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Renesas 71321SA25PF8
- Part No.:
- 71321SA25PF8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321SA25PF8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,661
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Product details
Overview
71321SA25PF8 from IDT (now Renesas) 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 features 25 ns max access time, TTL-compatible 5V ±10% operation, industrial temperature range (–40°C to +85°C), and dual independent asynchronous ports enabling concurrent read/write access - used in motor control co-processor memory buffers.
For engineers reviewing the 71321SA25PF8 datasheet, 71321SA25PF8 pinout, 71321SA25PF8 application, or 71321SA25PF8 equivalent, key selection considerations include its MASTER-only BUSY output architecture, interrupt mailbox addressing (7FEh/7FFh), port arbitration timing (tAPS = 5 ns), and 52-pin STQFP package compatibility with legacy IDT dual-port designs.
Technical Context
The 71321SA25PF8 implements on-chip port arbitration logic that resolves contention when both ports access the same address simultaneously - asserting BUSYL/BUSYR outputs based solely on chip enable (CEL/CER) and address match timing, independent of R/W state. 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 drives open-drain BUSY outputs requiring 270 Ω pull-up resistors, while supporting battery backup data retention only in LA variants (not applicable to this SA-grade part). It operates fully asynchronously per port, with separate CE/OE/R/W controls and independent I/O drivers for left/right sides.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), 16 kbit total capacity - supports byte-wide parallel data exchange between two processors. |
| Access Time (max) | 25 ns - guarantees deterministic latency for real-time control loops requiring sub-40 MHz bus timing. |
| Supply Voltage | 5.0 V ±10% (4.5–5.5 V) - compatible with legacy 5V TTL logic families without level shifting. |
| Operating Temperature | –40°C to +85°C - qualified for industrial automation, motor drives, and transportation electronics. |
| Power Consumption | Active: 110 mA typ. (550 mW), Standby (ISB1): 30 mA typ. - enables low-idle-power multi-processor coordination. |
| Interrupt Addressing | INTL triggered by write to 7FEh, INTR by write to 7FFh - provides hardware-synchronized mailbox signaling without shared registers. |
| BUSY Arbitration | tAPS = 5 ns setup time required - ensures deterministic priority resolution during simultaneous address matches. |
Pinout & Package
71321SA25PF8 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 memory access (000h–7FFh); must be stable before CEL assertion. |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; high-impedance when OEL = VIH or CEL = VIH - enables bus sharing. |
| CEL, OEL, R/WL | Left port controls | Chip Enable (active-low), Output Enable (active-low), Read/Write (high=read, low=write) - fully asynchronous operation. |
| INTL, BUSYL | Left port interrupt & BUSY | INTL is open-drain interrupt flag; BUSYL is open-drain BUSY output requiring 270 Ω pull-up - signals contention or mailbox event. |
| A0R–A10R | Right port address inputs | Independent 11-bit address bus; supports simultaneous but non-conflicting access to different memory locations. |
| I/O0R–I/O7R | Right port bidirectional data | Electrically isolated from left I/O; allows true dual-bus architecture without external multiplexing. |
| CER, OER, R/WR | Right port controls | Functionally identical to left-side controls but electrically separate - enables lock-step or independent timing. |
| INTR, BUSYR | Right port interrupt & BUSY | INTR is open-drain flag; BUSYR is open-drain output - provides symmetric signaling for right-port-initiated events. |
| VCC, GND | Power supply | Multiple VCC/GND pins distributed across package - reduces switching noise and improves signal integrity in high-speed operation. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous same-address access deterministically via tAPS timing - eliminates need for external priority encoder or glue logic. |
| Dual independent interrupt mailboxes | Hardware-triggered flags (INTL/INTR) tied to fixed SRAM addresses (7FEh/7FFh) - enables zero-latency interprocessor notification without CPU intervention. |
