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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Renesas 70261S25PFI

Name: 70261S25PFI
Brand: Renesas
SKU: 70261S25PFI
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 70261S25PFI

Manufacturer:: Renesas

Category:: Memory

Package:: 100-LQFP

Datasheet:: 70261S25PFI.pdf

Description:: IC SRAM 256KBIT PARALLEL 100TQFP

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Product details

Overview

70261S25PFI from IDT is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 25 ns max access time (industrial grade), supporting simultaneous asynchronous reads/writes to the same memory location, and featuring separate upper/lower byte enables for multiplexed bus compatibility in real-time inter-processor communication systems.

For engineers reviewing the 70261S25PFI datasheet, 70261S25PFI pinout, 70261S25PFI application, or 70261S25PFI equivalent, this device serves as a critical shared-memory interface in dual-CPU architectures, telecom line cards, and industrial motion controllers where deterministic port arbitration and hardware mailbox signaling are required.

Technical Context

The 70261S25PFI implements fully independent left/right ports with dedicated address (A0–A13), data (I/O0–I/O15), and control lines (CE, R/W, OE, UB/LB, SEM), enabling concurrent access without external arbitration logic. Its on-chip arbitration resolves contention via BUSY flag assertion-either by address match or CE timing-with priority set-up time (tAPS = 5 ns) guaranteeing deterministic resolution.

It integrates full hardware semaphore support across eight flags (addressed by A0–A2), accessed via dedicated SEM/CE control states (CE = VIH, SEM = VIL), and provides interrupt generation through dedicated mailbox addresses (3FFE_H and 3FFF_H) with push-pull INTL/INTR outputs compliant with TTL levels under 5 V ±10% supply.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Organization	16,384 × 16-bit (16K × 16), 262,144 total bits
Access Time (max)	25 ns - guarantees sub-40-MHz synchronous read/write cycles in industrial temperature range
Operating Voltage	5.0 V ±10% - single-supply TTL-compatible interface, no level-shifting needed
Temperature Range	−40°C to +85°C - qualified for industrial embedded control and base station applications
Power Consumption	Active: 170 mA typ. (850 mW); Full standby: 1.0 mA typ. - enables low-power idle modes in always-on systems
Package	100-pin TQFP (14 mm × 14 mm × 1.4 mm) - surface-mount compatible with standard reflow profiles
Interrupt & Semaphore	Dedicated INTL/INTR flags + 8 hardware semaphores - eliminates software polling and race conditions in multi-core IPC

Pinout & Package

70261S25PFI is housed in a 100-pin Thin Quad Flatpack (TQFP) with exposed thermal pad, requiring all VCC and GND pins to be connected per layout guidelines. Pin functions are strictly segregated between left port (L) and right port (R), with no shared signal lines except power and ground.

Pin/Terminal	Circuit Role	Design Meaning
CEL / CER	Chip Enable (Left/Right)	Independent port selection; deassertion places respective port in low-power standby (ISB3 ≤ 1.0 mA)
R/WL / R/WR	Read/Write Control (Left/Right)	Active-low write enable; determines data direction on I/O bus during CE-active window
OEL / OER	Output Enable (Left/Right)	Tri-states I/O drivers independently; allows partial bus sharing without contention
UBL / UBR, LBL / LBR	Upper/Lower Byte Select	Enables 8-bit granularity writes-critical for mixed-width peripheral interfacing and legacy bus compliance
INTL / INTR	Interrupt Flag Output	Push-pull active-low signals indicating mailbox writes to 3FFE_H/3FFF_H; directly drive MCU interrupt inputs
BUSYL / BUSYR	Busy Flag (I/O depending on M/S)	When M/S = H: output indicating local port arbitration block; when M/S = L: input disabling writes during remote contention
M/S	Master/Slave Select	Configures BUSY pin behavior-enables cascaded 32-bit+ memory expansion using master/slave topology
SEML / SEMR	Semaphore Enable	Activates semaphore register bank (A0–A2 addressed) when CE = VIH; isolates semaphore access from main RAM space

