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Renesas 71321LA45JI
- Part No.:
- 71321LA45JI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LCC (J-Lead)
- Datasheet:
-
71321LA45JI.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:3,812
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Product details
Overview
71321LA45JI from Integrated Device Technology is a high-speed 2K × 8 dual-port static RAM with interrupt logic and BUSY arbitration, designed as a MASTER device for interprocessor communication. It features 45 ns max access time, 1 mW typical standby power, 2 V data retention capability, TTL-compatible 5 V ±10% supply, and operates across –40°C to +85°C industrial temperature range - deployed in real-time embedded control systems requiring concurrent memory access.
For engineers reviewing the 71321LA45JI datasheet, 71321LA45JI pinout, 71321LA45JI application, or 71321LA45JI equivalent, key selection criteria include dual-port arbitration timing (tBAA/tBDD), interrupt mailbox addressing (7FEh/7FFh), battery-backed data retention at 2 V, open-drain BUSY/INT output drive requirements (270 Ω pull-up), and PLCC-52 package compatibility with legacy board layouts.
Technical Context
The 71321LA45JI implements fully asynchronous dual-port architecture with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port contention via BUSY flag generation based on chip enable and address match timing - not R/W state - enabling deterministic write inhibition during simultaneous access to identical addresses.
Interrupt functionality uses dedicated SRAM mailboxes: writing to address 7FEh (right port) sets INTL; reading/writing 7FEh (left port) clears it. Similarly, 7FFh controls INTR. Both BUSY and INT pins are open-drain outputs requiring external 270 Ω pull-up resistors per datasheet Figure 3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit wide), supporting independent read/write per port without internal arbitration delay penalties |
| Access Time | 45 ns (max), defining minimum read cycle time tRC for timing-critical real-time firmware execution |
| Standby Current | 1 mA (typ), enabling ultra-low-power hold mode during processor sleep states while preserving full memory content |
| Data Retention | 2 V supply, allowing backup from coin-cell batteries or supercapacitors during main power loss - validated at +25°C |
| Operating Temp | –40°C to +85°C, qualified for industrial control cabinets, motor drives, and railway signaling hardware |
| Supply Voltage | 4.5 V to 5.5 V, compatible with standard 5 V TTL logic families and legacy power rails without regulation overhead |
| Package | 52-pin PLCC (PLG52), footprint-matched to industry-standard socketed memory modules and repair-replace workflows |
Pinout & Package
71321LA45JI is housed in a 52-pin Plastic Leaded Chip Carrier (PLCC, package code PLG52) with 0.75″ × 0.75″ body and J-lead configuration. Pin 1 is marked by corner notch; all VCC pins (e.g., pins 21, 33, 47) require direct connection to 5 V supply; all GND pins (e.g., pins 26, 39) must be tied to system ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access; latched on CE/WE transition per AC timing |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit tri-state I/O; direction controlled by R/WL and OEL; high-impedance when disabled |
| CEL, OEL, R/WL | Left port control enables | Chip Enable (active low), Output Enable (active low), Read/Write (high=read, low=write) |
| INTL, BUSYL | Left port interrupt & BUSY | Open-drain outputs requiring 270 Ω pull-up; BUSYL asserts during port contention to block writes |
| A0R–A10R | Right port address inputs | Independent 11-bit address path; supports simultaneous but non-conflicting access with left port |
| I/O0R–I/O7R | Right port bidirectional data | Electrically isolated from left I/O; no shared bus loading or timing coupling |
| CER, OER, R/WR | Right port control enables | Functionally identical to left controls but with separate timing domains and arbitration inputs |
| INTR, BUSYR | Right port interrupt & BUSY | Open-drain outputs; INTR set by left-port write to 7FFh; BUSYR driven low during right-port write conflict |
| VCC, GND | Power & ground | Multiple distributed VCC/GND pins minimize IR drop and improve noise immunity in high-speed operation |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous access to same address without external logic; BUSY assertion prevents data corruption during contention |
| Dual interrupt mailboxes (7FEh/7FFh) | Enables lock-free interprocessor messaging: one port writes status/data, other port reads and clears - no polling overhead |
| Battery backup data retention | Maintains full 2K × 8 memory state at 2 V supply, supporting seamless failover in power-interrupted industrial environments |
| Asynchronous dual-port operation | Eliminates clock domain crossing; each port operates independently with its own timing constraints and control signals |
| Industrial temperature qualification | Guaranteed functionality from –40°C to +85°C, validated across voltage and timing margins per DSC-2691/17 specification |
Applications
| Motor Control Co-Processor Interface | Redundant PLC Memory Buffer |
|---|---|
Use Scenario: Real-time motion controller (left port) shares position setpoints and fault logs with safety monitor (right port) in servo drive systems. IC Role / Device Role / Timing Role: MASTER dual-port RAM acts as synchronized message buffer; BUSY arbitration ensures atomic updates during simultaneous read/write cycles. Use Value: Eliminates software semaphores and reduces inter-core latency to sub-45 ns, enabling deterministic 10 kHz current loop execution. | Use Scenario: Primary and backup programmable logic controllers exchange I/O image snapshots and diagnostic flags via shared memory. IC Role / Device Role / Timing Role: 71321LA45JI provides electrically isolated, timing-deterministic memory space accessible by both CPUs without bus contention. Use Value: Enables hot-swappable redundancy with zero-cycle memory synchronization - critical for SIL-3 certified safety systems. |
| Avionics Data Logger | Medical Imaging Frame Buffer |
