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Renesas 71321SA55TF8
- Part No.:
- 71321SA55TF8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321SA55TF8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,442
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Product details
Overview
71321SA55TF8 from Integrated Device Technology is a high-speed 2K × 8 dual-port static RAM with on-chip port arbitration, two interrupt flags (INTL/INTR), and BUSY output logic for interprocessor communication. It operates at 55 ns max access time, supports fully asynchronous dual-port reads/writes, and uses a single 5V ±10% supply. It serves as a MASTER device in width-expanded memory systems with IDT71421 SLAVE devices in industrial embedded controllers.
For engineers reviewing the 71321SA55TF8 datasheet, 71321SA55TF8 pinout, 71321SA55TF8 application, or 71321SA55TF8 equivalent, this page delivers verified timing parameters, validated pin functions, confirmed interrupt mailbox behavior (7FEH/7FFH), and precise standby current specs (1.0 mA full standby) - all critical for real-time multi-CPU shared-memory designs.
Technical Context
The 71321SA55TF8 implements hardware-based port arbitration using CE and address-match detection (tAPS = 5 ns), asserting BUSYL/BUSYR outputs to block concurrent writes to identical addresses. Its interrupt logic uses dedicated SRAM locations (7FEH for INTL, 7FFH for INTR) with tINS/tINR ≤ 45 ns, enabling deterministic inter-processor signaling without software polling.
It features open-drain BUSY/INT outputs requiring 270 Ω pull-up resistors, TTL-compatible I/Os, and automatic power-down via CE control - delivering ISB3 = 1.0 mA (typ.) full standby current at VCC = 5V. The device supports battery backup data retention only in LA variants; the SA suffix confirms standard-power operation without retention capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), dual-port independent access |
| Max Access Time | 55 ns - defines minimum read cycle time (tRC) for worst-case timing closure |
| Supply Voltage | 4.5–5.5 V - requires single 5V ±10% rail; no dual-supply or level-shifting needed |
| Full Standby Current | 1.0 mA (typ.) - achieved when both CE pins > VCC − 0.2 V and inputs at CMOS levels |
| Interrupt Latency | tINS ≤ 45 ns - maximum delay from write to 7FFH/7FEH until INTR/INTL assertion |
| BUSY Arbitration Setup | tAPS = 5 ns - minimum setup time for address match to guarantee deterministic BUSY resolution |
| Operating Temperature | −40°C to +85°C - qualified for industrial ambient conditions without derating |
Pinout & Package
71321SA55TF8 is packaged in a 64-pin STQFP (PPG64), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad (not electrically connected). Pin assignments are validated per IDT DSC-2691 Rev. 17, Figure 3 (PPG64 top view).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access (000H–7FFH) |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access (000H–7FFH) |
| 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; high-impedance when OER = VIH or CER = VIH |
| 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 I/O drivers; does not affect internal memory access |
| R/WL / R/WR | Read/write control (left/right) | High = read, low = write; determines direction of I/O data flow |
| INTL / INTR | Interrupt flags (output) | Open-drain outputs; require external 270 Ω pull-up; assert on mailbox writes |
| BUSYL / BUSYR | BUSY status (output) | Open-drain outputs; indicate port contention; require 270 Ω pull-up |
| VCC | Power supply | Two dedicated pins (pins 33, 48); must be decoupled locally |
| GND | Ground | Two dedicated pins (pins 32, 47); mandatory connection to system ground plane |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous accesses to same address without external logic; guarantees one port wins deterministically |
| Dual interrupt mailboxes (7FEH/7FFH) | Enables hardware-synchronized interprocessor messaging with sub-45 ns flag assertion |
| Open-drain BUSY/INT outputs | Allows wired-OR expansion across multiple MASTER devices in wide-memory arrays |
| Asynchronous dual-port operation | Eliminates clock domain crossing; supports independent CPU, FPGA, or ASIC interfaces |
| Industrial temperature support | Validated operation from −40°C to +85°C with no timing or current derating |
Applications
| Industrial PLC Backplane Memory | Real-Time Multi-Core Communication Buffer |
|---|---|
Use Scenario: Two independent CPUs share status registers and command queues in a programmable logic controller chassis. IC Role / Device Role / Timing Role: MASTER dual-port SRAM providing atomic read-modify-write access to shared I/O mapping tables and fault logs. Use Value: BUSY arbitration prevents corrupted writes during simultaneous access; 55 ns access enables <100 ns round-trip message latency between cores. |
Use Scenario: An ARM Cortex-M7 and an FPGA exchange sensor fusion results and control commands in autonomous vehicle ECU. IC Role / Device Role / Timing Role: Asynchronous memory bridge with interrupt-driven mailbox protocol (7FEH/7FFH) for zero-polling synchronization. Use Value: tINS ≤ 45 ns ensures deterministic response to FPGA-initiated control updates; open-drain INT supports direct connection to M7's external interrupt controller. |
| Avionics Data Concentrator Interface | Medical Imaging Frame Buffer Controller |
Use Scenario: ARINC 429 receiver and MIL-STD-1553B bus controller coordinate timestamped telemetry packets in flight data recorder. IC Role / Device Role / Timing Role: Dual-port SRAM acting as time-stamped packet staging buffer with hardware-enforced write ordering. Use Value: tAPS = 5 ns arbitration setup ensures reliable conflict resolution even under worst-case skew between bus controllers' address strobes. |
Use Scenario: CT scanner subsystem uses two processors: one for image reconstruction, another for real-time display rendering. IC Role / Device Role / Timing Role: Shared frame buffer with separate read/write ports eliminating DMA coherency overhead. Use Value: 2K × 8 capacity supports dual 1024×1024 pixel buffers; ISB3 = 1.0 mA standby minimizes power in idle imaging cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C1371BV33-133AXC | 3.3V core supply; 133 MHz QDR interface; no native BUSY arbitration | Requires external logic for contention resolution; suited for high-bandwidth cache-like use, not interprocessor signaling | Select only if migrating to 3.3V ecosystem and adding custom arbitration logic |
| IDT71421SA55TF8 | SLAVE-only variant; BUSY pins are inputs; no on-chip arbitration logic | Must pair with 71321SA55TF8 MASTER; used only for width expansion beyond 8-bit data paths | Required companion part for building 16-bit+ memory systems; not standalone functional replacement |
Compared with CY7C1371BV33-133AXC and IDT71421SA55TF8, the 71321SA55TF8 uniquely integrates arbitration and interrupt logic in a 5V-compatible package - eliminating external glue logic for deterministic inter-CPU communication, unlike the QDR part, and enabling standalone MASTER operation, unlike the SLAVE-only 71421.
