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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Renesas 71421SA55J

Name: 71421SA55J
Brand: Renesas
SKU: 71421SA55J
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 71421SA55J

Manufacturer:: Renesas

Category:: Memory

Package:: 52-LCC (J-Lead)

Datasheet:: 71421SA55J.pdf

Description:: IC SRAM 16KBIT PARALLEL 52PLCC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

71421SA55J 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, featuring 55 ns max read cycle time, TTL-compatible 5 V ±10% operation, and dedicated BUSY input for port arbitration - used in real-time interprocessor communication buffers for industrial motion controllers.

For engineers reviewing the 71421SA55J datasheet, 71421SA55J pinout, 71421SA55J application, or 71421SA55J equivalent, key selection considerations include its role as SLAVE-only (no on-chip arbitration), 55 ns timing grade, SA power variant (325 mW active / 5 mW standby), and compatibility with IDT71321SA55J MASTER in 16-bit+ bus width implementations.

Technical Context

The 71421SA55J implements fully asynchronous dual-port access with independent left/right address, control, and I/O buses. Its BUSY pin functions strictly as an input to inhibit writes during contention - unlike the MASTER IDT71321, it contains no arbitration logic or BUSY output capability.

Interrupt functionality is supported via dedicated mailbox addresses (7FE_H for INTL, 7FF_H for INTR), with interrupt set/reset timing of ≤45 ns (tINS/tINR). It operates across industrial temperature range (–40°C to +85°C) and requires no external pull-up on BUSY when used with IDT71321 MASTER.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Organization	2K × 8 (2048 words × 8 bits), 16 KB total capacity
Access Time (tAA)	55 ns max - defines minimum address hold before valid data appears
Read Cycle Time (tRC)	55 ns max - sets minimum interval between successive reads on same port
Supply Voltage	4.5 V to 5.5 V - compatible with standard 5 V TTL logic rails
Active Current (ICC)	65 mA typ. - determines power budget for continuous dual-port operation
Standby Current (ISB1)	20 mA typ. - defines quiescent draw when both ports disabled (CE = VIH)
Operating Temperature	–40°C to +85°C - qualified for industrial embedded environments

Pinout & Package

71421SA55J is available in 52-pin STQFP (PPG52) package, measuring 10 mm × 10 mm × 1.4 mm, with exposed thermal pad and lead-free finish. Pin assignments are identical across SA/LA variants and match IDT71321 pinout for drop-in layout compatibility in MASTER/SLAVE pairs.

Pin/Terminal	Circuit Role	Design Meaning
A0L–A10L	Left port address inputs	11-bit address bus for left-side memory access (0x000–0x7FF)
A0R–A10R	Right port address inputs	11-bit address bus for right-side memory access (0x000–0x7FF)
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 respective port; controls power-down mode when high
OEL / OER	Output enable (left/right)	Active-low enables data outputs; overrides R/W for tri-state control
R/WL / R/WR	Read/write control (left/right)	High = read, low = write; determines direction of I/O bus
BUSYL / BUSYR	BUSY input (SLAVE only)	Active-low write-inhibit signal driven by MASTER's BUSY output
INTL / INTR	Interrupt flags (open-drain)	Indicate mailbox writes (7FE_H/7FF_H); require external pull-up
VCC / GND	Power supply pins	Multiple VCC/GND pairs ensure stable noise margin and thermal dissipation

Key Features

Feature	Design Value
SLAVE-only architecture	Eliminates need for external arbitration logic when paired with IDT71321 MASTER
55 ns industrial-grade timing	Enables deterministic response in real-time PLC and CNC motion control loops
Dual independent interrupt mailboxes	Supports lock-free interprocessor messaging without software polling overhead
TTL-compatible 5 V interface	Direct connection to legacy microcontrollers and FPGAs without level-shifting
Low-power SA variant	Reduces thermal load in densely packed industrial backplanes (5 mW standby)

Applications

Industrial Motion Controller	Real-Time PLC Communication Buffer
Use Scenario: Synchronized dual-CPU architecture where one CPU handles servo loop execution and another manages HMI and diagnostics. IC Role / Device Role / Timing Role: SLAVE dual-port RAM provides shared memory space with hardware-enforced write collision avoidance via BUSY input from MASTER. Use Value: Enables deterministic <55 ns inter-CPU data exchange without software arbitration or bus locking.	Use Scenario: High-speed data exchange between main PLC processor and safety co-processor over shared memory. IC Role / Device Role / Timing Role: Acts as interrupt-driven message buffer using 7FE_H/7FF_H mailboxes to signal task completion or fault events. Use Value: Reduces inter-processor latency to ≤45 ns (tINS/tINR), eliminating polling delays in safety-critical cycles.
Avionics Data Acquisition Module	Medical Imaging Frame Buffer
Use Scenario: Dual-processor acquisition system capturing sensor data at 10 kHz while simultaneously compressing and formatting packets. IC Role / Device Role / Timing Role: SLAVE RAM buffers raw ADC streams on one port while compressed frames are read out on the other. Use Value: 55 ns access ensures no frame loss during concurrent 16-bit-wide burst transfers at full rate.	Use Scenario: MRI subsystem requiring simultaneous image capture (via FPGA) and display rendering (via ARM SoC). IC Role / Device Role / Timing Role: Provides non-blocking memory access for parallel pixel stream ingestion and RGB output generation. Use Value: Asynchronous dual-port operation prevents pipeline stalls during real-time 1080p frame buffering.

Industrial Motion Controller

Real-Time PLC Communication Buffer

Use Scenario: Synchronized dual-CPU architecture where one CPU handles servo loop execution and another manages HMI and diagnostics.

