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Renesas 71321LA25TFGI
- Part No.:
- 71321LA25TFGI
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321LA25TFGI.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:1,395
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Product details
Overview
71321LA25TFGI from IDT (now part of Renesas) is a high-speed 2K × 8 dual-port static RAM with interrupt and BUSY arbitration logic, designed as a MASTER device for interprocessor communication. It delivers 25 ns max access time, 1 mW standby power, 2 V data retention, and operates on single 5V ±10% supply across –40°C to +85°C industrial temperature range - used in real-time embedded control systems requiring concurrent read/write access.
For engineers reviewing the 71321LA25TFGI datasheet, 71321LA25TFGI pinout, 71321LA25TFGI application, or 71321LA25TFGI equivalent, key selection criteria include dual-port arbitration timing (tBAA/tBDD), interrupt mailbox addressing (7FEh/7FFh), battery-backed data retention at 2 V, open-drain BUSY/INT outputs requiring 270 Ω pull-ups, and compatibility with IDT71421LA SLAVE devices in 16-bit+ width expansions.
Technical Context
The 71321LA25TFGI implements fully asynchronous dual-port operation with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port contention via BUSY flag generation based on chip enable (CEL/CER) and address match detection - not R/W state - ensuring deterministic write inhibition during simultaneous access to identical addresses.
Interrupt functionality uses dedicated mailbox addresses (7FEh for INTL, 7FFh for INTR) with edge-triggered flag assertion and software-clear capability. The device supports battery backup mode (2 V VCC) with ≤100 µA typical retention current, and features TTL-compatible inputs/outputs with open-drain BUSY/INT pins requiring external 270 Ω pull-up resistors per datasheet Figure 3.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit wide), enabling compact shared memory buffers between two processors or subsystems |
| Access Time | 25 ns (max) - guarantees sub-40 MHz synchronous interface timing when used with FPGA or microcontroller peripherals |
| Standby Current | 1 mW typ. (≈200 µA at 5 V) - enables ultra-low-power hold mode during system sleep without data loss |
| Data Retention | 2 V minimum VCC - allows direct connection to coin-cell battery (e.g., CR2032) for nonvolatile memory preservation during main power loss |
| Operating Temp | –40°C to +85°C - qualified for industrial control, motor drives, and transportation electronics without derating |
| Supply Voltage | 5.0 V ±10% - compatible with legacy 5 V logic families and eliminates need for level-shifting in mixed-voltage systems |
| Interrupt Logic | Dedicated mailbox addresses 7FEh (INTL) and 7FFh (INTR) - provides hardware-synchronized inter-processor signaling without polling overhead |
Pinout & Package
71321LA25TFGI is packaged in a 64-pin TQFP (PNG64) with 0.5 mm pitch, 14 mm × 14 mm body, and exposed thermal pad. Pin functions are symmetric for left/right ports, with dedicated BUSY/INT open-drain outputs requiring 270 Ω pull-up resistors.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L / A0R–A10R | Address Inputs (Left/Right) | 11-bit address bus per port - supports full 2K-word addressing independently on each side |
| I/O0L–I/O7L / I/O0R–I/O7R | Bidirectional Data Bus (Left/Right) | 8-bit parallel data path per port - enables simultaneous read/write operations without bus contention |
| CEL / CER | Chip Enable (Left/Right) | Active-low enable controlling port power-down - sets ISB1/ISB2/ISB4 standby current states per datasheet Table 04a/b |
| OEL / OER | Output Enable (Left/Right) | Active-low control for output drivers - places I/O pins in high-Z when deasserted to prevent bus conflicts |
| R/WL / R/WR | Read/Write Control (Left/Right) | Direction control for bidirectional I/O - HIGH = read, LOW = write per Truth Table I |
| BUSYL / BUSYR | BUSY Flag (Output on Master) | Open-drain output indicating port contention - requires 270 Ω pull-up; asserts LOW when opposite port accesses same address |
| INTL / INTR | Interrupt Flag (Output) | Open-drain interrupt output - asserts LOW when mailbox 7FEh (INTL) or 7FFh (INTR) is written by opposite port |
| VCC / GND | Power & Ground | Multiple VCC/GND pins distributed for low-noise operation - all must be connected per datasheet Note 1 & 2 |
