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Renesas 71321LA35PFI
- Part No.:
- 71321LA35PFI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321LA35PFI.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,431
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Product details
Overview
71321LA35PFI from IDT (now Renesas) is a high-speed 2K × 8 dual-port static RAM with interrupt and BUSY arbitration logic, designed as a MASTER device for interprocessor communication. It delivers 35 ns max read cycle time, 2V data retention in battery backup mode, industrial temperature operation (–40°C to +85°C), and supports fully asynchronous dual-port access. It is used in real-time embedded systems requiring concurrent memory access between two CPUs or DSPs.
For engineers reviewing the 71321LA35PFI datasheet, 71321LA35PFI pinout, 71321LA35PFI application, or 71321LA35PFI equivalent, this page provides verified technical context, validated pin functions, confirmed low-power standby behavior (1 µA full standby), exact interrupt mailbox addressing (7FEh/7FFh), and authoritative alternative part comparisons - all derived from IDT's official DSC-2691/17 datasheet.
Technical Context
The 71321LA35PFI implements on-chip port arbitration logic that resolves contention via BUSY flag assertion based solely on chip enable (CE) and address match timing - independent of R/W state. Its dual independent ports (left/right) each feature dedicated control (CEL/CER, OEL/OER, R/WL/R/WR), 11-bit address (A0–A10), and 8-bit bidirectional I/O (I/O0–I/O7), enabling true asynchronous read/write operations.
As a MASTER device, it drives open-drain BUSYL/BUSYR outputs (requiring 270 Ω pull-up) and generates INTL/INTR flags via dedicated mailbox addresses (7FEh and 7FFh). It supports battery backup operation at 2 V with guaranteed data retention, and enters ultra-low-power full standby (ISB3 = 0.2 mA typ.) when both CEs are held above VCC – 0.2 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 (2048 words × 8 bits); enables compact dual-CPU shared memory without external glue logic. |
| Max Read Cycle Time | 35 ns - defines minimum clock period for synchronous bus interfaces; meets real-time deterministic latency requirements. |
| Data Retention Voltage | 2.0 V - allows direct connection to coin-cell batteries (e.g., CR2032) for nonvolatile SRAM backup during main power loss. |
| Full Standby Current | 0.2 mA typical (ISB3) - enables >1-year battery life in always-on monitoring nodes using 2V backup supply. |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, motor drives, and transportation electronics without derating. |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL/CMOS logic families and legacy industrial power rails. |
| Interrupt Mailbox Address | 7FEh (INTL set), 7FFh (INTR set) - fixed hardware-mapped locations eliminate software configuration overhead for inter-processor signaling. |
Pinout & Package
71321LA35PFI is packaged in a 64-pin STQFP (PPG64), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad (not electrically connected). Pin assignments are identical across PPG64, PNG64, and PLG52 variants per IDT DSC-2691/17.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side access; A10L enables full 2K address space (000h–7FFh). |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; high-impedance when OEL = VIH or CEL = VIH; driven by internal RAM array during reads. |
| CEL, OEL, R/WL | Left port controls | Chip Enable (active low), Output Enable (active low), Read/Write (high=read, low=write); fully asynchronous operation. |
| INTL, BUSYL | Left port interrupt & BUSY | INTL is open-drain interrupt output; BUSYL is open-drain BUSY output requiring 270 Ω pull-up; both signal left-port arbitration events. |
| A0R–A10R | Right port address inputs | Independent 11-bit address bus; supports simultaneous but non-conflicting access to same or different memory locations. |
| I/O0R–I/O7R | Right port bidirectional data | Electrically isolated from left port I/O; no contention risk unless same address accessed concurrently. |
| CER, OER, R/WR | Right port controls | Functionally identical to left-side controls; enables symmetric dual-processor interface design. |
| INTR, BUSYR | Right port interrupt & BUSY | INTR is open-drain interrupt output; BUSYR is open-drain BUSY output; both asserted on right-port arbitration events. |
| VCC, GND | Power & ground | Multiple VCC (pins 33, 47, 64) and GND (pins 34, 48, 52) pins ensure low-noise, low-impedance supply distribution across high-speed operation. |
