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Renesas 70261S55PFI
- Part No.:
- 70261S55PFI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 100-LQFP
- Datasheet:
-
70261S55PFI.pdf
- Description:
- IC SRAM 256KBIT PARALLEL 100TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:4,661
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Product details
Overview
70261S55PFI 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 in commercial temperature range (0°C to +70°C), powered by single 5V ±10% supply, and packaged in 100-pin TQFP. It enables simultaneous independent read/write access to the same memory location across left and right ports for real-time inter-processor communication in embedded control systems.
For engineers reviewing the 70261S55PFI datasheet, 70261S55PFI pinout, 70261S55PFI application, or 70261S55PFI equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 40 ns), interrupt flag setup/reset times (tINS/tINR ≤ 40 ns), semaphore contention window (tSPS = 5 ns), and industrial-grade alternatives for extended temperature operation.
Technical Context
The 70261S55PFI implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port, enabling concurrent access without external arbitration logic. Its on-chip arbitration uses BUSY flag assertion (push-pull, not open-drain) triggered by address match or chip-enable overlap, with priority determined by tAPS (5 ns setup).
Interrupt generation is memory-mapped: writing to address 3FFFH sets INTR, reading 3FFFH clears it; writing to 3FFEH sets INTL, reading 3FFEH clears it. Semaphore flags (8 total) are accessed via A0–A2 with CE = VIH/SEM = VIL, supporting mutual exclusion in multi-processor environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 16K × 16 bits (256 Kbit), fully random-access SRAM array |
| Access Time (max) | 55 ns - defines minimum read cycle time (tRC) for worst-case timing closure |
| Supply Voltage | 4.5 V to 5.5 V - supports standard TTL-compatible 5V system rails with ±10% tolerance |
| Operating Temperature | 0°C to +70°C - commercial grade; not rated for industrial -40°C to +85°C operation |
| Power Consumption | Active: 150 mA typ. (750 mW); Standby (ISB1): 13 mA max - enables low-power idle states via CE control |
| Package | 100-pin Thin Quad Flatpack (TQFP), 14 mm × 14 mm body - surface-mount compatible with standard reflow profiles |
| Interrupt Timing | tINS/tINR ≤ 40 ns - ensures fast inter-processor signaling latency for real-time response |
Pinout & Package
70261S55PFI is housed in a 100-pin TQFP (PNG100) package with 0.5 mm pitch, 14 mm × 14 mm footprint, and 1.4 mm height. All VCC and GND pins must be individually decoupled per layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CEL / CER | Chip Enable (Left / Right) | Active-low enable controlling port power-down; CE = VIH places port in standby (ISB1/ISB2) |
| R/WL / R/WR | Read/Write Control (Left / Right) | Active-low signal determining data direction: VIL = write, VIH = read (with OE asserted) |
| OEL / OER | Output Enable (Left / Right) | Active-low control of I/O bus drivers; disables outputs to prevent bus contention |
| UBL / UBR, LBL / LBR | Upper/Lower Byte Select | Enable byte-level access (I/O8–I/O15 or I/O0–I/O7) for multiplexed bus compatibility |
| INTL / INTR | Interrupt Flag Output | Open-collector compatible (per datasheet note: push-pull), asserted when opposite port writes mailbox address |
| BUSYL / BUSYR | Busy Flag (Input/Output) | Push-pull BUSY: output when M/S = H (Master), input when M/S = L (Slave); stalls conflicting writes |
| M/S | Master/Slave Select | Configures device role in cascaded 32-bit+ systems: H = BUSY output (Master), L = BUSY input (Slave) |
| SEML / SEMR | Semaphore Enable | Active-high control for accessing 8 semaphore flags via A0–A2; requires CE = VIH for semaphore mode |
Key Features
| Feature | Design Value |
|---|---|
| True Dual-Port Architecture | Enables simultaneous, independent read/write to identical addresses without external logic or wait states |
| Hardware Semaphore Support | Eight dedicated flags accessible via A0–A2, enabling atomic resource locking between processors |
| On-Chip Arbitration Logic | Automatic BUSY assertion on address or CE overlap eliminates need for discrete priority encoders |
| Memory-Mapped Interrupts | Mailbox addresses 3FFEH (INTL) and 3FFFH (INTR) provide zero-software-overhead inter-processor signaling |
| Byte-Controlled I/O | Separate UBL/LBL and UBR/LBR allow 8-bit data transfers on 16-bit bus, easing integration with legacy peripherals |
Applications
| Industrial PLC Communication Module | Digital Signal Processor Co-Processor Interface |
|---|---|
Use Scenario: Two independent microcontrollers exchange sensor data and control commands in real time within a programmable logic controller chassis. IC Role / Device Role / Timing Role: 70261S55PFI serves as shared message buffer with hardware arbitration, eliminating software polling and reducing inter-CPU latency. Use Value: 55 ns access time and tBDD ≤ 40 ns ensure deterministic response under worst-case contention, meeting <100 µs cycle-time requirements. |
Use Scenario: A DSP offloads FFT computation while a host MCU manages I/O and scheduling; both require low-latency access to shared coefficient and result buffers. IC Role / Device Role / Timing Role: 70261S55PFI acts as dual-port scratchpad memory, with semaphore flags coordinating buffer ownership and preventing race conditions. Use Value: Built-in semaphore logic (tSPS = 5 ns) replaces 3+ discrete logic ICs, reducing BOM count and PCB area by >12 mm². |
| Avionics Data Concentrator Unit | Medical Imaging Real-Time Buffer |
