My Inquiry
My Account
Renesas 71256S35DB
- Part No.:
- 71256S35DB
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-CDIP (0.600", 15.24mm)
- Datasheet:
-
71256S35DB.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,591
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
71256S35DB from Renesas is a military-grade 256K (32K × 8-bit) CMOS static RAM with 35ns maximum access time, TTL-compatible I/O, and 5V ±10% supply operation across –55°C to +125°C. It features automatic low-power standby mode upon chip select deassertion and supports battery backup data retention at 2V for the L variant - though 71256S35DB is the standard-power military version in 600-mil ceramic DIP. It serves as main memory or buffer in avionics, radar processors, and hardened embedded controllers.
For engineers reviewing the 71256S35DB datasheet, 71256S35DB pinout, 71256S35DB application, or 71256S35DB equivalent, key selection criteria include its MIL-STD-883 Class B compliance, 35ns read cycle time, 28-pin CDIP package, industrial/military temperature support, and compatibility with legacy 5V TTL bus systems requiring deterministic static RAM timing.
Technical Context
The 71256S35DB implements a full CMOS static memory array with asynchronous parallel interface, using address decoding logic that enables single-cycle random-access reads/writes without clocks or refresh. Its control architecture relies on three independent active-low enables: CS (chip select), WE (write enable), and OE (output enable), supporting both CS-controlled and WE-controlled write cycles per JEDEC-standard SRAM timing conventions.
It operates exclusively in 5V ±10% supply with TTL-level input thresholds (VIH = 2.2V min, VIL = 0.8V max) and delivers guaranteed 35ns address access time (tAA), 35ns read cycle time (tRC), and 35ns write cycle time (tWC) under military temperature conditions (–55°C to +125°C). Standby current is 20mA (ISB) when CS is high, distinguishing it from the low-power 71256L variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256Kbit (32K × 8-bit) - provides byte-wide data path compatible with 8-bit microcontrollers and legacy bus architectures. |
| Access Time | 35ns max (tAA, tACS) - ensures deterministic read latency for real-time military control loops and signal processing buffers. |
| Supply Voltage | 5V ±10% - matches standard TTL/CMOS logic rails; no level-shifting required in legacy 5V systems. |
| Operating Temp | –55°C to +125°C - qualified per MIL-STD-883 Class B for deployment in airborne, missile, and ground vehicle electronics. |
| Package | 28-pin 600-mil ceramic DIP (CD28) - hermetically sealed, high-reliability package suitable for harsh-environment PCB mounting. |
| Standby Current | 20mA (ISB) - power consumption during CS-high standby; higher than L-version but optimized for speed/stability trade-off. |
| I/O Compatibility | TTL-input and TTL-output compatible - interoperable with 74LS, 74F, and other 5V logic families without interface buffers. |
Pinout & Package
71256S35DB is housed in a 28-pin 600-mil ceramic dual in-line package (CDIP, code CD28), featuring hermetic sealing and lead finish suitable for military soldering profiles and long-term reliability in thermal-cycling environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus accepting 0–32767; fully decoded internally to select one of 32K bytes. |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit parallel data path; high-impedance when CS high or OE high during read, or WE high during write. |
| CS | Chip Select | Active-low global enable; drives device into low-power standby (ISB = 20mA) when high. |
| WE | Write Enable | Active-low write strobe; initiates write cycle when CS and WE both low; controls data latching timing. |
| OE | Output Enable | Active-low output gate; enables data drivers only during read cycles; prevents bus contention. |
| VCC | Power Supply | +5V ±10% main supply; decoupling capacitor required near pin for noise immunity in high-speed operation. |
| GND | Ground Reference | Signal and power return; must be connected to system ground plane with low-inductance path. |
Key Features
| Feature | Design Value |
|---|---|
| MIL-STD-883 Class B Compliance | Fully tested to military screening standards including burn-in, temperature cycling, and hermeticity - essential for flight-critical and defense electronics qualification. |
| Asynchronous Parallel Interface | No clock required; timing governed solely by CS/WE/OE setup/hold relationships - simplifies integration with FPGA, ASIC, or microcontroller address/data buses. |
| 35ns Military-Speed Operation | Guaranteed tAA/tRC ≤35ns over full –55°C to +125°C range - enables real-time buffering in radar pulse processing and telemetry acquisition. |
| TTL-Compatible Signaling | VIH ≥2.2V, VIL ≤0.8V, VOH ≥2.4V, VOL ≤0.4V - eliminates need for level translators in legacy 5V systems. |
| Automatic Standby Mode | CS-high triggers immediate transition to ISB = 20mA state - reduces system power during idle intervals without software intervention. |
Applications
| Avionics Data Buffering | Radar Signal Processing Memory |
|---|---|
Use Scenario: Storing intermediate FFT results and pulse compression coefficients in airborne radar front-end modules. IC Role / Device Role / Timing Role: Asynchronous 32K×8-byte scratchpad memory accessed directly by DSP co-processor via parallel bus; timing-critical tAA ≤35ns ensures pipeline continuity. Use Value: Enables deterministic 35ns read/write latency under full military temperature range, eliminating timing margin uncertainty in real-time RF processing chains. |
Use Scenario: Holding target track tables and clutter map data in ground-based air defense systems. IC Role / Device Role / Timing Role: Non-volatile-configurable working memory interfaced to radiation-tolerant microcontroller; CS-driven standby reduces average power in always-on surveillance mode. Use Value: MIL-STD-883 Class B qualification ensures operational integrity after thermal shock and vibration exposure typical in mobile launcher platforms. |
| Hardened Industrial PLC Memory | Mission-Critical Telemetry Storage |