IC Role / Device Role / Timing Role: SLAVE dual-port RAM provides shared memory space with hardware-enforced write collision avoidance via BUSY input from MASTER.

Use Value: Enables deterministic <55 ns inter-CPU data exchange without software arbitration or bus locking.

Use Scenario: High-speed data exchange between main PLC processor and safety co-processor over shared memory.

IC Role / Device Role / Timing Role: Acts as interrupt-driven message buffer using 7FE_H/7FF_H mailboxes to signal task completion or fault events.

Use Value: Reduces inter-processor latency to ≤45 ns (tINS/tINR), eliminating polling delays in safety-critical cycles.

Avionics Data Acquisition Module

Medical Imaging Frame Buffer

Use Scenario: Dual-processor acquisition system capturing sensor data at 10 kHz while simultaneously compressing and formatting packets.

IC Role / Device Role / Timing Role: SLAVE RAM buffers raw ADC streams on one port while compressed frames are read out on the other.

Use Value: 55 ns access ensures no frame loss during concurrent 16-bit-wide burst transfers at full rate.

Use Scenario: MRI subsystem requiring simultaneous image capture (via FPGA) and display rendering (via ARM SoC).

IC Role / Device Role / Timing Role: Provides non-blocking memory access for parallel pixel stream ingestion and RGB output generation.

Use Value: Asynchronous dual-port operation prevents pipeline stalls during real-time 1080p frame buffering.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-port SRAM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
CY7C1371BV33-55AC	3.3 V core, 55 ns, 2K × 16 organization - requires voltage translation for 5 V systems	Targets low-voltage embedded designs; lacks native 5 V TTL compatibility	Select only if migrating entire system to 3.3 V logic and requiring wider word size
IDT71321SA55J	MASTER variant with on-chip arbitration logic and BUSY output - not interchangeable as SLAVE	Used in standalone or MASTER position; cannot replace SLAVE function without redesign	Required only when building MASTER/SLAVE pair - must be paired with 71421SA55J as SLAVE

Compared with CY7C1371BV33-55AC and IDT71321SA55J, the 71421SA55J uniquely delivers 5 V TTL compatibility, SLAVE-specific BUSY input behavior, and guaranteed 55 ns industrial timing - making it irreplaceable in legacy 5 V interprocessor buffer designs requiring hardware arbitration.

Availability

71421SA55J is available at Aetrix Electronics and suitable for industrial motion controllers, real-time PLC communication buffers, and avionics data acquisition modules requiring stable component supply and long-term obsolescence management.

Supply support for 71421SA55J 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 industrial systems.

The IDT71321/71421 family was designed specifically for deterministic interprocessor communication in real-time embedded systems - enabling hardware-synchronized dual-CPU architectures without external glue logic.

FAQ

What is the functional difference between 71421SA55J and IDT71321SA55J?

The 71421SA55J is a SLAVE-only dual-port SRAM with BUSY input and no internal arbitration logic, while IDT71321SA55J is the MASTER device containing on-chip arbitration, BUSY output, and priority resolution. They are complementary - 71421SA55J cannot operate standalone in arbitration mode and must be paired with a MASTER like IDT71321SA55J to form a complete system.

Does 71421SA55J support battery backup data retention?

No. The 71421SA55J is the SA (standard power) variant and does not support battery backup. Only LA versions (e.g., 71421LA55J) provide 2 V data retention capability. The SA variant draws 5 mW in standby but requires continuous 5 V supply to retain data.

Can 71421SA55J be used without a MASTER device?

Yes - as a standalone dual-port SRAM with independent left/right access, but without hardware arbitration or BUSY-based write collision prevention. In that configuration, software must manage contention, and interrupt mailboxes (7FE_H/7FF_H) remain fully functional for interprocessor signaling.

What is the purpose of the open-drain INTL and INTR pins on 71421SA55J?

The INTL and INTR pins are open-drain interrupt flags indicating mailbox writes (7FE_H and 7FF_H). They require external pull-up resistors (typically 4.7 kΩ to VCC) to generate active-low signals. Each flag is independently asserted/cleared by cross-port writes, enabling event-driven synchronization without polling.

Which package options are available for 71421SA55J?

The 71421SA55J is offered exclusively in the 52-pin STQFP (PPG52) package - 10 mm × 10 mm body, 1.4 mm height, lead-free, with exposed thermal pad. It is not available in PLCC, TQFP, or STQFP-64 variants; those packages apply only to other speed grades or LA versions.

71421SA55J Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 52-LCC (J-Lead)

Packaging:: Tube

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:: 52-PLCC (19.13x19.13)

71421SA55J FAQ

1.How can I place an order for 71421SA55J through Aetrix?

Please submit a Request for Quotation (RFQ) for 71421SA55J 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 71421SA55J reliable?

The price and inventory of 71421SA55J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71421SA55J is usually 5 days.

3.What payment methods are accepted for 71421SA55J?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71421SA55J transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 71421SA55J?

71421SA55J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 71421SA55J 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 71421SA55J?

For technical support, including 71421SA55J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71421SA55J requirements.

6.How does Aetrix verify that 71421SA55J is sourced from the original manufacturer or authorized distributors?

All 71421SA55J 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 71421SA55J meets industry standards.

7.What is the process for return or replacement of 71421SA55J?

All 71421SA55J units undergo pre-shipment inspection (PSI). If there is an issue with 71421SA55J, 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 71421SA55J part is unused and in its original packaging.

Return procedure for 71421SA55J:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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