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Renesas 71321LA25PF8
- Part No.:
- 71321LA25PF8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321LA25PF8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,909
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Product details
Overview
71321LA25PF8 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. It operates at 25 ns max access time, supports 5 V ±10% TTL-compatible supply, delivers 1 mW standby power (LA version), and enables battery-backed data retention down to 2 V. It is used in real-time embedded systems requiring concurrent read/write access across two independent CPU buses.
For engineers reviewing the 71321LA25PF8 datasheet, 71321LA25PF8 pinout, 71321LA25PF8 application, or 71321LA25PF8 equivalent, key selection criteria include dual-port arbitration timing (tBAA/tBDD), interrupt mailbox addressing (7FEh/7FFh), BUSY open-drain output requirements (270 Ω pull-up), and industrial temperature support (–40°C to +85°C).
Technical Context
The 71321LA25PF8 implements fully asynchronous dual-port architecture with separate address, control, and I/O pins per port-enabling simultaneous, independent access to any memory location. Its on-chip arbitration logic resolves contention via BUSY flag generation based on chip enable and address match timing (tAPS = 5 ns), not R/W state.
As a MASTER device, it features open-drain BUSYL/BUSYR outputs (requiring external 270 Ω pull-ups) and dual INTL/INTR flags for port-to-port signaling. The LA variant adds 2 V data retention capability and ultra-low ISB3 = 0.2 mA full-standby current under CMOS-level inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit wide), enabling compact shared-memory buffers between processors |
| Access Time | 25 ns (max), supporting 40 MHz bus synchronization without wait states in industrial designs |
| Supply Voltage | 4.5 V to 5.5 V, compatible with legacy 5 V TTL logic families and mixed-voltage board interfaces |
| Standby Current | 0.2 mA (ISB3, CMOS-level inputs), enabling low-power sleep modes in battery-backed systems |
| Data Retention | 2 V minimum VCC, allowing operation from backup coin cells or supercapacitors during main power loss |
| Operating Temp | –40°C to +85°C, qualified for industrial control, avionics, and transportation electronics |
| Interrupt Addresses | 7FEh (INTL set), 7FFh (INTR set), providing dedicated mailbox locations for software-triggered inter-CPU messaging |
Pinout & Package
71321LA25PF8 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/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side processor (2K = 2¹¹ address space) |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit parallel data path; high-impedance when OEL = VIH or CEL = VIH |
| R/WL, CEL, OEL | Left port control signals | Read/write direction, chip enable, and output enable-fully asynchronous with no clock required |
| INTL, BUSYL | Left port interrupt & BUSY | INTL is push-pull active-low flag; BUSYL is open-drain output requiring 270 Ω pull-up |
| A0R–A10R | Right port address inputs | Independent 11-bit address bus for second processor or DMA engine |
| I/O0R–I/O7R | Right port bidirectional data | Separate 8-bit data path-no bus contention with left port |
| R/WR, CER, OER | Right port control signals | Functionally identical to left-side controls but electrically isolated |
| INTR, BUSYR | Right port interrupt & BUSY | INTR is push-pull; BUSYR is open-drain-same pull-up requirement as BUSYL |
| VCC, GND | Power & ground | Multiple VCC/GND pins distributed for noise reduction and low-impedance decoupling |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration | Resolves simultaneous access to same address using tAPS = 5 ns priority setup, eliminating need for external logic |
| Dual interrupt mailboxes | Hardware-settable flags at fixed addresses (7FEh/7FFh) enable zero-overhead interprocessor signaling |
| Battery backup support | Retains valid data at VCC = 2.0 V with ICCDR ≤ 100 µA typical-critical for fail-safe logging |
| Open-drain BUSY outputs | Allows wired-AND expansion across multiple MASTER/SLAVE arrays without external gates |
| Industrial temperature range | Guaranteed operation from –40°C to +85°C with no derating-suitable for uncontrolled environments |
Applications
| Real-Time Motion Control | Avionics Data Recorder |
|---|---|
Use Scenario: Two microcontrollers coordinate motor position feedback and PWM command generation in closed-loop servo drives. IC Role / Device Role / Timing Role: 71321LA25PF8 serves as shared memory buffer with hardware arbitration, ensuring deterministic response to position updates and command writes. Use Value: Eliminates software polling or semaphores; BUSY timing guarantees atomic write completion before read access, preventing jitter in motion profiles. | Use Scenario: Flight data acquisition system logs sensor streams from multiple sources into nonvolatile storage during power interruption. IC Role / Device Role / Timing Role: 71321LA25PF8 acts as battery-backed FIFO buffer, retaining last 2 KB of telemetry while flash programming occurs. Use Value: 2 V data retention and ISB3 = 0.2 mA allow >72-hour hold-up from coin cell-meeting DO-160 lightning surge recovery requirements. |
| Industrial PLC Backplane | Radar Signal Processor Interface |
Use Scenario: Modular PLC chassis uses dual-CPU architecture where one CPU handles I/O scanning and another runs safety logic. IC Role / Device Role / Timing Role: 71321LA25PF8 provides synchronized mailbox communication between CPUs via INTL/INTR flags and address-based interrupts. Use Value: Hardware interrupt latency <25 ns ensures sub-millisecond coordination between safety and control threads-certifiable to IEC 61508 SIL-3. | Use Scenario: Radar front-end FPGA captures ADC samples and passes processed FFT bins to ARM host processor for tracking. IC Role / Device Role / Timing Role: 71321LA25PF8 functions as ping-pong buffer between FPGA (right port) and ARM (left port), with BUSY arbitration preventing overwrites. Use Value: 25 ns access time enables sustained 40 MB/s throughput across both ports-matching 16-bit @ 2.5 MSPS ADC interface rates. |
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 | 5 V, 2K × 8, 25 ns, but lacks built-in BUSY arbitration and interrupt logic; requires external glue logic | No native mailbox or port-to-port signaling-software-managed coherency increases firmware complexity | Select when cost sensitivity outweighs real-time determinism needs and board space allows discrete arbitration logic |
| IDT71421LA25PF8 | Same family SLAVE device: identical speed/package but BUSY pins are inputs only; no on-chip arbitration logic | Must be paired with a MASTER (e.g., 71321LA25PF8) for arbitration; cannot operate stand-alone as shared memory | Choose only for width-expansion configurations where multiple SLAVE devices share one MASTER's BUSY signal |
Compared with CY7C136-25JC, 71321LA25PF8 reduces BOM count and firmware overhead via integrated arbitration and interrupts; versus IDT71421LA25PF8, it provides autonomous MASTER functionality essential for standalone dual-CPU designs.
