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Renesas 71256L45TDB
- Part No.:
- 71256L45TDB
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-CDIP (0.300", 7.62mm)
- Datasheet:
-
71256L45TDB.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28CDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,913
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Product details
Overview
71256L45TDB from Renesas is a 256K (32K × 8-bit) low-power CMOS static RAM with 45ns maximum access time, TTL-compatible I/O, and battery-backed data retention down to 2V. It operates across the military temperature range (–55°C to +125°C), features automatic standby mode on chip select high, and is packaged in a 28-pin 300-mil ceramic DIP (SD28) for high-reliability avionics and defense systems.
For engineers reviewing the 71256L45TDB datasheet, 71256L45TDB pinout, 71256L45TDB application, or 71256L45TDB equivalent, key selection criteria include military-grade timing consistency, sub-5μW standby current at 2V, MIL-STD-883 Class B compliance, and direct TTL-level interfacing without level-shifting.
Technical Context
The 71256L45TDB implements a full CMOS SRAM architecture with asynchronous read/write control via independent CS, WE, and OE inputs. Its dual standby modes-TTL-level (ISB = 3mA max) and CMOS-level (ISB1 = 1.5μA max)-enable dynamic power scaling based on system bus activity and voltage thresholds.
Timing is defined by strict military-grade AC parameters: tAA ≤ 45ns, tRC ≤ 45ns, tCHZ ≤ 20ns, and tOHZ ≤ 20ns over –55°C to +125°C. Data retention at VCC ≥ 2.0V is guaranteed with ICCDR ≤ 800μA, supporting backup battery operation without external regulators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 256Kbit (32K × 8-bit) - supports byte-wide data buses without multiplexing or external address latching |
| Access Time | 45ns max (tAA, tACS) - enables integration into 22 MHz synchronous bus systems with margin |
| Supply Voltage | 5.0V ±10% - compatible with standard TTL/CMOS logic rails; no separate VDD/VSS sequencing required |
| Standby Current | 1.5μA max (ISB1, CMOS-level CS) - allows multi-year battery backup using coin cells in dormant systems |
| Data Retention | 2.0V min (VDR) - maintains stored data during brownout or main power loss without auxiliary circuitry |
| Operating Temp | –55°C to +125°C - qualified per MIL-STD-883 Class B for flight-critical and ground-vehicle electronics |
| I/O Compatibility | TTL input thresholds (VIH = 2.2V, VIL = 0.8V); VOH ≥ 2.4V / VOL ≤ 0.4V @ 8mA - interoperable with legacy 5V microcontrollers and FPGAs |
Pinout & Package
71256L45TDB uses a 28-pin 300-mil ceramic dual in-line package (CERDIP, SD28) with hermetic sealing for moisture resistance and long-term reliability in harsh environments.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus accepting full 32K-word space; no internal address multiplexing required |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit TTL-compatible data path; high-impedance state when CS or OE inactive prevents bus contention |
| CS | Chip Select | Active-low enable; drives device into low-power standby (ISB1) when held high at CMOS threshold |
| WE | Write Enable | Active-low write control; concurrent low CS + low WE initiates write cycle; tWP ≥ 35ns minimum |
| OE | Output Enable | Active-low output control; decouples data bus during reads only when CS is active (not standalone) |
| VCC | Power Supply | +5V supply pin; accepts 4.5–5.5V range; no bypass capacitor tolerance specified beyond standard 0.1μF |
| GND | Ground Reference | Signal and power return; pin 14 is dedicated GND; layout requires low-inductance connection to minimize noise |
Key Features
| Feature | Design Value |
|---|---|
| Low-power standby mode | 1.5μA max ISB1 current at VCC = 5.5V enables >10-year battery life in always-on monitoring nodes |
| Battery backup retention | Guaranteed data hold at VCC ≥ 2.0V with ICCDR ≤ 800μA - eliminates need for external voltage supervisors or backup regulators |
| MIL-STD-883 Class B compliance | Full screening including burn-in, thermal cycling, and mechanical shock testing ensures suitability for airborne and missile guidance systems |
| Direct TTL compatibility | No level shifters needed: VIH/VIL and VOH/VOL meet TTL specs across full temperature range - simplifies interface with legacy 80Cxx and Z80-based controllers |
| Two-package options | SD28 (300-mil CERDIP) and CD28 (600-mil CERDIP) allow board density vs. handling trade-offs without redesigning footprint or signal routing |
Applications
| Avionics Flight Control Memory | Tactical Radio Buffer Storage |
|---|---|
|
Use Scenario: Storing real-time sensor fusion coefficients and flight envelope limits in fly-by-wire ECUs operating under vibration and thermal stress. IC Role / Device Role / Timing Role: Nonvolatile configuration memory holding critical lookup tables; accessed asynchronously during servo loop execution with <45ns latency. Use Value: MIL-STD-883 qualification and –55°C to +125°C operation ensure deterministic timing across altitude and ambient extremes without derating. |
Use Scenario: Holding encrypted voice packet buffers and channel state information in manpack radios exposed to desert and arctic conditions. IC Role / Device Role / Timing Role: High-reliability scratchpad RAM for burst-mode digital signal processing; powered from primary battery with 2V retention fallback. Use Value: 1.5μA ISB1 current extends operational runtime between charges; TTL compatibility avoids adding level-shifter ICs in space-constrained RF modules. |
| Missile Guidance System Cache | Secure Embedded Crypto Key Store |
|
Use Scenario: Caching navigation waypoints and target coordinates in inertial measurement units subjected to high-G launch transients. IC Role / Device Role / Timing Role: Fast-access working memory for Kalman filter updates; retains mission-critical data during power interruption from pyro shock. Use Value: Hermetic SD28 ceramic package resists moisture ingress and particle contamination; 2V data retention sustains integrity through 100ms power dropout. |
