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Renesas 71421LA25PFI8
- Part No.:
- 71421LA25PFI8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71421LA25PFI8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
71421LA25PFI8 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 communication with BUSY input and interrupt flags (INTL/INTR), 25 ns read cycle time, industrial temperature range (–40°C to +85°C), and 2 V battery-backed data retention. It enables error-free 16-bit-or-wider memory systems without external arbitration logic.
For engineers reviewing the 71421LA25PFI8 datasheet, 71421LA25PFI8 pinout, 71421LA25PFI8 application, or 71421LA25PFI8 equivalent, key selection considerations include its role as a SLAVE dual-port SRAM with BUSY input (not output), interrupt mailbox addressing (7FEH/7FFH), 52-pin PLCC package, 5 V ±10% supply, and compatibility with IDT71321 MASTER devices in width-expanded systems.
Technical Context
The 71421LA25PFI8 operates as a SLAVE in MASTER/SLAVE dual-port configurations: BUSY is an input (not output) used to inhibit writes during address contention, and it lacks on-chip arbitration logic-relying entirely on the MASTER (IDT71321) for BUSY generation. Its interrupt function uses dedicated mailboxes at addresses 7FEH (left-port INTL set) and 7FFH (right-port INTR set), cleared by reading those same locations.
It supports independent asynchronous access on left (L) and right (R) ports, each with dedicated CE/OE/R/W, 11-bit address (A0–A10), and 8-bit bidirectional I/O. Power management includes four standby modes (ISB1–ISB4), with full CMOS-level standby drawing only 0.2 mA typical at 25°C, enabling ultra-low-power battery backup operation at 2 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), 16 kbit total capacity |
| Read Cycle Time (tRC) | 25 ns max - defines minimum time between successive reads on same port |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single 5 V ±10% rail, no dual supplies required |
| Data Retention Voltage | 2.0 V min - retains stored data during power loss using backup battery |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments without derating |
| Standby Current (ISB3) | 0.2 mA typical - ultra-low full-standby draw with CMOS-level inputs |
| Interrupt Mailbox Addresses | 7FEH (sets INTL), 7FFH (sets INTR) - user-accessible SRAM locations with dedicated flag behavior |
Pinout & Package
71421LA25PFI8 is packaged in a 52-pin Plastic Leaded Chip Carrier (PLCC), body size ≈ 19.05 mm × 19.05 mm × 4.32 mm, with gull-wing leads and surface-mount mounting. Pin 1 marked by corner notch; all VCC pins require connection to 5 V supply, all GND pins to ground.
| 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 (L/R) | Active-low enables respective port; controls power-down mode when high |
| OEL, OER | Output enable (L/R) | Active-low enables outputs; overrides R/W for tri-state control |
| R/WL, R/WR | Read/write control (L/R) | High = read, low = write; determines direction of I/O bus |
| BUSYL, BUSYR | BUSY input (L/R) | SLAVE-only: active-low write-inhibit signals driven by MASTER's BUSY outputs |
| INTL, INTR | Interrupt flags (L/R) | Open-drain outputs; asserted low when opposite port writes to 7FEH/7FFH |
| VCC, GND | Power and ground | Multiple VCC/GND pins required for noise immunity and current distribution |
Key Features
| Feature | Design Value |
|---|---|
| SLAVE-only BUSY interface | Accepts BUSYL/BUSYR as inputs to block concurrent writes-eliminates need for external AND gates in width-expanded arrays |
| Dual-mailbox interrupt logic | Hardware-set/clear interrupts at fixed SRAM addresses (7FEH/7FFH), enabling lightweight interprocessor messaging without polling overhead |
| 2 V data retention | Preserves memory contents during main power loss using coin-cell backup, critical for real-time control state preservation |
| Four-tier standby power control | ISB1–ISB4 modes support granular power gating per port (TTL/CMOS input levels), achieving 0.2 mA full-standby at 25°C |
| Industrial-grade timing | 25 ns tRC guaranteed over –40°C to +85°C, with full AC parameter validation including tBDD (BUSY disable to valid data) ≤35 ns |
Applications
| Industrial Motion Controller | Avionics Data Logger |
|---|---|
Use Scenario: Real-time coordination between motion trajectory processor (Port L) and safety watchdog (Port R) in servo drive systems. IC Role / Device Role / Timing Role: SLAVE dual-port SRAM provides shared memory with hardware BUSY arbitration and mailbox interrupts to prevent race conditions during position update writes. Use Value: Eliminates software semaphore overhead and guarantees atomic message delivery via 7FEH/7FFH mailboxes, reducing jitter in closed-loop response. |
Use Scenario: Continuous flight parameter capture with non-volatile storage during power interruption in black box recorders. IC Role / Device Role / Timing Role: SLAVE SRAM buffers sensor data streams on Port R while Port L services flash writes; 2 V retention preserves last 2K samples during brownout. Use Value: Enables zero-data-loss logging across power cycles without external backup controllers or supercapacitors. |
| Medical Imaging Subsystem | Telecom Line Card Buffer |
Use Scenario: Synchronized acquisition of ultrasound echo data (Port L) and beamforming coefficient updates (Port R) in portable scanners. IC Role / Device Role / Timing Role: SLAVE device in MASTER/SLAVE pair with IDT71321; BUSY input prevents coefficient corruption during simultaneous memory access. Use Value: Ensures deterministic latency for real-time image reconstruction by eliminating arbitration logic propagation delay. |
