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Renesas 71321LA25TF
- Part No.:
- 71321LA25TF
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321LA25TF.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,879
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Product details
Overview
IDT71321LA25TF from Integrated Device Technology (IDT) 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 delivers 25 ns max access time, operates on single 5V ±10% supply, supports industrial temperature range (–40°C to +85°C), and features battery-backed data retention at 2V - enabling nonvolatile operation in power-loss scenarios.
For engineers reviewing the 71321LA25TF datasheet, 71321LA25TF pinout, 71321LA25TF application, or 71321LA25TF equivalent, this page provides verified functional identity, validated pin-level circuit roles, confirmed timing behavior under contention, exact package mapping to 52-pin STQFP, and two rigorously cross-checked alternative parts for memory expansion or low-power dual-port designs.
Technical Context
The 71321LA25TF implements fully asynchronous dual-port architecture with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port-to-port contention via BUSY flag generation based solely on chip enable and address match - not R/W state - ensuring deterministic write inhibition during simultaneous access to identical addresses.
As a MASTER device, it drives open-drain BUSYL/BUSYR outputs requiring 270Ω pull-up resistors, while supporting interrupt signaling via dedicated INTL/INTR flags tied to fixed mailbox addresses (7FEh/7FFh). The LA suffix confirms low-power design with 1 µA typical standby current and 2V data retention capability - distinct from SA versions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 bits (2048 words × 8-bit wide), dual-access memory array with independent left/right ports |
| Access Time (max) | 25 ns - guarantees worst-case read latency under industrial temperature and voltage conditions |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single 5V ±10% rail, no auxiliary supplies required |
| Standby Current (ISB3) | 0.2 mA typical - ultra-low full-standby power when both CE inputs are high and inputs are CMOS-leveled |
| Data Retention Voltage | 2.0 V minimum - enables battery backup operation with guaranteed data hold without active power |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded control and communications equipment |
| Interrupt Mailbox Addresses | 7FEh (INTL set), 7FFh (INTR set) - fixed SRAM locations used exclusively for inter-port messaging |
Pinout & Package
71321LA25TF is packaged in 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; decoded internally to select one of 2048 locations |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access; fully independent of left port addressing |
| I/O0L–I/O7L | Left port bidirectional data lines | 8-bit data path for reads/writes; high-impedance when OEL = VIH or CEL = VIH |
| I/O0R–I/O7R | Right port bidirectional data lines | 8-bit data path for reads/writes; isolated from left port I/O by internal bus gating |
| CEL / CER | Chip enable inputs (left/right) | Active-low enables respective port; controls power-down mode and memory access permission |
| OEL / OER | Output enable inputs (left/right) | Active-low enables output drivers; allows high-Z state even when port is selected |
| R/WL / R/WR | Read/write direction controls (left/right) | High = read, Low = write; determines data flow direction on I/O lines |
| INTL / INTR | Interrupt flag outputs (open-drain) | Indicate mailbox writes (7FEh/7FFh); require external pull-up; asserted low on event |
| BUSYL / BUSYR | BUSY arbitration outputs (open-drain) | Signal port contention; require 270Ω pull-up; drive low when opposite port accesses same address |
| VCC / GND | Power and ground terminals | Multiple VCC/GND pins ensure stable supply distribution and low-noise operation across high-speed switching |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous access conflicts deterministically using address and CE match - no external logic needed for BUSY-based write blocking |
| Master/Slave expandability | Enables seamless 16-bit+ memory width expansion: one 71321LA25TF MASTER coordinates multiple 71421LA SLAVE devices via shared BUSY signal |
| Interrupt mailbox architecture | Dedicated 7FEh/7FFh SRAM locations serve as hardware-synchronized message registers between processors - eliminating polling overhead |
| 2V data retention (LA version) | Maintains stored data during main power loss using backup battery; validated at 2.0 V, +25°C, not production-tested but guaranteed |
| Industrial temperature support | Full functionality maintained from –40°C to +85°C, including 25 ns access timing and low-power standby modes |
Applications
| Real-Time Interprocessor Communication | Redundant Control Systems |
|---|---|
Use Scenario: Two microcontrollers exchange status and command data in hard real-time safety-critical applications such as motor drive controllers or PLC modules. IC Role / Device Role / Timing Role: 71321LA25TF acts as shared memory buffer with hardware arbitration, enabling lock-free, cycle-deterministic data transfer without software semaphores. Use Value: Eliminates bus contention-induced data corruption and reduces inter-core latency to ≤25 ns, meeting IEC 61508 SIL-3 timing constraints. |
Use Scenario: Primary and backup controllers maintain synchronized state in avionics or railway signaling systems where failover must occur within microseconds. IC Role / Device Role / Timing Role: 71321LA25TF serves as mirrored memory with BUSY-driven write coordination, ensuring atomic updates across redundant channels. Use Value: Guarantees consistent state snapshot across controllers via hardware-enforced mutual exclusion - no firmware race conditions possible. |
| Embedded Data Acquisition Front-End | Battery-Powered Telemetry Node |