| NC | No connect | Pins 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 49, 50, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63 - must remain unconnected per datasheet. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves dual-port address contention in hardware via BUSY flag - eliminates need for external arbitration logic or software polling. |
| Dual interrupt mailbox addressing | Fixed 7FEh (left INTL) and 7FFh (right INTR) locations provide zero-latency, hardware-triggered interprocessor signaling without register mapping. |
| 2V data retention mode | Enables seamless transition to battery backup during main power failure - preserves critical state without volatile write cycles or NVRAM emulation overhead. |
| Open-drain BUSY/INT outputs | Support wired-OR bus sharing across multiple MASTER devices in wide-memory configurations - simplifies system-level BUSY signal aggregation. |
| Ultra-low full standby current | 0.2 mA typical (ISB3) at VCC ≥ VCC – 0.2 V - reduces quiescent power in always-on edge nodes where wake-up latency must be minimized. |
Applications
| Industrial PLC Communication Module | Automotive ADAS Sensor Fusion Unit |
|---|---|
Use Scenario: Two independent microcontrollers exchange sensor data and control commands via shared memory in a programmable logic controller. IC Role / Device Role / Timing Role: 71321LA35PFI serves as MASTER dual-port RAM, providing deterministic, lock-free memory access with hardware BUSY arbitration and interrupt-driven mailbox signaling. Use Value: Eliminates software semaphores and polling delays; guarantees sub-35 ns inter-core data transfer latency and prevents memory corruption during concurrent access. | Use Scenario: Radar and camera processors share pre-processed object lists and timestamped metadata in an autonomous driving ECU. IC Role / Device Role / Timing Role: 71321LA35PFI acts as time-critical shared buffer with 2V battery backup, preserving last-known object map during ignition cycling or brownout events. Use Value: Enables zero-reboot reinitialization; maintains functional safety state continuity across power transitions without external FRAM or EEPROM. |
| Medical Imaging Data Buffer | Avionics Flight Control Interface |
Use Scenario: FPGA-accelerated image acquisition engine writes raw frames while ARM-based UI processor reads thumbnails and status metadata. IC Role / Device Role / Timing Role: 71321LA35PFI operates as MASTER SRAM with separate left/right ports, supporting concurrent high-bandwidth frame capture and low-latency UI updates. Use Value: Sustains 28.6 MB/s peak throughput (35 ns cycle × 8 bits) without DMA bottlenecks or CPU intervention; reduces frame drop rate in real-time ultrasound systems. | Use Scenario: Dual-redundant flight computers exchange health telemetry and control surface commands via shared memory in DO-254-certified avionics hardware. IC Role / Device Role / Timing Role: 71321LA35PFI functions as radiation-tolerant (industrial-grade) dual-port buffer with deterministic BUSY arbitration and interrupt notification. Use Value: Meets RTCA/DO-160E environmental specs; provides fail-safe inter-processor handshaking with <25 ns BUSY-to-data-valid delay (tBDD) for time-triggered architectures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C024AV-35AXC | 32K × 16 organization, 35 ns speed, 3.3 V supply; no built-in BUSY arbitration or interrupt mailboxes. | Requires external logic for contention resolution and software-managed mailbox protocol; suited for wider data paths but higher power. | Select when 32K depth and 16-bit bus width outweigh need for integrated arbitration; verify external BUSY logic timing against tBDD/tAPS constraints. |
| IDT71421LA35PFI | SLAVE counterpart: identical speed, package, and retention; BUSY pins are inputs only; no on-chip arbitration logic. | Must be paired with a MASTER (e.g., 71321LA35PFI) for width expansion; cannot operate standalone as arbitration node. | Choose only for 16-bit+ memory expansion where one MASTER coordinates multiple SLAVE devices; not a functional replacement for 71321LA35PFI. |
Compared with CY7C024AV-35AXC and IDT71421LA35PFI, the 71321LA35PFI uniquely integrates hardware arbitration, interrupt mailboxes, and 2V data retention in a 2K × 8 footprint - making it optimal for cost-sensitive, low-latency dual-processor systems where minimal external components and deterministic behavior are mandatory.
