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

Renesas 70261S55PFG

Name: 70261S55PFG
Brand: Renesas
SKU: 70261S55PFG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 70261S55PFG

Manufacturer:: Renesas

Category:: Memory

Package:: 100-LQFP

Datasheet:: 70261S55PFG.pdf

Description:: IC SRAM 256KBIT PARALLEL 100TQFP

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Product details

Overview

70261S55PFG from IDT (now Renesas) is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 55 ns max access time (commercial grade), supporting simultaneous independent read/write access to the same memory location from left and right ports, and featuring TTL-compatible 5 V ±10% supply - used in real-time inter-processor communication systems requiring deterministic arbitration.

For engineers reviewing the 70261S55PFG datasheet, 70261S55PFG pinout, 70261S55PFG application, or 70261S55PFG equivalent, key selection considerations include port-to-port BUSY arbitration timing (tBDD ≤ 40 ns), interrupt flag set/reset latency (tINS/tINR ≤ 40 ns), semaphore contention window (tSPS = 5 ns), and 100-pin TQFP package compatibility with 14 mm × 14 mm footprint.

Technical Context

This device implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port, enabling concurrent access without external glue logic. It integrates on-chip arbitration logic, push-pull BUSY/INT outputs, and eight hardware semaphores addressed via A0–A2 for inter-port synchronization.

Memory organization is 16,384 words × 16 bits (16K × 16), with independent chip enable (CEL/CER), read/write (R/WL/R/WR), output enable (OEL/OER), upper/lower byte select (UBL/UBR, LBL/LBR), and master/slave select (M/S) pins. Semaphore access requires CE = VIH and SEM = VIL, while RAM access requires CE = VIL and SEM = VIH.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Density	16K × 16 (256 Kbit), enabling 32-bit or wider data bus expansion via MASTER/SLAVE cascading
Access Time (max)	55 ns - defines minimum read cycle time (tRC) for commercial operation at 5 V
Supply Voltage	4.5 V to 5.5 V - TTL-compatible single 5 V ±10% rail, no auxiliary supplies required
Operating Temperature	0°C to +70°C - commercial grade only for 70261S55PFG variant
Power Consumption	Active: 150 mA typ. (ICC), Standby: 13 mA typ. (ISB1) - enables low-power idle states per port
Interrupt Latency	tINS ≤ 40 ns, tINR ≤ 40 ns - supports sub-40 ns inter-processor message acknowledgment
Semaphore Timing	tSPS = 5 ns - ensures deterministic token handoff between ports under contention

Pinout & Package

70261S55PFG is housed in a 100-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch, body size 14 mm × 14 mm × 1.4 mm. All VCC and GND pins must be connected per layout guidelines.

Pin/Terminal	Circuit Role	Design Meaning
CEL / CER	Chip Enable (Left / Right)	Independent port activation; drives respective port into standby when high
R/WL / R/WR	Read/Write Control (Left / Right)	Active-low write enable; high = read, low = write - asynchronous per port
OEL / OER	Output Enable (Left / Right)	Tri-states I/O drivers independently; allows shared bus usage without contention
UBL / UBR, LBL / LBR	Upper/Lower Byte Select	Enables byte-level writes (I/O0–I/O7 or I/O8–I/O15) for multiplexed bus compatibility
INTL / INTR	Interrupt Flag Output (Left / Right)	Push-pull active-low flags asserted on mailbox writes (3FFE/3FFF) - no external pull-up needed
BUSYL / BUSYR	Busy Flag (Left / Right)	Push-pull BUSY signals indicate port-to-port address collision; M/S = H → output, M/S = L → input
M/S	Master/Slave Select	Configures device as MASTER (BUSY output) or SLAVE (BUSY input); enables cascaded 32-bit+ systems
SEML / SEMR	Semaphore Enable	Activates semaphore register bank (8 flags) when low; CE = VIH required for semaphore access

