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Renesas 71321SA55TF
- Part No.:
- 71321SA55TF
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321SA55TF.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,033
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Product details
Overview
71321SA55TF from Integrated Device Technology is a high-speed 2K × 8 dual-port static RAM with interrupt logic and on-chip arbitration, designed as a MASTER device for interprocessor communication. It delivers 55 ns max access time, operates at 5 V ±10%, supports industrial temperature range (–40°C to +85°C), and features open-drain BUSY/INT outputs requiring 270 Ω pull-up resistors. It is used in real-time embedded systems requiring concurrent CPU/DSP memory access without external arbitration logic.
For engineers reviewing the 71321SA55TF datasheet, 71321SA55TF pinout, 71321SA55TF application, or 71321SA55TF equivalent, key selection criteria include its 55 ns read cycle time, dual independent port timing (tRC = 55 ns), MASTER-specific BUSY output and arbitration logic, interrupt mailbox addressing (7FEh/7FFh), and compatibility with IDT71421SLAVE devices for 16-bit+ width expansion.
Technical Context
The 71321SA55TF implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port-enabling simultaneous read/write access to any memory location. Its on-chip arbitration logic resolves contention via BUSY flag generation based on chip enable (CE) and address match timing, with priority set-up time tAPS = 5 ns.
As a MASTER device, it drives BUSYL/BUSYR as open-drain outputs (requiring external 270 Ω pull-ups) and provides two interrupt flags (INTL/INTR) tied to dedicated mailbox addresses (7FEh and 7FFh). It does not support battery backup-only LA variants do-confirming 71321SA55TF is a standard-power, non-retention variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2K × 8 bits (2048 words × 8-bit data width), sufficient for small real-time buffers or dual-CPU shared scratchpad. |
| Access Time (tAA) | 55 ns max - defines minimum address hold before valid data appears; critical for synchronizing with fast microcontrollers. |
| Read Cycle Time (tRC) | 55 ns max - determines maximum sustained read throughput (≈18.2 MHz) per port under worst-case conditions. |
| Supply Voltage | 4.5 V to 5.5 V - TTL-compatible single 5 V supply; no auxiliary rails or voltage regulators required. |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments including motor control, PLCs, and telecom line cards. |
| Power Consumption | Active: 110 mA typ. (550 mW @ 5 V); Standby (ISB1): 20 mA typ. - enables low-duty-cycle power management in burst-mode systems. |
| Interrupt Address Map | INTL asserted on right-port write to 7FEh; INTR asserted on left-port write to 7FFh - enables hardware-synchronized message passing without polling. |
Pinout & Package
71321SA55TF is packaged in a 64-pin STQFP (PPG64), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad (not electrically connected). Pin assignments are identical across 64-pin TQFP and STQFP variants per datasheet Figure 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left-port address inputs | 11-bit address bus for left-side access; decodes 2K locations (000h–7FFh). |
| A0R–A10R | Right-port address inputs | Independent 11-bit address bus enabling concurrent access to same or different memory locations. |
| 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 | Electrically isolated from left port; no bus contention risk during simultaneous reads/writes. |
| CEL / CER | Chip enable (left/right) | Active-low enables respective port; controls automatic power-down (ISB1/ISB2 modes). |
| OEL / OER | Output enable (left/right) | Active-low enables data drivers; allows tri-state control independent of CE. |
| R/WL / R/WR | Read/write control (left/right) | High = read, low = write; determines direction of I/O bus for each port. |
| BUSYL / BUSYR | Busy flag (output only) | Open-drain MASTER outputs; require 270 Ω pull-up; signal write contention to inhibit overlapping writes. |
| INTL / INTR | Interrupt flags (output only) | Open-drain outputs asserting on mailbox writes (7FEh/7FFh); support level-triggered CPU interrupt servicing. |