| Open-drain BUSY outputs with defined timing | BUSYL/BUSYR assert within 20 ns (tBAA) of address/CE match - provides precise, cycle-accurate write-inhibit signaling to slave devices. |
| Asynchronous dual-port operation | Fully independent control, address, and data paths per port - permits concurrent read/write operations at full speed without internal arbitration stalls. |
| TTL-compatible 5V interface | VIH = 2.2 V min., VIL = 0.8 V max., VOH = 2.4 V min. - interoperates directly with legacy microcontrollers, FPGAs, and ASICs using 5V logic. |
Applications
| Motor Control Co-Processor Buffer | Real-Time PLC Data Exchange |
|---|---|
|
Use Scenario: Two tightly coupled MCUs coordinate motion profiling - one handles trajectory calculation, the other executes PWM updates - sharing status, setpoints, and fault codes. IC Role / Device Role / Timing Role: 71321SA25PF8 serves as MASTER dual-port RAM, providing deterministic, low-latency memory access with hardware BUSY arbitration to prevent write collisions during joint axis synchronization. Use Value: Eliminates software semaphores and polling delays; 25 ns access ensures sub-microsecond response for safety-critical position loop updates. |
Use Scenario: A programmable logic controller uses separate CPUs for I/O scanning and ladder logic execution, requiring synchronized access to shared process variables and alarm tables. IC Role / Device Role / Timing Role: 71321SA25PF8 acts as shared memory hub with interrupt-driven mailbox (7FEh/7FFh) to signal data readiness between scan and execute cycles. Use Value: Reduces inter-CPU latency from milliseconds (polling) to nanoseconds (hardware interrupt), improving overall scan cycle consistency and determinism. |
| Industrial Ethernet Gateway Buffer | Dual-Core DSP Memory Bridge |
|
Use Scenario: An EtherCAT master node bridges fieldbus data between real-time Ethernet stack and legacy serial field devices, buffering packetized sensor/actuator data. IC Role / Device Role / Timing Role: 71321SA25PF8 functions as MASTER buffer with BUSY arbitration, allowing Ethernet MAC and serial controller to access overlapping memory regions without corruption. Use Value: Prevents packet loss during burst transfers; open-drain BUSY outputs interface directly with FPGA-based protocol engines without level-shifting. |
Use Scenario: A dual-core audio DSP splits algorithm tasks - one core handles FFT analysis, the other performs filter bank synthesis - requiring low-overhead shared coefficient and sample buffers. IC Role / Device Role / Timing Role: 71321SA25PF8 provides asymmetric memory access: analysis core writes results to 7FEh to trigger synthesis core via INTL, avoiding cache coherency overhead. Use Value: Enables lock-free inter-core communication; 52-pin STQFP footprint fits compact audio module layouts without routing congestion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C024AV-25AXC | 2K × 16 organization, 25 ns access, 3.3V core (5V-tolerant I/O), no built-in BUSY arbitration logic - requires external priority circuitry. | Best suited for new 3.3V designs where wider data bus reduces bus cycles; not drop-in for 5V-only systems or BUSY-driven architectures. | Select if migrating to lower-voltage logic and willing to add external arbitration; avoid when replicating IDT71321's integrated BUSY/INT behavior. |
| IDT71421SA25PF8 | SLAVE variant: BUSY pins are inputs (not outputs), no on-chip arbitration logic, identical timing and pinout - designed to pair with 71321 as width-expansion slave. | Used only in 16-bit+ memory expansions where 71321 acts as MASTER; cannot operate standalone as memory controller or interrupt source. | Choose only when building wide-bus systems requiring multiple 71421 slaves driven by one 71321 MASTER - not a functional substitute. |
Compared with CY7C024AV-25AXC and IDT71421SA25PF8, the 71321SA25PF8 uniquely integrates MASTER arbitration and interrupt mailbox logic in a 5V TTL-compatible package - making it irreplaceable for legacy industrial designs requiring hardware-coordinated dual-processor memory access without added logic.
Availability
71321SA25PF8 is available at Aetrix Electronics and suitable for motor control co-processors, real-time PLC data exchange, and industrial Ethernet gateway buffering requiring stable component supply across extended product lifecycles.
