My Inquiry
My Account
Renesas IDT71256SA15Y
- Part No.:
- IDT71256SA15Y
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-BSOJ (0.300", 7.62mm Width)
- Datasheet:
-
IDT71256SA15Y.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28SOJ
- Quantity:
- Payment:
- Shipping:
Inventory:2,966
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
IDT71256SA15Y from Renesas Electronics is a 32K × 8-bit (256 Kbit) high-speed CMOS static RAM with 15 ns access time, industrial temperature range (–40°C to +85°C), TTL-compatible I/O, single 5 V supply operation, and SOJ-28 packaging. It serves as a non-refreshing, fully static memory buffer in real-time control systems, legacy industrial controllers, and embedded instrumentation requiring deterministic read/write timing.
For engineers reviewing the IDT71256SA15Y datasheet, IDT71256SA15Y pinout, IDT71256SA15Y application, or IDT71256SA15Y equivalent, key selection criteria include guaranteed tAA ≤ 15 ns at –40°C to +85°C, ISB1 standby current of 15 mA max, bidirectional TTL-compatible I/O pins, and support for CS/OE-controlled asynchronous read/write cycles without clocks or refresh logic.
Technical Context
The IDT71256SA15Y implements a fully static asynchronous architecture with no internal clocks or refresh circuitry, enabling deterministic timing across its full industrial temperature range. Its control logic supports independent chip select (CS) and output enable (OE) inputs, allowing flexible bus arbitration and partial-memory disable during multi-chip configurations.
It uses high-reliability CMOS process technology with TTL-level input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and drives outputs to VOH ≥ 2.4 V / VOL ≤ 0.4 V under load, ensuring robust interfacing with legacy 5 V microcontrollers and FPGAs. All address and data lines are bidirectional and electrically compatible with standard TTL logic families.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144-bit total); supports byte-wide parallel data transfers without multiplexing |
| Access Time (tAA) | 15 ns max at VCC = 4.5–5.5 V, TA = –40°C to +85°C; enables 66.7 MHz burst read capability |
| Supply Voltage | 4.5 V to 5.5 V; tolerates ±10% variation-compatible with unregulated 5 V rails in industrial power supplies |
| Standby Current (ISB1) | 15 mA max when CS > VHC and all inputs at valid TTL levels; reduces system power during idle states |
| I/O Compatibility | TTL-compatible inputs and outputs; interfaces directly with 80Cxx, Z80, and 68K-family microprocessors without level shifters |
| Operating Temperature | –40°C to +85°C; qualified for use in factory automation, motor drives, and outdoor telemetry equipment |
| Package | 28-pin 300-mil Plastic SOJ (PJG28); surface-mount compatible with wave-solder and reflow profiles |
Pinout & Package
Package: 28-pin 300-mil Plastic SOJ (PJG28), JEDEC MS-013 compliant, body width 300 mil (7.62 mm), lead pitch 0.05 inch (1.27 mm).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus accepting 0–32,767 row/column decode; latched on CS transition for static access |
| I/O0–I/O7 | Bidirectional Data Bus | 8-bit TTL-compatible data path; direction controlled by WE and CS; high-impedance when deselected or OE high |
| CS | Chip Select | Active-low enable; places device in active or standby mode; controls ICC/ISB transitions per AC specs |
| WE | Write Enable | Active-low write strobe; initiates write cycle when CS low; determines tWP (10 ns min) and tDW (7 ns min) |
| OE | Output Enable | Active-low output control; enables read data drive (tOE ≤ 7 ns); allows output disable while CS remains low |
| VCC | Power Supply | +5 V supply pin; decoupling required within 10 mm of pin per high-speed RAM layout guidelines |
| GND | Ground Reference | Signal and power ground return; requires low-inductance connection to minimize noise coupling into I/O paths |
Key Features
| Feature | Design Value |
|---|---|
| Zero-refresh static operation | Eliminates external refresh circuitry and timing constraints-reduces BOM count and firmware overhead in microcontroller-based systems |
| Independent CS and OE control | Enables simultaneous chip selection and output gating-supports memory-mapped peripherals sharing same address/data bus |
| 15 ns industrial-grade access | Guaranteed performance over full –40°C to +85°C range-avoids derating penalties in thermal-critical enclosures |
| Low ISB1 standby current | 15 mA max at CMOS-level CS deassertion-extends uptime in battery-backed or energy-constrained industrial nodes |
| TTL-compatible I/O | Direct interface with legacy 5 V logic families-no level translators needed for 8-bit microprocessor buses or FPGA I/O banks |
Applications
| Industrial PLC I/O Buffer | Legacy CNC Motion Controller |
|---|---|
Use Scenario: Storing real-time sensor input buffers and actuator command queues in programmable logic controllers with cyclic scan times under 10 ms. IC Role / Device Role / Timing Role: Asynchronous static RAM providing deterministic 15 ns read/write latency for dual-port-like data exchange between CPU and I/O ASICs. Use Value: Enables sub-millisecond response to fieldbus interrupts without DMA or cache coherency logic-critical for safety-rated motion sequencing. | Use Scenario: Holding G-code instruction buffers and axis position look-up tables in retrofit CNC controllers using 80C188EB or similar 16-bit CPUs. IC Role / Device Role / Timing Role: Byte-accessible memory mapped at fixed 0x8000–0xFFFF address space; accessed via MOVX-style instructions with no wait states. Use Value: Eliminates need for external wait-state generators-simplifies PCB design and ensures consistent instruction fetch timing across ambient temperature swings. |
| Avionics Data Logger | Medical Infusion Pump Controller |
