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Renesas 71421SA55PF8
- Part No.:
- 71421SA55PF8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71421SA55PF8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:2,737
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Product details
Overview
71421SA55PF8 from IDT (now Renesas) is a high-speed 2K × 8 dual-port static RAM configured as a SLAVE device in MASTER/SLAVE memory expansion systems, featuring 55 ns max read cycle time, TTL-compatible 5V ±10% operation, industrial temperature range (–40°C to +85°C), and dedicated BUSY input for port arbitration - used in real-time interprocessor communication buffers and shared-memory embedded controllers.
For engineers reviewing the 71421SA55PF8 datasheet, 71421SA55PF8 pinout, 71421SA55PF8 application, or 71421SA55PF8 equivalent, this page delivers verified specifications, validated pin functions, confirmed SLAVE-side timing behavior (tWB, tWDD, tDDD), interrupt mailbox addressing (7FFH for INTR assertion), and precise package mapping to 64-pin TQFP (PNG64).
Technical Context
The 71421SA55PF8 implements fully asynchronous dual-port access with independent left/right address, control, and I/O buses. As a SLAVE device, it accepts BUSY as an input (not output) to inhibit writes during contention, and relies on external MASTER (e.g., 71321SA55PF8) for arbitration logic - no on-chip arbitration or BUSY generation.
It supports interrupt-driven interprocessor signaling via dedicated mailboxes: writing to address 7FFH from the left port asserts INTR; reading from 7FFH with CER = OER = VIL clears it. All timing parameters - including tWB (0 ns), tWDD (≤80 ns), and tDDD (≤55 ns) - are specified for SLAVE-only operation under industrial conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), non-volatile only during battery backup (LA version); SA version retains data only while powered |
| Max Read Cycle Time (tRC) | 55 ns - defines minimum time between successive reads on same port; critical for real-time deterministic latency |
| Supply Voltage | 5.0 V ±10% - requires single TTL-compatible rail; no separate I/O or core voltage rails |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments without derating |
| Standby Current (ISB1) | 20 mA max (both ports CE = VIH) - enables low-power idle states in multi-processor systems |
| BUSY Function | Input-only (SLAVE mode) - asserted by MASTER to block writes during address contention; requires external pull-up |
| Interrupt Mailbox Address | 7FFH (right port) - write from left port triggers INTR; read with CER/OER = VIL clears flag |
Pinout & Package
71421SA55PF8 is packaged in a 64-pin TQFP (PNG64), 14 mm × 14 mm × 1.4 mm body, lead-free and RoHS-compliant per IDT green parts policy.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side access; A10R enables full 2K decoding |
| I/O0R–I/O7R | Right port bidirectional data | 8-bit data path; high-impedance when OER = VIH or CER = VIH |
| CER, OER, R/WR | Right port control signals | CER enables chip, OER enables outputs, R/WR selects read (VIH) or write (VIL) |
| INTR | Right port interrupt output | Open-drain flag asserted when left port writes to 7FFH; requires external pull-up |
| BUSYR | Right port BUSY input | SLAVE-only input - driven LOW by MASTER to inhibit R/WR-controlled writes during contention |
| VCC, GND | Power supply pins | Multiple VCC (pins 33, 47, 48, 64) and GND (pins 32, 46, 63) ensure stable power delivery across high-speed switching |
| NC | No-connect terminals | Pins 19, 20, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62 - must be left unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Dual-port asynchronous access | Enables concurrent read/write from left and right ports without clock synchronization - essential for lock-free interprocessor communication |
| SLAVE-specific BUSY input | Eliminates need for external arbitration logic when paired with IDT71321 MASTER - reduces BOM count and PCB area |
| Hardware interrupt mailbox | Fixed-address (7FFH) flagging enables zero-software-overhead event signaling between processors |
| 55 ns industrial-grade timing | Guaranteed performance at –40°C to +85°C supports deterministic response in harsh environments |
| TTL-compatible 5V interface | Direct connection to legacy microcontrollers and FPGAs without level-shifting circuitry |
Applications
| Industrial PLC Backplane Memory | Avionics Data Exchange Buffer |
|---|---|
Use Scenario: Two independent CPU modules share status and command data via a common memory space on a ruggedized backplane. IC Role / Device Role / Timing Role: 71421SA55PF8 acts as SLAVE in a 16-bit+ dual-port array, accepting BUSY from MASTER to prevent simultaneous writes to same address. Use Value: Eliminates software semaphore overhead and guarantees atomic message passing with ≤55 ns read latency and hardware-enforced write collision avoidance. |
Use Scenario: Flight control computer and sensor acquisition unit exchange telemetry packets using mailbox-style interrupts. IC Role / Device Role / Timing Role: 71421SA55PF8 provides right-port INTR assertion upon left-port write to 7FFH, triggering immediate ISR execution. Use Value: Achieves sub-microsecond interrupt latency (tINS ≤45 ns) without polling, meeting DO-254 deterministic timing requirements. |
| Medical Imaging Real-Time FIFO | Test Equipment Pattern Generator Memory |
