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Renesas 71321LA55PPGI8
- Part No.:
- 71321LA55PPGI8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LQFP
- Datasheet:
-
71321LA55PPGI8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52TQFP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
71321LA55PPGI8 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 55 ns max read/write cycle time, supports industrial temperature range (–40°C to +85°C), operates on single 5V ±10% supply, and enables battery-backed data retention at 2V. It is used in real-time embedded systems requiring concurrent access by two independent CPUs or DMA controllers.
For engineers reviewing the 71321LA55PPGI8 datasheet, 71321LA55PPGI8 pinout, 71321LA55PPGI8 application, or 71321LA55PPGI8 equivalent, key selection criteria include its MASTER arbitration capability, dual-interrupt flag support (INTL/INTR), 2V data retention, 52-pin STQFP package, and compatibility with IDT71421LA SLAVE devices for 16-bit+ memory expansion.
Technical Context
The 71321LA55PPGI8 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 output assertion based on chip enable (CEL/CER) and address match timing - not R/W state - ensuring deterministic write inhibition during simultaneous access to identical addresses.
It integrates two dedicated interrupt flags (INTL and INTR) tied to fixed mailbox addresses (7FEh and 7FFh), enabling hardware-triggered interprocessor signaling without polling. The LA variant provides ultra-low standby current (1 mA typ. at TTL inputs, 0.2 mA typ. at CMOS inputs) and guaranteed 2V data retention, distinguishing it from SA versions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit wide), sufficient for small real-time buffers or dual-CPU shared workspaces. |
| Access Time | 55 ns max read cycle time - defines minimum clock period for synchronous interface designs or maximum bus frequency in asynchronous systems. |
| Supply Voltage | 5.0 V ±10% - compatible with legacy 5V TTL/CMOS logic families without level-shifting. |
| Temperature Range | –40°C to +85°C industrial grade - validated for deployment in automotive ECUs, industrial PLCs, and telecom line cards. |
| Data Retention | 2.0 V min - enables backup from coin cell or supercapacitor during main power loss, preserving critical state across brownouts. |
| Standby Current | 1 mA typical (both ports disabled, TTL-level inputs) - reduces system-level quiescent power in always-on subsystems. |
| Interrupt Addresses | Fixed mailboxes at 7FEh (sets INTL) and 7FFh (sets INTR) - eliminates software configuration overhead and ensures deterministic latency. |
Pinout & Package
71321LA55PPGI8 is packaged in a 52-pin STQFP (PPG52), measuring 10 mm × 10 mm × 1.4 mm, with exposed pad for thermal dissipation and standard surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side access; supports full 2K addressing without external decoding. |
| A0R–A10R | Right port address inputs | Independent 11-bit address bus enabling concurrent access to same or different memory locations. |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; high-impedance when OEL = VIH or CEL = VIH - enables bus sharing. |
| I/O0R–I/O7R | Right port bidirectional data | Electrically isolated from left port I/O; no internal contention - simplifies PCB routing. |
| CEL / CER | Chip enable (left/right) | Active-low enables respective port; controls automatic power-down - primary means of port gating and power management. |
| OEL / OER | Output enable (left/right) | Active-low enables I/O drivers; allows read-only access while keeping port active for arbitration. |
| R/WL / R/WR | Read/write control (left/right) | Active-low initiates write; high enables read - determines direction during CE/OE assertion. |
| INTL / INTR | Interrupt flags (output) | Open-drain outputs requiring external pull-up; assert on mailbox writes (7FEh/7FFh) - trigger CPU interrupts directly. |
| BUSYL / BUSYR | BUSY arbitration signals | Open-drain outputs (MASTER only); drive low to inhibit writes on contested addresses - hardware-enforced mutual exclusion. |
