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Renesas IDT71256SA25YI
- Part No.:
- IDT71256SA25YI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-BSOJ (0.300", 7.62mm Width)
- Datasheet:
-
IDT71256SA25YI.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28SOJ
- Quantity:
- Payment:
- Shipping:
Inventory:3,581
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Product details
Overview
IDT71256SA25YI from Renesas Electronics is a 32K × 8-bit (256 Kbit) high-speed CMOS static RAM with industrial temperature support (–40°C to +85°C), 25 ns read/write cycle time, TTL-compatible I/O, and single 5 V supply operation. It serves as main or buffer memory in embedded controllers, legacy industrial PLCs, and instrumentation systems requiring deterministic, non-refreshed data retention.
For engineers reviewing the IDT71256SA25YI datasheet, IDT71256SA25YI pinout, IDT71256SA25YI application, or IDT71256SA25YI equivalent, key selection criteria include industrial-grade timing consistency, low standby current (ISB1 = 15 mA), bidirectional TTL I/O compatibility, and SOJ-28 package footprint for through-hole or socketed legacy board upgrades.
Technical Context
The IDT71256SA25YI implements fully static asynchronous architecture-no clocks or refresh cycles required-enabling seamless integration into microcontroller-based systems with irregular memory access patterns. Its dual control scheme uses independent Chip Select (CS) and Output Enable (OE) pins to support both chip-level deselection (standby ISB1 = 15 mA) and output gating without affecting internal state.
Timing is defined by fixed-cycle parameters: tRC = 25 ns, tAA = 25 ns, tWC = 25 ns, with guaranteed tOH = 3 ns hold time and tCHZ = 11 ns high-impedance transition after CS deassertion. All inputs meet TTL voltage thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and drive ±8 mA outputs compliant with standard TTL loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144-bit total); supports byte-wide parallel bus interfacing without external data multiplexing |
| Access/Cycle Time | 25 ns; ensures compatibility with 40 MHz Z80, 80C88, and similar legacy CPU buses without wait-state insertion |
| Supply Voltage | 4.5 V to 5.5 V; tolerates nominal 5 V rail variation in unregulated industrial power domains |
| Operating Temperature | –40°C to +85°C; qualified for deployment in factory-floor automation, motor drives, and outdoor metering enclosures |
| Standby Current (ISB1) | 15 mA max at VCC = 5.5 V; enables low-power sleep mode during CPU idle periods without data loss |
| I/O Compatibility | TTL input thresholds and output drive strength; eliminates need for level-shifting logic when interfacing with 74LS/74HC peripherals |
| Package | 28-pin 300-mil Plastic SOJ (PJG28); provides mechanical robustness and thermal performance suitable for reflow or wave-soldered industrial PCBs |
Pinout & Package
Package: 28-pin 300-mil Plastic SOJ (PJG28), gull-wing lead form, JEDEC MS-013AC compliant, body width 390 mil, lead pitch 50 mil.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus accepting full 32K range; latched on CS low transition for asynchronous access |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit TTL-compatible data path; direction controlled implicitly by WE and CS states per truth table |
| CS | Chip Select | Active-low enable; places device in standby (ISB1 = 15 mA) when high, enabling system-level power gating |
| WE | Write Enable | Active-low write strobe; initiates write cycle only when CS is also low; controls data latch timing (tWP = 20 ns min) |
| OE | Output Enable | Active-low output gate; allows shared bus usage by disabling outputs (high-Z) while CS remains asserted |
| VCC | Power Supply | +5 V supply pin; decoupling capacitor placement adjacent to this pin critical for noise immunity in noisy industrial environments |
| GND | Ground Reference | Signal and power ground return; requires low-inductance connection to minimize ground bounce during I/O transitions |
Key Features
| Feature | Design Value |
|---|---|
| Fully static operation | No clock, no refresh required-ideal for battery-backed or intermittently powered systems where deterministic latency is mandatory |
| Dual standby modes | ISB = 40 mA (TTL-level CS high) and ISB1 = 15 mA (CMOS-level CS high) enable hierarchical power management |
| Guaranteed 25 ns timing | All AC parameters (tRC, tAA, tWC) specified at worst-case industrial temperature and voltage extremes-no derating needed |
| TTL-compatible interface | Direct connection to legacy microprocessor buses (e.g., 8086, 68000) without bus transceivers or level shifters |
| Green packaging option | Halogen-free, RoHS-compliant materials meet industrial environmental compliance requirements without performance trade-offs |
Applications
| Industrial PLC Memory Expansion | Legacy Test Equipment Data Buffer |
|---|---|
Use Scenario: Adding local program/data storage to DIN-rail mounted programmable logic controllers operating in ambient temperatures up to +85°C. IC Role / Device Role / Timing Role: Non-volatile SRAM replacement for EPROM-based firmware overlays; provides zero-wait-state execution of ladder logic routines. Use Value: Eliminates need for external wait-state generators and supports real-time I/O scanning at 10 ms cycle times under full thermal load. | Use Scenario: Capturing transient analog waveform samples in benchtop oscilloscopes and signal analyzers with aging CPU architectures. IC Role / Device Role / Timing Role: High-speed acquisition buffer interfaced directly to 8-bit ISA or VME bus; synchronized via hardware trigger lines. Use Value: Sustains 40 MB/s burst write throughput (tWC = 25 ns) without DMA controller overhead, preserving signal fidelity during glitch capture. |
| Avionics Maintenance Terminal RAM | Ruggedized Point-of-Sale Controller |
