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Renesas 71321SA55PF
- Part No.:
- 71321SA55PF
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71321SA55PF.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
Inventory:2,391
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Product details
Overview
71321SA55PF 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 read cycle time, supports TTL-compatible 5V ±10% supply, operates across industrial temperature (–40°C to +85°C), and features open-drain BUSY/INT outputs requiring 270 Ω pull-up resistors - used in real-time embedded control systems requiring concurrent memory access.
For engineers reviewing the 71321SA55PF datasheet, 71321SA55PF pinout, 71321SA55PF application, or 71321SA55PF equivalent, key selection criteria include its 55 ns timing grade, MASTER-only arbitration logic, dual-interrupt flag support (INTL/INTR), BUSY output behavior, and compatibility with IDT71421SLAVE devices in 16-bit+ width expansions.
Technical Context
The 71321SA55PF implements fully asynchronous dual-port operation with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves port contention using chip-enable and address-match detection - asserting BUSYL/BUSYR outputs when both ports access the same 2K × 8 memory location simultaneously.
Interrupt functionality is implemented via dedicated mailbox addresses: writing to 7FEH sets INTL; reading from 7FEH clears it. Similarly, 7FFH controls INTR. Both flags are active-low, open-drain outputs requiring external pull-ups, and operate independently of data bus activity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), 16,384 total bits - supports byte-wide parallel data paths per port |
| Max Read Cycle Time (tRC) | 55 ns - defines minimum time between successive read operations on same port |
| Supply Voltage | 5.0 V ±10% (4.5–5.5 V) - single TTL-compatible rail; all VCC pins must be connected |
| Operating Temperature | –40°C to +85°C - qualified for industrial environments without derating |
| Standby Current (ISB1) | 20 mA max (both ports disabled, TTL-level inputs) - enables low-power idle states in multi-processor systems |
| Output Type | Open-drain BUSY/INT pins - require 270 Ω external pull-up for proper logic level assertion |
| Interrupt Mailbox Addresses | 7FEH (left port INTL), 7FFH (right port INTR) - user-accessible SRAM locations with dedicated flag semantics |
Pinout & Package
71321SA55PF is packaged in a 52-pin STQFP (PPG52), measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad (not electrically connected). All VCC and GND pins must be individually decoupled per datasheet layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0L–A10L | Left port address inputs | 11-bit address bus for left-side memory access (0–2047) |
| A0R–A10R | Right port address inputs | 11-bit address bus for right-side memory access (0–2047) |
| 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 (left/right) | Active-low enables port; drives internal power-down when high |
| OEL / OER | Output enable (left/right) | Active-low enables I/O drivers; does not affect CE-controlled standby |
| R/WL / R/WR | Read/write control (left/right) | Active-low write; high = read (outputs enabled only if OE and CE also active) |
| BUSYL / BUSYR | BUSY flag (output only) | Open-drain outputs indicating port contention; require 270 Ω pull-up to VCC |
| INTL / INTR | Interrupt flags (output only) | Open-drain interrupt indicators tied to mailbox writes at 7FEH/7FFH |
| VCC, GND | Power and ground | Multiple dedicated pins - all must be connected; decoupling required per pin |
Key Features
| Feature | Design Value |
|---|---|
| On-chip port arbitration logic | Resolves simultaneous left/right access to same address without external logic - eliminates race conditions in dual-CPU systems |
| Dual interrupt mailbox architecture | Hardware-accelerated interprocessor signaling via dedicated SRAM addresses (7FEH/7FFH), reducing software overhead |
| 55 ns industrial-grade timing | Guaranteed performance at –40°C to +85°C, enabling deterministic real-time response in motor control and avionics |
| Master-only BUSY output capability | Enables scalable width expansion with IDT71421 SLAVE devices - one MASTER arbitrates, multiple SLAVES obey BUSY input |
| TTL-compatible 5V interface | Direct connection to legacy microcontrollers and FPGAs without level-shifting circuitry |
Applications
| Industrial PLC Memory Buffer | Avionics Dual-Processor Data Exchange |
|---|---|
Use Scenario: Two independent CPUs in a programmable logic controller share status registers and I/O mapping tables via shared memory. IC Role / Device Role / Timing Role: 71321SA55PF acts as MASTER dual-port RAM, providing synchronized, contention-free access to 2K × 8 shared memory with hardware arbitration. Use Value: Eliminates software semaphores and polling delays; 55 ns access ensures sub-microsecond inter-CPU message latency. |
Use Scenario: Flight management unit (FMU) and autopilot processor exchange navigation updates and fault reports in real time. IC Role / Device Role / Timing Role: 71321SA55PF serves as interrupt-enabled shared memory buffer, with mailbox-based signaling at 7FEH/7FFH. Use Value: Hardware interrupts replace polling loops, reducing CPU load by >40% and guaranteeing <100 ns response to critical events. |
| Medical Imaging Frame Buffer | Test Equipment Pattern Generator |
Use Scenario: MRI scanner subsystem uses one processor for image acquisition and another for real-time reconstruction. IC Role / Device Role / Timing Role: 71321SA55PF provides non-blocking memory access for streaming raw pixel data into reconstruction pipeline. Use Value: Asynchronous dual-port operation prevents acquisition stalls during reconstruction bursts; 55 ns timing meets 18 MHz pixel clock requirements. |
Use Scenario: Automated test equipment streams stimulus patterns from host PC while DUT reads responses concurrently. IC Role / Device Role / Timing Role: 71321SA55PF functions as MASTER in width-expanded configuration with IDT71421 SLAVEs for 16-bit pattern storage. Use Value: BUSY-driven arbitration ensures glitch-free pattern updates during active DUT testing - no firmware intervention needed. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-port SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT71321SA35PF | 35 ns max read cycle time; lower speed grade, same PPG52 package and pinout | Suitable for cost-sensitive designs where 55 ns timing margin is excessive | Select when system clock constraints allow relaxed timing and lower power consumption is prioritized |
| Cypress CY7C024AV-55AXC | 55 ns, 2K × 8, but lacks integrated BUSY arbitration and interrupt mailboxes; requires external logic for contention resolution | Used where custom arbitration or simplified interrupt handling is acceptable | Choose only if existing design already implements external arbitration or interrupt state machines |
Compared with IDT71321SA35PF, the 71321SA55PF trades higher speed for identical feature set and package; compared with CY7C024AV-55AXC, it delivers integrated arbitration and mailbox interrupts - eliminating up to 4 external logic ICs and reducing PCB area by 12 mm².