Key Features

Feature	Design Value
True Dual-Port Architecture	Simultaneous independent read/write to identical addresses - eliminates software polling or external arbitration logic
Hardware Semaphore Logic	Eight dedicated flags accessible via A0–A2, enabling atomic resource locking across processors without CPU intervention
On-Chip Arbitration	Automatic BUSY assertion with priority resolution (tAPS = 5 ns) - guarantees deterministic access order during contention
Interrupt Mailbox Support	Dedicated 16-bit SRAM locations (3FFE/3FFF) serve as hardware-triggered inter-processor messaging registers
Byte-Controlled Writes	Separate UBL/LBL and UBR/LBR allow partial-word updates - critical for mixed-data-width system interfaces
Low-Power Standby	Per-port CE control reduces ISB1 to 13 mA typ.; full CMOS standby (ISB3) draws ≤1.0 mA - suitable for burst-mode systems

Applications

Industrial PLC Communication	Avionics Data Exchange
Use Scenario: Two independent microcontrollers exchange status and control commands in a safety-critical programmable logic controller. IC Role / Device Role / Timing Role: Dual-port SRAM acts as shared message buffer with hardware-enforced mutual exclusion via semaphores and BUSY arbitration. Use Value: Eliminates race conditions during concurrent access; 55 ns access enables sub-100 ns inter-processor handshake cycles.	Use Scenario: Flight management unit (FMU) and autopilot processor share sensor fusion results and actuator commands in real time. IC Role / Device Role / Timing Role: 70261S55PFG serves as deterministic, low-latency inter-processor memory with interrupt-driven mailbox signaling. Use Value: tINS ≤ 40 ns interrupt set time ensures <50 ns command acknowledgment - meets DO-254 deterministic timing budgets.
Medical Imaging Subsystem	Test Equipment Pattern Memory
Use Scenario: Image acquisition FPGA writes raw pixel data while DSP core reads and processes frames in parallel. IC Role / Device Role / Timing Role: Dual-port RAM buffers streaming image data with zero-wait-state access from both domains. Use Value: 16K × 16 capacity supports 256×256 monochrome frame buffering; 55 ns access sustains >18 MHz pixel throughput.	Use Scenario: Automated test equipment uses two pattern generators to load stimulus and expected response vectors simultaneously. IC Role / Device Role / Timing Role: 70261S55PFG provides synchronized, conflict-free access to vector memory banks for parallel test execution. Use Value: Hardware semaphore coordination prevents vector corruption during dynamic test sequence updates.

Industrial PLC Communication

Avionics Data Exchange

Use Scenario: Two independent microcontrollers exchange status and control commands in a safety-critical programmable logic controller.

IC Role / Device Role / Timing Role: Dual-port SRAM acts as shared message buffer with hardware-enforced mutual exclusion via semaphores and BUSY arbitration.

Use Value: Eliminates race conditions during concurrent access; 55 ns access enables sub-100 ns inter-processor handshake cycles.

Use Scenario: Flight management unit (FMU) and autopilot processor share sensor fusion results and actuator commands in real time.

IC Role / Device Role / Timing Role: 70261S55PFG serves as deterministic, low-latency inter-processor memory with interrupt-driven mailbox signaling.

Use Value: tINS ≤ 40 ns interrupt set time ensures <50 ns command acknowledgment - meets DO-254 deterministic timing budgets.

Medical Imaging Subsystem

Test Equipment Pattern Memory

Use Scenario: Image acquisition FPGA writes raw pixel data while DSP core reads and processes frames in parallel.

IC Role / Device Role / Timing Role: Dual-port RAM buffers streaming image data with zero-wait-state access from both domains.

Use Value: 16K × 16 capacity supports 256×256 monochrome frame buffering; 55 ns access sustains >18 MHz pixel throughput.

Use Scenario: Automated test equipment uses two pattern generators to load stimulus and expected response vectors simultaneously.

IC Role / Device Role / Timing Role: 70261S55PFG provides synchronized, conflict-free access to vector memory banks for parallel test execution.

