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Renesas 71256SA25YG
- Part No.:
- 71256SA25YG
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-BSOJ (0.300", 7.62mm Width)
- Datasheet:
-
71256SA25YG.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28SOJ
- Quantity:
- Payment:
- Shipping:
Inventory:3,869
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Product details
Overview
71256SA25YG from Renesas Electronics is a 32K × 8-bit (256 Kbit) high-speed CMOS static RAM with industrial-grade temperature range (–40°C to +85°C), 25 ns read/write cycle time, TTL-compatible I/O, and single 5 V supply operation. It serves as a non-refreshing, asynchronous memory buffer in real-time control systems, legacy industrial controllers, and embedded instrumentation requiring deterministic access timing.
For engineers reviewing the 71256SA25YG datasheet, 71256SA25YG pinout, 71256SA25YG application, or 71256SA25YG equivalent, key selection criteria include standby current (ISB1 = 15 mA), chip select access time (tACS = 25 ns), output enable delay (tOE = 11 ns), and SOJ-28 package compatibility with legacy PCB footprints.
Technical Context
The 71256SA25YG implements fully static asynchronous circuitry-no clocks or refresh required-and uses dual-control logic with independent Chip Select (CS) and Output Enable (OE) inputs to manage read/write state transitions. Its bidirectional I/O architecture supports direct TTL-level interfacing without level-shifting.
It features three power states: active read/write (ICC = 145 mA), TTL-level standby (ISB = 40 mA), and CMOS-level deep standby (ISB1 = 15 mA), enabling dynamic power management in battery-backed or energy-constrained systems. All timing parameters are guaranteed over the full industrial temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144-bit total); supports byte-wide data bus interfacing without external demultiplexing |
| Access Time (tAA) | 25 ns max; ensures predictable latency for deterministic real-time firmware execution |
| Read Cycle Time (tRC) | 25 ns max; enables sustained 40 MHz burst read throughput in synchronous bus environments |
| Standby Current (ISB1) | 15 mA max at CMOS-level CS deassertion; reduces system idle power in always-on monitoring nodes |
| Supply Voltage | 4.5 V to 5.5 V; compatible with standard 5 V TTL/CMOS logic rails and legacy power domains |
| Operating Temperature | –40°C to +85°C; qualified for deployment in uncontrolled industrial enclosures and outdoor equipment |
| I/O Compatibility | TTL input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and output drive (VOH ≥ 2.4 V @ –4 mA, VOL ≤ 0.4 V @ 8 mA) |
Pinout & Package
71256SA25YG is packaged in a 28-pin 300-mil Plastic SOJ (PJG28) with gull-wing leads, designed for wave-solder compatibility and legacy board reuse. Pin 1 is marked by a beveled corner on the top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus supporting full 32K-word decoding; no internal latching - requires stable address during CS low |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit TTL-compatible data path; high-impedance when CS or OE is inactive; no external bus transceivers needed |
| CS | Chip Select | Primary device enable; asserts memory array and I/O drivers when low; supports CMOS-level deep standby when high > VHC |
| OE | Output Enable | Controls output drivers only; allows read data to appear within 11 ns of activation while CS remains asserted |
| WE | Write Enable | Active-low write strobe; initiates write on falling edge coincident with CS low; disables outputs during write |
| VCC, GND | Power Supply | Single 5 V supply with dedicated VCC (Pin 24) and GND (Pin 12); decoupling recommended per JEDEC SOJ guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous Static Operation | No clock, no refresh, no wait states - simplifies timing-critical microcontroller interfaces and eliminates DRAM controller overhead |
| Dual-Enable Control (CS + OE) | Enables partial bus sharing: OE can gate output without deselecting chip, reducing bus contention in multi-device systems |
| Low-Power Deep Standby (ISB1) | 15 mA max at CMOS-level CS deassertion - cuts standby power by 62.5% vs. TTL-level standby (40 mA) in intermittent-read applications |
| Industrial Temperature Qualification | Guaranteed 25 ns timing across –40°C to +85°C - supports deployment in motor drives, PLC backplanes, and railway signaling hardware |
| Green (RoHS-Compliant) Packaging | Lead-free SOJ construction with halogen-free molding compound - meets IPC-1752A material declaration requirements |
Applications
| Industrial PLC Memory Buffer | Legacy Test Equipment Data Cache |
|---|---|
|
Use Scenario: Storing real-time I/O scan data and ladder logic intermediate values in modular programmable logic controllers with 8-bit microcontrollers. IC Role / Device Role / Timing Role: Asynchronous byte-wide SRAM providing zero-wait-state access to firmware-executed control routines. Use Value: 25 ns tAA ensures deterministic response under worst-case thermal conditions, eliminating jitter in motion control loops. |
Use Scenario: Holding digitized waveform samples and calibration coefficients in benchtop oscilloscopes and signal generators built on 1990s-era ASIC platforms. IC Role / Device Role / Timing Role: Drop-in replacement for obsolete 28-pin SOJ SRAMs in field-repairable modules requiring identical footprint and timing. Use Value: PJG28 SOJ package and 25 ns speed match original design specs, avoiding board rework during component obsolescence mitigation. |
| Energy-Meter Firmware Stack | Railway Signaling Diagnostic Module |
|
Use Scenario: Caching tariff tables, event logs, and communication protocol buffers in Class 0.2 revenue-grade electricity meters operating in outdoor cabinets. IC Role / Device Role / Timing Role: Non-volatile-supporting volatile memory holding runtime variables between metering cycles and firmware updates. Use Value: ISB1 = 15 mA enables >10-year battery backup life in tamper-detection circuits powered by primary lithium cells. |