Use Scenario: Field-deployable diagnostic terminals used for aircraft subsystem verification in hangar environments with wide thermal cycling. IC Role / Device Role / Timing Role: Configuration and calibration parameter store accessed by MIL-STD-1553B host processor via discrete address decoding. Use Value: Maintains data integrity across –40°C to +85°C without refresh circuitry, reducing BOM count and improving MTBF. | Use Scenario: Embedded payment terminal running proprietary OS on 80C188EB, requiring reliable local memory for transaction logging and encryption keys. IC Role / Device Role / Timing Role: Secure, tamper-resistant working memory mapped into CPU's lower 32K address space with hardware write-protection via WE gating. Use Value: Enables atomic 8-byte writes (tDW = 13 ns) to prevent partial-record corruption during unexpected power loss. |
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 uses 28-pin TSOP (SOIC-type) instead of SOJ; ISB1 = 10 µA vs 15 mA | Lower standby current suits battery-powered portable testers; TSOP footprint requires PCB redesign from SOJ | Select when ultra-low ISB1 and surface-mount assembly are priorities over mechanical robustness and socket compatibility |
| AS6C4008-25ZIN | 25 ns speed, industrial temp, but operates at 2.7–5.5 V; VIH/VIL thresholds differ (CMOS, not TTL) | Requires level-shifting for legacy 5 V TTL buses; wider VCC range supports mixed-supply designs | Select when migrating toward modern low-voltage systems or integrating with 3.3 V microcontrollers alongside 5 V peripherals |
Compared with CY62256LL-25ZSXIT and AS6C4008-25ZIN, the IDT71256SA25YI offers proven mechanical reliability in SOJ packaging, native TTL compatibility for drop-in legacy replacement, and consistent 25 ns timing across full industrial temperature range-making it optimal for retrofit and long-lifecycle industrial hardware.
Availability
IDT71256SA25YI is available at Aetrix Electronics and suitable for industrial PLCs, avionics maintenance terminals, and ruggedized point-of-sale controllers requiring stable component supply across extended product lifecycles.
Supply support for IDT71256SA25YI 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 IDT71256SA25YI belongs to Renesas' legacy high-reliability static RAM product line, designed specifically for industrial and aerospace systems demanding deterministic timing, wide temperature operation, and long-term supply stability.
FAQ
What is the maximum operating frequency supported by the IDT71256SA25YI?
The IDT71256SA25YI does not operate on a clock signal-it is a fully static RAM. Its maximum effective bus frequency is derived from its 25 ns cycle time, supporting up to 40 MHz sustained random-access throughput on compatible 8-bit buses. No external clock is required, and timing is governed solely by address and control signal setup/hold windows per the datasheet AC specifications.
Does the IDT71256SA25YI require refresh circuitry or periodic memory maintenance?
No, the IDT71256SA25YI is a true static RAM and requires no refresh cycles, clocks, or periodic maintenance. Its CMOS latch-based memory cells retain data indefinitely as long as VCC is applied within specification (4.5 V to 5.5 V) and ambient temperature remains within –40°C to +85°C. This eliminates refresh overhead in microcontroller firmware and simplifies system design.
Can the IDT71256SA25YI be used as a direct replacement for the IDT71256SA20YI in an existing design?
Yes, the IDT71256SA25YI is pin- and function-compatible with the IDT71256SA20YI, sharing identical pinout, voltage levels, control protocol, and SOJ-28 package. The only difference is timing: IDT71256SA25YI has 25 ns access/cycle versus 20 ns. System timing margins must be verified, but no PCB or firmware changes are required for substitution.
What is the meaning of "YI" in the part number IDT71256SA25YI?
In the IDT71256SA25YI ordering code, "Y" denotes the 28-pin 300-mil Plastic SOJ package (PJG28), and "I" indicates Industrial temperature grade (–40°C to +85°C). This distinguishes it from commercial-grade variants (e.g., IDT71256SA25YG) and other package options like TSOP ("PZG") or PDIP ("TPG").
Is the IDT71256SA25YI RoHS-compliant and halogen-free?
Yes, the IDT71256SA25YI is a green part: it meets RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. This is confirmed in the Renesas datasheet revision history (June 2020 update) and ordering information, where "Green" status is explicitly assigned to all YI variants including IDT71256SA25YI.
IDT71256SA25YI 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOJ
IDT71256SA25YI FAQ
1.How can I place an order for IDT71256SA25YI through Aetrix?
Please submit a Request for Quotation (RFQ) for IDT71256SA25YI 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 IDT71256SA25YI reliable?
The price and inventory of IDT71256SA25YI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IDT71256SA25YI is usually 5 days.
3.What payment methods are accepted for IDT71256SA25YI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IDT71256SA25YI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for IDT71256SA25YI?
IDT71256SA25YI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your IDT71256SA25YI 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 IDT71256SA25YI?
For technical support, including IDT71256SA25YI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IDT71256SA25YI requirements.
6.How does Aetrix verify that IDT71256SA25YI is sourced from the original manufacturer or authorized distributors?
All IDT71256SA25YI 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 IDT71256SA25YI meets industry standards.
7.What is the process for return or replacement of IDT71256SA25YI?
All IDT71256SA25YI units undergo pre-shipment inspection (PSI). If there is an issue with IDT71256SA25YI, 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 IDT71256SA25YI part is unused and in its original packaging.
Return procedure for IDT71256SA25YI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
IDT71256SA25YI Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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