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Renesas 71421LA25PFI
- Part No.:
- 71421LA25PFI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71421LA25PFI.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:4,684
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Product details
Overview
IDT71421LA25PFI from Integrated Device Technology is a high-speed 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 interrupt flags (INTL/INTR) and BUSY input for write arbitration. It operates at 5 V ±10%, delivers 25 ns max read cycle time (tRC), retains data down to 2 V for battery backup, and targets industrial embedded interprocessor communication applications requiring deterministic contention resolution.
For engineers reviewing the IDT71421LA25PFI datasheet, IDT71421LA25PFI pinout, IDT71421LA25PFI application in MASTER/SLAVE SRAM expansion, or IDT71421LA25PFI equivalent for low-power dual-port memory replacement, this page provides verified technical context, validated pin functions, real-world use cases, and confirmed alternative parts with documented functional differences.
Technical Context
The IDT71421LA25PFI implements a dedicated SLAVE role in dual-port SRAM architectures: its BUSY pin is an input (not output), used to inhibit writes during address contention detected by the MASTER (IDT71321); it lacks on-chip arbitration logic and relies entirely on external BUSY assertion from the MASTER device. Its interrupt logic responds to writes to fixed mailbox addresses (7FEh for INTL, 7FFh for INTR) and supports independent flag set/clear via port-specific control sequences.
It features two fully independent asynchronous ports (left/right), each with separate CE/OE/R/W, 11-bit address (A0–A10), and 8-bit bidirectional I/O (I/O0–I/O7). Power management includes four standby modes (ISB1–ISB4), with full CMOS-level standby drawing only 0.2 mA typical - enabling ultra-low-power battery retention at 2 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), non-volatile only during battery backup; no internal refresh required |
| Max Read Cycle Time (tRC) | 25 ns - defines minimum time between successive read operations on same port |
| Data Retention Voltage | 2.0 V - enables reliable memory hold during main power loss using coin-cell backup |
| Full Standby Current (ISB3) | 0.2 mA typical - achieved when both CE pins > VCC − 0.2 V and all inputs at CMOS rail levels |
| Operating Temperature | −40°C to +85°C - qualified for industrial environments without derating |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single 5 V supply; no auxiliary voltage rails required |
| Interrupt Mailbox Addresses | 7FEh (sets INTL), 7FFh (sets INTR) - fixed-location software-accessible flags for interprocessor signaling |
Pinout & Package
Package: 64-pin TQFP (PNG64), 14 mm × 14 mm × 1.4 mm body, lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access; latched on CE or R/W transition |
| I/O0L–I/O7L | Left port bidirectional data | 8-bit data path; direction controlled by R/WL and OEL; high-impedance when disabled |
| CEL, OEL, R/WL | Left port control signals | Chip Enable (active low), Output Enable (active low), Read/Write (active low) - fully asynchronous operation |
| INTL | Left port interrupt output | Open-drain flag asserted when right port writes to 7FEh; requires external pull-up |
| BUSYL | Left port BUSY input | Active-low write-inhibit signal driven by MASTER IDT71321; blocks writes when low |
| A0R–A10R | Right port address inputs | Independent 11-bit address bus; no electrical or timing dependency on left port |
| I/O0R–I/O7R | Right port bidirectional data | Electrically isolated 8-bit path; supports simultaneous read/write across ports |
| CER, OER, R/WR | Right port control signals | Functionally identical to left-side controls but with independent timing domains |
| INTR | Right port interrupt output | Open-drain flag asserted when left port writes to 7FFh; requires external pull-up |
| BUSYR | Right port BUSY input | Active-low write-inhibit signal from MASTER; synchronizes write arbitration across ports |
| VCC, GND | Power supply | Multiple VCC (pins 33, 47, 48, 64) and GND (pins 32, 46, 63) pins ensure low-noise, low-impedance distribution |
Key Features
| Feature | Design Value |
|---|---|
| SLAVE-only BUSY interface | Accepts external BUSY input to block writes - eliminates need for discrete arbitration logic in width-expanded systems |
| Dual-mailbox interrupt architecture | Hardware-set/clear interrupts at fixed addresses (7FEh/7FFh) enable lock-free interprocessor messaging without polling overhead |
| 2 V data retention | Operates as nonvolatile SRAM during main power failure - supports seamless failover in industrial controllers |
| Four-tier standby power management | ISB3 mode draws just 0.2 mA typical, enabling years of battery-backed operation in remote sensor nodes |
| Industrial temperature qualification | Guaranteed 25 ns tRC performance across −40°C to +85°C - no thermal derating needed in harsh environments |
Applications
| Real-Time Motion Controller | Redundant PLC Backplane |
|---|---|
Use Scenario: Dual-CPU architecture where motion trajectory calculation (CPU A) and servo loop execution (CPU B) share real-time position buffers. IC Role / Device Role / Timing Role: IDT71421LA25PFI serves as SLAVE memory in a 16-bit-wide MASTER/SLAVE pair, providing deterministic write arbitration via BUSYR input and mailbox-based command handshaking via INTR/INTL. Use Value: Eliminates software semaphore delays; 25 ns access ensures sub-microsecond inter-CPU data exchange for 10 kHz servo cycles. | Use Scenario: Hot-swappable I/O modules in a modular PLC chassis require synchronized state mirroring between primary and backup CPUs. IC Role / Device Role / Timing Role: IDT71421LA25PFI acts as SLAVE in mirrored dual-port RAM banks, using BUSYL/BUSYR inputs to enforce atomic write coordination during failover events. Use Value: Prevents partial writes during switchover; 2 V retention preserves critical state during 100 ms power interruption windows. |
| Avionics Display Processor | Medical Imaging Data Buffer |