Use Scenario: Storing ladder logic state variables and I/O image tables in oilfield downhole control units exposed to extreme ambient temperatures. IC Role / Device Role / Timing Role: Primary program/data RAM for ruggedized 8-bit controller; operates reliably at –55°C without derating or thermal management. Use Value: Ceramic DIP package resists moisture ingress and thermal fatigue, extending service life beyond plastic-packaged alternatives in sealed enclosures. |
Use Scenario: Capturing sensor telemetry bursts during rocket launch phase where power may be interrupted. IC Role / Device Role / Timing Role: High-speed buffer between analog front-end and fault-tolerant UART; fast tRC allows rapid capture before power loss. Use Value: 35ns cycle time enables >28.5 MHz effective throughput - sufficient to log 16-bit sensor samples at 100kSPS across 8 channels. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 71256S35TDB | Same speed (35ns), same military temp grade, but 300-mil SOJ (SD28) package instead of 600-mil CDIP. | Used where board space is constrained and surface-mount assembly is preferred; lacks hermetic seal of ceramic DIP. | Select 71256S35TDB for compact PCB layouts; choose 71256S35DB for maximum environmental robustness and through-hole reliability. |
| 71256S25DB | Faster 25ns access time, identical military spec, same CD28 package - higher performance at increased power and cost. | Suitable for next-generation systems requiring tighter timing margins or higher sustained bandwidth. | Choose 71256S25DB if system timing budget requires <35ns latency; otherwise 71256S35DB offers optimal cost/performance balance for legacy-compliant designs. |
Compared with 71256S35TDB, the 71256S35DB offers superior mechanical ruggedness and hermetic reliability in vibration-prone platforms, while compared with 71256S25DB it trades 10ns latency for lower cost and proven stability in fielded military hardware.
Availability
71256S35DB is available at Aetrix Electronics and suitable for avionics data buffering, radar signal processing memory, and hardened industrial PLC memory requiring stable component supply across extended lifecycle programs.
Supply support for 71256S35DB 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 71256S35DB belongs to Renesas' legacy high-reliability static RAM product line, designed specifically for military and aerospace applications demanding MIL-STD-883 qualification, wide temperature operation, and deterministic timing behavior.
FAQ
What is the operating temperature range specified for the 71256S35DB?
The 71256S35DB is rated for –55°C to +125°C operation and is fully qualified to MIL-STD-883 Class B screening requirements. This range is validated across all AC and DC electrical parameters, including 35ns access time and 20mA standby current, ensuring reliable functionality in extreme environmental conditions encountered in defense and aerospace platforms.
Does the 71256S35DB support battery backup data retention?
No, the 71256S35DB is the standard-power (S) variant and does not provide battery backup data retention. That feature is exclusive to the low-power (L) versions such as 71256L35DB, which specify 2V data retention and sub-5μW standby current. The 71256S35DB draws 20mA in standby (ISB) and requires continuous 5V supply for data retention.
What package type is used for the 71256S35DB?
The 71256S35DB uses a 28-pin 600-mil ceramic dual in-line package (CDIP), identified by package code CD28. This hermetically sealed package provides superior moisture resistance, thermal stability, and mechanical robustness compared to plastic or SOJ variants - critical for long-term reliability in military deployments.
Is the 71256S35DB pin-compatible with other members of the 71256 family?
Yes, all 71256S and 71256L variants share identical 28-pin pinout and functional assignment (A0–A14, I/O0–I/O7, CS, WE, OE, VCC, GND), regardless of speed grade or package. This allows direct substitution between 71256S25DB, 71256S35DB, and 71256S45DB in the same CDIP footprint, provided timing and power requirements are met.
What is the maximum power dissipation specification for the 71256S35DB?
The 71256S35DB has a maximum power dissipation rating of 1.0W, as defined in its Absolute Maximum Ratings table. Under typical operation at 5V and 35ns access, dynamic current (ICC) is 135mA max, yielding ~675mW typical power - well within the 1.0W limit, even at maximum junction temperature.
71256S35DB 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:
- 35ns
- Access Time:
- 35 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
71256S35DB FAQ
1.How can I place an order for 71256S35DB through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256S35DB 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 71256S35DB reliable?
The price and inventory of 71256S35DB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256S35DB is usually 5 days.
3.What payment methods are accepted for 71256S35DB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256S35DB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256S35DB?
71256S35DB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256S35DB 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 71256S35DB?
For technical support, including 71256S35DB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256S35DB requirements.
6.How does Aetrix verify that 71256S35DB is sourced from the original manufacturer or authorized distributors?
All 71256S35DB 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 71256S35DB meets industry standards.
7.What is the process for return or replacement of 71256S35DB?
All 71256S35DB units undergo pre-shipment inspection (PSI). If there is an issue with 71256S35DB, 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 71256S35DB part is unused and in its original packaging.
Return procedure for 71256S35DB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71256S35DB Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
-
AT24C02C-SSHM-T
Microchip Technology
-
24LC01BT-I/OT
Microchip Technology
-
M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
-
AT24C08C-STUM-T
Microchip Technology
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