| VCC / GND | Power supply pins | Multiple VCC (pins 33, 47, 64) and GND (pins 32, 46, 63) pins ensure low-noise, low-impedance distribution. |
Key Features
| Feature | Design Value |
|---|---|
| On-chip arbitration logic | Resolves port-to-port address contention without external logic; asserts BUSY within 20 ns (tBAA) to block conflicting writes. |
| Dual independent interrupt mailboxes | Hardware-interrupt generation via dedicated SRAM addresses (7FEh/7FFh), eliminating software polling overhead in real-time OS tasks. |
| Master-only BUSY output architecture | Enables scalable width expansion: one 71321SA55TF MASTER coordinates multiple IDT71421 SLAVEs without external AND gates. |
| Full asynchronous dual-port operation | Each port operates independently-no clock required; timing governed solely by CE/R/W/OE setup/hold constraints. |
| TTL-compatible 5 V interface | Direct connection to legacy microcontrollers (e.g., 80C51, TMS320C2x) without level-shifting or bus buffers. |
Applications
| Industrial PLC Data Exchange | DSP + Microcontroller Shared Memory |
|---|---|
|
Use Scenario: Two independent processors (e.g., ARM Cortex-M7 and TI C6748 DSP) share sensor fusion results and control commands in real time. IC Role / Device Role / Timing Role: 71321SA55TF acts as MASTER dual-port RAM, providing concurrent, lock-free access with hardware arbitration and interrupt-driven mailbox signaling. Use Value: Eliminates software semaphores and reduces inter-processor latency to ≤55 ns, enabling deterministic sub-10 µs response in closed-loop motion control. |
Use Scenario: A motor drive system uses one processor for field-oriented control (FOC) and another for safety monitoring and diagnostics. IC Role / Device Role / Timing Role: 71321SA55TF serves as shared buffer for current/voltage samples and fault logs, with BUSY preventing write collisions during simultaneous updates. Use Value: Guarantees atomic mailbox writes (7FEh/7FFh) and prevents data corruption during concurrent FOC loop execution and safety watchdog checks. |
| Redundant Communication Controller Buffer | Legacy Bus Bridge Interface |
|
Use Scenario: Dual CAN/FlexRay controllers exchange status and configuration data in automotive gateway ECUs. IC Role / Device Role / Timing Role: 71321SA55TF functions as MASTER inter-processor RAM, using INTL/INTR to signal frame readiness and BUSY to serialize configuration writes. Use Value: Enables fail-operational behavior: if primary controller fails, secondary assumes full control using consistent, collision-free shared state. |
Use Scenario: Bridging ISA-bus industrial PC to modern FPGA-based I/O module via parallel memory-mapped interface. IC Role / Device Role / Timing Role: 71321SA55TF provides synchronous, low-latency handshaking between legacy 8/16-bit host and high-speed peripheral. Use Value: Replaces discrete glue logic (latches, arbiters, interrupt encoders) with single IC, reducing BOM count and PCB area by >40%. |
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 CY7C1362V-55AXC | 55 ns access, 2K × 16 organization, 3.3 V core (5 V tolerant I/O), no built-in BUSY arbitration logic. | Requires external logic for port contention resolution; better suited for 16-bit native buses but adds design complexity. | Select when migrating to lower-voltage systems and external arbitration is acceptable; avoid when minimizing component count is critical. |
| IDT71421SA55TF | Same speed grade and package, but SLAVE-only: BUSY pins are inputs (not outputs), no on-chip arbitration logic. | Cannot operate standalone; must be paired with a MASTER (e.g., 71321SA55TF) for width expansion or arbitration. | Use only as companion SLAVE in 16-bit+ memory arrays; never a functional substitute for 71321SA55TF's MASTER capabilities. |
Compared with CY7C1362V-55AXC and IDT71421SA55TF, the 71321SA55TF uniquely integrates MASTER arbitration, interrupt mailboxes, and open-drain BUSY/INT outputs-making it the only drop-in solution for compact, low-latency dual-processor designs requiring zero external logic for synchronization.
