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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Renesas 71256S70TDB

Name: 71256S70TDB
Brand: Renesas
SKU: 71256S70TDB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 71256S70TDB

Manufacturer:: Renesas

Category:: Memory

Package:: 28-CDIP (0.300", 7.62mm)

Datasheet:: 71256S70TDB.pdf

Description:: IC SRAM 256KBIT PARALLEL 28CDIP

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Product details

Overview

71256S70TDB from Renesas Electronics is a 256K (32K × 8-bit) high-speed CMOS static RAM with 70 ns maximum 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, consumes 135 mA dynamic current at V_CC = 5.5 V, and supports battery backup data retention in low-power standby mode. It serves as main memory or buffer in avionics control units requiring deterministic timing and radiation-tolerant operation.

For engineers reviewing the 71256S70TDB datasheet, 71256S70TDB pinout, 71256S70TDB application, or 71256S70TDB equivalent, this page delivers verified electrical specs, military temperature performance, DIP package details, and real-world design context for embedded systems operating under extreme environmental stress.

Technical Context

This device implements a fully decoded 15-bit address space (A0–A14) driving a 262,144-bit SRAM array with bidirectional 8-bit I/O (I/O0–I/O7). Its control logic uses three independent active-low enables-CS, WE, and OE-with defined priority: CS governs standby entry/exit, WE selects write cycles, and OE enables output drivers without affecting internal state.

Timing behavior is strictly cycle-based: read cycle time (t_RC) equals 70 ns, address access time (t_AA) is ≤70 ns, and chip select access time (t_ACS) matches t_AA. Standby current drops to 20 mA (TTL-level CS) or 20 mA (CMOS-level CS), with no power-down sequencing required-only CS high assertion is needed to enter low-power mode.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Organization	32K × 8-bit (262,144 bits), single-port asynchronous SRAM
Access Time (t_AA)	70 ns max - guarantees data valid within 70 ns after stable address and CS assertion
Supply Voltage	5.0 V ±10% (4.5–5.5 V) - compatible with standard TTL/CMOS logic rails
Operating Temperature	–55°C to +125°C - qualified per MIL-STD-883 Class B for harsh-environment deployment
Dynamic Current (I_CC)	135 mA max at f_MAX - defines worst-case system power budget during continuous read/write cycling
Standby Current (I_SB)	20 mA max - sets minimum quiescent draw when CS = VIH, enabling thermal/power management
I/O Compatibility	TTL input thresholds (VIH = 2.2 V, VIL = 0.8 V) and output drive (VOL = 0.4 V @ 8 mA) - eliminates level-shifting in legacy 5 V systems

Pinout & Package

71256S70TDB is supplied in a 28-pin 300-mil ceramic dual in-line package (CDIP), designated SD28 per Renesas ordering nomenclature. This hermetically sealed package ensures long-term reliability in high-humidity, high-vibration, and radiation-prone environments typical of aerospace and defense platforms.

Pin/Terminal	Circuit Role	Design Meaning
A0–A14	Address Inputs	15-bit unidirectional address bus; fully decoded to select one of 32,768 memory locations
I/O0–I/O7	Data Input/Output	Bidirectional 8-bit data bus; high-impedance when CS = VIH or OE = VIH during reads/writes
CS	Chip Select	Active-low enable controlling device activation and automatic entry into standby mode when deasserted
WE	Write Enable	Active-low signal qualifying write cycles; must be low concurrently with CS low to store data
OE	Output Enable	Active-low control for output drivers only; does not affect internal memory state or power mode
V_CC	Power Supply	+5 V supply pin; requires local 0.1 µF ceramic decoupling adjacent to pin for noise immunity
GND	Ground Reference	Signal and power ground return; must be connected to low-impedance system ground plane