Availability
71321LA25PF8 is available at Aetrix Electronics and suitable for real-time motion control, avionics data recorders, and industrial PLC backplanes requiring stable component supply across extended product lifecycles.
Supply support for 71321LA25PF8 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 power solutions for high-performance computing and communications.
The IDT71321/71421 product line was engineered specifically for deterministic interprocessor communication in hard real-time systems-prioritizing low-latency arbitration, hardware mailboxing, and industrial-grade reliability over raw density or speed.
FAQ
What is the function of the BUSY pin on the 71321LA25PF8?
The BUSY pin (BUSYL or BUSYR) on the 71321LA25PF8 is an open-drain output that signals port contention when both ports attempt simultaneous access to the same memory address. It must be pulled up externally with a 270 Ω resistor to VCC. When asserted low, it inhibits writes on the contending port-ensuring data coherency without software intervention. This behavior is intrinsic to the 71321LA25PF8 as a MASTER device.
Does the 71321LA25PF8 support true dual-port operation without external arbitration logic?
Yes, the 71321LA25PF8 supports fully asynchronous dual-port operation with on-chip arbitration. Its internal logic resolves address-contention events using tAPS = 5 ns priority setup time and generates BUSY flags automatically. No external gates or controllers are needed-making the 71321LA25PF8 self-contained for real-time interprocessor communication.
How does the interrupt functionality work in the 71321LA25PF8?
The 71321LA25PF8 implements hardware interrupts via dedicated mailbox addresses: writing to 7FEh sets the INTL flag (left port), and writing to 7FFh sets the INTR flag (right port). Each flag is cleared by reading its respective address. These are push-pull outputs with <25 ns set/reset timing-enabling low-latency event signaling between processors without polling overhead in the 71321LA25PF8.
Can the 71321LA25PF8 retain data during main power loss?
Yes, the 71321LA25PF8 (LA variant) supports battery-backed data retention at VCC = 2.0 V, drawing only 100 µA typical current (ICCDR). This allows seamless hold-up from backup sources such as coin cells or supercapacitors. The 71321LA25PF8 maintains valid SRAM contents indefinitely at 2 V-critical for black-box recording and fail-safe state preservation.
What package type is used for the 71321LA25PF8 and what are its layout considerations?
The 71321LA25PF8 uses a 52-pin STQFP (PPG52) package: 10 mm × 10 mm × 1.4 mm with exposed thermal pad. Layout requires symmetric decoupling (0.1 µF X7R ceramic near each VCC pin), 270 Ω pull-up resistors on BUSYL/BUSYR, and strict length matching for A0–A10 and I/O0–I/O7 traces on both ports to maintain 25 ns timing margins. The 71321LA25PF8 has no thermal pad solder requirement per IDT documentation.
71321LA25PF8 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:
- 25ns
- Access Time:
- 25 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 (14x14)
71321LA25PF8 FAQ
1.How can I place an order for 71321LA25PF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA25PF8 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 71321LA25PF8 reliable?
The price and inventory of 71321LA25PF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA25PF8 is usually 5 days.
3.What payment methods are accepted for 71321LA25PF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA25PF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA25PF8?
71321LA25PF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA25PF8 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 71321LA25PF8?
For technical support, including 71321LA25PF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA25PF8 requirements.
6.How does Aetrix verify that 71321LA25PF8 is sourced from the original manufacturer or authorized distributors?
All 71321LA25PF8 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 71321LA25PF8 meets industry standards.
7.What is the process for return or replacement of 71321LA25PF8?
All 71321LA25PF8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA25PF8, 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 71321LA25PF8 part is unused and in its original packaging.
Return procedure for 71321LA25PF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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