Key Features

Feature	Design Value
True Dual-Port Architecture	Simultaneous read/write to identical addresses with hardware BUSY arbitration-no external logic required for conflict resolution
Hardware Semaphore Logic	Eight dedicated flags accessible via A0–A2, written via I/O0, readable on all 16 I/O lines-enables lock-free resource sharing between CPUs
Interrupt Mailbox Function	Two dedicated 16-bit SRAM locations (3FFE_H, 3FFF_H) trigger INTL/INTR on write; clear via read-supports zero-latency inter-processor messaging
Byte-Controlled Write Enable	Separate UB/LB controls allow independent 8-bit writes-essential for PCI, VME, and other multiplexed data bus implementations
Low-Power Standby Modes	Four distinct standby states (ISB1–ISB4) with full CMOS-level ISB3 ≤ 1.0 mA-ideal for battery-backed or energy-constrained systems

Applications

Telecom Line Card Control	Industrial Motion Controller
Use Scenario: Dual-DSP architecture where one processor handles real-time servo loop execution while the other manages HMI and network stack. IC Role / Device Role / Timing Role: Shared memory buffer with hardware semaphore coordination and interrupt-driven command handoff between DSPs. Use Value: Eliminates software mutex overhead; 25 ns access ensures <100 ns round-trip message latency between processors.	Use Scenario: CNC machine controller with separate motion planning CPU and safety-monitoring microcontroller. IC Role / Device Role / Timing Role: Synchronized data exchange via mailbox addresses (3FFE_H/3FFF_H) and semaphore-protected parameter tables. Use Value: Hardware-enforced atomic access prevents parameter corruption during emergency stop transitions.
Avionics Data Concentrator	Medical Imaging Subsystem
Use Scenario: ARINC 429 data concentrator aggregating sensor inputs for flight management system. IC Role / Device Role / Timing Role: Dual-port RAM buffers incoming serial data (right port) while feeding processed frames to host processor (left port). Use Value: Concurrent access avoids FIFO overflow during bursty sensor traffic; BUSY logic prevents overwrites during host read cycles.	Use Scenario: MRI subsystem where FPGA-acquired raw k-space data is transferred to ARM-based reconstruction engine. IC Role / Device Role / Timing Role: High-bandwidth memory bridge with byte-select writes enabling partial frame updates without full-buffer reload. Use Value: 16-bit parallel interface sustains >32 MB/s sustained throughput; 5 V tolerance simplifies interface to legacy FPGA I/O banks.

Telecom Line Card Control

Industrial Motion Controller

Use Scenario: Dual-DSP architecture where one processor handles real-time servo loop execution while the other manages HMI and network stack.

IC Role / Device Role / Timing Role: Shared memory buffer with hardware semaphore coordination and interrupt-driven command handoff between DSPs.

Use Value: Eliminates software mutex overhead; 25 ns access ensures <100 ns round-trip message latency between processors.

Use Scenario: CNC machine controller with separate motion planning CPU and safety-monitoring microcontroller.

IC Role / Device Role / Timing Role: Synchronized data exchange via mailbox addresses (3FFE_H/3FFF_H) and semaphore-protected parameter tables.

Use Value: Hardware-enforced atomic access prevents parameter corruption during emergency stop transitions.

Avionics Data Concentrator

Medical Imaging Subsystem

Use Scenario: ARINC 429 data concentrator aggregating sensor inputs for flight management system.

IC Role / Device Role / Timing Role: Dual-port RAM buffers incoming serial data (right port) while feeding processed frames to host processor (left port).

Use Value: Concurrent access avoids FIFO overflow during bursty sensor traffic; BUSY logic prevents overwrites during host read cycles.

Use Scenario: MRI subsystem where FPGA-acquired raw k-space data is transferred to ARM-based reconstruction engine.

IC Role / Device Role / Timing Role: High-bandwidth memory bridge with byte-select writes enabling partial frame updates without full-buffer reload.