Availability
71321SA55PF is available at Aetrix Electronics and suitable for industrial PLC memory buffers, avionics dual-processor data exchange, and medical imaging frame buffers requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature compliance.
Supply support for 71321SA55PF 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 power solutions for communications, computing, and industrial markets.
The IDT71321 family was engineered specifically for deterministic, low-latency interprocessor communication in real-time embedded systems - emphasizing hardware arbitration, interrupt offload, and industrial-grade reliability over general-purpose SRAM functionality.
FAQ
What is the function of the BUSY pins on the 71321SA55PF?
The BUSYL and BUSYR pins on the 71321SA55PF are open-drain outputs that signal port contention - asserted low when both left and right ports attempt simultaneous access to the same memory address. They require 270 Ω pull-up resistors to VCC. Unlike SLAVE devices, the 71321SA55PF never accepts BUSY as an input; it only generates BUSY signals as a MASTER device.
How do the interrupt mailboxes work in the 71321SA55PF?
The 71321SA55PF uses SRAM addresses 7FEH and 7FFH as hardware-managed interrupt mailboxes: a write to 7FEH from the right port sets INTL; a write to 7FFH from the left port sets INTR. Reading those addresses clears the respective flags. Both are active-low, open-drain outputs requiring external pull-ups - no software polling is needed.
Can the 71321SA55PF operate with a 3.3V supply?
No. The 71321SA55PF is strictly a 5V device, specified for 4.5 V to 5.5 V operation per its Recommended DC Operating Conditions. It is TTL-compatible and not 3.3V tolerant - applying 3.3V to VCC or inputs will result in undefined operation and potential damage. Level-shifting circuitry is required for interfacing with 3.3V controllers.
Is the 71321SA55PF pin-compatible with the IDT71421 SLAVE device?
No. The 71321SA55PF and IDT71421 are functionally complementary but not pin-compatible. While both use the same PPG52 package footprint, BUSYL/BUSYR are outputs on the 71321SA55PF (MASTER) but inputs on the IDT71421 (SLAVE), and their internal logic connections differ. Direct substitution would cause functional failure - they are intended for coordinated use in MASTER/SLAVE pairs, not interchangeability.
What is the data retention capability of the 71321SA55PF?
The 71321SA55PF is the SA (Standard Active) version and does not support battery backup data retention. Only the LA (Low-power Active) variants (e.g., 71321LA55PF) guarantee 2V data retention. The 71321SA55PF requires continuous 5V supply to maintain memory contents - loss of VCC results in immediate data loss.
71321SA55PF 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 (14x14)
71321SA55PF FAQ
1.How can I place an order for 71321SA55PF through Aetrix?
Please submit a Request for Quotation (RFQ) for 71321SA55PF 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 71321SA55PF reliable?
The price and inventory of 71321SA55PF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71321SA55PF is usually 5 days.
3.What payment methods are accepted for 71321SA55PF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71321SA55PF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71321SA55PF?
71321SA55PF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71321SA55PF 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 71321SA55PF?
For technical support, including 71321SA55PF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71321SA55PF requirements.
6.How does Aetrix verify that 71321SA55PF is sourced from the original manufacturer or authorized distributors?
All 71321SA55PF 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 71321SA55PF meets industry standards.
7.What is the process for return or replacement of 71321SA55PF?
All 71321SA55PF units undergo pre-shipment inspection (PSI). If there is an issue with 71321SA55PF, 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 71321SA55PF part is unused and in its original packaging.
Return procedure for 71321SA55PF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
71321SA55PF Tags
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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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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