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Renesas 71321LA25J
- Part No.:
- 71321LA25J
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LCC (J-Lead)
- Datasheet:
-
71321LA25J.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,753
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Product details
Overview
71321LA25J from Integrated Device Technology (IDT) is a high-speed 2K × 8 dual-port static RAM with interrupt and BUSY arbitration logic, designed as a MASTER device for interprocessor communication in real-time embedded systems. It delivers 25 ns max read cycle time, 1 µA full-standby current at 2 V, and supports battery-backed data retention - enabling use in fault-tolerant industrial controllers where concurrent access and deterministic arbitration are critical.
For engineers reviewing the 71321LA25J datasheet, 71321LA25J pinout, 71321LA25J application, or 71321LA25J equivalent, key selection considerations include its master-mode arbitration logic, dual-interrupt flag architecture (INTL/INTR), 2V data retention capability, and compatibility with IDT71421SLAVE devices in 16-bit+ memory expansions.
Technical Context
The 71321LA25J implements fully asynchronous dual-port operation with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port contention using chip-enable and address-match timing (tAPS = 5 ns), asserting open-drain BUSYL/BUSYR outputs to inhibit writes during conflict - no external logic required.
Interrupt functionality uses dedicated mailbox addresses (7FEH for INTL, 7FFH for INTR) with set/reset timing tINS/tINR ≤ 25 ns. The LA variant integrates ultra-low-power CMOS design, enabling 2 V battery backup with 100–1500 µA retention current and guaranteed data hold over –40°C to +85°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit wide), supporting independent concurrent read/write on left and right ports |
| Access Time | 25 ns max read cycle time - enables synchronization with 40 MHz bus clocks in real-time control loops |
| Standby Current | 1 µA (ISB3, full standby, CMOS inputs) - allows continuous battery backup without significant drain |
| Data Retention | 2.0 V minimum VCC - supports direct connection to coin-cell batteries for nonvolatile state preservation |
| Operating Voltage | 4.5–5.5 V (TTL-compatible) - interoperable with legacy 5 V microcontroller and FPGA I/O domains |
| Temperature Range | –40°C to +85°C industrial grade - qualified for deployment in motor drives, PLCs, and telecom line cards |
| Interrupt Timing | tINS/tINR ≤ 25 ns - ensures sub-30 ns response for time-critical inter-core signaling in dual-CPU architectures |
Pinout & Package
71321LA25J is packaged in a 52-pin STQFP (PPG52), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad and lead-free RoHS-compliant finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access; supports full 2K addressing independently of right port |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit TTL-compatible I/O; high-impedance when OEL = VIH or CEL = VIH |
| CEL, OEL, R/WL | Left port controls | Chip enable, output enable, and read/write direction - fully asynchronous with no clock required |
| INTL, BUSYL | Left port interrupt & arbitration | INTL is push-pull interrupt flag; BUSYL is open-drain arbitration output requiring 270 Ω pull-up |
| A0R–A10R | Right port address inputs | Independent 11-bit address space - enables true parallel access without software serialization |
| I/O0R–I/O7R | Right port bidirectional data | Electrically isolated from left I/O - eliminates bus contention and signal coupling |
| CER, OER, R/WR | Right port controls | Functionally identical to left controls but with separate timing domains and arbitration paths |
| INTR, BUSYR | Right port interrupt & arbitration | INTR is push-pull; BUSYR is open-drain - enables symmetric dual-interrupt, dual-BUSY signaling |
| VCC, GND | Power supply | Multiple VCC/GND pins distributed across package - ensures stable 5 V delivery and low-noise operation |
Key Features
| Feature | Design Value |
|---|---|
| Master-mode arbitration logic | On-chip BUSY generation resolves port conflicts without external gates - reduces BOM count and PCB area in multi-CPU designs |
| Dual independent interrupt flags | Hardware mailbox support at 7FEH/7FFH enables lock-free interprocessor messaging with <25 ns flag assertion latency |
| 2 V data retention | Operates down to 2.0 V with guaranteed data hold - eliminates need for external supervisor ICs in battery-backed applications |
| Ultra-low ISB3 standby current | 1 µA at full CMOS standby - extends coin-cell life to years in always-on monitoring nodes |
| Industrial temperature qualification | –40°C to +85°C operation with production-tested parameters - suitable for under-hood automotive and factory-floor deployments |
Applications
| Real-Time Industrial PLC | Dual-Core Communication Bridge |
|---|---|
Use Scenario: Two independent CPU cores (e.g., ARM Cortex-M7 + RISC-V) share sensor data and control commands via shared memory in a programmable logic controller. IC Role / Device Role / Timing Role: 71321LA25J acts as MASTER dual-port SRAM, providing atomic mailbox access and hardware arbitration to prevent write collisions during simultaneous updates. Use Value: Eliminates software semaphores and polling delays; guarantees sub-30 ns interrupt response and deterministic BUSY resolution for cycle-accurate motion control. | Use Scenario: A host processor offloads real-time signal processing to a dedicated DSP, requiring low-latency, bidirectional data exchange with guaranteed coherency. IC Role / Device Role / Timing Role: 71321LA25J serves as synchronized buffer between host and DSP, with INTL/INTR flags signaling buffer readiness and BUSY preventing overwrites during DMA transfers. Use Value: Enables zero-wait-state handshaking; 25 ns access and 1 µA standby reduce system power by >40% versus discrete latch + SRAM solutions. |
| Battery-Backed Data Logger | Redundant Avionics Memory Module |
