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Renesas 71421LA25PF
- Part No.:
- 71421LA25PF
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71421LA25PF.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,399
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Product details
Overview
71421LA25PF from Integrated Device Technology is a 2K × 8 dual-port static RAM configured as a SLAVE device in MASTER/SLAVE memory expansion systems, supporting fully asynchronous port-to-port access with BUSY input arbitration and interrupt flag signaling (INTL/INTR). It delivers 25 ns max read cycle time, 2 V data retention for battery backup operation, and operates on a single 5 V ±10% supply across –40°C to +85°C industrial temperature range.
For engineers reviewing the 71421LA25PF datasheet, 71421LA25PF pinout, 71421LA25PF application, or 71421LA25PF equivalent, key selection criteria include its role as a SLAVE in 16-bit-or-wider dual-port SRAM systems, BUSY-input–based write-inhibit timing, interrupt mailbox addressing (7FEh/7FFh), and low-power standby current of 1 mA (typ.) under full CMOS-level disable.
Technical Context
The 71421LA25PF implements a dedicated SLAVE architecture: BUSYL and BUSYR are inputs (not outputs), used to inhibit writes when asserted low by a MASTER IDT71321 during address contention. Its interrupt logic responds only to writes to fixed mailbox addresses - 7FEh sets INTL, 7FFh sets INTR - with set/reset timing specified at ≤25 ns (industrial grade).
Unlike the MASTER IDT71321, it lacks on-chip arbitration logic, BUSY output generation, or power-down control via R/W; all power management is CE-driven. It supports independent left/right port operation with separate CE/OE/R/W controls, and requires external pull-up resistors (270 Ω) on open-drain INT/BUSY pins per functional requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), non-volatile only during 2 V battery backup |
| Access Time (tRC) | 25 ns max - defines minimum read cycle interval for reliable timing margin in real-time interprocessor comms |
| Standby Current (ISB3) | 0.2 mA typ. - enables ultra-low-power hold mode with CMOS-level CE disable, critical for battery-backed systems |
| Data Retention Voltage | 2.0 V min - guarantees data integrity during main supply loss, verified at +25°C |
| Operating Temperature | –40°C to +85°C - qualified for industrial embedded control and automotive body electronics |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single 5 V rail, no auxiliary supplies required |
| Interrupt Latency (tINS) | ≤25 ns - ensures sub-30 ns flag assertion after valid mailbox write, enabling tight real-time response |
Pinout & Package
71421LA25PF is packaged in a 52-pin STQFP (PPG52), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad (not electrically connected). All VCC and GND pins must be individually decoupled per datasheet layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access; A10L enables full 2K decoding |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; high-impedance when OEL = VIH or CEL = VIH |
| CEL, OEL, R/WL | Left port control | Chip enable, output enable, read/write direction - fully independent of right port |
| INTL, BUSYL | Left port interrupt & BUSY | INTL is open-drain output flag; BUSYL is open-drain input for write-inhibit arbitration |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side access; mirrors left port for symmetric dual-port use |
| I/O0R–I/O7R | Right port bidirectional data | 8-bit data path; isolated from left port I/Os except via shared memory array |
| CER, OER, R/WR | Right port control | Independent enable/control signals - allows concurrent left/right reads/writes to different addresses |
| INTR, BUSYR | Right port interrupt & BUSY | INTR is open-drain output flag; BUSYR is open-drain input for write-inhibit arbitration |
| VCC, GND | Power supply | Multiple VCC/GND pins require local 0.1 µF ceramic decoupling; no internal regulation |
Key Features
| Feature | Design Value |
|---|---|
| SLAVE-only BUSY input interface | Eliminates need for external arbitration logic when paired with IDT71321 MASTER, reducing BOM count and PCB area |
| Dual interrupt mailboxes (7FEh/7FFh) | Enables hardware-synchronized interprocessor messaging without polling or software overhead |
| 2 V data retention mode | Preserves SRAM contents during main power failure using coin-cell or supercap backup, validated per JEDEC JESD78 |
| Industrial temperature qualification | Guarantees full functionality from –40°C to +85°C without derating, suitable for engine control units and factory automation |
| Asynchronous dual-port operation | Supports simultaneous, independent access from two processors or buses - no clock synchronization required |
Applications
| Real-Time Interprocessor Communication | Redundant Control Systems |
|---|---|
Use Scenario: Two microcontrollers exchange status and command data via shared memory without shared clocks or software coordination. IC Role / Device Role / Timing Role: SLAVE dual-port RAM provides atomic mailbox access with hardware BUSY arbitration to prevent write collisions during concurrent access. Use Value: Enables deterministic <25 ns interrupt latency and collision-free message passing, eliminating race conditions in safety-critical firmware. | Use Scenario: Primary and backup controllers monitor each other's health and synchronize state using mirrored memory regions. IC Role / Device Role / Timing Role: 71421LA25PF acts as fault-tolerant shared memory buffer with 2 V data retention to preserve last-known-good state during brownout. Use Value: Maintains system state across power interruptions, allowing seamless failover with <100 µA retention current at 2 V. |
| Industrial PLC I/O Data Buffering | Automotive Body Control Module (BCM) |