Use Value: 16-bit parallel interface sustains >32 MB/s sustained throughput; 5 V tolerance simplifies interface to legacy FPGA I/O banks.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
CY7C1362BV33-25BGXI	3.3 V core, 25 ns access, 16K × 16, but lacks integrated semaphore logic and interrupt mailboxes	Requires external logic or firmware for resource arbitration; unsuitable for lock-free IPC designs	Select only if system already uses 3.3 V supply and can implement software semaphores
IDT70V261S25PF	Pin-compatible 3.3 V variant of same family; identical pinout and function but different voltage rating and lower active current (120 mA typ.)	Direct drop-in replacement only in 3.3 V systems; not interoperable with 5 V buses without level translation	Choose for new 3.3 V designs seeking lower power; verify VIO compatibility with host logic

Compared with CY7C1362BV33-25BGXI and IDT70V261S25PF, the 70261S25PFI uniquely delivers hardware semaphore and interrupt mailbox functionality within a 5 V TTL ecosystem-making it irreplaceable in legacy industrial and telecom platforms requiring deterministic, zero-software-overhead inter-processor communication.

Availability

70261S25PFI is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and avionics applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for 70261S25PFI 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

IDT (Integrated Device Technology) is a fabless semiconductor company specializing in timing, memory interface, and RF solutions, acquired by Renesas Electronics in 2019.

The IDT70261 product line was engineered for high-reliability dual-processor shared-memory systems in telecom switching, industrial PLCs, and military computing-prioritizing hardware arbitration, deterministic latency, and industrial-grade robustness.

FAQ

What is the maximum operating frequency supported by the 70261S25PFI?

The 70261S25PFI does not specify a clock frequency; it is an asynchronous SRAM. Its 25 ns maximum access time supports effective operation up to approximately 40 MHz in systems with zero wait-state timing-verified by tRC = 25 ns read cycle time and tWC = 25 ns write cycle time under industrial conditions.

Does the 70261S25PFI support both master and slave configurations in the same system?

Yes-the 70261S25PFI uses the M/S pin to configure BUSYL/BUSYR as outputs (master) or inputs (slave). Multiple devices can be cascaded: one master coordinates arbitration while slaves respond to BUSY input, enabling scalable 32-bit or wider memory expansion without external glue logic.

How are the interrupt mailbox addresses 3FFE_H and 3FFF_H used in the 70261S25PFI?

In the 70261S25PFI, writing to address 3FFE_H (right port) asserts INTL; reading it clears the flag. Writing to 3FFF_H (left port) asserts INTR; reading it clears the flag. These are standard SRAM locations-user data written there becomes the message payload, enabling flexible inter-processor communication.

Can the 70261S25PFI operate with only one port enabled while the other remains inactive?

Yes-the 70261S25PFI supports asymmetric operation: CEL = VIH disables the left port (ISB2 = 105 mA typ.), while CER = VIL enables the right port. This reduces dynamic power and allows partial system operation during maintenance or failover scenarios without reconfiguring PCB layout.

What is the role of the SEM pin during normal RAM access versus semaphore access in the 70261S25PFI?

In the 70261S25PFI, SEM = VIH enables standard RAM access (with CE = VIL); SEM = VIL (and CE = VIH) switches the device into semaphore mode, redirecting A0–A2 to select one of eight semaphore flags-ensuring strict isolation between main memory and synchronization primitives without address decoding overhead.

70261S25PFI Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 100-LQFP

Packaging:: Tray

Product Status:: Obsolete

Programmable:: Not Verified

Memory Type:: Volatile

Memory Format:: SRAM

Technology:: SRAM - Dual Port, Asynchronous

Memory Size:: 256Kbit

Memory Organization:: 16K x 16

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:: 100-TQFP (14x14)

70261S25PFI FAQ

1.How can I place an order for 70261S25PFI through Aetrix?

Please submit a Request for Quotation (RFQ) for 70261S25PFI 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 70261S25PFI reliable?

The price and inventory of 70261S25PFI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 70261S25PFI is usually 5 days.

3.What payment methods are accepted for 70261S25PFI?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 70261S25PFI transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 70261S25PFI?

70261S25PFI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 70261S25PFI 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 70261S25PFI?

For technical support, including 70261S25PFI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 70261S25PFI requirements.

6.How does Aetrix verify that 70261S25PFI is sourced from the original manufacturer or authorized distributors?

All 70261S25PFI 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 70261S25PFI meets industry standards.

7.What is the process for return or replacement of 70261S25PFI?

All 70261S25PFI units undergo pre-shipment inspection (PSI). If there is an issue with 70261S25PFI, 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 70261S25PFI part is unused and in its original packaging.

Return procedure for 70261S25PFI:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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