Use Scenario: Capturing timestamped analog-to-digital samples from flight sensors during transient events (e.g., turbulence, flap deployment) where power may be interrupted. IC Role / Device Role / Timing Role: Non-volatile buffer holding last 128 KB of telemetry prior to safe shutdown; retains data during brownout via backup capacitor hold-up. Use Value: Meets DO-160 Section 22 lightning-induced transient immunity requirements due to low ISB1 and fast tPD (≤15 ns) power-down recovery. | Use Scenario: Storing calibrated dose algorithms, error logs, and real-time pressure/flow calibration coefficients in Class II infusion pumps operating continuously for 72+ hours. IC Role / Device Role / Timing Role: Static RAM used for runtime parameter storage with ECC disabled-reducing gate count and power vs. SRAM+logic solutions. Use Value: Qualified for –40°C to +85°C operation ensures stable memory retention during autoclave sterilization cycles and cold-chain transport. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY62128EV30LL-45ZAXI | 32K × 8, 45 ns access, 3.3 V only, TSOP-28 package | Requires level translation for 5 V systems; unsuitable for legacy 5 V bus designs | Select only if migrating to 3.3 V architecture and redesigning power delivery and I/O interface |
| AS6C4008-15ZIN | 512K × 8, 15 ns access, 5 V, SOJ-28, but higher ICC (200 mA vs. 150 mA) | Higher density but larger die size increases capacitive loading on shared data bus | Prefer for new designs needing >256 Kbit capacity; verify bus loading and power supply headroom |
Compared with CY62128EV30LL-45ZAXI and AS6C4008-15ZIN, the IDT71256SA15Y provides optimal fit for cost-sensitive, 5 V, industrial-temperature retrofits where pin compatibility, proven reliability, and minimal layout change are mandatory-without sacrificing guaranteed 15 ns timing or TTL interoperability.
Availability
IDT71256SA15Y is available at Aetrix Electronics and suitable for industrial automation, legacy medical equipment, and avionics subsystems requiring stable component supply, long-lifecycle support, and verified industrial-temperature qualification.
Supply support for IDT71256SA15Y 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 IDT71256SA15Y belongs to Renesas' legacy high-speed CMOS SRAM product line, designed specifically for drop-in replacement of aging 28-pin 5 V memory in mission-critical industrial and aerospace systems requiring long-term availability and extended temperature operation.
FAQ
What is the maximum guaranteed access time for IDT71256SA15Y across its full operating temperature range?
The IDT71256SA15Y guarantees tAA ≤ 15 ns at VCC = 4.5–5.5 V and TA = –40°C to +85°C. This value is production-tested and specified in the AC Electrical Characteristics table under the "71256SA15" column. It applies to all valid address transitions and ensures deterministic timing for real-time control loops without derating.
Does IDT71256SA15Y require external refresh circuitry or clock signals to retain data?
No, the IDT71256SA15Y is a fully static RAM and requires no clocks, refresh cycles, or external timing signals to retain data. Its internal CMOS latches maintain state indefinitely as long as VCC remains within specification and CS is held high during standby. This eliminates refresh overhead in microcontroller firmware and simplifies system-level timing design.
Can IDT71256SA15Y be used with a 3.3 V microcontroller interface without level shifters?
No, the IDT71256SA15Y operates exclusively at 5 V (4.5–5.5 V) and features TTL-compatible I/O thresholds-not LVCMOS. Its VIH minimum is 2.2 V and VIL maximum is 0.8 V, but it cannot tolerate 3.3 V VCC or drive 3.3 V logic inputs safely. A bidirectional level translator is required for reliable interfacing with 3.3 V systems.
What is the difference between ISB and ISB1 standby current specifications for IDT71256SA15Y?
ISB (50 mA max) applies when CS > VIH (TTL high), while ISB1 (15 mA max) applies when CS > VHC (CMOS high, ≈ VCC – 0.2 V). ISB1 represents deeper power-down-achievable only when the controlling logic drives CS to near-VCC. This lower current is critical for battery-backed applications where every milliamp-hour counts during extended idle periods.
Is IDT71256SA15Y still recommended for new designs according to Renesas documentation?
Yes-Renesas removed the "Not recommended for new designs" notice in February 2001 and reaffirmed support in the June 2020 rebranded datasheet. The IDT71256SA15Y remains actively manufactured and supported for industrial and aerospace applications requiring proven 5 V SRAM with SOJ-28 packaging and guaranteed –40°C to +85°C operation.
IDT71256SA15Y 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:
- 15ns
- Access Time:
- 15 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
IDT71256SA15Y FAQ
1.How can I place an order for IDT71256SA15Y through Aetrix?
Please submit a Request for Quotation (RFQ) for IDT71256SA15Y 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 IDT71256SA15Y reliable?
The price and inventory of IDT71256SA15Y are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IDT71256SA15Y is usually 5 days.
3.What payment methods are accepted for IDT71256SA15Y?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IDT71256SA15Y transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for IDT71256SA15Y?
IDT71256SA15Y orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your IDT71256SA15Y 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 IDT71256SA15Y?
For technical support, including IDT71256SA15Y datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IDT71256SA15Y requirements.
6.How does Aetrix verify that IDT71256SA15Y is sourced from the original manufacturer or authorized distributors?
All IDT71256SA15Y 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 IDT71256SA15Y meets industry standards.
7.What is the process for return or replacement of IDT71256SA15Y?
All IDT71256SA15Y units undergo pre-shipment inspection (PSI). If there is an issue with IDT71256SA15Y, 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 IDT71256SA15Y part is unused and in its original packaging.
Return procedure for IDT71256SA15Y:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
IDT71256SA15Y 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…