Key Features

Feature	Design Value
MIL-STD-883 Class B compliance	Validated screening and testing for military applications including burn-in, temperature cycling, and hermeticity verification
70 ns guaranteed access time	Enables integration into real-time control loops with sub-100 ns memory latency requirements, e.g., radar pulse processing
Automatic standby on CS high	Reduces system power by >90% without firmware intervention-critical for battery-backed mission-critical subsystems
TTL-compatible interface	Direct connection to legacy 5 V microcontrollers (e.g., Intel 80C186, Motorola 68000) without level translators or glue logic
Hermetic 300-mil CDIP (SD28)	Provides moisture resistance and mechanical robustness for extended service life in airborne and spaceborne electronics

Applications

Avionics Flight Control Unit	Tactical Radio Baseband Processor
Use Scenario: Real-time storage of sensor fusion data and flight command buffers in fly-by-wire systems operating at –55°C to +125°C. IC Role / Device Role / Timing Role: Primary working memory for deterministic interrupt servicing and servo loop updates with ≤70 ns latency. Use Value: MIL-STD-883 qualification ensures uninterrupted operation during rapid thermal transients and EMI exposure in jet engine bays.	Use Scenario: Storing encrypted voice packet headers and channel equalization coefficients in manpack radios deployed in desert and arctic conditions. IC Role / Device Role / Timing Role: Low-latency scratchpad for baseband DSP co-processors requiring synchronous burst reads/writes. Use Value: TTL compatibility eliminates interface logic, reducing BOM count and PCB area in SWaP-constrained handheld radios.
Missile Guidance Inertial Measurement Unit	Satellite Onboard Telemetry Buffer
Use Scenario: Capturing high-rate gyroscope and accelerometer samples during launch vibration and zero-gravity coast phases. IC Role / Device Role / Timing Role: High-reliability data capture buffer with guaranteed 70 ns access and full standby on CS deassertion. Use Value: Hermetic SD28 package prevents moisture ingress and maintains parametric stability over 15+ year orbital missions.	Use Scenario: Temporary storage of housekeeping telemetry before downlink transmission during eclipse periods with limited power. IC Role / Device Role / Timing Role: Power-managed memory holding critical status logs while primary processor is in deep sleep. Use Value: 20 mA standby current enables weeks-long data retention on auxiliary battery without compromising mission lifetime.

Avionics Flight Control Unit

Tactical Radio Baseband Processor

Use Scenario: Real-time storage of sensor fusion data and flight command buffers in fly-by-wire systems operating at –55°C to +125°C.

IC Role / Device Role / Timing Role: Primary working memory for deterministic interrupt servicing and servo loop updates with ≤70 ns latency.

Use Value: MIL-STD-883 qualification ensures uninterrupted operation during rapid thermal transients and EMI exposure in jet engine bays.

Use Scenario: Storing encrypted voice packet headers and channel equalization coefficients in manpack radios deployed in desert and arctic conditions.

IC Role / Device Role / Timing Role: Low-latency scratchpad for baseband DSP co-processors requiring synchronous burst reads/writes.

Use Value: TTL compatibility eliminates interface logic, reducing BOM count and PCB area in SWaP-constrained handheld radios.

Missile Guidance Inertial Measurement Unit

Satellite Onboard Telemetry Buffer

Use Scenario: Capturing high-rate gyroscope and accelerometer samples during launch vibration and zero-gravity coast phases.

IC Role / Device Role / Timing Role: High-reliability data capture buffer with guaranteed 70 ns access and full standby on CS deassertion.

Use Value: Hermetic SD28 package prevents moisture ingress and maintains parametric stability over 15+ year orbital missions.

Use Scenario: Temporary storage of housekeeping telemetry before downlink transmission during eclipse periods with limited power.

IC Role / Device Role / Timing Role: Power-managed memory holding critical status logs while primary processor is in deep sleep.

Use Value: 20 mA standby current enables weeks-long data retention on auxiliary battery without compromising mission lifetime.

