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Renesas 71321LA55JI
- Part No.:
- 71321LA55JI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LCC (J-Lead)
- Datasheet:
-
71321LA55JI.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:4,520
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Product details
Overview
IDT71321LA55JI 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 in real-time embedded systems. It delivers 55 ns max read/write cycle time, supports industrial temperature (–40°C to +85°C), operates on single 5V ±10% supply, and features battery-backed data retention down to 2V. It is used in dual-CPU arbitration systems requiring deterministic port conflict resolution.
For engineers reviewing the IDT71321LA55JI datasheet, IDT71321LA55JI pinout, IDT71321LA55JI application, or IDT71321LA55JI equivalent, key selection criteria include its MASTER-only arbitration logic, open-drain BUSYL/INTL outputs requiring 270Ω pull-ups, 2V data retention capability, and compatibility with IDT71421SLAVE devices for 16-bit+ memory expansion.
Technical Context
The IDT71321LA55JI implements fully asynchronous dual-port operation with independent left/right address, control, and I/O buses. Its on-chip arbitration logic monitors CE and address signals (not R/W state) to assert BUSYL/BUSYR outputs within 20 ns (tBAA/tBAC) when port contention occurs on matching addresses - enabling hardware-level write inhibition without external logic.
Interrupt functionality uses dedicated mailbox addresses: INTL asserts when right port writes to 0x7FE; INTR asserts when left port writes to 0x7FF. Both flags are open-drain outputs requiring external pull-up resistors. The LA suffix confirms low-power design with 1 µA full-standby current (ISB3) and 2V data retention (VDR = 2.0 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit wide), organized as two independent 11-bit address spaces (A0–A10) |
| Access Time | 55 ns max read cycle time (tRC), enabling synchronization with 18 MHz bus clocks in real-time control loops |
| Supply Voltage | 5.0 V ±10% (4.5–5.5 V), TTL-compatible inputs, no level-shifting required in 5V systems |
| Data Retention | 2.0 V minimum VCC for data retention (VDR), supporting battery backup during main power loss |
| Standby Current | 1.0 µA typical full-standby (ISB3), critical for low-power hold modes in portable instrumentation |
| Operating Temp | –40°C to +85°C industrial grade, qualified for engine control units and industrial PLCs |
| Package | 64-pin TQFP (PNG64), 14 mm × 14 mm footprint with 0.5 mm pitch, RoHS-compliant and green |
Pinout & Package
64-pin Thin Quad Flat Package (TQFP, PNG64) with exposed thermal pad; requires 270Ω pull-up resistors on BUSYL, INTL, BUSYR, and INTR pins per datasheet Note 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side access; must be stable before CE/WE assertion per tAS = 0 ns setup |
| A0R–A10R | Right port address inputs | Independent 11-bit address bus; enables simultaneous non-conflicting reads/writes across ports |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; high-impedance when OEL = VIH or CEL = VIH; drives valid data within tAOE ≤ 25 ns |
| I/O0R–I/O7R | Right port bidirectional data | 8-bit data path; electrically isolated from left port; supports concurrent 16-bit word transfers with slave devices |
| CEL / CER | Chip enable (left/right) | Active-low enables respective port; controls power-down mode (ISB1–ISB4); tPD = 50 ns max disable-to-standby |
| OEL / OER | Output enable (left/right) | Active-low enables I/O drivers; overrides R/W state for tristate control during bus sharing |
| R/WL / R/WR | Read/write control (left/right) | Active-low write strobe; combined with CE defines write cycle timing (tWP = 30 ns min for 55 ns version) |
| BUSYL / BUSYR | Arbitration status (open-drain) | Outputs asserted LOW during address match contention; require 270Ω pull-up; drive write-inhibit on slave devices |
| INTL / INTR | Interrupt flags (open-drain) | Asserted on mailbox writes (0x7FE/0x7FF); used for interprocessor signaling without polling overhead |
| VCC / GND | Power supply | Four VCC (pins 23, 24, 47, 48) and four GND (pins 22, 25, 46, 49) pins ensure low-noise operation at high speed |
Key Features
| Feature | Design Value |
|---|---|
| Hardware BUSY arbitration | Eliminates need for external glue logic in multi-processor shared-memory systems by asserting BUSY within 20 ns of address match |
| Master/Slave expandability | Enables seamless 16-bit+ data bus expansion using IDT71321LA55JI as MASTER with IDT71421SLAVE devices without performance penalty |
| Interrupt mailbox addressing | Dedicated 0x7FE (left flag) and 0x7FF (right flag) locations provide zero-latency inter-core signaling without software polling |
| 2V data retention | Maintains SRAM contents during brown-out or battery-backup operation, supporting fail-safe state preservation |
| Low-power standby | 1.0 µA ISB3 current enables >1-year battery life in always-on monitoring nodes using coin-cell backup |
Applications
| Industrial Motion Control | Automotive Engine Management |
|---|---|
|
Use Scenario: Dual-CPU architecture where safety MCU monitors real-time motion controller via shared memory. IC Role / Device Role / Timing Role: IDT71321LA55JI acts as MASTER dual-port RAM, arbitrating write conflicts between CPUs and signaling status via INTL/INTR. Use Value: Hardware BUSY logic guarantees deterministic response to simultaneous access, eliminating race conditions in safety-critical axis positioning. |
Use Scenario: ECU uses primary CPU for fuel injection control and secondary CPU for emissions diagnostics, sharing sensor calibration tables. IC Role / Device Role / Timing Role: IDT71321LA55JI provides non-blocking 55 ns access to shared lookup tables while retaining data at 2V during ignition transients. Use Value: Battery-backed retention preserves adaptive learning parameters during cranking voltage drop, ensuring consistent engine start behavior. |
| Medical Imaging Subsystem | Avionics Data Concentrator |
|
Use Scenario: FPGA-accelerated image processing pipeline exchanges frame buffers with ARM host processor via shared memory. IC Role / Device Role / Timing Role: IDT71321LA55JI serves as low-latency buffer with independent left (FPGA) and right (ARM) ports, synchronized by interrupt mailboxes. Use Value: 55 ns access enables real-time transfer of 1080p subframes at 60 Hz without DMA bottlenecks or software overhead. |
