My Inquiry
My Account
Renesas 71256SA25TPG
- Part No.:
- 71256SA25TPG
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 28-DIP (0.300", 7.62mm)
- Datasheet:
-
71256SA25TPG.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 28DIP
- Quantity:
- Payment:
- Shipping:
Inventory:778
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
71256SA25TPG from Renesas Electronics is a 32K × 8-bit (256 Kbit) high-speed CMOS static RAM with 25 ns access time, TTL-compatible I/O, single 5 V supply operation, and industrial-grade temperature range support (–40°C to +85°C). It serves as a non-refreshing, asynchronous memory buffer in embedded controllers, instrumentation front-ends, and legacy industrial PLCs requiring deterministic read/write timing.
For engineers reviewing the 71256SA25TPG datasheet, 71256SA25TPG pinout, 71256SA25TPG application, or 71256SA25TPG equivalent, key selection criteria include verified 25 ns tAA/tRC timing at full industrial temperature range, CS/OE dual-control read enable, standby current of 40 mA (ISB) and 15 mA (ISB1), and compatibility with 28-pin 300-mil plastic DIP (PTG28) footprint.
Technical Context
The 71256SA25TPG implements fully static asynchronous circuitry-no clocks or refresh required-and uses high-reliability CMOS fabrication for stable operation across voltage (4.5 V–5.5 V) and temperature extremes. Its control logic supports both chip-select–driven and output-enable–driven read cycles, with tOE = 11 ns and tCLZ = 4 ns ensuring fast data assertion after CS or OE activation.
Write operations are governed by overlapping CS and WE low states, with tWP = 20 ns minimum pulse width and tDW = 13 ns data-valid-to-end-of-write timing. The device features bidirectional TTL-compatible I/O pins (I/O0–I/O7), one Chip Select (CS), one Output Enable (OE), one Write Enable (WE), and 15 address inputs (A0–A14), enabling direct integration into 8-bit microprocessor buses without level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 32K × 8-bit (262,144-bit total); matches standard 8-bit data bus width with no interleaving needed |
| Access Time (tAA) | 25 ns max at VCC = 4.5–5.5 V, TA = –40°C to +85°C; guarantees deterministic read latency in real-time control loops |
| Supply Voltage | 4.5 V to 5.5 V; compatible with legacy 5 V TTL/CMOS systems without regulation overhead |
| Standby Current (ISB1) | 15 mA max at CMOS-level deselect (CS > VHC); enables low-power sleep mode in battery-backed systems |
| 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) |
| Operating Temperature | –40°C to +85°C industrial grade; qualified for deployment in uncontrolled cabinet environments |
| Package | 28-pin 300-mil plastic DIP (PTG28); through-hole mountable with 2.54 mm pitch, compatible with legacy PCB tooling |
Pinout & Package
71256SA25TPG is housed in a 28-pin 300-mil plastic DIP (PTG28) package with 0.3-inch body width and standard dual-in-line footprint. Pin 1 is marked with a notch or dot; pin numbering follows standard counter-clockwise layout when viewed from top.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus accepting full 32K address space; no internal latching-address must be stable before CS/WE assertion |
| I/O0–I/O7 | Bidirectional Data I/O | 8-bit TTL-compatible data path; direction controlled by CS/WE/OE state-no external transceivers required |
| CS | Chip Select | Active-low enable; device enters standby (high-Z outputs, ISB = 40 mA) when high; tPD = 25 ns exit delay |
| OE | Output Enable | Active-low read control; enables outputs only when CS is low; tOE = 11 ns propagation ensures tight timing closure |
| WE | Write Enable | Active-low write strobe; initiates write on falling edge when CS is low; tWP = 20 ns minimum pulse width |
| VCC | Power Supply | +5 V supply pin (Pin 24); requires local 0.1 µF ceramic decoupling per JEDEC guidelines |