Supply support for 71321SA25PF8 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
IDT (Integrated Device Technology), now part of Renesas Electronics, is a fabless semiconductor company specializing in high-performance memory, timing, and interface solutions for communications and industrial markets.
The IDT71321 family was engineered specifically for deterministic interprocessor communication in hard real-time systems - delivering hardware-enforced memory arbitration and interrupt signaling to eliminate software bottlenecks in dual-CPU architectures.
FAQ
What is the function of the BUSY pins on the 71321SA25PF8?
The BUSYL and BUSYR pins on the 71321SA25PF8 are open-drain outputs that signal memory contention when both ports attempt to access the same address. They require 270 Ω pull-up resistors and assert within 20 ns (tBAA) to inhibit writes on the contending port. This hardware arbitration is exclusive to the MASTER 71321 - unlike SLAVE parts where BUSY is an input. The 71321SA25PF8 uses this to guarantee deterministic access ordering without software intervention.
How do the interrupt flags INTL and INTR work in the 71321SA25PF8?
In the 71321SA25PF8, INTL asserts when the right port writes to address 7FEh, and INTR asserts when the left port writes to 7FFh - per Truth Table II. Both flags are open-drain and require pull-ups. Clearing is performed by reading the same address with OE active (e.g., CEL = OEL = VIL for INTL). These mailbox addresses are standard SRAM locations, so unused bits retain user data. The 71321SA25PF8 enables zero-latency interprocessor signaling without dedicated registers or polling.
Can the 71321SA25PF8 operate in battery backup mode?
No, the 71321SA25PF8 is an SA-grade part and does not support battery backup operation. Only LA variants (e.g., 71321LA25PF8) provide 2V data retention capability with typical 200 µW standby current. The SA version draws 30 mA in TTL-level standby (ISB1) and requires continuous 5V supply. If battery-backed memory is required, the 71321SA25PF8 must be replaced with its LA counterpart - which shares pinout and timing but differs in power architecture and temperature specs.
What package type is used for the 71321SA25PF8?
The 71321SA25PF8 uses a 52-pin STQFP package (IDT designation PPG52), measuring 10 mm × 10 mm × 1.4 mm with an exposed thermal pad. It is RoHS-compliant and pin-compatible with other 52-pin IDT dual-port SRAMs like the 71321SA20PF8 and 71321SA35PF8. The PPG52 footprint supports reflow soldering and provides better thermal performance than PLCC variants, making it suitable for dense industrial PCB layouts where the 71321SA25PF8 operates continuously at +85°C.
Is the 71321SA25PF8 compatible with the IDT71421 series?
The 71321SA25PF8 is functionally and pin-compatible with IDT71421SA25PF8 for width expansion - but they serve complementary roles: 71321SA25PF8 is the MASTER with BUSY outputs and arbitration logic, while 71421SA25PF8 is the SLAVE with BUSY inputs and no arbitration. They share identical timing, voltage, and package specs, enabling seamless 16-bit+ memory builds. However, the 71321SA25PF8 cannot be substituted with 71421SA25PF8 in standalone MASTER applications due to missing arbitration circuitry.
71321SA25PF8 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)
71321SA25PF8 FAQ
1.How can I place an order for 71321SA25PF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321SA25PF8 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 71321SA25PF8 reliable?
The price and inventory of 71321SA25PF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321SA25PF8 is usually 5 days.
3.What payment methods are accepted for 71321SA25PF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321SA25PF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321SA25PF8?
71321SA25PF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321SA25PF8 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 71321SA25PF8?
For technical support, including 71321SA25PF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321SA25PF8 requirements.
6.How does Aetrix verify that 71321SA25PF8 is sourced from the original manufacturer or authorized distributors?
All 71321SA25PF8 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 71321SA25PF8 meets industry standards.
7.What is the process for return or replacement of 71321SA25PF8?
All 71321SA25PF8 units undergo pre-shipment inspection (PSI). If there is an issue with 71321SA25PF8, 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 71321SA25PF8 part is unused and in its original packaging.
Return procedure for 71321SA25PF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321SA25PF8 Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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AT24C08C-STUM-T
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