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Renesas 71321LA20J
- Part No.:
- 71321LA20J
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LCC (J-Lead)
- Datasheet:
-
71321LA20J.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,763
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Product details
Overview
IDT71321LA20J from Integrated Device Technology 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 features 20 ns max read cycle time, 5 V ±10% single-supply operation, industrial temperature range (–40°C to +85°C), and battery-backed data retention at 2 V - enabling use in fault-tolerant dual-CPU architectures requiring concurrent memory access without software coordination.
For engineers reviewing the IDT71321LA20J datasheet, IDT71321LA20J pinout, IDT71321LA20J application, or IDT71321LA20J equivalent, key selection considerations include its MASTER-only BUSY output behavior, interrupt mailbox addressing (0x7FE/0x7FF), 1 mW standby power, 52-pin STQFP package, and compatibility with IDT71421SLAVE devices for 16-bit+ width expansion.
Technical Context
The IDT71321LA20J 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 solely on chip enable (CEL/CER) and address match timing - not R/W state - ensuring deterministic write inhibition during simultaneous access to identical addresses.
As a MASTER-only device, it provides open-drain BUSYL/BUSYR outputs (requiring 270 Ω pull-up) and two interrupt flags (INTL/INTR) tied to dedicated SRAM mailboxes (0x7FE and 0x7FF). It lacks SLAVE-side BUSY input functionality and cannot operate standalone as a SLAVE; pairing with IDT71421 devices is required for full MASTER/SLAVE width expansion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 bits (2048 words × 8 data lines), dual-port SRAM with separate left/right address/control/I/O |
| Access Time (tRC) | 20 ns maximum - defines minimum read cycle duration for guaranteed valid data at outputs |
| Supply Voltage | 5.0 V ±10% - TTL-compatible single supply; no auxiliary voltage rails required |
| Standby Current (ISB3) | 0.2 mA typical - ultra-low full-standby power enabled by CMOS design and LA low-power variant |
| Data Retention | 2.0 V minimum - retains memory contents during brown-out or backup battery operation |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments without derating |
| Interrupt Mailbox Addresses | 0x7FE (left INTL set), 0x7FF (right INTR set) - user-accessible SRAM locations used as hardware message registers |
Pinout & Package
Package: 52-pin STQFP (PPG52), 10 mm × 10 mm × 1.4 mm body, surface-mount, lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access (0–2047) |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access (0–2047) |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; direction controlled by R/WL and OEL |
| I/O0R–I/O7R | Right port bidirectional data | 8-bit data path; direction controlled by R/WR and OER |
| CEL / CER | Chip enable (left/right) | Active-low enables respective port; controls power-down mode when high |
| OEL / OER | Output enable (left/right) | Active-low enables data outputs; high-Z when disabled |
| R/WL / R/WR | Read/write control (left/right) | High = read, low = write; determines I/O direction and internal write strobe |
| BUSYL / BUSYR | BUSY flag (output only) | Open-drain outputs indicating port contention; require external 270 Ω pull-up resistors |
| INTL / INTR | Interrupt flags (output only) | Active-low interrupt signals asserted on mailbox writes (0x7FE/0x7FF) |
| VCC / GND | Power supply pins | Multiple VCC (pins 18, 26, 39, 46) and GND (pins 21, 33, 40, 47) for noise reduction and current distribution |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Hardware-resolved contention detection using CE/address timing - eliminates need for external arbitration logic or software polling |
| Two independent interrupt flags | INTL and INTR provide hardware signaling of interprocessor messages via dedicated SRAM mailboxes (0x7FE/0x7FF) |
| 2 V data retention | Preserves memory contents during main power loss using backup battery or capacitor hold-up, critical for fail-safe logging |
| Master-only BUSY output architecture | BUSYL/BUSYR are open-drain outputs only - enables wired-AND expansion across multiple MASTER/SLAVE arrays without external gates |
| Industrial-grade reliability | Qualified over –40°C to +85°C with 100% production-tested AC/DC parameters and 1000-hour HTOL stress validation |
Applications
| Real-Time Dual-Processor Systems | Redundant Control Units |
|---|---|
Use Scenario: Two independent CPUs share status, commands, and sensor data via shared memory without OS-level synchronization. IC Role / Device Role / Timing Role: IDT71321LA20J acts as MASTER dual-port SRAM, providing deterministic BUSY arbitration and interrupt-driven mailbox communication between processors. Use Value: Eliminates race conditions and software locks; 20 ns access enables sub-microsecond inter-CPU messaging latency. |
Use Scenario: Primary and backup controllers maintain synchronized state in safety-critical infrastructure (e.g., rail signaling, medical devices). IC Role / Device Role / Timing Role: IDT71321LA20J serves as fault-tolerant shared memory with 2 V data retention, preserving last-known-good state during power interruption. Use Value: Enables seamless switchover with zero data loss; industrial temp rating ensures operation in harsh cabinet environments. |
| Communications Protocol Bridges | Test & Measurement Instrumentation |
Use Scenario: Bridging dissimilar protocols (e.g., CAN-to-Ethernet) where protocol engines run on separate MCUs with isolated clock domains. IC Role / Device Role / Timing Role: IDT71321LA20J functions as asynchronous buffer with interrupt-triggered packet handoff between protocol stacks. Use Value: Prevents data overrun via hardware BUSY flow control; mailbox interrupts reduce CPU polling overhead by >90%. |