| VCC / GND | Power and ground | Multiple VCC/GND pins distributed across package - reduce switching noise and improve signal integrity in high-speed operation. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous access conflicts at hardware level using CEL/CER and address match - eliminates need for external arbitration logic or software locks. |
| Dual interrupt mailbox architecture | Hardwired 7FEh/7FFh addresses provide zero-latency, deterministic interprocessor signaling - avoids polling overhead and race conditions. |
| 2V data retention mode | Preserves full memory contents during main power failure using backup supply - enables fast resume without reloading firmware or state tables. |
| Master/Slave expandability | One 71321LA55PPGI8 MASTER coordinates arbitration for multiple IDT71421LA SLAVEs - scales memory width to 16-bit or more without performance penalty. |
| Ultra-low standby power | 0.2 mA typical full-standby current (CMOS inputs) - extends battery life in portable or energy-constrained edge devices. |
Applications
| Real-Time Dual-CPU Systems | Industrial Motion Controllers |
|---|---|
Use Scenario: Two independent microcontrollers share sensor data and control commands via a common memory buffer while executing parallel tasks. IC Role / Device Role / Timing Role: 71321LA55PPGI8 acts as MASTER dual-port SRAM, providing non-blocking read/write access and hardware arbitration to prevent data corruption during concurrent access. Use Value: Eliminates software semaphores and polling delays; guarantees sub-55 ns response for time-critical coordination between motion planning and servo loop execution. | Use Scenario: A PLC main CPU offloads high-frequency I/O scanning to a dedicated motion coprocessor, with synchronized parameter updates and status reporting. IC Role / Device Role / Timing Role: 71321LA55PPGI8 serves as shared register bank with interrupt-driven mailbox signaling - INTR triggers coprocessor action on new setpoints; INTL confirms completion. Use Value: Reduces scan cycle jitter by >30% versus UART or SPI-based handshaking; supports deterministic <100 µs inter-core latency. |
| Telecom Line Card Buffers | Automotive ADAS Sensor Fusion |
Use Scenario: High-speed packet processing ASIC and host ARM processor exchange frame descriptors and metadata in real time across a backplane interface. IC Role / Device Role / Timing Role: 71321LA55PPGI8 functions as low-latency descriptor ring buffer, leveraging BUSY arbitration to prevent descriptor overwrites during burst traffic. Use Value: Sustains 100+ Mbps descriptor throughput with zero packet loss under worst-case contention; 2V retention preserves last valid descriptor during hot-swap events. | Use Scenario: Radar and camera processors write timestamped object lists into shared memory for fusion by a central domain controller, requiring atomic updates and event notification. IC Role / Device Role / Timing Role: 71321LA55PPGI8 operates as mailbox + buffer, where 7FFh writes from radar core assert INTR to wake domain controller; 7FEh writes from camera core set INTL. Use Value: Enables sub-millisecond sensor-to-fusion latency; 2V retention maintains latest fused object list across ignition cycles for cold-start context recovery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT71421LA55PPGI8 | SLAVE-only device; lacks on-chip arbitration logic and BUSY output; BUSY pins are inputs only. | Cannot operate standalone; requires pairing with a MASTER (e.g., 71321LA) for width expansion; no interrupt generation capability. | Select only when building multi-chip 16-bit+ memory arrays where one 71321LA55PPGI8 coordinates arbitration for several 71421LA units. |
| Cypress CY7C1371DV33-55ZXC | 3.3V core supply; 55 ns access; no built-in BUSY arbitration; interrupt logic requires external logic or firmware. | Requires level shifters for 5V systems; lacks hardware arbitration - increases software complexity and risk of race conditions. | Consider only for new 3.3V designs prioritizing lower voltage operation over deterministic arbitration; not drop-in compatible. |
Compared with IDT71421LA55PPGI8 and CY7C1371DV33-55ZXC, the 71321LA55PPGI8 uniquely combines MASTER arbitration, dual interrupt flags, and 2V data retention in a single 5V-compatible device - making it irreplaceable for robust, low-latency interprocessor communication in industrial and automotive environments.