Availability
71321SA55TF8 is available at Aetrix Electronics and suitable for industrial PLC backplanes, avionics data concentrators, and medical imaging subsystems requiring stable component supply, long-term lifecycle support, and guaranteed industrial-temperature performance.
Supply support for 71321SA55TF8 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, designs high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.
The IDT71321 family was engineered specifically for deterministic, low-latency interprocessor communication in real-time embedded systems - prioritizing hardware arbitration, interrupt mailboxing, and industrial-grade reliability over raw bandwidth.
FAQ
What is the function of the BUSY pins on the 71321SA55TF8?
The BUSYL and BUSYR pins on the 71321SA55TF8 are open-drain outputs that signal port contention when both ports attempt to access the same memory address. They require 270 Ω pull-up resistors and directly inhibit writes on the contending port. This hardware arbitration eliminates race conditions without software intervention - a core feature distinguishing the 71321SA55TF8 from standard SRAMs.
Does the 71321SA55TF8 support battery backup data retention?
No. The 71321SA55TF8 is an SA-suffix device, indicating standard-power operation without battery backup capability. Only LA-suffix variants (e.g., 71321LA55TF8) support 2V data retention. The SA version draws 1.0 mA (typ.) in full standby but does not retain data below 4.5V - confirmed by DC Electrical Characteristics Table 4a and Data Retention Characteristics Table 6.
How do the interrupt flags (INTL/INTR) operate in the 71321SA55TF8?
The 71321SA55TF8 uses fixed SRAM addresses 7FEH (for INTL) and 7FFH (for INTR) as interrupt mailboxes. Writing to 7FFH via the left port asserts INTR; reading 7FFH via the right port clears it. Similarly, 7FEH controls INTL. Timing is guaranteed: tINS ≤ 45 ns and tINR ≤ 45 ns at 55 ns speed grade - enabling hard real-time interprocessor signaling without polling overhead.
Can the 71321SA55TF8 be used without external pull-up resistors on BUSY/INT pins?
No. The BUSYL, BUSYR, INTL, and INTR pins are open-drain outputs and will not drive HIGH without external 270 Ω pull-up resistors to VCC, as explicitly required in Notes 1 and 2 of the Functional Block Diagram and Pin Configurations. Omitting these resistors results in undefined logic levels and failed arbitration or interrupt signaling - a design requirement, not a recommendation.
What is the difference between 71321SA55TF8 and 71421SA55TF8?
The 71321SA55TF8 is the MASTER device with on-chip arbitration logic, BUSY outputs, and interrupt generation capability. The 71421SA55TF8 is the SLAVE device: its BUSY pins are inputs (not outputs), it lacks arbitration logic, and it cannot generate interrupts independently. They are complementary - not interchangeable - and designed to be used together in width-expanded memory systems per IDT's MASTER/SLAVE architecture.
71321SA55TF8 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:
- 55ns
- Access Time:
- 55 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)
71321SA55TF8 FAQ
1.How can I place an order for 71321SA55TF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321SA55TF8 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 71321SA55TF8 reliable?
The price and inventory of 71321SA55TF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321SA55TF8 is usually 5 days.
3.What payment methods are accepted for 71321SA55TF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321SA55TF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321SA55TF8?
71321SA55TF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321SA55TF8 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 71321SA55TF8?
For technical support, including 71321SA55TF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321SA55TF8 requirements.
6.How does Aetrix verify that 71321SA55TF8 is sourced from the original manufacturer or authorized distributors?
All 71321SA55TF8 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 71321SA55TF8 meets industry standards.
7.What is the process for return or replacement of 71321SA55TF8?
All 71321SA55TF8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321SA55TF8, 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 71321SA55TF8 part is unused and in its original packaging.
Return procedure for 71321SA55TF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321SA55TF8 Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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