Use Scenario: High-speed data acquisition systems capturing waveform samples while simultaneously running real-time analysis on a second processor. IC Role / Device Role / Timing Role: IDT71321LA20J operates as dual-port FIFO buffer, with one port writing raw ADC data and the other reading processed results. Use Value: 20 ns access supports >50 MHz sample streaming; low standby power extends portable instrument battery life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Cypress CY7C1371DV33-200BZI | 3.3 V supply, 200 MHz QDR interface, no native BUSY arbitration or interrupt mailboxes | Requires external logic for contention resolution; suited for high-bandwidth streaming, not interprocessor messaging | Select only if migrating to 3.3 V system with QDR controller support and external arbitration capability |
| IDT71421LA20J | SLAVE-only counterpart; BUSY pins are inputs (not outputs); no on-chip arbitration logic | Must be paired with IDT71321LA20J in MASTER/SLAVE configuration; cannot operate standalone as MASTER | Use exclusively as width-expansion slave in 16-bit+ systems; never a drop-in replacement for IDT71321LA20J |
Compared with CY7C1371DV33-200BZI and IDT71421LA20J, the IDT71321LA20J uniquely integrates MASTER arbitration, interrupt mailboxes, and 2 V retention in a 5 V industrial package - making it irreplaceable for legacy dual-CPU designs requiring hardware-coordinated shared memory without external glue logic.
Availability
IDT71321LA20J is available at Aetrix Electronics and suitable for real-time dual-processor systems, redundant control units, and communications protocol bridges requiring stable component supply, long-term industrial lifecycle support, and guaranteed pin-and-function compatibility.
Supply support for IDT71321LA20J 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 IDT71321LA20J belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in hard real-time systems where software-based synchronization introduces unacceptable latency or jitter.
FAQ
What is the function of BUSYL and BUSYR on the IDT71321LA20J?
BUSYL and BUSYR are open-drain output flags on the IDT71321LA20J that indicate port contention when both left and right ports attempt simultaneous access to the same memory address. They require external 270 Ω pull-up resistors and are asserted low to inhibit writes on the contending port. These signals are outputs only - the IDT71321LA20J does not accept BUSY as an input.
Can the IDT71321LA20J operate as a SLAVE device in a MASTER/SLAVE configuration?
No, the IDT71321LA20J is strictly a MASTER device and cannot function as a SLAVE. Its BUSY pins are outputs only, and it contains on-chip arbitration logic incompatible with SLAVE operation. To build a width-expanded system, IDT71321LA20J must be paired with IDT71421LA20J (SLAVE) devices - the latter have BUSY pins configured as inputs and lack arbitration circuitry.
How do the interrupt mailboxes (0x7FE and 0x7FF) work on the IDT71321LA20J?
Writing to address 0x7FE (with CER/R/WR active) asserts INTL; writing to 0x7FF asserts INTR. Reading those addresses clears the respective flag. These are standard SRAM locations - the stored 8-bit value is user-defined data (e.g., command code, status byte). The IDT71321LA20J generates the interrupt signal autonomously; no firmware polling is needed.
Does the IDT71321LA20J support battery backup operation?
Yes, the IDT71321LA20J (LA variant) supports true battery backup: it retains memory contents at VCC = 2.0 V with ICCDR ≤ 1500 µA (commercial) or ≤ 4000 µA (industrial). This is a hardware feature - no external circuitry beyond the backup source is required. The SA variant does not support this capability.
What package type is used for the IDT71321LA20J, and are there alternatives?
The IDT71321LA20J is supplied in a 52-pin STQFP (PPG52) package: 10 mm × 10 mm × 1.4 mm, surface-mount, RoHS-compliant. Alternative packages exist for other variants (e.g., 64-pin TQFP), but IDT71321LA20J is specifically qualified and marked for PPG52 only - no pin-compatible 64-pin version exists for this speed/temp/part number combination.
71321LA20J 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:
- 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)
71321LA20J FAQ
1.How can I place an order for 71321LA20J through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA20J 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 71321LA20J reliable?
The price and inventory of 71321LA20J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA20J is usually 5 days.
3.What payment methods are accepted for 71321LA20J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA20J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA20J?
71321LA20J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA20J 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 71321LA20J?
For technical support, including 71321LA20J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA20J requirements.
6.How does Aetrix verify that 71321LA20J is sourced from the original manufacturer or authorized distributors?
All 71321LA20J 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 71321LA20J meets industry standards.
7.What is the process for return or replacement of 71321LA20J?
All 71321LA20J units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA20J, 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 71321LA20J part is unused and in its original packaging.
Return procedure for 71321LA20J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA20J Tags
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