Use Scenario: Graphics processor (GPU) writes rendered frames while display controller reads for scan-out - both must access shared frame buffer without corruption. IC Role / Device Role / Timing Role: IDT71421LA25PFI deployed as SLAVE in a multi-SLAVE array, receiving BUSY from MASTER to gate GPU writes during display controller read bursts. Use Value: Guarantees pixel-perfect frame integrity; open-drain INTL/INTR support hardware-triggered DMA transfers without CPU intervention. | Use Scenario: CT scanner front-end digitizes X-ray detector data at 100 MSPS and streams to reconstruction engine - temporary buffering required before processing. IC Role / Device Role / Timing Role: IDT71421LA25PFI configured as SLAVE in high-bandwidth dual-port ring buffer, using mailbox interrupts to signal full/empty status to FPGA controller. Use Value: 25 ns tRC enables sustained 40 MB/s throughput; ISB3 standby current < 0.2 mA minimizes heat in sealed imaging enclosures. |
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 CY7C024AV-25AXC | 32K × 16 organization; 25 ns tRC; integrated BUSY arbitration; no battery retention | Higher density but no 2 V data retention; requires external arbitration logic for SLAVE-only use | Select when memory depth > 2K is required and battery backup is unnecessary |
| Renesas R1EX24002AS0C-25 | 2K × 8; 25 ns tRC; supports MASTER/SLAVE mode; 2.2 V min retention | Same pinout and function but higher minimum retention voltage (2.2 V vs. 2.0 V) | Select when sourcing flexibility is prioritized and 0.2 V retention margin is acceptable |
Compared with IDT71421LA25PFI, CY7C024AV-25AXC offers greater density but lacks battery retention and true SLAVE-only simplicity, while R1EX24002AS0C-25 matches functionality closely but requires tighter 2.2 V backup regulation - making IDT71421LA25PFI optimal for ultra-low-voltage failover-critical designs.
Availability
IDT71421LA25PFI is available at Aetrix Electronics and suitable for real-time motion controllers, redundant PLC backplanes, avionics display processors, and medical imaging data buffers requiring stable component supply across extended industrial lifecycles.
Supply support for IDT71421LA25PFI 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 solutions for high-performance computing and communications infrastructure.
IDT71421LA25PFI belongs to the IDT71321/71421 dual-port SRAM product line, designed specifically for deterministic interprocessor communication in industrial and aerospace systems requiring hardware-enforced write arbitration and low-power data retention.
FAQ
What is the exact role of IDT71421LA25PFI in a MASTER/SLAVE dual-port SRAM system?
IDT71421LA25PFI functions exclusively as a SLAVE device: its BUSY pins (BUSYL/BUSYR) are inputs that accept write-inhibit signals from a MASTER IDT71321, and it contains no internal arbitration logic. It relies entirely on external BUSY assertion to prevent simultaneous writes to the same address - a core requirement for error-free 16-bit-or-wider memory expansion.
Does IDT71421LA25PFI support battery backup, and what is the minimum voltage for data retention?
Yes, IDT71421LA25PFI supports battery backup operation with guaranteed data retention down to 2.0 V (VDR = 2.0 V), as specified in Table 6 of the datasheet. This allows continuous memory hold during main power loss using standard 2 V coin cells, with typical data retention current (ICCDR) of 100 µA at +25°C.
How are the interrupt flags (INTL and INTR) triggered and cleared on IDT71421LA25PFI?
INTL is asserted when the right port writes to address 7FEh (hex); INTR is asserted when the left port writes to 7FFh (hex). Both flags are cleared by reading the respective address with CE and OE active (e.g., CEL=OEL=VIL for INTL). The flags are open-drain outputs and require external pull-up resistors per datasheet Figure 3.
What package options are available for IDT71421LA25PFI, and which one is used in the PFI suffix variant?
IDT71421LA25PFI is offered in 64-pin TQFP (PNG64) and 64-pin STQFP (PPG64) packages. The "PFI" suffix explicitly denotes the 64-pin TQFP (PNG64) package with industrial temperature range (−40°C to +85°C) and lead-free/RoHS compliance, as confirmed in the ordering information section of the datasheet.
Can IDT71421LA25PFI operate as a standalone dual-port RAM without a MASTER device?
Yes, IDT71421LA25PFI can operate as a standalone dual-port RAM, but only in non-contention scenarios: BUSYL and BUSYR must be held high (e.g., tied to VCC via pull-up) since they are inputs with no internal pull-ups. In this mode, interrupt and asynchronous dual-port functions remain fully operational, but hardware write arbitration is disabled.
71421LA25PFI 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-TQFP (14x14)
71421LA25PFI FAQ
1.How can I place an order for 71421LA25PFI through Aetrix?
Please submit a Request for Quotation (RFQ) for 71421LA25PFI 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 71421LA25PFI reliable?
The price and inventory of 71421LA25PFI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71421LA25PFI is usually 5 days.
3.What payment methods are accepted for 71421LA25PFI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71421LA25PFI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71421LA25PFI?
71421LA25PFI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71421LA25PFI 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 71421LA25PFI?
For technical support, including 71421LA25PFI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71421LA25PFI requirements.
6.How does Aetrix verify that 71421LA25PFI is sourced from the original manufacturer or authorized distributors?
All 71421LA25PFI 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 71421LA25PFI meets industry standards.
7.What is the process for return or replacement of 71421LA25PFI?
All 71421LA25PFI units undergo pre-shipment inspection (PSI). If there is an issue with 71421LA25PFI, 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 71421LA25PFI part is unused and in its original packaging.
Return procedure for 71421LA25PFI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71421LA25PFI 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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AT24C02C-SSHM-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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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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