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Renesas 71321LA35TFI8
- Part No.:
- 71321LA35TFI8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321LA35TFI8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,856
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Product details
Overview
IDT71321LA35TFI8 from Renesas Electronics (formerly IDT) 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 delivers 35 ns max read cycle time, 2V battery-backed data retention, industrial temperature operation (–40°C to +85°C), and supports fully asynchronous dual-port access - used in motor control co-processor memory buffers and industrial PLC shared-memory subsystems.
For engineers reviewing the IDT71321LA35TFI8 datasheet, IDT71321LA35TFI8 pinout, IDT71321LA35TFI8 application, or IDT71321LA35TFI8 equivalent, key selection considerations include its MASTER-only BUSY output behavior, 52-pin STQFP package, 2V data retention capability, interrupt mailbox addressing (7FEh/7FFh), and compatibility with IDT71421LA SLAVE devices in 16-bit+ width expansions.
Technical Context
The IDT71321LA35TFI8 implements on-chip port arbitration logic that asserts open-drain BUSYL/BUSYR outputs when address contention occurs between left and right ports - requiring external 270 Ω pull-up resistors. Its interrupt logic uses dedicated SRAM addresses (7FEh for INTL, 7FFh for INTR) to signal cross-port events without software polling.
As a MASTER-only device, it features internal arbitration priority setup (tAPS = 5 ns), BUSY timing referenced to address or chip enable (tBAA/tBAC ≤ 30 ns), and supports R/W-controlled or CE-controlled write cycles. It does not accept BUSY as input - unlike SLAVE IDT71421 - and cannot be used standalone as a slave unit.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), dual independent ports |
| Access Time (max) | 35 ns - defines minimum read cycle time (tRC) for timing-critical real-time firmware |
| Data Retention Voltage | 2.0 V - enables battery backup operation during main power loss, critical for nonvolatile state storage |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, factory automation, and transportation electronics |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single 5 V ±10% rail, no auxiliary supplies required |
| Standby Current (ISB3) | 0.2 mA typ. - ultra-low full-standby power when both ports disabled via CMOS-level CE inputs |
| Interrupt Address Map | INTL asserted at A0L–A10L = 7FEh; INTR asserted at A0R–A10R = 7FFh - fixed mailbox locations for hardware signaling |
Pinout & Package
Package: 52-pin STQFP (PPG52), 10 mm × 10 mm × 1.4 mm body, 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; decoded internally to 2K space |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access; fully asynchronous vs. left port |
| 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; isolated from left port I/O lines electrically and timing-wise |
| CEL / CER | Chip enable (left/right) | Active-low enables respective port; controls power-down mode (ISB1–ISB4) |
| OEL / OER | Output enable (left/right) | Active-low enables data drivers; allows read-only tri-state control per port |
| R/WL / R/WR | Read/write control (left/right) | Active-low = write; high = read; determines direction of I/O bus per port |
| BUSYL / BUSYR | BUSY flag outputs (MASTER only) | Open-drain outputs requiring 270 Ω pull-up; indicate address contention to block writes |
| INTL / INTR | Interrupt flags (open-drain) | Asserted low on mailbox write (7FEh/7FFh); require external pull-up for logic-high default |
| VCC / GND | Power supply pins | Multiple VCC (pins 18, 27, 40, 47) and GND (pins 21, 33, 45, 52) for noise reduction and current distribution |
Key Features
| Feature | Design Value |
|---|---|
| On-chip arbitration logic | Eliminates need for external glue logic in multi-processor shared-memory designs; resolves contention in hardware |
| 2V data retention (LA version) | Preserves memory contents during brown-out or backup battery operation - validated at TA = +25°C |
| Dual interrupt mailboxes | Hardware-signaled cross-port messaging via fixed SRAM addresses (7FEh/7FFh), reducing CPU polling overhead |
| Asynchronous dual-port operation | Independent clockless access from left and right ports enables deterministic latency in real-time systems |
| Industrial temperature grade | Qualified across –40°C to +85°C with full DC/AC specs - suitable for uncontrolled cabinet environments |
| Low-power standby modes | ISB3 = 0.2 mA typ. enables energy-efficient sleep states in battery-powered edge controllers |
Applications
| Motor Control Co-Processor Buffer | Industrial PLC Shared Memory |
|---|---|
Use Scenario: Real-time motion controller (left port) shares position setpoints and status flags with safety monitor (right port) in servo drive system. IC Role / Device Role / Timing Role: MASTER dual-port SRAM acts as deterministic, lock-free shared memory with hardware BUSY arbitration preventing concurrent writes to same address. Use Value: Eliminates software semaphores and reduces inter-core latency to <35 ns - enabling sub-100 µs control loop synchronization. |
Use Scenario: PLC main CPU (right port) writes I/O scan results into memory while logic solver (left port) reads and executes ladder logic in parallel. IC Role / Device Role / Timing Role: Dual-port interface provides zero-wait-state memory access for both execution and I/O update threads. Use Value: Enables deterministic scan-cycle timing independent of I/O bus load; 2V retention preserves last scan state during power interruption. |
| Avionics Data Logger Interface | Railway Signaling Cross-Check Module |
Use Scenario: Flight data recorder (left port) streams sensor telemetry while maintenance interface (right port) reads logs for diagnostics without halting recording. IC Role / Device Role / Timing Role: Asynchronous dual-port buffer decouples high-rate write stream from infrequent read access. Use Value: Guarantees uninterrupted 35 ns write throughput even during diagnostic polling; open-drain INTL/INTR support discrete interrupt wiring. |
Use Scenario: Redundant safety processors (Port A and Port B) compare outputs in real time using shared memory to detect divergence. IC Role / Device Role / Timing Role: MASTER arbitration ensures only one processor wins write contention - preventing inconsistent state updates. Use Value: Hardware-enforced atomicity replaces complex voting algorithms; BUSY timing (tBDD ≤ 50 ns) meets SIL-4 response deadlines. |
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 CY7C024AV-35AXC | 3.3 V core, 5 V tolerant I/O; no built-in BUSY arbitration; requires external logic for contention resolution | Lacks MASTER/SLAVE expansion capability and interrupt mailboxes; suited for simpler dual-CPU bridges | Select when migrating to lower-voltage systems and external arbitration is acceptable |
| Renesas IDT71421LA35TFI8 | SLAVE-only counterpart; BUSY pins are inputs (not outputs); no on-chip arbitration logic | Must be paired with IDT71321LA as MASTER; used only in 16-bit+ width expansions | Select only as companion device in multi-chip memory arrays - not standalone replacement |
Compared with IDT71321LA35TFI8, CY7C024AV-35AXC offers voltage flexibility but adds design complexity for arbitration, while IDT71421LA35TFI8 is functionally dependent and cannot operate without a MASTER - making IDT71321LA35TFI8 the sole self-contained solution for standalone dual-processor shared memory with hardware coordination.