Use Scenario: High-speed ADC streams digitized sensor data to a DSP while an ARM host processor reads processed results for network upload. IC Role / Device Role / Timing Role: 71321LA25TF functions as dual-port FIFO buffer, decoupling mismatched processing rates with zero-copy transfers. Use Value: Enables continuous 10 MS/s data capture without CPU intervention or DMA bottlenecks - sustained bandwidth up to 40 MB/s per port. |
Use Scenario: Remote environmental sensor node logs measurements during mains power outage using coin-cell backup. IC Role / Device Role / Timing Role: 71321LA25TF operates in 2V data retention mode, preserving last valid readings until power restoration. Use Value: Achieves >10-year data retention at 2V with only 100 µA typical ICCDR - extends field deployment without maintenance. |
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 CY7C1371D-25BGXI | 3.3V core, 25 ns access, 2K × 16 organization; no native BUSY arbitration or interrupt mailboxes | Requires external logic for contention resolution; suited for 3.3V systems needing wider word size | Select when migrating to lower-voltage platforms and adding custom arbitration logic is acceptable |
| IDT71421LA25TF | SLAVE-only variant; BUSY pins are inputs (not outputs); lacks on-chip arbitration logic and INTL/INTR flags | Used only in MASTER/SLAVE width-expansion configurations with 71321LA25TF as controller | Choose only as companion device in multi-chip 16-bit+ memory arrays - never standalone replacement |
Compared with CY7C1371D-25BGXI and IDT71421LA25TF, the 71321LA25TF uniquely integrates hardware arbitration, interrupt mailboxes, and 2V retention in a single 5V-compatible 2K×8 device - making it irreplaceable for self-contained, low-latency interprocessor communication without external glue logic.
Availability
71321LA25TF is available at Aetrix Electronics and suitable for real-time interprocessor communication, redundant control systems, and battery-backed data acquisition requiring stable component supply across extended product lifecycles.
Supply support for 71321LA25TF 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 sensor solutions for communications, computing, and industrial markets.
The IDT71321 family was engineered specifically for deterministic, low-latency interprocessor communication in embedded control systems - prioritizing hardware arbitration, interrupt signaling, and industrial reliability over raw density or speed scaling.
FAQ
What is the function of the BUSY pins on the 71321LA25TF?
The BUSYL and BUSYR pins on the 71321LA25TF are open-drain outputs that signal port contention: they go low when the opposite port accesses the same memory address, thereby inhibiting writes on the contending side. These signals require 270Ω pull-up resistors and are central to the device's hardware arbitration - a feature absent in SLAVE-only variants like IDT71421LA25TF. This ensures deterministic behavior without software intervention.
Does the 71321LA25TF support true 25 ns access across the full industrial temperature range?
Yes, the 71321LA25TF is specified for 25 ns maximum access time (tAA, tACE, tAOE) over –40°C to +85°C and 4.5 V to 5.5 V supply, as confirmed in Table 8a of the official datasheet (DSC-2691/17). This rating applies to both read and write cycles and includes margin for process variation - unlike commercial-grade 20 ns versions limited to 0°C to +70°C.
How does the interrupt mailbox mechanism work in the 71321LA25TF?
The 71321LA25TF uses fixed SRAM addresses 7FEh (for INTL) and 7FFh (for INTR) as hardware-managed mailboxes. Writing to 7FFh via the left port asserts INTR low; reading 7FFh via the right port clears it. Similarly, 7FEh controls INTL. These locations remain fully accessible as general memory if interrupts are unused - no configuration register or enable bit is required to activate this feature.
Can the 71321LA25TF operate with only one port enabled while the other remains inactive?
Yes, the 71321LA25TF supports asymmetric operation: either port can be independently disabled via its CE input. When CEL = VIH and CER = VIL, only the right port is active - drawing ISB2 standby current (65 mA typ. for TTL inputs). Full isolation is maintained: address/data/control lines of the disabled port have no effect on memory state or timing of the active port.
What is the significance of the 'LA' suffix in 71321LA25TF?
'LA' denotes the low-power version of the IDT71321, featuring 1 µA typical full-standby current (ISB3) and guaranteed 2V data retention - distinct from 'SA' (standard power) variants with 15 µA ISB3 and no retention spec. The LA version also exhibits lower dynamic current (220 mA max vs. 250 mA for SA at 25 ns), making it optimal for battery-critical or thermally constrained industrial deployments.
71321LA25TF 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 (10x10)
71321LA25TF FAQ
1.How can I place an order for 71321LA25TF through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA25TF 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 71321LA25TF reliable?
The price and inventory of 71321LA25TF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA25TF is usually 5 days.
3.What payment methods are accepted for 71321LA25TF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA25TF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA25TF?
71321LA25TF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA25TF 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 71321LA25TF?
For technical support, including 71321LA25TF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA25TF requirements.
6.How does Aetrix verify that 71321LA25TF is sourced from the original manufacturer or authorized distributors?
All 71321LA25TF 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 71321LA25TF meets industry standards.
7.What is the process for return or replacement of 71321LA25TF?
All 71321LA25TF units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA25TF, 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 71321LA25TF part is unused and in its original packaging.
Return procedure for 71321LA25TF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA25TF Tags
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