Use Scenario: Storing fault-code history and configuration registers in EN 5012x-compliant trackside diagnostic units exposed to wide ambient swings. IC Role / Device Role / Timing Role: Industrial-temperature SRAM ensuring reliable boot-time parameter loading and runtime status tracking. Use Value: Full –40°C to +85°C operation with guaranteed 25 ns timing prevents cold-start failures in northern European rail infrastructure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY62256LL-25ZSXIT | Same 32K × 8 organization, 25 ns speed, but 32-pin TSOP-II (SOIC-32 footprint); higher ICC (160 mA) and ISB (50 mA) | Requires PCB redesign due to different pin count and layout; better suited for new designs with space-constrained layouts | Select when migrating to surface-mount-only assembly and higher-density board stacking is required |
| AS6C4008-25ZIN | Pin-compatible 28-pin SOJ, same 25 ns speed, but lower ISB1 (5 mA) and wider VCC range (2.7–5.5 V); not qualified for industrial temp | Limited to commercial-grade environments; unsuitable for extended outdoor or under-hood use | Select only for cost-sensitive consumer or lab-grade instruments where temperature range is not critical |
Compared with CY62256LL-25ZSXIT and AS6C4008-25ZIN, the 71256SA25YG uniquely balances industrial temperature qualification, SOJ-28 drop-in compatibility, and proven reliability in legacy infrastructure-making it the preferred choice for repair, refurbishment, and long-lifecycle maintenance programs.
Availability
71256SA25YG is available at Aetrix Electronics and suitable for industrial automation, legacy test equipment, and energy metering applications requiring stable component supply and long-term obsolescence management.
Supply support for 71256SA25YG 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 delivering trusted embedded solutions for automotive, industrial, infrastructure, and IoT applications.
The 71256SA25YG belongs to Renesas' legacy high-speed CMOS SRAM product line, engineered for reliability in mission-critical industrial control and instrumentation where long-term availability and pin-level compatibility are essential.
FAQ
What is the maximum guaranteed access time for the 71256SA25YG?
The 71256SA25YG has a maximum guaranteed address access time (tAA) of 25 ns across its full industrial operating temperature range (–40°C to +85°C), as specified in the AC Electrical Characteristics table under the 71256SA25 speed grade. This value is production-tested and applies to all valid address and control combinations when VCC is maintained between 4.5 V and 5.5 V.
Does the 71256SA25YG require a refresh circuit or clock signal?
No, the 71256SA25YG is a fully static RAM and requires neither a refresh circuit nor a clock signal. Its internal circuitry operates asynchronously using only CS, OE, WE, and address/data signals. This eliminates timing complexity in microcontroller-based systems and avoids refresh-induced bus contention common in DRAM implementations.
What package type and lead finish does the 71256SA25YG use?
The 71256SA25YG uses a 28-pin 300-mil Plastic SOJ (PJG28) package with gull-wing leads and RoHS-compliant lead-free (Pb-free) finish. The package conforms to JEDEC MO-050AC and is compatible with standard wave soldering processes and legacy SOJ sockets used in industrial backplanes.
Can the 71256SA25YG operate from a 3.3 V supply?
No, the 71256SA25YG is specified only for 4.5 V to 5.5 V operation. Its TTL-compatible input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and output drive capability (VOH ≥ 2.4 V @ –4 mA) are optimized for 5 V logic families. Using 3.3 V violates the Absolute Maximum Ratings and will result in undefined behavior or failure to meet timing specifications.
How does the standby current differ between TTL-level and CMOS-level chip deselect on the 71256SA25YG?
The 71256SA25YG offers two standby modes: ISB = 40 mA when CS is held above VIH (TTL-level deselect), and ISB1 = 15 mA when CS is driven above VHC (CMOS-level deselect). This dual-threshold design allows designers to reduce system idle power by 62.5% in applications where precise control of the CS voltage level is feasible, such as with actively driven control logic.
71256SA25YG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 28-BSOJ (0.300", 7.62mm Width)
- 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:
- 25ns
- Access Time:
- 25 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOJ
71256SA25YG FAQ
1.How can I place an order for 71256SA25YG through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256SA25YG 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 71256SA25YG reliable?
The price and inventory of 71256SA25YG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256SA25YG is usually 5 days.
3.What payment methods are accepted for 71256SA25YG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256SA25YG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256SA25YG?
71256SA25YG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256SA25YG 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 71256SA25YG?
For technical support, including 71256SA25YG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256SA25YG requirements.
6.How does Aetrix verify that 71256SA25YG is sourced from the original manufacturer or authorized distributors?
All 71256SA25YG 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 71256SA25YG meets industry standards.
7.What is the process for return or replacement of 71256SA25YG?
All 71256SA25YG units undergo pre-shipment inspection (PSI). If there is an issue with 71256SA25YG, 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 71256SA25YG part is unused and in its original packaging.
Return procedure for 71256SA25YG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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