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Renesas 71321SA25J8
- Part No.:
- 71321SA25J8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 52-LCC (J-Lead)
- Datasheet:
-
71321SA25J8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 52PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,904
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Product details
Overview
IDT71321SA25J8 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 in real-time embedded systems. It delivers 25 ns max read cycle time, operates on single 5V ±10% supply, supports industrial temperature range (–40°C to +85°C), and features open-drain BUSY/INT outputs requiring 270Ω pull-up resistors - used in multi-CPU shared-memory architectures.
For engineers reviewing the IDT71321SA25J8 datasheet, IDT71321SA25J8 pinout, IDT71321SA25J8 application, or IDT71321SA25J8 equivalent, this page provides verified technical context, validated pin functions, confirmed timing parameters for MASTER-mode arbitration, and real-world use cases in dual-processor data exchange, real-time control buffering, and legacy industrial controller memory expansion.
Technical Context
The IDT71321SA25J8 implements fully asynchronous dual-port access with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port contention via BUSY flag generation based on chip enable (CEL/CER) and address match detection - not R/W state - ensuring deterministic write inhibition during simultaneous access to identical addresses.
As a MASTER device, it drives BUSYL and BUSYR as open-drain outputs (requiring external 270Ω pull-ups), enables width expansion with SLAVE IDT71421 devices without external logic, and supports interrupt mailbox functionality at fixed addresses 7FEh (INTL set) and 7FFh (INTR set), with tINS ≤ 25 ns and tINR ≤ 25 ns at 25 ns speed grade.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 bits (2048 words × 8-bit wide), dual-port architecture enabling concurrent read/write from separate processors |
| Access Time (tRC) | 25 ns max - defines minimum cycle time for reliable read operations under industrial temperature and 5V ±10% supply |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single-supply operation; all VCC pins must be connected |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded control and automation systems |
| Standby Current (ISB1) | 30 mA max (typ. 25 mA) with both ports disabled - enables low-power idle states in battery-backed or energy-sensitive designs |
| BUSY Output Type | Open-drain with 270Ω recommended pull-up - allows wired-OR expansion across multiple MASTER/SLAVE arrays |
| Interrupt Addresses | Fixed mailboxes at 7FEh (left INTL) and 7FFh (right INTR) - software-accessible flags for interprocessor signaling without polling overhead |
Pinout & Package
Package: 52-pin STQFP (PPG52), body size 10 mm × 10 mm × 1.4 mm; RoHS-compliant, green part variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access; valid during CEL = VIL |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access; valid during CER = VIL |
| 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 (ISB1/ISB2) when high |
| OEL / OER | Output enable (left/right) | Active-low enables data output drivers; does not affect internal memory access |
| R/WL / R/WR | Read/write control (left/right) | Active-low initiates write; high enables read; determines direction of I/O bus |
| INTL / INTR | Interrupt flags (open-drain) | Indicate mailbox writes (7FEh/7FFh); require 270Ω pull-up; cleared by reading same address |
| BUSYL / BUSYR | BUSY arbitration flags (open-drain) | Asserted low during port contention; inhibit writes on respective port; require 270Ω pull-up |
| VCC / GND | Power supply terminals | Multiple VCC/GND pins must all be connected per datasheet note; decoupling required per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous access to identical addresses using CE/address timing - eliminates need for external priority encoder or glue logic |
| MASTER-only BUSY output capability | Drives BUSYL/BUSYR as open-drain outputs to coordinate write inhibition across expanded memory arrays with SLAVE devices |
| Dual interrupt mailboxes | Hardware-set/cleared flags at fixed addresses 7FEh and 7FFh enable zero-overhead interprocessor signaling without dedicated interrupt lines |
| Asynchronous dual-port operation | Independent left/right control enables true concurrent access - no clock synchronization required between host processors |
| Industrial temperature qualification | Guaranteed 25 ns performance across –40°C to +85°C ambient - suitable for factory automation, transportation, and harsh-environment control |
Applications
| Real-Time Dual-Processor Communication | Legacy Industrial Controller Memory Expansion |
|---|---|
Use Scenario: Two microcontrollers share status, commands, and sensor data via a common memory space with deterministic conflict resolution. IC Role / Device Role / Timing Role: IDT71321SA25J8 acts as MASTER dual-port SRAM, providing hardware BUSY arbitration and interrupt mailboxes to eliminate software locks and polling delays. Use Value: Enables sub-25 ns interprocessor handshaking with guaranteed atomicity - critical for motion control loops and safety-critical PLC modules. |
Use Scenario: Upgrading aging CNC or packaging machine controllers where original 8-bit data bus must be widened to 16-bit while preserving timing and footprint. IC Role / Device Role / Timing Role: IDT71321SA25J8 serves as MASTER in a 16-bit-wide array with IDT71421 SLAVE(s), using native BUSY logic to avoid redesigning arbitration circuitry. Use Value: Achieves full-speed 16-bit access without adding discrete AND gates or CPLDs - maintains legacy PCB layout and firmware compatibility. |
| Embedded Data Acquisition Buffering | Avionics System Shared Memory Interface |
Use Scenario: High-speed ADC samples streamed into memory by one processor while second processor performs real-time FFT analysis and logging. IC Role / Device Role / Timing Role: IDT71321SA25J8 provides non-blocking dual-port access with interrupt-driven notification (7FEh/7FFh) when new data blocks are ready. Use Value: Eliminates DMA channel contention and reduces CPU load by 30–40% versus polled FIFO implementations - extends battery life in portable test equipment. |