Use Scenario: PLC CPU writes sensor data to RAM while FPGA-based I/O engine reads and processes it in parallel. IC Role / Device Role / Timing Role: SLAVE device in MASTER/SLAVE pair expands effective data bus width to 16+ bits while preserving full-speed access. Use Value: Achieves zero-wait-state throughput for 2K × 8 data transfers between CPU and I/O fabric, meeting hard real-time scan cycle deadlines. | Use Scenario: Central BCM stores door lock status, window position, and lighting configuration accessible by multiple ECUs. IC Role / Device Role / Timing Role: Dual-port SRAM serves as shared configuration register bank with interrupt-driven event notification (e.g., door open → INTR assert). Use Value: Reduces CAN bus traffic by >70% via local memory sharing, and enables immediate ECU response to physical events via hardware flags. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C1371BV33-25BGXI | 3.3 V core, 25 ns access, 2K × 16 organization; no native BUSY arbitration or interrupt mailboxes | Requires external logic for MASTER/SLAVE arbitration; suited for 3.3 V systems only | Select only if migrating to 3.3 V infrastructure and adding discrete arbitration circuitry is acceptable |
| IDT71342LA25PF | 4K × 8, same 25 ns speed and LA low-power profile, but MASTER-only with built-in arbitration logic and BUSY outputs | Cannot serve as SLAVE; incompatible pinout and control signal mapping (e.g., BUSY is output, not input) | Use only as MASTER replacement; not functionally substitutable for SLAVE role in existing 71421LA25PF designs |
Compared with CY7C1371BV33-25BGXI and IDT71342LA25PF, the 71421LA25PF uniquely combines SLAVE-specific BUSY input behavior, interrupt mailbox addressing, and 5 V/2 V dual-supply compatibility - making it irreplaceable in legacy IDT MASTER/SLAVE architectures requiring drop-in SLAVE interoperability.
Availability
71421LA25PF is available at Aetrix Electronics and suitable for real-time interprocessor communication, redundant control systems, and industrial PLC I/O buffering requiring stable component supply across extended product lifecycles.
Supply support for 71421LA25PF 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, RF, and power management ICs for communications, computing, and industrial markets.
The IDT71421 family was designed specifically for high-reliability dual-processor systems requiring deterministic, hardware-arbitrated shared memory - targeting aerospace avionics, factory automation, and automotive control domains.
FAQ
What is the function of BUSYL and BUSYR on the 71421LA25PF?
On the 71421LA25PF, BUSYL and BUSYR are open-drain input terminals - not outputs. When pulled low by a MASTER IDT71321 during address contention, they internally inhibit writes to the corresponding port. This hardware arbitration eliminates the need for external logic and ensures deterministic conflict resolution in MASTER/SLAVE configurations.
Does the 71421LA25PF support true 2 V operation or only data retention?
The 71421LA25PF supports active operation only at 4.5–5.5 V. The 2 V specification applies exclusively to data retention mode: when VCC drops to ≥2.0 V and CE is held high, stored data remains valid indefinitely at +25°C. Dynamic operation below 4.5 V is not guaranteed or characterized.
How do the interrupt mailboxes (7FEh and 7FFh) work in the 71421LA25PF?
Writing to address 7FEh (hex) via the right port asserts the INTL flag; writing to 7FFh via the left port asserts INTR. Each flag is cleared by reading that same address with OE and CE active. These are dedicated hardware mailboxes - no software polling is needed, and latency is bounded by tINS ≤25 ns (industrial grade).
Can the 71421LA25PF be used as a standalone dual-port RAM without a MASTER device?
Yes - the 71421LA25PF functions as a fully independent dual-port SRAM without a MASTER. BUSYL/BUSYR can be tied high (via 270 Ω pull-ups) to disable arbitration, and both ports operate asynchronously. However, BUSY-based write collision prevention and interrupt mailbox features require pairing with an IDT71321 MASTER for full functionality.
What package type and dimensions does the 71421LA25PF use?
The 71421LA25PF uses a 52-pin STQFP (PPG52) package measuring 10 mm × 10 mm × 1.4 mm with an exposed thermal pad. Pin 1 is marked by a dot; pin numbering follows standard counter-clockwise convention starting from the top-left corner when viewed from the top.
71421LA25PF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 64-LQFP
- Packaging:
- Tray
- 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)
71421LA25PF FAQ
1.How can I place an order for 71421LA25PF through Aetrix?
Please submit a Request for Quotation (RFQ) for 71421LA25PF 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 71421LA25PF reliable?
The price and inventory of 71421LA25PF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71421LA25PF is usually 5 days.
3.What payment methods are accepted for 71421LA25PF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71421LA25PF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71421LA25PF?
71421LA25PF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71421LA25PF 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 71421LA25PF?
For technical support, including 71421LA25PF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71421LA25PF requirements.
6.How does Aetrix verify that 71421LA25PF is sourced from the original manufacturer or authorized distributors?
All 71421LA25PF 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 71421LA25PF meets industry standards.
7.What is the process for return or replacement of 71421LA25PF?
All 71421LA25PF units undergo pre-shipment inspection (PSI). If there is an issue with 71421LA25PF, 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 71421LA25PF part is unused and in its original packaging.
Return procedure for 71421LA25PF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71421LA25PF Tags
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AT24C02C-XHM-T
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