| GND | Ground | Reference return (Pin 12); separate ground plane recommended for noise-sensitive analog-adjacent layouts |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous Static Operation | No clock, no refresh, no wait states-simplifies timing design in microcontroller-based systems with irregular memory access patterns |
| Dual-Enable Read Control | Independent CS and OE pins allow flexible bus arbitration: CS selects device, OE gates output drivers-enables shared-bus multiplexing |
| Low-Power Standby Modes | Two-tier standby: ISB = 40 mA (TTL-level CS high), ISB1 = 15 mA (CMOS-level CS high)-supports hierarchical power management |
| TTL-Compatible I/O | Direct interface to 80Cxx, Z80, and 68000-family processors without level shifters or bus buffers |
| Industrial Temperature Qualification | Full AC/DC specs guaranteed from –40°C to +85°C-validated for use in motor drives, factory automation, and outdoor telemetry |
Applications
| Industrial PLC Data Buffer | Legacy Microprocessor System Memory |
|---|---|
Use Scenario: Storing real-time I/O scan data and ladder logic variables in programmable logic controllers operating in factory-floor cabinets. IC Role / Device Role / Timing Role: Asynchronous SRAM providing zero-wait-state read/write access to CPU during cyclic scan execution. Use Value: 25 ns tAA ensures sub-microsecond variable fetch within 1 ms scan cycles; industrial temp rating eliminates thermal derating in uncooled enclosures. | Use Scenario: Serving as main program/data RAM in 8-bit embedded systems based on Z80 or 8085 CPUs with discrete bus control. IC Role / Device Role / Timing Role: Non-volatile-buffered memory mapped at fixed address range, accessed via dedicated address decoder and bus transceivers. Use Value: TTL-compatible I/O and 28-pin DIP footprint enable drop-in replacement of older 2716/6116 parts without board redesign. |
| Test Equipment FIFO Buffer | Medical Diagnostic Front-End Storage |
Use Scenario: Capturing high-speed analog-to-digital samples in benchtop oscilloscopes and signal analyzers prior to DSP processing. IC Role / Device Role / Timing Role: Dual-port–emulated buffer using CS/OE sequencing to decouple acquisition clock from analysis clock domain. Use Value: tCLZ = 4 ns and tOHZ = 10 ns allow rapid output enable/disable cycling-critical for glitch-free sample streaming at >10 MHz burst rates. | Use Scenario: Holding patient waveform data (ECG, EEG) in portable diagnostic devices before wireless transmission or local storage. IC Role / Device Role / Timing Role: Battery-backed volatile memory storing transient clinical data during power transitions or brownouts. Use Value: ISB1 = 15 mA standby current extends backup runtime; industrial temp range ensures reliability during sterilization or transport in varying climates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar static RAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY62256ELL-70SNXI | 32K × 8, 70 ns access, SOIC-28, 5 V, –40°C to +85°C | Slower timing invalidates use in <25 ns cycle-critical systems; lower ICC (35 mA) but higher tAA limits real-time response | Select only if system timing budget allows ≥70 ns latency and SOIC footprint is preferred over DIP |
| AS6C4008-25ZIN | 512K × 8, 25 ns access, TSOP-32, 3.3 V, –40°C to +85°C | Higher density and 3.3 V operation require level translation and board layout changes; not pin-compatible | Choose for future-proofing where 3.3 V infrastructure exists and 512K capacity justifies redesign effort |
Compared with CY62256ELL-70SNXI and AS6C4008-25ZIN, the 71256SA25TPG uniquely delivers 25 ns performance in a through-hole 28-pin DIP at 5 V while maintaining industrial temperature compliance-making it optimal for legacy system repair, calibration equipment, and cost-sensitive industrial retrofits where layout change is prohibited.
Availability
71256SA25TPG is available at Aetrix Electronics and suitable for industrial PLCs, legacy microprocessor systems, test equipment FIFO buffers, and medical diagnostic front-end storage requiring stable component supply across extended product lifecycles.