Key Features
| Feature | Design Value |
|---|---|
| On-chip arbitration logic | Resolves simultaneous access to identical addresses without external logic - eliminates race conditions in multi-CPU systems |
| Hardware interrupt mailboxes | Fixed 7FEh/7FFh locations provide zero-software-overhead inter-processor signaling - reduces latency vs. polling-based schemes |
| 2 V data retention | Enables seamless battery backup without external supervisor IC - preserves SRAM contents during AC power failure or brownout |
| Open-drain BUSY/INT outputs | Allows wired-OR connection of multiple devices - simplifies system-level BUSY bus implementation in expanded memory arrays |
| Master-only BUSY generation | Only IDT71321 variants (not IDT71421) drive BUSY outputs - ensures deterministic arbitration in MASTER/SLAVE configurations |
Applications
| Industrial PLC Communication Buffer | Real-Time Motor Control Co-Processor Interface |
|---|---|
Use Scenario: Two independent microcontrollers exchange status, setpoints, and fault codes in a programmable logic controller chassis. IC Role / Device Role / Timing Role: 71321LA25TFGI acts as MASTER dual-port RAM providing synchronized, contention-free memory sharing with hardware arbitration and interrupt signaling. Use Value: Eliminates software semaphores and polling delays; 25 ns access enables sub-10 µs message round-trip latency between CPUs. | Use Scenario: A motion controller CPU offloads trajectory calculation to a co-processor while maintaining real-time servo loop execution. IC Role / Device Role / Timing Role: 71321LA25TFGI serves as low-latency shared memory with mailbox interrupts triggering task handoff between controllers. Use Value: Enables deterministic inter-CPU handshaking; 2 V retention preserves motion profile data during brief power interruptions. |
| Redundant Avionics Data Exchange | Medical Imaging Subsystem Synchronization |
Use Scenario: Dual-redundant flight management units exchange sensor fusion results and health monitoring data. IC Role / Device Role / Timing Role: 71321LA25TFGI operates as MASTER in a fault-tolerant dual-port buffer with BUSY arbitration preventing corrupted writes during failover transitions. Use Value: Hardware-enforced atomicity ensures data consistency without software intervention - critical for DO-254 compliance. | Use Scenario: MRI subsystem modules (gradient control, RF pulse generation, image reconstruction) coordinate timing-critical operations. IC Role / Device Role / Timing Role: 71321LA25TFGI provides synchronized memory access between real-time DSP and ARM-based host processor using interrupt mailboxes. Use Value: 25 ns access and deterministic arbitration meet <100 ns jitter requirements for pulse sequence synchronization. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CY7C136-25JC | 2K × 8, 25 ns, 5 V, but no built-in BUSY arbitration or interrupt logic - requires external glue logic for contention handling | Lacks hardware mailbox interrupts and automatic port arbitration - increases PCB area and firmware complexity | Select when cost sensitivity outweighs need for integrated arbitration; verify external logic meets tBDD/tAPS timing |
| IDT71421LA25TFGI | Same package, speed, and retention, but SLAVE-only - BUSY pin is input only, no arbitration logic, no INT flag generation | Must be paired with IDT71321LA as MASTER; cannot operate standalone as arbitration node | Use only in width-expanded systems where 71321LA25TFGI serves as MASTER and 71421LA devices extend data bus to 16+ bits |
Compared with CY7C136-25JC, 71321LA25TFGI integrates arbitration and interrupts - reducing BOM count and firmware latency. Compared with IDT71421LA25TFGI, it provides autonomous MASTER functionality essential for standalone dual-CPU designs without external coordination logic.
Availability
71321LA25TFGI is available at Aetrix Electronics and suitable for industrial PLCs, avionics data exchange, and medical imaging subsystems requiring stable component supply, long-term lifecycle support, and guaranteed 2 V data retention capability.
Supply support for 71321LA25TFGI 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 IDT71321/71421 family was engineered specifically for deterministic interprocessor communication in real-time embedded systems - emphasizing hardware arbitration, low-latency interrupts, and battery-backed data integrity over raw density or speed.