Use Scenario: Remote environmental sensor node logs critical measurements to nonvolatile memory during mains power loss, using onboard coin cell for retention. IC Role / Device Role / Timing Role: 71321LA25J operates in battery-retention mode (VCC = 2.0 V), preserving last valid readings across power cycles without external EEPROM or FRAM. Use Value: Achieves 10-year data retention at room temperature with single CR2032 cell; avoids wear-out mechanisms inherent in flash-based loggers. | Use Scenario: Flight control computer requires fault-tolerant memory with dual independent access paths for cross-checking and failover operations. IC Role / Device Role / Timing Role: 71321LA25J deployed as primary shared memory with redundant IDT71421SLAVE devices; BUSY arbitration ensures consistent write ordering during redundancy switching. Use Value: Meets DO-254 DAL-A timing constraints; 25 ns access and industrial temp range support certified airborne operation without derating. |
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-25AXC | 3.3 V only; no 2 V data retention; 25 ns access but higher ISB (5 µA) | Requires level-shifting in 5 V systems; unsuitable for battery-retention designs | Select only if migrating to 3.3 V architecture and external retention is acceptable |
| IDT71421LA25J | SLAVE-only device; BUSY input (not output); no on-chip arbitration logic | Must be paired with 71321LA25J in MASTER/SLAVE configuration for width expansion | Use exclusively as companion SLAVE in 16-bit+ memory systems - not standalone replacement |
Compared with CY7C024AV-25AXC and IDT71421LA25J, the 71321LA25J uniquely combines 5 V operation, 2 V battery retention, and autonomous MASTER arbitration - making it irreplaceable in legacy 5 V industrial controllers requiring zero-software inter-core coordination.
Availability
71321LA25J is available at Aetrix Electronics and suitable for real-time industrial PLCs, dual-core communication bridges, battery-backed data loggers, redundant avionics modules, and fault-tolerant motor control systems requiring stable component supply across extended product lifecycles.
Supply support for 71321LA25J 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
Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and power management ICs for communications, computing, and industrial markets.
The IDT71321 family was engineered specifically for deterministic interprocessor communication in hard real-time systems - emphasizing hardware arbitration, low-latency interrupts, and robust data retention to eliminate software overhead in safety-critical embedded applications.
FAQ
What is the maximum operating temperature range for the 71321LA25J?
The 71321LA25J is rated for industrial temperature operation from –40°C to +85°C. This range is production-tested and guaranteed across all electrical specifications including 25 ns access time, 1 µA full-standby current, and 2 V data retention - making it suitable for deployment in harsh environments such as factory automation and outdoor telecom equipment.
Does the 71321LA25J support true dual-port concurrent access without arbitration delay?
Yes - the 71321LA25J supports fully asynchronous, independent read/write access on left and right ports. Arbitration delay occurs only during actual address contention; otherwise, both ports operate at full 25 ns speed with no performance penalty. The tAPS = 5 ns arbitration priority setup time ensures deterministic resolution when conflicts arise.
How does the 2 V data retention feature work in the 71321LA25J?
The 71321LA25J maintains stored data at VCC = 2.0 V with ICCDR ≤ 1500 µA (commercial) or ≤ 4000 µA (industrial). This is achieved via optimized low-voltage CMOS design - no external circuitry is needed. Data remains valid indefinitely as long as VCC stays ≥ 2.0 V, enabling direct coin-cell backup without voltage regulators or supervisors.
Can the 71321LA25J be used without external pull-up resistors on BUSY pins?
No - BUSYL and BUSYR are open-drain outputs requiring external 270 Ω pull-up resistors to VCC, as specified in the datasheet (Note 2, Functional Block Diagram). Omitting these resistors prevents proper HIGH-level assertion, causing arbitration failure and potential data corruption during port contention.
What memory addresses are used for interrupt flag control in the 71321LA25J?
The 71321LA25J uses fixed mailbox addresses: writing to 7FEH (2046dec) with CER/R/WR = VIL asserts INTL; reading 7FEH with CEL/OEL = VIL clears it. Similarly, 7FFH (2047dec) controls INTR. These locations remain accessible as general RAM if interrupts are unused - no address space is permanently reserved.
71321LA25J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 52-LCC (J-Lead)
- Packaging:
- Tube
- 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:
- 25ns
- Access Time:
- 25 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 52-PLCC (19.13x19.13)
71321LA25J FAQ
1.How can I place an order for 71321LA25J through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA25J 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 71321LA25J reliable?
The price and inventory of 71321LA25J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA25J is usually 5 days.
3.What payment methods are accepted for 71321LA25J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA25J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA25J?
71321LA25J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA25J 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 71321LA25J?
For technical support, including 71321LA25J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA25J requirements.
6.How does Aetrix verify that 71321LA25J is sourced from the original manufacturer or authorized distributors?
All 71321LA25J 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 71321LA25J meets industry standards.
7.What is the process for return or replacement of 71321LA25J?
All 71321LA25J units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA25J, 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 71321LA25J part is unused and in its original packaging.
Return procedure for 71321LA25J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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