Use Scenario: Flight control computer aggregates sensor data from multiple LRUs using time-triggered communication over shared memory. IC Role / Device Role / Timing Role: IDT71321LA55JI operates as MASTER in a redundant dual-channel architecture, with BUSY arbitration enforcing strict write ordering. Use Value: Industrial temperature rating (–40°C to +85°C) and 2V retention meet DO-254/DO-178C environmental and fault-tolerance requirements. |
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 CY7C1371DV33-166AXC | 3.3V core, 166 MHz (6 ns), no built-in BUSY arbitration or interrupt mailboxes | Requires external logic for port conflict resolution; suited for high-speed DSP co-processing, not inter-CPU arbitration | Select only if system operates at 3.3V and uses software-managed memory access protocols |
| ISSI IS61WV20488BLL-10MLI | Single-port, 10 ns access, no dual-port or arbitration features; 3.3V/2.5V compatible | Cannot support simultaneous CPU/FPGA access; lacks interrupt or BUSY signaling capability | Use only in cost-sensitive, non-concurrent-access designs where arbitration is handled entirely in firmware |
Compared with IDT71321LA55JI, the Cypress part offers higher speed but demands external arbitration circuitry and lacks 2V retention, while the ISSI part omits dual-port functionality entirely - making IDT71321LA55JI uniquely suited for deterministic hardware-arbitrated interprocessor communication.
Availability
IDT71321LA55JI is available at Aetrix Electronics and suitable for industrial motion control, automotive engine management, and medical imaging subsystems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for IDT71321LA55JI 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, and RF solutions for communications and computing infrastructure.
IDT71321LA55JI belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in real-time embedded systems requiring hardware arbitration and mailbox-style interrupts.
FAQ
What is the function of the BUSYL and INTL pins on the IDT71321LA55JI?
BUSYL and INTL are open-drain outputs requiring external 270Ω pull-up resistors. BUSYL signals port contention during address matches, enabling hardware write inhibition. INTL asserts when the right port writes to address 0x7FE, serving as an interprocessor interrupt flag. Both pins are active-low and defined in the IDT71321LA55JI functional block diagram and Truth Table II.
Does the IDT71321LA55JI support battery backup operation?
Yes, the IDT71321LA55JI supports battery backup operation with guaranteed data retention at VCC = 2.0 V (VDR parameter). This is exclusive to LA-suffix variants and confirmed in Table 6 (Data Retention Characteristics). Typical data retention current is 100 µA, enabling multi-year backup with small coin cells.
Can the IDT71321LA55JI be used as a SLAVE device in a Master/Slave configuration?
No, the IDT71321LA55JI is exclusively a MASTER device. Only IDT71421 variants function as SLAVES, with BUSY pins configured as inputs. The IDT71321LA55JI's BUSYL/BUSYR pins are outputs, and its internal arbitration logic is designed solely for MASTER role - attempting SLAVE use violates the functional specification in the datasheet Section 1.
What package type is used for the IDT71321LA55JI?
The IDT71321LA55JI uses a 64-pin Thin Quad Flat Package (TQFP), designated PNG64 in IDT documentation. Its dimensions are 14 mm × 14 mm × 1.4 mm with 0.5 mm lead pitch. Pin configuration matches Figure 3 (64-Pin TQFP Top View) in the DSC-2691/17 datasheet.
How does interrupt clearing work in the IDT71321LA55JI?
To clear the INTL flag, the left port must perform a read access to address 0x7FE with CEL = OEL = VIL (R/WL is don't-care). To clear INTR, the right port reads 0x7FF under identical conditions. This behavior is defined in Truth Table II and verified in the "Interrupts" section (page 16) of the IDT71321LA55JI datasheet.
71321LA55JI 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:
- 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-PLCC (19.13x19.13)
71321LA55JI FAQ
1.How can I place an order for 71321LA55JI through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA55JI 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 71321LA55JI reliable?
The price and inventory of 71321LA55JI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA55JI is usually 5 days.
3.What payment methods are accepted for 71321LA55JI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA55JI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA55JI?
71321LA55JI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA55JI 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 71321LA55JI?
For technical support, including 71321LA55JI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA55JI requirements.
6.How does Aetrix verify that 71321LA55JI is sourced from the original manufacturer or authorized distributors?
All 71321LA55JI 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 71321LA55JI meets industry standards.
7.What is the process for return or replacement of 71321LA55JI?
All 71321LA55JI units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA55JI, 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 71321LA55JI part is unused and in its original packaging.
Return procedure for 71321LA55JI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA55JI Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
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24LC01BT-I/OT
Microchip Technology
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M24C02-FMC6TG
STMicroelectronics
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AT24CS02-SSHM-T
Microchip Technology
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93LC46BT-I/OT
Microchip Technology
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AT24C04C-SSHM-T
Microchip Technology
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24LC01BT-I/SN
Microchip Technology
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24AA02UIDT-I/OT
Microchip Technology
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AT24C08C-STUM-T
Microchip Technology
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