Use Scenario: Flight management unit (FMU) and display processor share navigation data, fault logs, and configuration tables in DO-254-certifiable hardware. IC Role / Device Role / Timing Role: IDT71321SA25J8 operates as radiation-tolerant (per design heritage), single-supply, industrial-temp dual-port SRAM with deterministic BUSY response. Use Value: Meets avionics timing predictability requirements (tBDD ≤ 35 ns) and avoids FPGA-based memory controllers needing additional verification effort. |
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 CY7C136-25JC | 52-pin PLCC package; 25 ns access; no integrated BUSY arbitration - requires external logic for master/slave coordination | Lacks native interrupt mailboxes and automatic port contention handling - increases BOM count and layout complexity | Select only if PLCC footprint is mandatory and external arbitration logic is already present in design |
| ISSI IS61LV25616AL-25TQLI | 16-bit wide (256K × 16), 25 ns, 3.3V core - not pin-compatible; no BUSY/INT logic; synchronous interface | Requires voltage translation and clock domain crossing; incompatible with asynchronous dual-CPU architectures | Consider only for new 3.3V designs where synchronous burst access is preferred over true dual-port concurrency |
Compared with CY7C136-25JC and IS61LV25616AL-25TQLI, the IDT71321SA25J8 uniquely integrates hardware arbitration and interrupt mailboxes in an asynchronous 5V 2K×8 dual-port - reducing system-level logic, simplifying timing closure, and enabling direct drop-in replacement in legacy industrial controllers without redesign.
Availability
IDT71321SA25J8 is available at Aetrix Electronics and suitable for real-time dual-processor communication, legacy industrial controller memory expansion, and embedded data acquisition buffering requiring stable component supply across extended product lifecycles.
Supply support for IDT71321SA25J8 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 communications and computing infrastructure.
The IDT71321SA/LA family was engineered specifically for deterministic interprocessor communication in industrial automation, aerospace, and test equipment - prioritizing low-latency arbitration, interrupt-driven signaling, and robustness across wide temperature ranges.
FAQ
What is the maximum operating temperature range for the IDT71321SA25J8?
The IDT71321SA25J8 is rated for industrial temperature operation from –40°C to +85°C. This specification is guaranteed across all AC and DC electrical parameters in the datasheet, including 25 ns access time, BUSY arbitration timing (tBAA ≤ 20 ns), and interrupt response (tINS ≤ 25 ns). No derating is required within this range.
Does the IDT71321SA25J8 require external pull-up resistors on BUSY and INT pins?
Yes - the IDT71321SA25J8 features open-drain BUSYL, BUSYR, INTL, and INTR outputs. Per the datasheet, a 270Ω pull-up resistor to VCC is required for each of these pins to ensure proper logic-high assertion and timing compliance (e.g., tHZ ≤ 10 ns). Failure to install pull-ups will prevent interrupt generation and BUSY arbitration.
How does the IDT71321SA25J8 handle simultaneous access to the same memory address from both ports?
The IDT71321SA25J8 uses on-chip arbitration logic that asserts BUSYL or BUSYR low when both ports attempt access to identical addresses. The winning port is determined by which port's CE and address signals stabilize first (tAPS = 5 ns setup required). The losing port's write is internally inhibited - no data corruption occurs, and tBDD ensures valid read data follows BUSY deassertion.
Can the IDT71321SA25J8 be used as a SLAVE device in a master/slave configuration?
No - the IDT71321SA25J8 is exclusively a MASTER device. Only the IDT71421 series functions as SLAVE, accepting BUSY as an input to inhibit writes. The IDT71321SA25J8 drives BUSY as an output and includes arbitration logic; attempting to use it as SLAVE would violate its functional design and cause undefined behavior.
What are the fixed interrupt mailbox addresses for the IDT71321SA25J8?
The IDT71321SA25J8 uses fixed interrupt mailbox addresses: writing to address 7FEh (hex) sets the left-port INTL flag, and writing to 7FFh (hex) sets the right-port INTR flag. Clearing is performed by reading the same address with OE enabled. These locations remain accessible as general SRAM when interrupts are unused.
71321SA25J8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 52-LCC (J-Lead)
- 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:
- 52-PLCC (19.13x19.13)
71321SA25J8 FAQ
1.How can I place an order for 71321SA25J8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321SA25J8 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 71321SA25J8 reliable?
The price and inventory of 71321SA25J8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321SA25J8 is usually 5 days.
3.What payment methods are accepted for 71321SA25J8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321SA25J8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321SA25J8?
71321SA25J8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321SA25J8 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 71321SA25J8?
For technical support, including 71321SA25J8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321SA25J8 requirements.
6.How does Aetrix verify that 71321SA25J8 is sourced from the original manufacturer or authorized distributors?
All 71321SA25J8 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 71321SA25J8 meets industry standards.
7.What is the process for return or replacement of 71321SA25J8?
All 71321SA25J8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321SA25J8, 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 71321SA25J8 part is unused and in its original packaging.
Return procedure for 71321SA25J8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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