Use Value: Hardware semaphore coordination prevents vector corruption during dynamic test sequence updates.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
CY7C028V-55AXC	55 ns access, 16K × 16, but lacks integrated interrupt/mailbox logic and uses different BUSY arbitration scheme	Requires external logic for interrupt generation and semaphore emulation	Select when interrupt/semaphore features are unnecessary and Cypress ecosystem integration is preferred
AS7C316000B-55PCN	55 ns access, 16K × 16, no BUSY/INT pins; only basic dual-port functionality with separate I/Os	No hardware arbitration or inter-processor signaling - software-managed coherency required	Choose for cost-sensitive designs where deterministic hardware arbitration is not required

Compared with CY7C028V-55AXC and AS7C316000B-55PCN, the 70261S55PFG uniquely integrates interrupt mailboxes, push-pull BUSY signaling, and eight hardware semaphores - reducing BOM count and eliminating firmware arbitration overhead in tightly coupled multi-processor systems.

Availability

70261S55PFG is available at Aetrix Electronics and suitable for industrial PLC communication, avionics data exchange, medical imaging subsystems, test equipment pattern memory, and real-time embedded control applications requiring stable component supply and long-term lifecycle support.

Supply support for 70261S55PFG 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 (formerly Integrated Device Technology) is a global semiconductor leader specializing in microcontrollers, analog, power management, and memory solutions for industrial, automotive, and communications markets.

The IDT70261 family was designed specifically for deterministic inter-processor communication in real-time embedded systems - delivering hardware-accelerated arbitration, mailbox interrupts, and semaphore logic in a single 100-pin TQFP package.

FAQ

What is the maximum operating temperature range for the 70261S55PFG?

The 70261S55PFG is rated for commercial temperature operation only: 0°C to +70°C. It is not qualified for industrial (-40°C to +85°C) use - that capability is reserved for variants like 70261S20PFG or 70261S25PFG. This limitation is specified in the Absolute Maximum Ratings table and confirmed by ordering information in the datasheet.

Does the 70261S55PFG support true simultaneous read/write to the same address?

Yes, the 70261S55PFG implements true dual-ported memory cells that permit simultaneous access of the same memory location. When contention occurs, on-chip arbitration asserts BUSY on the later-arriving port, allowing the first port to complete its operation - a behavior verified in Truth Table IV and Timing Waveform 11.

How are interrupt mailboxes configured on the 70261S55PFG?

The 70261S55PFG uses fixed SRAM addresses 3FFE_H (left port interrupt) and 3FFF_H (right port interrupt) as hardware-triggered mailboxes. Writing to 3FFF_H from the left port asserts INTR; reading 3FFF_H from the right port clears it - all governed by Truth Table III in the official datasheet.

What is the function of the M/S pin on the 70261S55PFG?

The M/S (Master/Slave Select) pin configures arbitration behavior: when high, BUSY is an output (MASTER mode); when low, BUSY is an input (SLAVE mode). This enables cascading multiple 70261S55PFG devices for 32-bit-or-wider word systems without external logic, as described in the Functional Block Diagram and Pin Configuration notes.

Can the 70261S55PFG operate with mixed voltage interfaces?

No - the 70261S55PFG requires a single 5 V ±10% supply (4.5 V to 5.5 V) and is strictly TTL-compatible. Input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and output drive levels (VOH ≥ 2.4 V, VOL ≤ 0.4 V) are defined only for 5 V operation; interfacing with 3.3 V or lower logic requires level translation.

70261S55PFG Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 100-LQFP

Packaging:: Tube

Product Status:: Active

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:: 55ns

Access Time:: 55 ns

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 100-TQFP (14x20)

70261S55PFG FAQ

1.How can I place an order for 70261S55PFG through Aetrix?

Please submit a Request for Quotation (RFQ) for 70261S55PFG 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 70261S55PFG reliable?

The price and inventory of 70261S55PFG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 70261S55PFG is usually 5 days.

3.What payment methods are accepted for 70261S55PFG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 70261S55PFG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 70261S55PFG?

70261S55PFG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 70261S55PFG 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 70261S55PFG?

For technical support, including 70261S55PFG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 70261S55PFG requirements.

6.How does Aetrix verify that 70261S55PFG is sourced from the original manufacturer or authorized distributors?

All 70261S55PFG 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 70261S55PFG meets industry standards.

7.What is the process for return or replacement of 70261S55PFG?

All 70261S55PFG units undergo pre-shipment inspection (PSI). If there is an issue with 70261S55PFG, 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 70261S55PFG part is unused and in its original packaging.

Return procedure for 70261S55PFG:

1.Submit a request within 90 days.

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

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