Use Scenario: Packet buffering between line-side PHY (Port L) and switch fabric interface (Port R) in carrier-grade Ethernet cards. IC Role / Device Role / Timing Role: Dual-port SRAM acts as elastic buffer with independent clock domains; interrupt flags signal packet arrival/completion to respective controllers. Use Value: Reduces packet drop rate under burst traffic by decoupling ingress/egress timing, leveraging 25 ns access for <100 ns round-trip latency. |
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 | 32K × 16 organization, 3.3 V core, no built-in BUSY arbitration or interrupt mailboxes | Requires external logic for MASTER/SLAVE arbitration and interrupt generation | Select when higher density and lower voltage are prioritized over integrated interprocessor signaling |
| IDT71321LA25PFI8 | MASTER variant with on-chip arbitration logic, BUSY output, and identical timing/package | Must be paired with SLAVE (e.g., 71421LA25PFI8) for width expansion; cannot operate standalone as SLAVE | Choose as companion MASTER to enable plug-and-play 16-bit+ memory expansion with no discrete glue logic |
Compared with CY7C024AV-25AXC, 71421LA25PFI8 delivers hardware-accelerated interprocessor coordination via BUSY input and mailbox interrupts, reducing BOM count and firmware complexity. Against IDT71321LA25PFI8, it serves the complementary SLAVE role-enabling scalable memory width without redesigning arbitration architecture.
Availability
71421LA25PFI8 is available at Aetrix Electronics and suitable for industrial motion control, avionics data logging, medical imaging subsystems, telecom line card buffering, and embedded real-time systems requiring stable component supply with long-term lifecycle assurance.
Supply support for 71421LA25PFI8 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 IDT71321/71421 family was designed specifically for high-reliability interprocessor communication in real-time embedded systems, delivering deterministic dual-port access, hardware arbitration, and battery-backed retention without external support components.
FAQ
What is the function of BUSYL and BUSYR on the 71421LA25PFI8?
BUSYL and BUSYR are dedicated input terminals on the 71421LA25PFI8, not outputs. As a SLAVE device, it uses these signals-driven low by a MASTER IDT71321-to internally inhibit write operations during address contention. This eliminates the need for external arbitration logic and ensures deterministic write blocking in width-expanded memory systems.
Does the 71421LA25PFI8 support true 25 ns access across the full industrial temperature range?
Yes, the 71421LA25PFI8 guarantees a maximum read cycle time (tRC) of 25 ns over the full –40°C to +85°C operating range, as validated in the official IDT DSC-2691/17 datasheet. This includes all AC parameters such as tAA, tACE, and tAOE, ensuring consistent performance in demanding industrial environments without derating.
How does the interrupt functionality work in the 71421LA25PFI8?
The 71421LA25PFI8 implements hardware interrupts via two dedicated SRAM mailboxes: writing to address 7FEH sets the INTL flag (low-active open-drain), and writing to 7FFH sets the INTR flag. Clearing is performed by reading those same addresses. These flags operate independently per port and require no firmware polling-enabling efficient event-driven interprocessor communication.
Can the 71421LA25PFI8 operate as a standalone dual-port SRAM without a MASTER device?
Yes, the 71421LA25PFI8 functions as a fully independent dual-port SRAM with separate left and right control/address/I/O buses. BUSY inputs default to inactive (VIH) when unused, and interrupt flags remain operational. However, its SLAVE-specific BUSY interface and lack of on-chip arbitration logic mean MASTER/SLAVE expansion requires pairing with IDT71321 for hardware-controlled width scaling.
What is the significance of the 'LA' suffix in 71421LA25PFI8?
The 'LA' suffix denotes the low-power, battery-backed version of the IDT71421. It specifies 2 V data retention capability, reduced standby currents (e.g., 0.2 mA ISB3 typical), and industrial temperature qualification. This distinguishes it from the 'SA' variant, which offers higher speed grades but lacks battery backup and has higher standby power consumption.
71421LA25PFI8 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-TQFP (14x14)
71421LA25PFI8 FAQ
1.How can I place an order for 71421LA25PFI8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71421LA25PFI8 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 71421LA25PFI8 reliable?
The price and inventory of 71421LA25PFI8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71421LA25PFI8 is usually 5 days.
3.What payment methods are accepted for 71421LA25PFI8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71421LA25PFI8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71421LA25PFI8?
71421LA25PFI8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71421LA25PFI8 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 71421LA25PFI8?
For technical support, including 71421LA25PFI8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71421LA25PFI8 requirements.
6.How does Aetrix verify that 71421LA25PFI8 is sourced from the original manufacturer or authorized distributors?
All 71421LA25PFI8 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 71421LA25PFI8 meets industry standards.
7.What is the process for return or replacement of 71421LA25PFI8?
All 71421LA25PFI8 units undergo pre-shipment inspection (PSI). If there is an issue with 71421LA25PFI8, 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 71421LA25PFI8 part is unused and in its original packaging.
Return procedure for 71421LA25PFI8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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