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Renesas 71256SA12TPG
- Part No.:
- 71256SA12TPG
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-DIP (0.300", 7.62mm)
- Datasheet:
-
71256SA12TPG.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,967
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Product details
Overview
71256SA12TPG from Renesas Electronics is a 32K × 8 (256 Kbit) high-speed CMOS static RAM with 12 ns access time, TTL-compatible I/O, single 5 V supply operation, and commercial temperature range (0°C to +70°C). It features independent Chip Select (CS) and Output Enable (OE) pins, bidirectional data bus, and low-power standby modes - deployed in legacy industrial controllers and embedded instrumentation requiring deterministic read/write timing.
For engineers reviewing the 71256SA12TPG datasheet, 71256SA12TPG pinout, 71256SA12TPG application, or 71256SA12TPG equivalent, key selection criteria include access time consistency across address changes, CS/OE dual-control flexibility for bus arbitration, TTL-level compatibility with legacy microcontrollers, and PDIP-28 package suitability for through-hole prototyping and repair.
Technical Context
The 71256SA12TPG implements fully static asynchronous logic with no clocks or refresh required. Its memory array uses high-reliability CMOS technology and supports concurrent address decoding and I/O control via dedicated logic blocks for CS, OE, and WE.
All inputs meet TTL voltage thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V), outputs drive ±4 mA/±8 mA loads, and standby current drops to 50 mA (TTL-level deselect) or 15 mA (CMOS-level deselect), enabling power-aware system design without external gating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 32K × 8-bit (262,144-bit) organization - supports byte-wide data bus interfacing without external multiplexing |
| Access Time (tAA) | 12 ns max - guarantees deterministic read latency from address valid to data stable under worst-case commercial conditions |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL/CMOS logic rails and tolerant of nominal ±5% regulation |
| I/O Compatibility | TTL input thresholds and output drive strength - interoperable with legacy 80Cxx, Z80, and 68K-family microprocessors |
| Standby Current (ISB) | 50 mA max at VIH-level CS - enables low-power sleep mode while retaining data without refresh circuitry |
| Package | 28-pin 300-mil Plastic DIP (PTG28) - supports hand-soldering, socket-based testing, and legacy PCB layouts |
| Temperature Range | 0°C to +70°C - qualified for commercial-grade embedded systems with controlled thermal environments |
Pinout & Package
71256SA12TPG is housed in a 28-pin 300-mil Plastic Dual In-line Package (PDIP), designated PTG28 per Renesas ordering nomenclature. The package is through-hole mountable, RoHS-compliant, and rated for commercial temperature operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus accepting full 32K-word space; no internal latching - requires stable address during CS low |
| 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 for device selection; controls power-up/down timing (tPU/tPD) and output Z-state entry/exit |
| OE | Output Enable | Active-low control for output drivers only; allows read data gating without disabling chip - enables shared-bus arbitration |
| WE | Write Enable | Active-low signal defining write cycle boundaries; determines tWP, tDW, and tDH timing windows |
| VCC, GND | Power Supply | Single 5 V supply with decoupling recommended; GND pin (Pin 14) serves as reference for all DC/AC parameters |
Key Features
| Feature | Design Value |
|---|---|
| Equal access and cycle times | tRC = tAA = 12 ns - eliminates timing margin uncertainty between successive reads/writes in burst-access systems |
| Dual control enable (CS + OE) | Independent OE allows output gating while maintaining chip selection - critical for multi-master bus contention management |
| TTL-compatible I/O | VIH = 2.2 V min, VOL = 0.4 V max at 8 mA - ensures direct interface with 5 V microcontrollers without level-shifting |
| Low-power standby modes | ISB1 = 15 mA at CMOS-level CS high - reduces idle power by >70% versus TTL-level deselect in battery-backed applications |
| Fully static operation | No clock, no refresh, no dynamic timing constraints - simplifies controller firmware and eliminates hidden refresh overhead |
Applications
| Industrial PLC I/O Modules | Legacy Test Equipment Memory Buffers |
|---|---|
Use Scenario: Storing real-time sensor acquisition data and control command queues in modular programmable logic controllers with 8-bit parallel buses. IC Role / Device Role / Timing Role: Byte-addressable SRAM buffer providing zero-wait-state read/write access for deterministic scan-cycle execution. Use Value: 12 ns tAA ensures sub-microsecond response to I/O status changes, meeting <1 ms PLC scan requirements without DMA or caching complexity. | Use Scenario: Holding waveform capture buffers and calibration lookup tables in benchtop oscilloscopes and signal generators using Z80 or 8085-based controllers. IC Role / Device Role / Timing Role: Non-refreshing memory resource mapped into CPU address space for fast parameter recall and trace storage. Use Value: TTL-compatible I/O and PDIP-28 package allow drop-in replacement of obsolete 27C256 EPROMs in field-repair scenarios without board rework. |
| Medical Diagnostic Device Boot Memory | Avionics Display Controller Frame Buffers |