Availability
71321SA55TF is available at Aetrix Electronics and suitable for industrial PLCs, motor drive controllers, redundant automotive gateways, and legacy bus bridge interfaces requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.
Supply support for 71321SA55TF 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 product line was engineered specifically for real-time embedded systems requiring deterministic, hardware-arbitrated memory sharing between heterogeneous processors-prioritizing low latency, industrial reliability, and minimal external component count.
FAQ
What is the function of the BUSY pins on the 71321SA55TF?
The BUSYL and BUSYR pins on the 71321SA55TF are open-drain outputs that signal write contention when both ports attempt simultaneous access to the same memory address. They require external 270 Ω pull-up resistors and assert low to inhibit writes on the contending port. This hardware arbitration eliminates the need for software locks or external logic, ensuring deterministic behavior in real-time systems using the 71321SA55TF.
Can the 71321SA55TF operate with a 3.3 V supply?
No, the 71321SA55TF is specified only for 5 V ±10% operation (4.5 V to 5.5 V) and is not 3.3 V compatible. Its input thresholds (VIH = 2.2 V min, VIL = 0.8 V max) and internal circuitry are designed for TTL-level signaling. Using 3.3 V will result in undefined operation, failed arbitration, or permanent damage. For 3.3 V systems, consider newer alternatives like Renesas IS61WV25616BLL-10MLI, not the 71321SA55TF.
How do the interrupt flags (INTL and INTR) work on the 71321SA55TF?
The 71321SA55TF uses dedicated SRAM addresses 7FEh (left port) and 7FFh (right port) as interrupt mailboxes. Writing to 7FEh with the right port asserts INTL; writing to 7FFh with the left port asserts INTR. Both flags are open-drain outputs requiring pull-ups. Clearing is done by reading the same address. This enables hardware-triggered, low-latency interprocessor messaging without polling-core to the 71321SA55TF's real-time design.
Is the 71321SA55TF suitable for battery-backed applications?
No, the 71321SA55TF is an SA (standard power) variant and does not support battery backup or data retention below 4.5 V. Only LA variants (e.g., 71321LA55TF) guarantee 2 V data retention. Attempting battery backup with the 71321SA55TF will result in immediate data loss when VCC drops below ~3.5 V. Select the LA version explicitly if nonvolatile retention is required-71321SA55TF is intended for main-supply-only operation.
What package type is used for the 71321SA55TF?
The 71321SA55TF is supplied in a 64-pin STQFP (Small Thin Quad Flat Package), also designated PPG64 per IDT documentation. Its dimensions are 10 mm × 10 mm × 1.4 mm with an exposed thermal pad. This package is pin-compatible with the 64-pin TQFP (PNG64) variant, though mechanical mounting differs. The 71321SA55TF is not offered in PLCC or 52-pin packages-those apply to other speed grades or variants, not this specific part.
71321SA55TF 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:
- 55ns
- Access Time:
- 55 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)
71321SA55TF FAQ
1.How can I place an order for 71321SA55TF through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321SA55TF 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 71321SA55TF reliable?
The price and inventory of 71321SA55TF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321SA55TF is usually 5 days.
3.What payment methods are accepted for 71321SA55TF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321SA55TF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321SA55TF?
71321SA55TF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321SA55TF 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 71321SA55TF?
For technical support, including 71321SA55TF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321SA55TF requirements.
6.How does Aetrix verify that 71321SA55TF is sourced from the original manufacturer or authorized distributors?
All 71321SA55TF 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 71321SA55TF meets industry standards.
7.What is the process for return or replacement of 71321SA55TF?
All 71321SA55TF units undergo pre-shipment inspection (PSI). If there is an issue with 71321SA55TF, 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 71321SA55TF part is unused and in its original packaging.
Return procedure for 71321SA55TF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321SA55TF Tags
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