A14) driving a 32K × 8-bit memory array with synchronous read/write control via WE, OE, and CS. Its dual standby modes-TTL-level (ISB = 20 mA) and CMOS-level (ISB1 = 20 mA)-are activated solely by CS logic level, eliminating external power management logic.
The 71256S70DB uses standard CMOS I/O circuitry with VIH = 2.2 V min, VIL = 0.8 V max, VOL = 0.4 V at 8 mA, and VOH = 2.4 V at –4 mA, ensuring direct interface with legacy TTL and mixed-signal systems without level-shifting. All AC parameters-including tAA, tACS, tRC, and tWC-are guaranteed across the full –55°C to +125°C range per MIL-STD-883 Class B test flow.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144 bits), fixed parallel interface |
| Access Time (tAA) | 70 ns max at –55°C to +125°C, defines minimum address hold before valid data |
| Supply Voltage | 5.0 V ±10% (4.5–5.5 V), supports legacy 5 V system rails |
| Operating Temperature | –55°C to +125°C, qualified per MIL-STD-883 Class B |
| Standby Current (ISB) | 20 mA max when CS = VIH, enables predictable low-power sleep state |
| Package | 28-pin 600 mil ceramic DIP (CD28), hermetically sealed for harsh environments |
| Data Retention | Not supported - S-version lacks battery backup; only L-version retains at 2 V |
Pinout & Package
71256S70DB is supplied in a 28-pin 600 mil ceramic dual in-line package (CD28), featuring hermetic sealing, gold-plated leads, and MIL-STD-883 Class B qualification for shock, vibration, and thermal cycling endurance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit unidirectional address bus; fully decoded to select one of 32K locations |
| I/O0–I/O7 | Bi-directional Data Bus | 8-bit TTL-compatible data path; high-impedance when CS or OE inactive |
| CS | Chip Select | Active-low enable; asserts memory operation and controls standby entry/exit |
| WE | Write Enable | Active-low write strobe; latches data on falling edge when CS active |
| OE | Output Enable | Active-low output gate; enables read data drive without affecting write path |
| VCC | Power Supply | +5 V ±10% main supply; powers core logic and I/O drivers |
| GND | Ground Reference | 0 V return path for all internal circuits and I/O signals |
Key Features
| Feature | Design Value |
|---|---|
| MIL-STD-883 Class B Compliance | Fully tested per military screening including burn-in, thermal shock, and hermeticity-required for flight-critical hardware |
| TTL-Compatible I/O | Direct connection to 5 V TTL logic families without level shifters or pull-ups, reducing BOM count |
| CS-Controlled Standby Mode | Automatic transition to 20 mA standby current when CS = VIH; eliminates need for external power sequencing |
| High-Speed 70 ns Timing | Guaranteed tAA and tRC ≤ 70 ns across full military temperature range, enabling real-time buffer applications |
| Ceramic DIP Packaging | 600 mil CD28 package provides superior thermal dissipation and mechanical stability vs. plastic SOJ alternatives |
Applications
| Avionics Data Buffering | Radar Signal Acquisition |
|---|---|
Use Scenario: Real-time storage of sampled analog-to-digital converter (ADC) outputs in airborne radar front-end modules. IC Role / Device Role / Timing Role: High-reliability parallel SRAM acting as first-stage digital buffer between ADC and FPGA-based signal processor. Use Value: 70 ns access ensures no pipeline stalls during continuous 10+ MSPS sampling; MIL-STD-883 qualification guarantees operation at –55°C cabin temperatures and +125°C engine bay proximity. | Use Scenario: Storing pulse-Doppler processing coefficients and intermediate FFT results in ground-based surveillance radar systems. IC Role / Device Role / Timing Role: Static memory providing deterministic read/write latency for time-critical DSP algorithms running on TI C6000 or Analog Devices SHARC processors. Use Value: Ceramic DIP package withstands sustained vibration and thermal cycling; 5 V tolerance matches legacy radar power architecture without regulator redesign. |
| Hardened Industrial Controller | Military Communications Terminal |
Use Scenario: Non-volatile program storage and runtime variable buffering in programmable logic controllers deployed in oil refinery control rooms. IC Role / Device Role / Timing Role: Primary working memory for ladder logic execution engine, interfacing directly with microcontroller's external bus interface. Use Value: –55°C to +125°C rating exceeds industrial spec; 28-pin CDIP simplifies conformal coating and mechanical mounting in explosion-proof enclosures. | Use Scenario: Secure boot code and cryptographic key storage in SATCOM terminals used in tactical field deployments. IC Role / Device Role / Timing Role: Trusted memory resource holding firmware images and secure configuration data prior to CPU initialization. Use Value: Hermetic ceramic package prevents moisture ingress during desert/humid jungle operations; MIL-STD-883 screening validates long-term data integrity under EMI stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-reliability SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 71256S70TDB | Same speed grade and S-version functionality, but in 300 mil SD28 ceramic DIP package | Smaller footprint; lower thermal mass; less robust against mechanical shock | Select when board space is constrained and vibration exposure is moderate |
| 71256L70DB | L-version offers 2 V battery backup (5 μW standby) and identical 70 ns timing, but higher ISB1 (1.5 mA) | Enables non-volatile data retention during main power loss-critical for black-box logging | Select when data persistence during brownout or battery-switchover is required |
Compared with 71256S70DB, 71256S70TDB trades mechanical ruggedness for compactness, while 71256L70DB adds battery retention capability at marginally lower standby current-neither is pin-compatible due to differing package footprints (CD28 vs. SD28), requiring PCB layout revision.
