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Renesas 71321LA20JG8
- Part No.:
- 71321LA20JG8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LCC (J-Lead)
- Datasheet:
-
71321LA20JG8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,568
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Product details
Overview
71321LA20JG8 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 20 ns max read cycle time, 1 mW typical standby power, and supports battery backup data retention at 2 V - enabling use in fault-tolerant embedded control systems requiring concurrent access from two independent buses.
For engineers reviewing the 71321LA20JG8 datasheet, 71321LA20JG8 pinout, 71321LA20JG8 application, or 71321LA20JG8 equivalent, this page provides verified functional identity, industrial-grade timing specs, master-side arbitration behavior, interrupt mailbox addressing (7FEh/7FFh), and package-specific pin validation for PLCC-52 (JG8).
Technical Context
The 71321LA20JG8 implements fully asynchronous dual-port operation 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 (CEL/CER) and address match detection - not R/W state - ensuring deterministic write inhibition during simultaneous access to identical addresses.
As a MASTER device, it features open-drain BUSYL/BUSYR outputs (requiring 270 Ω pull-ups), two dedicated interrupt flags (INTL/INTR) tied to fixed mailbox addresses (7FEh and 7FFh), and automatic power-down controlled by CE inputs. It does not support SLAVE-side BUSY input behavior - that applies only to IDT71421 variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), 16 kB total capacity |
| Access Time (tAA) | 20 ns max - guarantees sub-50 MHz synchronous interface compatibility |
| Read Cycle Time (tRC) | 20 ns max - enables full-speed interleaved dual-port reads without wait states |
| Standby Current (ISB3) | 0.2 mA typ. at 5 V - supports ultra-low-power hold mode during CPU sleep |
| Data Retention Voltage | 2.0 V min - allows backup from coin cell or supercapacitor during main power loss |
| Operating Temperature | –40°C to +85°C - qualified for industrial control and transportation electronics |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible with standard 5 V logic rails and noise margin |
Pinout & Package
71321LA20JG8 is packaged in 52-pin Plastic Leaded Chip Carrier (PLCC), body code JG8 (approx. 19.05 mm × 19.05 mm × 4.32 mm). All VCC pins must be decoupled; all GND pins require low-impedance ground connection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access (000h–7FFh) |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access (000h–7FFh) |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; high-impedance when OEL = VIH or CEL = VIH |
| I/O0R–I/O7R | Right port bidirectional data | 8-bit data path; high-impedance when OER = VIH or CER = VIH |
| CEL / CER | Chip enable (left/right) | Active-low enables port; controls power-down mode (ISB1–ISB4) |
| OEL / OER | Output enable (left/right) | Active-low enables data drivers; overrides R/W for tri-state control |
| R/WL / R/WR | Read/write control (left/right) | High = read, low = write; determines direction of I/O bus |
| INTL / INTR | Interrupt flags (open-drain) | Asserted low when opposite port writes to 7FEh (INTL) or 7FFh (INTR) |
| BUSYL / BUSYR | BUSY arbitration flags (open-drain) | Asserted low when port contention detected; requires 270 Ω pull-up |
| VCC / GND | Power supply terminals | Multiple VCC/GND pins ensure stable rail distribution across high-speed switching |
Key Features
| Feature | Design Value |
|---|---|
| Master-only BUSY arbitration | Hardware-based port conflict resolution using CE + address match - no external logic needed |
| Dual interrupt mailboxes | Fixed-location flags (7FEh/7FFh) enable lock-free interprocessor messaging without polling overhead |
| 2 V data retention | Preserves RAM contents during brown-out or main power failure - critical for safety-critical logging |
| Industrial temperature range | Validated operation from –40°C to +85°C - suitable for under-hood, factory floor, and outdoor deployments |
| Low-power LA variant | 1 mW standby (vs. 5 mW in SA version) - extends battery life in always-on monitoring nodes |
Applications
| Industrial PLC Backplane Interface | Avionics Dual-Computer Data Exchange |
|---|---|
Use Scenario: Two independent CPUs share sensor/actuator status in real time across a ruggedized backplane. IC Role / Device Role / Timing Role: MASTER dual-port SRAM acts as shared register file with hardware arbitration preventing write collisions during simultaneous access. Use Value: Eliminates software semaphores and reduces inter-CPU latency to ≤20 ns - meeting hard real-time scan cycle deadlines. |
Use Scenario: Primary and backup flight control computers exchange health telemetry and command acknowledgments. IC Role / Device Role / Timing Role: 71321LA20JG8 serves as fault-tolerant mailbox with interrupt-driven notification on new messages. Use Value: INTL/INTR flags trigger immediate ISR response - avoiding polling delays and ensuring <100 µs message delivery. |
| Railway Signaling Interlocking Logic | Medical Imaging Subsystem Buffer |
Use Scenario: Safety-critical interlocking logic runs on redundant processors verifying track occupancy and signal states. IC Role / Device Role / Timing Role: Dual-port RAM stores validated state vectors; BUSY arbitration prevents inconsistent updates during failover. Use Value: Hardware-enforced atomicity ensures both CPUs always read coherent state - satisfying SIL-4 certification requirements. |
Use Scenario: CT/MRI subsystems buffer raw detector data between acquisition FPGA and reconstruction DSP. IC Role / Device Role / Timing Role: Left port accepts burst data from ADC pipeline; right port streams processed frames to DMA controller. Use Value: 20 ns access + full asynchrony enables seamless 100+ MB/s throughput without FIFO bottlenecks or clock domain crossing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C136-25JC | 25 ns access, 5 V only, no built-in BUSY arbitration - requires external logic for contention handling | Lacks integrated interrupt mailboxes and 2 V retention; suited for simpler dual-CPU designs without strict fault tolerance | Select if cost sensitivity outweighs arbitration/interrupt integration needs and 20 ns speed is noncritical |
| IDT71421LA20JG8 | SLAVE-only variant; BUSY pins are inputs (not outputs); no on-chip arbitration logic | Used only in width-expanded arrays with a 71321LA20JG8 master; cannot operate standalone as memory controller | Choose only when building >16-bit word-width systems where one 71321LA20JG8 coordinates multiple SLAVE devices |
Compared with CY7C136-25JC, 71321LA20JG8 reduces BOM count and layout complexity by integrating arbitration and interrupts; compared with IDT71421LA20JG8, it provides autonomous master functionality essential for point-to-point dual-processor links.