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	3.3 V supply, 10 ns access, 256K × 16 organization, commercial/industrial temp only	Lacks MIL-STD-883 qualification and extended temperature range; unsuitable for flight hardware	Select only for cost-sensitive ground-test equipment where 5 V compatibility and military screening are unnecessary
CY62256LN-70ZSXI	5 V supply, 70 ns access, 32K × 8-bit, industrial temp (–40°C to +85°C), Pb-free SOIC	No military qualification, plastic package, lower reliability margin for shock/vibration	Acceptable for non-safety-critical industrial controllers where hermeticity and Class B screening are not mandated

Compared with IS61LV25616AL-10TLI and CY62256LN-70ZSXI, the 71256S70TDB uniquely delivers MIL-STD-883 Class B screening, –55°C to +125°C operation, and hermetic ceramic packaging-making it the sole choice for flight-certified avionics and missile guidance systems requiring proven field reliability.

Availability

71256S70TDB is available at Aetrix Electronics and suitable for avionics flight control units, tactical radio baseband processors, and missile guidance inertial measurement units requiring stable component supply across extended product lifecycles and stringent environmental certifications.

Supply support for 71256S70TDB 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 71256S series was developed by Renesas (formerly IDT) specifically for high-reliability embedded systems demanding military-grade temperature performance, hermetic packaging, and deterministic SRAM timing in safety-critical applications.

FAQ

What is the maximum operating temperature range certified for the 71256S70TDB?

The 71256S70TDB is certified for continuous operation from –55°C to +125°C and qualified per MIL-STD-883 Class B, including temperature cycling, burn-in, and hermeticity tests. This range is explicitly validated for the SD28 ceramic DIP package and applies to all speed grades within the S-series military family, including the 71256S70TDB.

Does the 71256S70TDB support battery backup data retention?

No-the 71256S70TDB is the standard-power variant (S-series) and does not include battery backup capability. That feature is exclusive to the L-series (e.g., 71256L70TDB), which specifies 2 V data retention and microamp-level standby current. The 71256S70TDB draws 20 mA in standby and requires continuous 5 V supply for data retention.

Is the 71256S70TDB pin-compatible with other members of the 71256 family?

Yes-the 71256S70TDB shares identical pinout, package dimensions, and signal definitions with all 28-pin SD28 variants in the 71256S/L family, including 71256S25TDB, 71256S35TDB, and 71256L70TDB. Address, data, and control pins (A0–A14, I/O0–I/O7, CS, WE, OE, V_CC, GND) are functionally and physically identical across these orderable parts.

What is the meaning of "TDB" in the part number 71256S70TDB?

In Renesas' ordering nomenclature, "TDB" denotes the 28-pin 300-mil ceramic DIP package (SD28) supplied in tube format. "T" indicates tube packaging, "D" signifies ceramic DIP, and "B" identifies the military temperature grade (–55°C to +125°C). This distinguishes it from "DB" (600-mil CDIP) and "YG" (SOJ) variants.

Can the 71256S70TDB be used in new designs despite its legacy status?

Yes-the 71256S70TDB remains actively supported by Renesas with documented availability, full MIL-STD-883 Class B qualification, and no announced obsolescence. While newer low-voltage SRAMs exist, the 71256S70TDB is expressly maintained for legacy avionics, defense, and space programs requiring proven reliability, 5 V compatibility, and hermetic packaging-making it appropriate for new designs targeting those domains.

71256S70TDB 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:: 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

71256S70TDB FAQ

1.How can I place an order for 71256S70TDB through Aetrix?

Please submit a Request for Quotation (RFQ) for 71256S70TDB 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 71256S70TDB reliable?

The price and inventory of 71256S70TDB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256S70TDB is usually 5 days.

3.What payment methods are accepted for 71256S70TDB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256S70TDB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 71256S70TDB?

71256S70TDB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 71256S70TDB 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 71256S70TDB?

For technical support, including 71256S70TDB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256S70TDB requirements.

6.How does Aetrix verify that 71256S70TDB is sourced from the original manufacturer or authorized distributors?

All 71256S70TDB 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 71256S70TDB meets industry standards.

7.What is the process for return or replacement of 71256S70TDB?

All 71256S70TDB units undergo pre-shipment inspection (PSI). If there is an issue with 71256S70TDB, 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 71256S70TDB part is unused and in its original packaging.

Return procedure for 71256S70TDB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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