Availability
IDT71321LA35TFI8 is available at Aetrix Electronics and suitable for industrial PLCs, motor control drives, avionics data loggers, and railway signaling systems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for IDT71321LA35TFI8 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
Renesas Electronics acquired Integrated Device Technology (IDT) in 2019 and maintains full support for legacy IDT memory products including the 71321/71421 family.
The IDT71321LA series was designed specifically for deterministic interprocessor communication in real-time industrial and transportation systems - emphasizing hardware arbitration, low-latency access, and robust data retention under power stress.
FAQ
What is the function of BUSYL and BUSYR on IDT71321LA35TFI8?
BUSYL and BUSYR are open-drain output flags indicating address contention between left and right ports. When asserted low (with 270 Ω pull-up), they inhibit writes to the contended port. These signals are outputs only - IDT71321LA35TFI8 is a MASTER device and does not accept BUSY as input. Their timing is defined by tBAA/tBDA ≤ 30 ns.
Does IDT71321LA35TFI8 support battery backup operation?
Yes, IDT71321LA35TFI8 supports 2 V data retention, a feature exclusive to LA-grade parts. At VCC = 2.0 V and TA = +25°C, it retains stored data with ICCDR ≤ 1500 µA (commercial) or ≤ 4000 µA (industrial). This enables use in systems with backup coin cells or supercapacitors during main power failure.
How are interrupts generated and cleared in IDT71321LA35TFI8?
INTL is asserted when the right port writes to address 7FEh; INTR is asserted when the left port writes to 7FFh. Both flags are open-drain and require external pull-up. To clear INTL, the left port reads or writes 7FEh with CEL = OEL = VIL; to clear INTR, the right port accesses 7FFh under same conditions. IDT71321LA35TFI8 implements this entirely in hardware.
Can IDT71321LA35TFI8 be used as a SLAVE device in a MASTER/SLAVE configuration?
No, IDT71321LA35TFI8 is exclusively a MASTER device. Its BUSY pins are outputs, and it contains on-chip arbitration logic - features absent in SLAVE devices. For SLAVE functionality, IDT71421LA35TFI8 must be used. Attempting to substitute IDT71321LA35TFI8 as a SLAVE will result in incorrect BUSY behavior and potential data corruption.
What package and pin count does IDT71321LA35TFI8 use?
IDT71321LA35TFI8 is packaged in a 52-pin STQFP (PPG52) with 10 mm × 10 mm footprint and 1.4 mm height. Pinout matches the standard IDT71321/71421 functional diagram: dual I/O buses (I/O0L–I/O7L / I/O0R–I/O7R), separate CE/OE/RW controls per port, and dedicated INTL/INTR/BUSYL/BUSYR signals - all verified in the official IDT DSC-2691 datasheet.
71321LA35TFI8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 64-LQFP
- Packaging:
- Tape & Reel (TR)
- 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:
- 35ns
- Access Time:
- 35 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-TQFP (10x10)
71321LA35TFI8 FAQ
1.How can I place an order for 71321LA35TFI8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA35TFI8 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 71321LA35TFI8 reliable?
The price and inventory of 71321LA35TFI8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA35TFI8 is usually 5 days.
3.What payment methods are accepted for 71321LA35TFI8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA35TFI8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA35TFI8?
71321LA35TFI8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA35TFI8 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 71321LA35TFI8?
For technical support, including 71321LA35TFI8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA35TFI8 requirements.
6.How does Aetrix verify that 71321LA35TFI8 is sourced from the original manufacturer or authorized distributors?
All 71321LA35TFI8 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 71321LA35TFI8 meets industry standards.
7.What is the process for return or replacement of 71321LA35TFI8?
All 71321LA35TFI8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA35TFI8, 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 71321LA35TFI8 part is unused and in its original packaging.
Return procedure for 71321LA35TFI8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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