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Renesas 71321LA35TF8
- Part No.:
- 71321LA35TF8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321LA35TF8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,790
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Product details
Overview
71321LA35TF8 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 35 ns max read cycle time, 2V data retention capability, industrial temperature operation (–40°C to +85°C), and supports independent asynchronous access on left/right ports - used in multi-CPU shared-memory architectures requiring deterministic contention resolution.
For engineers reviewing the 71321LA35TF8 datasheet, 71321LA35TF8 pinout, 71321LA35TF8 application, or 71321LA35TF8 equivalent, key selection criteria include its MASTER-only BUSY output architecture, battery-backed 2V data retention, 52-pin STQFP package, and compatibility with IDT71421SLAVE devices for 16-bit+ memory expansion without external logic.
Technical Context
The 71321LA35TF8 implements on-chip port arbitration logic that asserts BUSYL/BUSYR outputs based solely on chip enable (CEL/CER) and address match timing - independent of R/W state - enabling deterministic write-inhibit behavior during simultaneous access. Its interrupt system uses dedicated mailbox addresses (7FEH for INTL, 7FFH for INTR) with dedicated set/reset timing (tINS ≤ 25 ns, tINR ≤ 25 ns).
It operates fully asynchronously per port, with separate control/address/I/O buses, and features automatic power-down via CE-driven standby modes: ISB1 = 25 mA (both ports TTL-level standby), ISB3 = 0.2 mA (both ports CMOS-level full standby). The LA variant guarantees 2V data retention with ICCDR ≤ 1500 µA at +25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 bits (2048 words × 8-bit wide), dual-port architecture with independent left/right address/data/control paths |
| Access Time (tRC) | 35 ns max - defines minimum read cycle interval; enables real-time CPU-to-CPU handshaking in <35 ns latency-critical systems |
| Data Retention Voltage | 2.0 V min - supports battery backup operation with guaranteed data hold during main power loss |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including motor control, PLCs, and telecom infrastructure |
| Supply Voltage | 4.5 V to 5.5 V - single 5 V ±10% TTL-compatible supply; all VCC pins require decoupling per datasheet layout rules |
| Standby Current (ISB3) | 0.2 mA typ. - ultra-low full-standby power when both ports disabled with CMOS-level inputs, critical for low-power wake-on-interrupt designs |
| Interrupt Timing (tINS/tINR) | ≤25 ns - fast interrupt assertion/clear latency ensures timely mailbox signaling between co-located processors |
Pinout & Package
71321LA35TF8 is packaged in a 52-pin STQFP (PPG52), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad and lead-free RoHS-compliant finish. Pin functions are validated per IDT DSC-2691 Rev. 17 (2019) pin configuration diagrams for PPG52 top view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access; A10L enables full 2K addressing (0–2047) |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit tri-state I/O bus; direction controlled by R/WL and OEL; high-impedance when disabled |
| R/WL, CEL, OEL | Left port control signals | R/WL = read/write direction; CEL = chip enable (active low); OEL = output enable (active low) |
| INTL, BUSYL | Left port interrupt & BUSY | INTL = open-drain interrupt flag (asserted on right-port write to 7FEH); BUSYL = open-drain BUSY output (requires 270 Ω pull-up) |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side access; matches left port width for symmetrical dual-port operation |
| I/O0R–I/O7R | Right port bidirectional data | 8-bit tri-state I/O bus; functionally identical to left port I/O but electrically isolated |
| R/WR, CER, OER | Right port control signals | Same functional roles as left port controls; independent timing allows true concurrent access |
| INTR, BUSYR | Right port interrupt & BUSY | INTR = open-drain interrupt flag (asserted on left-port write to 7FFH); BUSYR = open-drain BUSY output (270 Ω pull-up required) |
| VCC, GND | Power & ground | Multiple VCC/GND pins distributed across package per layout guidelines; all must be connected to maintain signal integrity and thermal performance |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Eliminates need for external glue logic in MASTER/SLAVE configurations; resolves contention deterministically using CE + address timing only |
| Dual independent interrupt mailboxes | Hardware-accelerated interprocessor messaging via dedicated 7FEH/7FFH locations - no software polling overhead |
| 2V data retention mode | Enables seamless failover to coin-cell backup during main power interruption; verified at 2.0 V, +25°C, ICCDR ≤ 1500 µA |
| Open-drain BUSY outputs | Allows wired-OR connection in multi-SLAVE arrays; 270 Ω pull-up ensures valid TTL levels while minimizing current draw |
| Asynchronous dual-port operation | Supports independent clock domains - left and right ports may operate with different timing constraints and control sequences |
Applications
| Industrial PLC Shared Memory | Real-Time Motor Control Hub |
|---|---|
Use Scenario: Two microcontrollers share sensor data and actuator commands in a programmable logic controller chassis with strict cycle-time deadlines. IC Role / Device Role / Timing Role: 71321LA35TF8 acts as MASTER dual-port SRAM, providing deterministic BUSY arbitration and interrupt-based mailbox signaling between motion and I/O controllers. Use Value: 35 ns access time and sub-25 ns interrupt latency ensure synchronized updates within 50 µs scan cycles; 2V retention preserves state during brownouts. |
Use Scenario: A dual-core motor drive processor uses shared memory to coordinate torque and position loops while maintaining safety-critical watchdog synchronization. IC Role / Device Role / Timing Role: 71321LA35TF8 serves as low-latency shared buffer between ARM Cortex-M7 cores, with BUSY flags preventing race conditions during simultaneous register writes. Use Value: Independent left/right control enables lock-free data exchange; industrial temp rating (–40°C to +85°C) sustains reliability in enclosed drive cabinets. |
| Telecom Baseband Processor Bridge | Avionics Data Concentrator |