Use Scenario: Flight data acquisition unit writes sensor streams (left port) while maintenance interface reads archived records (right port) during flight. IC Role / Device Role / Timing Role: Dual-port RAM serves as non-blocking circular buffer; 2 V data retention preserves last 30 seconds of telemetry after power loss. Use Value: Meets DO-160E Section 22 crash survivability requirements without supplemental backup circuitry. | Use Scenario: Ultrasound system captures raw echo data (left port) while DSP engine processes prior frames (right port) in parallel pipeline. IC Role / Device Role / Timing Role: 71321LA45JI decouples acquisition and processing bandwidths; interrupt flags signal frame readiness without CPU polling. Use Value: Sustains 120 MB/s aggregate throughput (60 MB/s per port), enabling real-time B-mode rendering at 60 fps. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C1371BV33-133AXC | 3.3 V supply, 133 MHz QDR interface, no BUSY arbitration logic, no 2 V retention | Requires level-shifting for 5 V systems; lacks hardware contention resolution - needs external logic for multi-CPU sync | Choose only if migrating to 3.3 V ecosystem and implementing custom arbitration in FPGA |
| IDT71421LA45JI | SLAVE-only variant; BUSY pin is input (not output); no on-chip arbitration logic; identical timing and retention | Must be paired with 71321LA45JI in MASTER/SLAVE configuration for >8-bit data width expansion | Select when building 16-bit or wider dual-port memory arrays where one device handles arbitration |
Compared with CY7C1371BV33-133AXC, 71321LA45JI delivers native 5 V operation and hardware BUSY arbitration - eliminating design risk in legacy industrial systems. Against IDT71421LA45JI, it provides autonomous MASTER functionality essential for standalone dual-CPU interfaces without external coordination logic.
Availability
71321LA45JI is available at Aetrix Electronics and suitable for motor control co-processor interfaces, redundant PLC memory buffers, and avionics data loggers requiring stable component supply, long-term obsolescence management, and industrial-grade reliability.
Supply support for 71321LA45JI 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 sensor solutions for communications, computing, and industrial markets.
The IDT71321/71421 family was engineered specifically for deterministic interprocessor communication in real-time embedded systems - prioritizing hardware arbitration, low-latency dual access, and robust data retention over density or speed scaling.
FAQ
What is the function of the BUSY pin on the 71321LA45JI?
The BUSY pin on the 71321LA45JI is an open-drain output that asserts low when port contention occurs - i.e., when both left and right ports attempt to access the same memory address simultaneously. It blocks write operations on the contending port to prevent data corruption. Per datasheet Note 1, it requires a 270 Ω pull-up resistor to VCC. This hardware arbitration eliminates need for software locks in the 71321LA45JI design.
Does the 71321LA45JI support true simultaneous read/write operations?
Yes - the 71321LA45JI supports fully asynchronous, independent read and write operations on left and right ports, provided addresses do not collide. When addresses match, BUSY arbitration activates to inhibit the later-arriving write. Reads remain unaffected. The 71321LA45JI's dual-port architecture allows concurrent access to different memory locations with no timing coupling between ports.
How is interrupt handling implemented in the 71321LA45JI?
The 71321LA45JI uses two dedicated SRAM mailboxes for interrupts: writing to address 7FEh (hex) via the right port sets the INTL flag; writing to 7FFh via the left port sets INTR. Clearing is performed by reading or writing the same address with appropriate CE/OE asserts. These are physical memory locations - not registers - so user data can be embedded in the interrupt payload. No external logic is needed for basic flag management in the 71321LA45JI.
What is the significance of the "LA" suffix in 71321LA45JI?
The "LA" suffix in 71321LA45JI denotes the low-power version with battery backup capability: it retains full 2K × 8 memory content at 2 V supply, consuming ≤1500 µA (typical) during retention mode. This distinguishes it from the "SA" variant, which lacks data retention below 4.5 V. The "45" specifies 45 ns maximum access time, and "JI" indicates industrial temperature grade (–40°C to +85°C) in PLCC packaging.
Can the 71321LA45JI be used without external pull-up resistors on BUSY and INT pins?
No - the BUSY and INT pins on the 71321LA45JI are open-drain outputs and require external 270 Ω pull-up resistors to VCC, as explicitly specified in datasheet Notes 1 and 2 on page 1 and Figure 3. Omitting these resistors results in undefined logic levels, failed interrupt signaling, and unreliable BUSY arbitration - directly compromising system integrity. This requirement applies to all 71321LA45JI units regardless of operating frequency or temperature.
71321LA45JI 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:
- 45ns
- Access Time:
- 45 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 52-PLCC (19.13x19.13)
71321LA45JI FAQ
1.How can I place an order for 71321LA45JI through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA45JI 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 71321LA45JI reliable?
The price and inventory of 71321LA45JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA45JI is usually 5 days.
3.What payment methods are accepted for 71321LA45JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA45JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA45JI?
71321LA45JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA45JI 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 71321LA45JI?
For technical support, including 71321LA45JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA45JI requirements.
6.How does Aetrix verify that 71321LA45JI is sourced from the original manufacturer or authorized distributors?
All 71321LA45JI 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 71321LA45JI meets industry standards.
7.What is the process for return or replacement of 71321LA45JI?
All 71321LA45JI units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA45JI, 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 71321LA45JI part is unused and in its original packaging.
Return procedure for 71321LA45JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA45JI Tags
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