Availability
71321LA55PPGI8 is available at Aetrix Electronics and suitable for real-time dual-CPU systems, industrial motion controllers, and telecom line card buffers requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for 71321LA55PPGI8 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 IDT71321/71421 family was engineered specifically for deterministic interprocessor communication in hard real-time systems - delivering hardware-enforced arbitration, interrupt-driven synchronization, and battery-backed data integrity without software overhead.
FAQ
What is the function of the BUSYL and BUSYR pins on the 71321LA55PPGI8?
The BUSYL and BUSYR pins on the 71321LA55PPGI8 are open-drain arbitration outputs that drive low when the corresponding port attempts to write to an address already being accessed by the opposite port. This hardware signal inhibits the write operation, preventing data corruption. External 270 Ω pull-up resistors are required per datasheet specification. As a MASTER device, the 71321LA55PPGI8 asserts BUSY; SLAVE devices like IDT71421 use these pins as inputs.
Does the 71321LA55PPGI8 support true simultaneous read operations from both ports?
Yes, the 71321LA55PPGI8 supports fully asynchronous, simultaneous reads from both left and right ports without arbitration delay or BUSY assertion. Reads do not trigger BUSY, and no port contention occurs - enabling concurrent data fetching for dual-CPU architectures. Write operations, however, activate arbitration logic if addresses overlap.
How does the interrupt functionality work in the 71321LA55PPGI8?
The 71321LA55PPGI8 uses fixed-address mailboxes: writing to address 7FEh (hex) via the right port sets the INTL flag, and writing to 7FFh via the left port sets the INTR flag. Each flag is an open-drain output requiring a pull-up resistor. Clearing is performed by reading the same address with OE enabled - no separate reset command is needed. This mechanism is implemented entirely in hardware with no firmware dependency.
Can the 71321LA55PPGI8 be used without external pull-up resistors on INTL, INTR, BUSYL, and BUSYR?
No - the 71321LA55PPGI8 specifies 270 Ω external pull-up resistors for all open-drain outputs (INTL, INTR, BUSYL, BUSYR) per Figure 3 and Notes 1–2 in the datasheet. Omitting them prevents proper logic-level definition, resulting in undefined interrupt or BUSY states and potential system lockup during contention scenarios.
What is the significance of the 'LA' suffix in 71321LA55PPGI8?
'LA' denotes the low-power, battery-retention variant of the IDT71321. It features 1 mA typical standby current (vs. 5 mA for SA), 0.2 mA full-standby current with CMOS inputs, and guaranteed data retention down to 2.0 V - enabling operation from backup batteries or supercapacitors. The '55' indicates 55 ns maximum access time, and 'PPGI8' specifies the 52-pin STQFP package with industrial temperature grade (–40°C to +85°C).
71321LA55PPGI8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 52-LQFP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Type:
- Volatile
- Memory Format:
- SRAM
- Technology:
- SRAM - Dual Port, Synchronous
- Memory Size:
- 16Kbit
- Memory Organization:
- 2K x 8
- 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:
- 52-TQFP (10x10)
71321LA55PPGI8 FAQ
1.How can I place an order for 71321LA55PPGI8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA55PPGI8 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 71321LA55PPGI8 reliable?
The price and inventory of 71321LA55PPGI8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA55PPGI8 is usually 5 days.
3.What payment methods are accepted for 71321LA55PPGI8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA55PPGI8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA55PPGI8?
71321LA55PPGI8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA55PPGI8 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 71321LA55PPGI8?
For technical support, including 71321LA55PPGI8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA55PPGI8 requirements.
6.How does Aetrix verify that 71321LA55PPGI8 is sourced from the original manufacturer or authorized distributors?
All 71321LA55PPGI8 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 71321LA55PPGI8 meets industry standards.
7.What is the process for return or replacement of 71321LA55PPGI8?
All 71321LA55PPGI8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA55PPGI8, 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 71321LA55PPGI8 part is unused and in its original packaging.
Return procedure for 71321LA55PPGI8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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