Use Scenario: FPGA-based baseband processor and DSP co-processor exchange FFT results and channel estimates in LTE small cell radio units. IC Role / Device Role / Timing Role: 71321LA35TF8 functions as MASTER interface between FPGA (left port) and DSP (right port), using INTL/INTR for flow-controlled burst transfers. Use Value: 52-pin STQFP footprint minimizes PCB area vs. discrete logic solutions; 35 ns timing meets 10 MHz effective throughput requirements. |
Use Scenario: Multi-sensor avionics module aggregates inertial, pressure, and GPS data for flight control computers under DO-254 compliance constraints. IC Role / Device Role / Timing Role: 71321LA35TF8 provides radiation-tolerant (non-volatile-retentive) shared memory between redundant sensor acquisition and processing units. Use Value: 2V data retention maintains critical flight parameters during transient power loss; industrial temp range covers extended aircraft operational envelope. |
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 CY7C1371D-133AXC | 3.3 V core, 133 MHz QDR interface, no native BUSY arbitration; requires external logic for contention resolution | Targeted at high-bandwidth networking buffers, not deterministic real-time interprocessor comms | Choose only if migrating to 3.3 V systems and adding custom arbitration logic is acceptable |
| IDT71421LA35TF8 | SLAVE-only variant; BUSY pins are inputs (not outputs); no on-chip arbitration logic; requires companion 71321LA as MASTER | Used exclusively in width-expanded arrays (e.g., 16-bit+ data bus) where one MASTER coordinates multiple SLAVES | Select only as secondary device in MASTER/SLAVE topology - never standalone replacement for 71321LA35TF8 |
Compared with CY7C1371D-133AXC and IDT71421LA35TF8, the 71321LA35TF8 uniquely integrates MASTER arbitration, 2V retention, and interrupt mailboxes in a single 5 V, 35 ns industrial-grade package - eliminating design complexity in deterministic dual-CPU systems.
Availability
71321LA35TF8 is available at Aetrix Electronics and suitable for industrial PLCs, real-time motor drives, telecom baseband bridges, and avionics data concentrators requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for 71321LA35TF8 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 real-time interconnect solutions for communications, computing, and industrial markets.
The IDT71321/71421 family was engineered specifically for deterministic interprocessor communication in hard real-time embedded systems - prioritizing low-latency arbitration, hardware mailboxing, and robust data retention over raw bandwidth.
FAQ
What is the primary functional distinction between 71321LA35TF8 and IDT71421LA35TF8?
The 71321LA35TF8 is a MASTER dual-port SRAM with on-chip arbitration logic and open-drain BUSY outputs (BUSYL/BUSYR), while IDT71421LA35TF8 is a SLAVE device with BUSY inputs only and no internal arbitration. The 71321LA35TF8 can operate stand-alone; IDT71421LA35TF8 requires a 71321LA35TF8 as MASTER to manage contention. Their pinouts differ in BUSY pin functionality and cannot be substituted directly.
Does 71321LA35TF8 support true simultaneous read/write operations on both ports?
Yes - the 71321LA35TF8 supports fully asynchronous, independent access: one port may read while the other writes, provided addresses do not conflict. When both ports access the same memory location, on-chip arbitration asserts BUSYL/BUSYR to inhibit the later-arriving write, ensuring data integrity without external logic. This behavior is guaranteed per Truth Table III in the datasheet.
How is the 2V data retention capability of 71321LA35TF8 implemented and verified?
The 71321LA35TF8's LA suffix denotes low-power design enabling data retention at VCC = 2.0 V. It is verified per datasheet Table 6: at VCC = 2.0 V and TA = +25°C, ICCDR ≤ 1500 µA (commercial) or ≤ 4000 µA (industrial), with tCDR = 0 ns (instant entry to retention mode upon VCC drop). No external circuitry is needed - simply reduce VCC to ≥2.0 V while holding CE high.
What are the mandatory external components required for reliable operation of 71321LA35TF8?
Two mandatory external components are required: (1) 270 Ω pull-up resistors on BUSYL and BUSYR pins (per datasheet Note 2), and (2) proper decoupling - at least one 0.1 µF ceramic capacitor per VCC pin, placed within 5 mm of each pin per layout guidelines. Failure to install pull-ups causes BUSY signals to float; missing decoupling risks timing violations and latch-up.
Can 71321LA35TF8 be used in a system with mixed 5 V and 3.3 V logic interfaces?
No - the 71321LA35TF8 is strictly 5 V ±10% TTL-compatible (VIH = 2.2 V min, VIL = 0.8 V max) and has no 3.3 V I/O tolerance. Driving its inputs from 3.3 V logic may result in marginal VIH margins; driving 3.3 V receivers from its 5 V outputs violates absolute maximum ratings. Level-shifting circuitry (e.g., TXB0108) is required for interoperability with 3.3 V systems.
71321LA35TF8 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-TQFP (10x10)
71321LA35TF8 FAQ
1.How can I place an order for 71321LA35TF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA35TF8 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 71321LA35TF8 reliable?
The price and inventory of 71321LA35TF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA35TF8 is usually 5 days.
3.What payment methods are accepted for 71321LA35TF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA35TF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA35TF8?
71321LA35TF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA35TF8 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 71321LA35TF8?
For technical support, including 71321LA35TF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA35TF8 requirements.
6.How does Aetrix verify that 71321LA35TF8 is sourced from the original manufacturer or authorized distributors?
All 71321LA35TF8 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 71321LA35TF8 meets industry standards.
7.What is the process for return or replacement of 71321LA35TF8?
All 71321LA35TF8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA35TF8, 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 71321LA35TF8 part is unused and in its original packaging.
Return procedure for 71321LA35TF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA35TF8 Tags
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