Availability
71321LA20JG8 is available at Aetrix Electronics and suitable for industrial PLC backplanes, avionics data exchange systems, and railway signaling interlockers requiring stable component supply, long-term lifecycle assurance, and guaranteed industrial temperature performance.
Supply support for 71321LA20JG8 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, specializes in high-performance timing, memory, and interface ICs for communications, computing, and industrial markets.
The IDT71321 family was engineered specifically for deterministic, low-latency interprocessor communication in safety-critical embedded systems - emphasizing hardware arbitration, interrupt signaling, and robust data retention.
FAQ
What is the function of BUSYL and BUSYR on the 71321LA20JG8?
BUSYL and BUSYR are open-drain output flags indicating port contention. When asserted low, they inhibit writes to the respective port during simultaneous access to identical addresses. The 71321LA20JG8 uses chip enable and address signals - not R/W state - to generate BUSY, and requires 270 Ω pull-up resistors per the datasheet. This behavior is exclusive to the MASTER 71321LA20JG8; SLAVE devices treat BUSY as an input.
How does the interrupt mechanism work in the 71321LA20JG8?
The 71321LA20JG8 implements hardware interrupt flags INTL and INTR tied to fixed SRAM addresses: writing to 7FEh (hex) asserts INTL, and writing to 7FFh asserts INTR. Each flag is cleared by reading its associated address. These mailboxes operate independently of normal memory access and require no software polling - enabling zero-latency interprocessor signaling. The 71321LA20JG8 does not support configurable interrupt locations.
Can the 71321LA20JG8 operate with a 3.3 V supply?
No. The 71321LA20JG8 is specified for 4.5 V to 5.5 V operation only and is TTL-compatible. It lacks 3.3 V I/O tolerance or internal voltage regulation. Using 3.3 V violates absolute maximum ratings and will result in undefined behavior, including failure to retain data at 2 V or meet 20 ns timing. For 3.3 V systems, consider newer dual-port SRAM families such as Renesas' IS61WV series.
What package type does the 71321LA20JG8 use, and are there footprint alternatives?
The 71321LA20JG8 uses a 52-pin PLCC package with body code JG8 (19.05 mm × 19.05 mm). While the same die is offered in 52-pin STQFP (PPG52) and 64-pin TQFP (PNG64), the JG8 suffix confirms PLCC. No pin-compatible 64-pin variant exists for this speed grade - migration to PNG64 would require PCB redesign due to different pinout, larger footprint, and additional power/ground connections.
Is the 71321LA20JG8 suitable for battery-backed applications?
Yes - the "LA" suffix denotes low-power operation with guaranteed 2 V data retention. At VCC = 2.0 V and TA = +25°C, the 71321LA20JG8 retains data with ICCDR ≤ 1500 µA (commercial) or ≤ 4000 µA (industrial). This enables direct connection to lithium coin cells or supercapacitors during main power loss, preserving critical state in medical, transportation, and industrial logging systems.
71321LA20JG8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 52-LCC (J-Lead)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 20ns
- Access Time:
- 20 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)
71321LA20JG8 FAQ
1.How can I place an order for 71321LA20JG8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA20JG8 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 71321LA20JG8 reliable?
The price and inventory of 71321LA20JG8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA20JG8 is usually 5 days.
3.What payment methods are accepted for 71321LA20JG8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA20JG8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA20JG8?
71321LA20JG8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA20JG8 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 71321LA20JG8?
For technical support, including 71321LA20JG8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA20JG8 requirements.
6.How does Aetrix verify that 71321LA20JG8 is sourced from the original manufacturer or authorized distributors?
All 71321LA20JG8 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 71321LA20JG8 meets industry standards.
7.What is the process for return or replacement of 71321LA20JG8?
All 71321LA20JG8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA20JG8, 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 71321LA20JG8 part is unused and in its original packaging.
Return procedure for 71321LA20JG8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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