Use Scenario: Multiple sensor acquisition units write raw telemetry to a central buffer, while a safety monitor reads and validates data streams concurrently. IC Role / Device Role / Timing Role: 70261S55PFI functions as fault-tolerant shared memory with interrupt-driven notification (tINS ≤ 40 ns) upon new data arrival. Use Value: Push-pull BUSY/INT outputs eliminate external pull-ups, simplifying interface design and improving noise immunity in EMI-prone avionics bays. |
Use Scenario: An FPGA-acquired ultrasound frame stream is written to memory while a display processor reads prior frames for rendering without frame drops. IC Role / Device Role / Timing Role: 70261S55PFI provides non-blocking dual-port video buffer, using upper/lower byte enables to align with 8-bit pixel pipelines. Use Value: 16-bit data width and 55 ns access support 25 MHz pixel clocks (40 ns period), enabling full HD (1920×1080@60Hz) buffering with margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 70261L55PFI | Same speed grade (55 ns), lower standby current (ISB3 = 0.2 mA vs. 1.0 mA), but only available in commercial temp range | Identical pinout and function; preferred where ultra-low standby power is critical and ambient stays <70°C | Select 70261L55PFI if system sleep current budget is <100 µA and thermal environment is controlled. |
| 70261S20PFI | Slower access (20 ns max), industrial temp rating (-40°C to +85°C), same 100-pin TQFP package | Supports harsh environments but requires 2.75× longer read cycles; incompatible for 55 ns timing-critical paths | Choose 70261S20PFI only when extended temperature operation is mandatory and system timing budget allows ≥20 ns latency. |
Compared with 70261S55PFI, the 70261L55PFI reduces full-standby current by 80% with no timing or interface trade-offs, while the 70261S20PFI sacrifices speed for industrial temperature resilience-neither is pin-compatible drop-in replacements due to differing DC/AC specs and qualification grades.
Availability
70261S55PFI is available at Aetrix Electronics and suitable for industrial PLC communication modules, digital signal processor co-processor interfaces, and avionics data concentrators requiring stable component supply and guaranteed commercial-grade performance.
Supply support for 70261S55PFI 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), now part of Renesas Electronics, designs high-performance memory and timing solutions for communications, computing, and industrial markets.
The IDT70261 family was engineered specifically for real-time multi-processor systems requiring deterministic, hardware-arbitrated shared memory-enabling seamless inter-processor communication without software overhead or external logic.
FAQ
What is the maximum operating frequency supported by the 70261S55PFI?
The 70261S55PFI does not specify a clock frequency; it is an asynchronous SRAM. Its maximum effective throughput is governed by the 55 ns read cycle time (tRC), allowing up to ~18.2 MHz sustained random-access bandwidth per port when interfaced with appropriately timed control logic.
Does the 70261S55PFI support industrial temperature operation?
No. The 70261S55PFI is rated only for commercial temperature range (0°C to +70°C). For industrial operation (-40°C to +85°C), consider the 70261S20PFI or 70261L20PFI variants, which share the same pinout but are characterized across the extended range.
How does the BUSY arbitration logic work in the 70261S55PFI?
In the 70261S55PFI, BUSY asserts when both ports attempt access to the same address simultaneously. With M/S = H (Master), BUSYL/BUSYR are outputs that stall the later-arriving write. Priority is resolved by tAPS (5 ns setup), ensuring deterministic resolution without external logic.
Can the 70261S55PFI be used in a 32-bit data path configuration?
Yes. The 70261S55PFI supports cascaded MASTER/SLAVE operation using the M/S pin. Two devices can be combined-one as Master (M/S = H), one as Slave (M/S = L)-to construct a 32-bit wide dual-port memory without additional glue logic.
What are the voltage levels required for interrupt flag operation on the 70261S55PFI?
The 70261S55PFI interrupt flags (INTL/INTR) are push-pull outputs compatible with TTL logic: VOH ≥ 2.4 V at IOH = −4 mA, VOL ≤ 0.4 V at IOL = 4 mA. No external pull-up resistors are needed, simplifying interface design in 5V systems.
70261S55PFI 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:
- 55ns
- Access Time:
- 55 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)
70261S55PFI FAQ
1.How can I place an order for 70261S55PFI through Aetrix?
Please submit a Request for Quotation (RFQ) for 70261S55PFI 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 70261S55PFI reliable?
The price and inventory of 70261S55PFI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 70261S55PFI is usually 5 days.
3.What payment methods are accepted for 70261S55PFI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 70261S55PFI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 70261S55PFI?
70261S55PFI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 70261S55PFI 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 70261S55PFI?
For technical support, including 70261S55PFI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 70261S55PFI requirements.
6.How does Aetrix verify that 70261S55PFI is sourced from the original manufacturer or authorized distributors?
All 70261S55PFI 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 70261S55PFI meets industry standards.
7.What is the process for return or replacement of 70261S55PFI?
All 70261S55PFI units undergo pre-shipment inspection (PSI). If there is an issue with 70261S55PFI, 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 70261S55PFI part is unused and in its original packaging.
Return procedure for 70261S55PFI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
70261S55PFI Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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