Use Scenario: Storing boot firmware images and configuration registers in portable ultrasound and ECG units where power cycling is frequent. IC Role / Device Role / Timing Role: Static non-volatile-adjacent memory holding initialization code prior to loading from flash or EEPROM. Use Value: ISB1 = 15 mA standby current enables >100-hour battery hold time during powered-off storage without data loss. | Use Scenario: Providing pixel line buffers and overlay attribute storage in CRT-based flight display systems with strict EMI and thermal constraints. IC Role / Device Role / Timing Role: Deterministic-latency frame buffer supporting fixed-rate video timing generation without jitter-inducing DRAM refresh. Use Value: Equal tAA/tRC eliminates pipeline stalls during raster-scan memory access, ensuring stable sync pulse generation across temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY62256LN-12ZSXI | Same 32K×8 organization, 12 ns speed, but SOIC-28 package and -40°C to +85°C industrial rating | Suitable for new designs requiring surface-mount assembly and extended temperature compliance | Select when upgrading from through-hole to SMT or expanding operating range beyond commercial grade |
| AS6C4008-12ZIN | Pin-compatible 32K×8 SRAM with identical PDIP-28 footprint and 12 ns access, but lower ISB (5 mA) and 2.7–5.5 V supply range | Enables dual-supply systems and ultra-low-power standby where 5 V rail is not available | Choose when reducing system standby power or supporting mixed-voltage architectures is prioritized over Renesas pedigree |
Compared with CY62256LN-12ZSXI and AS6C4008-12ZIN, the 71256SA12TPG offers proven reliability in legacy through-hole deployments and tighter tCLZ/tCHZ specs (4 ns/6 ns) for faster bus release timing - making it optimal for repair, reverse-engineering, and long-lifecycle maintenance programs.
Availability
71256SA12TPG is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy test equipment memory buffers, and medical diagnostic device boot memory requiring stable component supply across extended product lifecycles.
Supply support for 71256SA12TPG 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 microcontrollers, analog, power, and memory solutions for automotive, industrial, and IoT applications.
The IDT71256SA family - now part of Renesas' legacy memory portfolio - was engineered for high-reliability, pin-compatible replacement of aging NMOS and early CMOS SRAMs in mission-critical embedded systems.
FAQ
What is the maximum guaranteed access time for the 71256SA12TPG?
The 71256SA12TPG has a maximum guaranteed address access time (tAA) of 12 ns under commercial temperature conditions (0°C to +70°C) and VCC = 4.5 V to 5.5 V. This value is production-tested and applies to all address transitions with CS and OE asserted, ensuring deterministic timing for tight-loop embedded firmware.
Does the 71256SA12TPG require a clock or refresh signal to retain data?
No, the 71256SA12TPG is a fully static RAM and requires neither a clock nor periodic refresh. Data retention depends solely on continuous VCC supply; it holds contents indefinitely as long as power remains within 4.5 V–5.5 V and temperature stays within 0°C to +70°C - a key advantage over DRAM in simple controller designs.
Can the 71256SA12TPG be used with a 3.3 V microcontroller interface?
No - the 71256SA12TPG is strictly a 5 V device with TTL-compatible thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and no 3.3 V tolerance. Direct connection to 3.3 V logic risks undervoltage I/O recognition and potential damage if VCC is misapplied; level translation is mandatory for mixed-voltage systems.
What is the function of the Output Enable (OE) pin on the 71256SA12TPG?
The OE pin on the 71256SA12TPG is an active-low signal that independently controls output driver state without affecting chip selection. When OE is high, I/O0–I/O7 enter high-impedance regardless of CS or WE state - enabling clean bus sharing among multiple devices without toggling CS and avoiding unnecessary power transitions.
Is the 71256SA12TPG RoHS-compliant and lead-free?
Yes, the 71256SA12TPG is a green-part designation per Renesas' ordering information, meaning it complies with RoHS Directive 2011/65/EU and contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE. The "G" suffix in the part number confirms halogen-free and lead-free construction.
71256SA12TPG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 28-DIP (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:
- 12ns
- Access Time:
- 12 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-PDIP
71256SA12TPG FAQ
1.How can I place an order for 71256SA12TPG through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256SA12TPG 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 71256SA12TPG reliable?
The price and inventory of 71256SA12TPG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256SA12TPG is usually 5 days.
3.What payment methods are accepted for 71256SA12TPG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256SA12TPG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256SA12TPG?
71256SA12TPG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256SA12TPG 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 71256SA12TPG?
For technical support, including 71256SA12TPG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256SA12TPG requirements.
6.How does Aetrix verify that 71256SA12TPG is sourced from the original manufacturer or authorized distributors?
All 71256SA12TPG 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 71256SA12TPG meets industry standards.
7.What is the process for return or replacement of 71256SA12TPG?
All 71256SA12TPG units undergo pre-shipment inspection (PSI). If there is an issue with 71256SA12TPG, 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 71256SA12TPG part is unused and in its original packaging.
Return procedure for 71256SA12TPG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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