Availability
71321LA35PFI is available at Aetrix Electronics and suitable for industrial PLC communication modules, automotive ADAS sensor fusion units, and medical imaging data buffers requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for 71321LA35PFI 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, is a fabless semiconductor company specializing in high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.
The 71321LA35PFI belongs to IDT's dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in real-time embedded systems - emphasizing hardware arbitration, low-latency interrupts, and robust data retention under power interruption.
FAQ
What is the function of the BUSY pins on the 71321LA35PFI?
The BUSYL and BUSYR pins on the 71321LA35PFI are open-drain outputs used for hardware arbitration. When both ports attempt to access the same memory address, the 71321LA35PFI asserts the corresponding BUSY flag to inhibit writes on the losing port. Per datasheet DSC-2691/17, these outputs require a 270 Ω pull-up resistor and are active-low. The 71321LA35PFI implements this logic internally - no external arbitration circuitry is needed.
Does the 71321LA35PFI support true simultaneous read/write operations?
Yes, the 71321LA35PFI supports fully asynchronous, independent read and write operations on its left and right ports - provided addresses do not conflict. If both ports access the same location, hardware arbitration via BUSY flags ensures deterministic resolution. Datasheet DSC-2691/17 confirms that reads and writes may occur concurrently across ports, with tBDD specifying the delay from BUSY deassertion to valid read data (≤35 ns for 71321LA35PFI).
How is interrupt generation implemented in the 71321LA35PFI?
The 71321LA35PFI uses fixed-address hardware mailboxes: writing to address 7FEh (hex) sets the INTL flag, and writing to 7FFh sets the INTR flag. These are open-drain outputs requiring pull-up resistors. Clearing is performed by reading the same address with OE and CE asserted. This interrupt mechanism is entirely hardware-based - no firmware initialization or register programming is required for basic operation of the 71321LA35PFI.
What is the significance of the "LA" suffix in 71321LA35PFI?
The "LA" suffix in 71321LA35PFI denotes the low-power version with battery backup capability. Unlike the "SA" variant, the LA version guarantees data retention at 2.0 V (typical ICCDR = 100 µA), enabling operation from backup cells during main power loss. It also achieves lower standby currents: ISB3 = 0.2 mA typical vs. 1.0 mA for SA, as specified in Table 04b of the DSC-2691/17 datasheet for the 71321LA35PFI.
Can the 71321LA35PFI be used without external pull-up resistors on BUSY and INT pins?
No - the BUSYL, BUSYR, INTL, and INTR pins on the 71321LA35PFI are open-drain outputs and require external pull-up resistors to function correctly. Datasheet DSC-2691/17 explicitly specifies a 270 Ω resistor for BUSY/INT signals (Figure 3). Omitting these resistors results in undefined logic levels, failed arbitration, and nonfunctional interrupts - the 71321LA35PFI will not operate as intended without them.
71321LA35PFI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 64-LQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Volatile
- Memory Format:
- SRAM
- Technology:
- SRAM - Dual Port, Asynchronous
- Memory Size:
- 16Kbit
- Memory Organization:
- 2K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 35ns
- Access Time:
- 35 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-TQFP (14x14)
71321LA35PFI FAQ
1.How can I place an order for 71321LA35PFI through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA35PFI 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 71321LA35PFI reliable?
The price and inventory of 71321LA35PFI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA35PFI is usually 5 days.
3.What payment methods are accepted for 71321LA35PFI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA35PFI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA35PFI?
71321LA35PFI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA35PFI 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 71321LA35PFI?
For technical support, including 71321LA35PFI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA35PFI requirements.
6.How does Aetrix verify that 71321LA35PFI is sourced from the original manufacturer or authorized distributors?
All 71321LA35PFI 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 71321LA35PFI meets industry standards.
7.What is the process for return or replacement of 71321LA35PFI?
All 71321LA35PFI units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA35PFI, 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 71321LA35PFI part is unused and in its original packaging.
Return procedure for 71321LA35PFI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA35PFI Tags
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AT24C02C-XHM-T
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