Supply support for 71256SA25TPG 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 rebranded under Renesas-was designed specifically for high-reliability, pin-compatible replacement of legacy 256 Kbit SRAMs in industrial control, instrumentation, and military-grade systems requiring long-term availability and temperature resilience.
FAQ
What is the maximum guaranteed access time for 71256SA25TPG across its full industrial temperature range?
The 71256SA25TPG has a maximum guaranteed address access time (tAA) of 25 ns and read cycle time (tRC) of 25 ns when operated from –40°C to +85°C at VCC = 4.5 V to 5.5 V. These values are production-tested and specified in the Renesas datasheet revision Jun.29.20, Table 9, under the 71256SA25 column. This timing applies directly to the 71256SA25TPG part number.
Does 71256SA25TPG support true bidirectional data transfer without external transceivers?
Yes, the 71256SA25TPG integrates bidirectional I/O drivers on pins I/O0–I/O7 that are TTL-compatible and internally controlled by CS, WE, and OE logic. When CS is low and WE is high, outputs are enabled upon OE low; when WE is low, inputs are latched. No external transceivers or direction-control logic are required-this capability is inherent to the 71256SA25TPG architecture.
What are the two standby current modes of 71256SA25TPG and how are they triggered?
The 71256SA25TPG offers two standby current modes: ISB = 40 mA (TTL-level standby, triggered when CS > VIH) and ISB1 = 15 mA (CMOS-level standby, triggered when CS > VHC ≈ VCC – 0.2 V). Both modes place outputs in high-impedance and reduce dynamic current; ISB1 delivers deeper power savings but requires tighter input threshold control. These specifications are confirmed for the 71256SA25TPG in Table 6 of the datasheet.
Is 71256SA25TPG pin-compatible with earlier IDT71256 variants in the same PTG28 package?
Yes, the 71256SA25TPG maintains identical pinout, electrical behavior, and timing architecture as other IDT71256SA speed grades (e.g., 71256SA12TPG, 71256SA15TPG) in the PTG28 package. All share the same 28-pin DIP mapping, address/data/control signal assignments, and DC/AC characteristics-enabling field-upgrade of timing performance without hardware modification. This compatibility is documented in Renesas' Pin Configurations section (Figure 2a).
Can 71256SA25TPG operate reliably at 4.5 V supply voltage across its full industrial temperature range?
Yes, the 71256SA25TPG is fully specified and production-tested at VCC = 4.5 V to 5.5 V across –40°C to +85°C. DC parameters-including VOH ≥ 2.4 V, VOL ≤ 0.4 V, and VIH ≥ 2.2 V-are guaranteed at VCC = 4.5 V min, and AC timing (tAA = 25 ns, tRC = 25 ns) holds under these conditions. This validation is explicitly stated in Tables 4 and 9 of the Renesas 71256SA25TPG datasheet.
71256SA25TPG 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:
- 25ns
- Access Time:
- 25 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
71256SA25TPG FAQ
1.How can I place an order for 71256SA25TPG through Aetrix?
Please submit a Request for Quotation (RFQ) for 71256SA25TPG 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 71256SA25TPG reliable?
The price and inventory of 71256SA25TPG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71256SA25TPG is usually 5 days.
3.What payment methods are accepted for 71256SA25TPG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71256SA25TPG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71256SA25TPG?
71256SA25TPG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71256SA25TPG 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 71256SA25TPG?
For technical support, including 71256SA25TPG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71256SA25TPG requirements.
6.How does Aetrix verify that 71256SA25TPG is sourced from the original manufacturer or authorized distributors?
All 71256SA25TPG 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 71256SA25TPG meets industry standards.
7.What is the process for return or replacement of 71256SA25TPG?
All 71256SA25TPG units undergo pre-shipment inspection (PSI). If there is an issue with 71256SA25TPG, 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 71256SA25TPG part is unused and in its original packaging.
Return procedure for 71256SA25TPG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71256SA25TPG 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…