FAQ
What is the function of the BUSY pin on the 71321LA25TFGI?
The BUSY pin on the 71321LA25TFGI is an open-drain output that asserts LOW when the opposite port attempts to access the same memory address simultaneously - indicating contention. As a MASTER device, it generates this signal autonomously using CE and address match detection (per Truth Table III). External 270 Ω pull-up resistors are required per datasheet Figure 3. This signal directly inhibits writes on the contending port without software intervention.
How does the interrupt functionality work in the 71321LA25TFGI?
The 71321LA25TFGI uses fixed mailbox addresses: writing to 7FEh (hex) via the right port asserts INTL (left interrupt), and writing to 7FFh via the left port asserts INTR (right interrupt). Flags are cleared by reading the same address with OE and CE active. These are hardware-generated, edge-triggered signals - no polling required. The 71321LA25TFGI implements this entirely on-die; no external logic or firmware flags are needed for basic inter-processor signaling.
Can the 71321LA25TFGI operate with a 3.3 V supply?
No. The 71321LA25TFGI is specified exclusively for 5.0 V ±10% operation (4.5 V to 5.5 V) per Recommended DC Operating Conditions (Table 03). It is TTL-compatible and not 3.3 V tolerant. Applying 3.3 V will result in undefined behavior, failure to meet timing specs (e.g., tAA, tRC), and potential data retention loss below 4.5 V. For 3.3 V systems, level translation or alternative dual-port SRAMs (e.g., IDT70V27L) must be used.
What is the significance of the "LA" suffix in 71321LA25TFGI?
The "LA" suffix in 71321LA25TFGI denotes the Low-Power, Battery-Backup variant. It guarantees 2 V data retention (vs. SA's 4.5 V minimum), achieves 1 mW typical standby power (vs. SA's 5 mW), and targets industrial temperature range (–40°C to +85°C). The "25" indicates 25 ns maximum access time, "T" = TQFP package, "F" = lead-free, "G" = RoHS-compliant, and "I" = industrial temperature grade - all confirmed in IDT DSC-2691/17 datasheet Section 1 and Ordering Information.
How does the 71321LA25TFGI differ from the IDT71421LA25TFGI?
The 71321LA25TFGI is the MASTER dual-port SRAM with on-chip arbitration logic, BUSY output pins, and interrupt flag generation. The IDT71421LA25TFGI is the SLAVE device: its BUSY pins are inputs (not outputs), it lacks arbitration logic, and it cannot generate INTL/INTR flags. They share identical memory size, speed, and package - but 71321LA25TFGI operates standalone as a dual-CPU buffer, while IDT71421LA25TFGI only functions in width-expanded systems under control of a 71321LA25TFGI MASTER.
71321LA25TFGI 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 (10x10)
71321LA25TFGI FAQ
1.How can I place an order for 71321LA25TFGI through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321LA25TFGI 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 71321LA25TFGI reliable?
The price and inventory of 71321LA25TFGI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321LA25TFGI is usually 5 days.
3.What payment methods are accepted for 71321LA25TFGI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321LA25TFGI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321LA25TFGI?
71321LA25TFGI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321LA25TFGI 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 71321LA25TFGI?
For technical support, including 71321LA25TFGI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321LA25TFGI requirements.
6.How does Aetrix verify that 71321LA25TFGI is sourced from the original manufacturer or authorized distributors?
All 71321LA25TFGI 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 71321LA25TFGI meets industry standards.
7.What is the process for return or replacement of 71321LA25TFGI?
All 71321LA25TFGI units undergo pre-shipment inspection (PSI). If there is an issue with 71321LA25TFGI, 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 71321LA25TFGI part is unused and in its original packaging.
Return procedure for 71321LA25TFGI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321LA25TFGI Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
Microchip Technology
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AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
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24LC01BT-I/OT
Microchip Technology
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M24C02-FMC6TG
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AT24CS02-SSHM-T
Microchip Technology
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93LC46BT-I/OT
Microchip Technology
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AT24C04C-SSHM-T
Microchip Technology
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24LC01BT-I/SN
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24AA02UIDT-I/OT
Microchip Technology
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AT24C08C-STUM-T
Microchip Technology
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