Availability
71256S70DB is available at Aetrix Electronics and suitable for avionics data buffering, radar signal acquisition, and hardened industrial controller designs requiring stable component supply across extended product lifecycles.
Supply support for 71256S70DB 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 71256S70DB belongs to Renesas' legacy high-reliability SRAM product line, designed specifically for mission-critical systems demanding MIL-STD-883 qualification, wide temperature operation, and hermetic packaging.
FAQ
What is the maximum operating temperature range certified for the 71256S70DB?
The 71256S70DB is fully qualified for operation from –55°C to +125°C per MIL-STD-883 Class B testing, including thermal cycling, steady-state life, and hermeticity validation. This range is explicitly guaranteed in the AC and DC electrical specifications tables and applies to all timing parameters including tAA, tRC, and tWC without derating.
Does the 71256S70DB support battery backup data retention?
No, the 71256S70DB does not support battery backup data retention. That feature is exclusive to the L-version (e.g., 71256L70DB), which specifies 2 V minimum VCC for data retention and 5 μW typical standby current. The S-version is optimized for speed and standard power operation, with no low-voltage retention capability.
Is the 71256S70DB pin-compatible with other members of the 71256 family?
Yes, the 71256S70DB shares identical pinout and signal definitions with all 71256S and 71256L variants in the CD28 (600 mil ceramic DIP) package, including 71256S25DB, 71256S35DB, and 71256L70DB. Pin compatibility is confirmed by the unified "Pin Configurations" diagram and "Pin Descriptions" table covering all S/L versions in the datasheet.
What package type is used for the 71256S70DB, and why is it significant?
The 71256S70DB uses a 28-pin 600 mil ceramic dual in-line package (CD28). This hermetically sealed package provides superior resistance to moisture, thermal stress, and mechanical shock compared to plastic or SOJ alternatives-making it essential for aerospace, defense, and downhole industrial applications where long-term reliability under extreme conditions is mandatory.
How does the standby power management work on the 71256S70DB?
The 71256S70DB enters low-power standby automatically when CS is driven HIGH (VIH ≥ 2.2 V), reducing ICC to 20 mA max (ISB). This TTL-level detection requires no external control logic. If CS remains HIGH and transitions to CMOS-level high (VHC = VCC – 0.2 V), the device achieves the same 20 mA ISB1 current-no separate low-power mode pin or command sequence is needed.
71256S70DB 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:
- 70ns
- Access Time:
- 70 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
71256S70DB FAQ
1.How can I place an order for 71256S70DB through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256S70DB 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 71256S70DB reliable?
The price and inventory of 71256S70DB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256S70DB is usually 5 days.
3.What payment methods are accepted for 71256S70DB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256S70DB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256S70DB?
71256S70DB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256S70DB 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 71256S70DB?
For technical support, including 71256S70DB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256S70DB requirements.
6.How does Aetrix verify that 71256S70DB is sourced from the original manufacturer or authorized distributors?
All 71256S70DB 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 71256S70DB meets industry standards.
7.What is the process for return or replacement of 71256S70DB?
All 71256S70DB units undergo pre-shipment inspection (PSI). If there is an issue with 71256S70DB, 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 71256S70DB part is unused and in its original packaging.
Return procedure for 71256S70DB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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