Use Scenario: Storing ephemeral cryptographic keys in tamper-resistant hardware security modules deployed in field-deployable comms gear. IC Role / Device Role / Timing Role: Secure volatile storage with zero external leakage paths; data erased only on intentional power removal or CS deassertion. Use Value: Sub-5μW standby draw minimizes detectable thermal signature; MIL-grade packaging deters physical probing attempts during reverse engineering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IS61LV25616AL-10TLI | 3.3V-only supply; 10ns access; 256K × 16 organization | Requires voltage translation for 5V systems; wider data bus increases PCB trace count | Prefer for new 3.3V designs needing higher bandwidth; not drop-in for 71256L45TDB's 5V/TTL interface |
| AS6C4008-55ZIN | 5V supply; 55ns access; industrial temp only (–40°C to +85°C) | Lacks MIL-STD-883 qualification and battery retention capability | Suitable for cost-sensitive commercial/industrial upgrades where military reliability is not mandated |
Compared with 71256L45TDB, IS61LV25616AL-10TLI offers faster speed but mandates 3.3V infrastructure, while AS6C4008-55ZIN provides lower cost and availability but omits military screening and 2V data retention-making 71256L45TDB irreplaceable for legacy 5V defense platforms requiring guaranteed operation at extreme temperatures.
Availability
71256L45TDB is available at Aetrix Electronics and suitable for avionics subsystems, tactical radio development, missile guidance hardware, and secure crypto module production requiring stable component supply across extended lifecycle programs.
Supply support for 71256L45TDB 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 is a global semiconductor leader specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and aerospace markets.
The 71256L45TDB belongs to Renesas' legacy high-reliability SRAM product line, engineered specifically for military and aerospace applications demanding guaranteed performance under extreme environmental stress and long-term obsolescence resilience.
FAQ
What is the maximum operating temperature range for the 71256L45TDB?
The 71256L45TDB is rated for continuous operation from –55°C to +125°C and is fully qualified to MIL-STD-883 Class B, including thermal cycling, mechanical shock, and burn-in testing. This makes it suitable for engine-mounted avionics, missile seeker electronics, and other high-stress military platforms where commercial or industrial grade parts would fail.
Does the 71256L45TDB support true battery backup operation below 5V?
Yes-the 71256L45TDB guarantees data retention at VCC ≥ 2.0V with ICCDR ≤ 800μA, enabling direct connection to lithium or alkaline backup cells without regulation. This feature is exclusive to the "L" (low-power) variant and is validated across the full military temperature range, unlike many commercial SRAMs that specify retention only at room temperature.
Is the 71256L45TDB pin-compatible with earlier IDT-branded versions?
Yes-the 71256L45TDB retains identical pinout, timing, and electrical specifications as the original Integrated Device Technology (IDT) version. Renesas acquired IDT's memory business and continues manufacturing this part under the same ordering code, datasheet revision, and qualification standards without functional or mechanical changes.
What package type does the "TDB" suffix indicate for the 71256L45TDB?
The "TDB" suffix denotes the 28-pin 300-mil ceramic dual in-line package (CERDIP) with SD28 footprint. This hermetically sealed package provides superior moisture resistance and thermal stability compared to plastic SOJ or larger 600-mil DIP variants, making it preferred for high-reliability applications where long-term solder joint integrity is critical.
Can the 71256L45TDB be used in systems requiring zero standby current during deep sleep?
No-the 71256L45TDB has a minimum standby current of 1.5μA (ISB1) when CS is held high at CMOS threshold. While exceptionally low, it is not zero-current. For true zero-leakage retention, external power gating or nonvolatile alternatives (e.g., FRAM) would be required; however, 1.5μA supports >10-year battery life in most field-deployable systems.
71256L45TDB 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
71256L45TDB FAQ
1.How can I place an order for 71256L45TDB through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256L45TDB 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 71256L45TDB reliable?
The price and inventory of 71256L45TDB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256L45TDB is usually 5 days.
3.What payment methods are accepted for 71256L45TDB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256L45TDB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256L45TDB?
71256L45TDB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256L45TDB 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 71256L45TDB?
For technical support, including 71256L45TDB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256L45TDB requirements.
6.How does Aetrix verify that 71256L45TDB is sourced from the original manufacturer or authorized distributors?
All 71256L45TDB 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 71256L45TDB meets industry standards.
7.What is the process for return or replacement of 71256L45TDB?
All 71256L45TDB units undergo pre-shipment inspection (PSI). If there is an issue with 71256L45TDB, 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 71256L45TDB part is unused and in its original packaging.
Return procedure for 71256L45TDB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71256L45TDB Tags
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AT24C02C-XHM-T
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AT24CS02-SSHM-T
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