Use Scenario: High-speed image frame buffer where acquisition engine writes and display engine reads concurrently. IC Role / Device Role / Timing Role: 71421SA55PF8 serves as SLAVE in width-expanded memory bank, synchronized to MASTER's BUSY to throttle writes during display read cycles. Use Value: Prevents visual artifacts by enforcing hardware-gated write enable, ensuring pixel data integrity at 20+ MB/s throughput. |
Use Scenario: Automated test system stores stimulus patterns in SRAM and streams them to DUT via parallel bus. IC Role / Device Role / Timing Role: 71421SA55PF8 operates as SLAVE in multi-chip pattern memory array, with BUSYR driven by MASTER to coordinate write sequencing across banks. Use Value: Enables glitch-free pattern updates during active test cycles - no firmware intervention required for bank arbitration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C1362BV33-55AC | 3.3V core/I/O, 55 ns, 2K × 16 organization - requires redesign of data bus width and power delivery | Targeted at low-voltage FPGA-based systems; lacks native 5V TTL compatibility | Select only if migrating to 3.3V architecture and expanding to 16-bit word width |
| AS7C3256B-55PCN | Single-port CMOS SRAM, 32K × 8, 55 ns - no dual-port or interrupt capability | Suitable for buffered storage but cannot support true interprocessor communication without external logic | Choose only for cost-sensitive applications where concurrent access and hardware arbitration are unnecessary |
Compared with CY7C1362BV33-55AC and AS7C3256B-55PCN, the 71421SA55PF8 uniquely delivers 5V TTL-compatible dual-port operation with integrated SLAVE arbitration and interrupt mailboxing - eliminating external glue logic and preserving legacy system voltage and timing budgets.
Availability
71421SA55PF8 is available at Aetrix Electronics and suitable for industrial PLC backplanes, avionics data exchange buffers, and medical imaging real-time FIFOs requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.
Supply support for 71421SA55PF8 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, computing, and industrial markets.
The 71421SA55PF8 belongs to IDT's dual-port SRAM product line, designed specifically for deterministic interprocessor communication in real-time embedded systems requiring hardware arbitration and interrupt signaling without software overhead.
FAQ
What is the role of 71421SA55PF8 in a MASTER/SLAVE dual-port configuration?
The 71421SA55PF8 functions exclusively as a SLAVE device: it receives BUSY as an input (not output) to inhibit writes during address contention, relies on an external MASTER (e.g., 71321SA55PF8) for arbitration, and supports interrupt signaling via right-port INTR flag triggered by left-port writes to address 7FFH. It does not generate BUSY or perform arbitration internally.
Does 71421SA55PF8 support battery backup data retention?
No - the 71421SA55PF8 is the SA (standard power) variant and does not support battery backup. Only LA versions (e.g., 71421LA55PF8) provide 2V data retention capability. The SA version loses all data when VCC drops below operating threshold.
What is the function of BUSYR on 71421SA55PF8?
BUSYR is a dedicated input pin on the 71421SA55PF8. When driven LOW by the MASTER device (e.g., 71321SA55PF8), it internally inhibits write operations on the right port - preventing data corruption during simultaneous access to the same memory location. It requires an external pull-up resistor per datasheet Figure 3.
How is the INTR flag cleared on 71421SA55PF8?
The INTR flag on 71421SA55PF8 is cleared by the right port reading from address 7FFH while CER = OER = VIL (chip and output enables active). R/WR state is irrelevant during clear operation. This hardware-clear mechanism avoids software race conditions and ensures deterministic flag reset timing.
Which package does 71421SA55PF8 use, and are there pin-compatible alternatives?
The 71421SA55PF8 uses a 64-pin TQFP (PNG64) package per IDT datasheet DSC-2691/17. No pin-compatible alternatives exist across manufacturers due to proprietary dual-port control signal allocation (e.g., separate BUSY input vs. output, dedicated INTR/INTL). Migration requires PCB redesign and firmware adaptation.
71421SA55PF8 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 (14x14)
71421SA55PF8 FAQ
1.How can I place an order for 71421SA55PF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71421SA55PF8 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 71421SA55PF8 reliable?
The price and inventory of 71421SA55PF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71421SA55PF8 is usually 5 days.
3.What payment methods are accepted for 71421SA55PF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71421SA55PF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71421SA55PF8?
71421SA55PF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71421SA55PF8 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 71421SA55PF8?
For technical support, including 71421SA55PF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71421SA55PF8 requirements.
6.How does Aetrix verify that 71421SA55PF8 is sourced from the original manufacturer or authorized distributors?
All 71421SA55PF8 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 71421SA55PF8 meets industry standards.
7.What is the process for return or replacement of 71421SA55PF8?
All 71421SA55PF8 units undergo pre-shipment inspection (PSI). If there is an issue with 71421SA55PF8, 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 71421SA55PF8 part is unused and in its original packaging.
Return procedure for 71421SA55PF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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