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Renesas 71421LA20PF8
- Part No.:
- 71421LA20PF8
- Manufacturer:
- Renesas
- Category:
- Memory
- Package:
- 64-LQFP
- Datasheet:
-
71421LA20PF8.pdf
- Description:
- IC SRAM 16KBIT PARALLEL 64TQFP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
IDT71421LA20PF8 from Integrated Device Technology (IDT) is a 2K × 8 dual-port static RAM configured as a SLAVE device in MASTER/SLAVE memory expansion systems, supporting fully asynchronous, independent read/write access on left and right ports with 20 ns max read cycle time, 2V battery-backed data retention, and industrial temperature operation (–40°C to +85°C). It enables error-free 16-bit-or-wider memory bus expansion when paired with IDT71321 MASTER devices in embedded interprocessor communication systems.
For engineers reviewing the IDT71421LA20PF8 datasheet, IDT71421LA20PF8 pinout, IDT71421LA20PF8 application, or IDT71421LA20PF8 equivalent, key selection considerations include its SLAVE-only BUSY input behavior, 20 ns timing grade, LA low-power/battery-retention variant, 64-pin TQFP package, and interrupt mailbox addressing at 7FEh/7FFh.
Technical Context
The IDT71421LA20PF8 implements port-to-port arbitration via external BUSY signaling - it accepts BUSY as an input (not output), disabling writes when asserted, unlike the MASTER IDT71321 which generates BUSY. Its interrupt logic uses dedicated address locations (7FEh for INTL, 7FFh for INTR) to signal cross-port events without software polling.
It operates with TTL-compatible 5V ±10% supply, supports full CMOS-level standby (ISB3 = 5 µA typ.), and delivers 2V data retention with ICCDR ≤ 1500 µA (commercial) - a defining feature of the LA suffix. All control, address, and I/O lines are fully independent per port, enabling true concurrent access.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 2K × 8 (2048 words × 8 bits), 16 kB total capacity |
| Read Cycle Time (tRC) | 20 ns max - defines minimum interval between successive reads on same port |
| Data Retention Voltage | 2.0 V min - enables battery backup operation without active VCC |
| Standby Current (ISB3) | 5 µA typical - ultra-low power in full CMOS-level standby mode |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded systems |
| Supply Voltage | 4.5 V to 5.5 V - single 5V ±10% rail, TTL-compatible inputs |
| Interrupt Address Map | INTL set at A0L–A10L = 7FEh; INTR set at A0R–A10R = 7FFh - fixed mailbox addresses |
Pinout & Package
Package: 64-pin TQFP (PNG64), 14 mm × 14 mm × 1.4 mm body, lead-free and RoHS-compliant.
| 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 access and disables internal circuitry for standby |
| OEL, OER | Output enable (left/right) | Active-low controls I/O drivers; overrides R/W for read-enable |
| R/WL, R/WR | Read/write control (left/right) | Active-low write; high = read (outputs enabled only if OE active) |
| BUSYL, BUSYR | BUSY input (SLAVE mode) | Active-low write-inhibit signals - must be driven by MASTER's BUSY outputs |
| INTL, INTR | Interrupt flags (open-drain) | Active-low outputs indicating cross-port mailbox writes (7FEh/7FFh) |
| VCC, GND | Power and ground | Multiple VCC/GND pins required for noise immunity; all must be connected |
Key Features
| Feature | Design Value |
|---|---|
| SLAVE-only BUSY interface | Accepts BUSY as input to block writes - eliminates need for external arbitration logic in MASTER/SLAVE arrays |
| 2V battery data retention | Preserves memory contents during main power loss using coin-cell or backup supply, critical for fault-tolerant systems |
| Dual-mailbox interrupt architecture | Hardware-set/cleared interrupts at fixed addresses (7FEh/7FFh) reduce CPU polling overhead in real-time IPC |
| Ultra-low ISB3 standby current | 5 µA typical at full CMOS-level standby enables multi-year battery life in always-on monitoring nodes |
| Industrial temperature range | –40°C to +85°C operation ensures reliability in automotive ECUs, industrial PLCs, and outdoor telecom equipment |
| 64-pin TQFP footprint | Standardized 0.5 mm pitch package supports automated assembly and thermal management in dense PCB layouts |
Applications
| Real-Time Interprocessor Communication | Redundant Control System Memory |
|---|---|
Use Scenario: Two microcontrollers exchange status and command data via shared memory without shared clocks or software coordination. IC Role / Device Role / Timing Role: IDT71421LA20PF8 serves as SLAVE in a MASTER/SLAVE pair, receiving BUSY from IDT71321 to prevent simultaneous writes, while providing 20 ns access for deterministic latency. Use Value: Eliminates race conditions and software mutex overhead, enabling sub-20 ns inter-core handshaking in avionics and robotics controllers. |
Use Scenario: Primary and backup controllers maintain synchronized state in safety-critical infrastructure (e.g., rail signaling, medical devices). IC Role / Device Role / Timing Role: IDT71421LA20PF8 provides mirrored memory space with hardware arbitration, where BUSY enforces write exclusivity and 2V retention preserves state during failover. Use Value: Guarantees atomic state transfer and zero-data-loss recovery after primary controller failure, meeting SIL-2/IEC 61508 requirements. |
| Embedded Data Acquisition Buffer | Legacy Bus Width Expansion |
Use Scenario: High-speed ADC streams data into one port while DSP processes it from the other, requiring uninterrupted concurrent access. IC Role / Device Role / Timing Role: IDT71421LA20PF8 acts as SLAVE in dual-device configuration, delivering 20 ns read cycles and 2V retention to buffer transient sensor bursts during power dips. Use Value: Sustains 50+ MS/s acquisition without FIFO overflow or data loss, even during brownout events affecting main supply. |
Use Scenario: Expanding 8-bit microcontroller data bus to 16-bit or wider using multiple dual-port SRAMs without adding discrete glue logic. IC Role / Device Role / Timing Role: IDT71421LA20PF8 functions as SLAVE unit, accepting BUSY from IDT71321 MASTER to coordinate writes across parallel memory banks. Use Value: Achieves full-width, cycle-accurate memory access at 20 ns speed - no wait states or external arbitration ICs required. |
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 CY7C1371DV33-200BZI | 3.3V core, 200 MHz QDR interface, no BUSY arbitration logic, no battery retention | Designed for high-bandwidth networking buffers, not interprocessor arbitration | Select only for 3.3V systems requiring QDR burst access - not drop-in compatible with IDT71421LA20PF8's 5V/BUSY/retention features |
| ISSI IS61WV20488BLL-20MLI | Single-port, 3.3V, 20 ns, no interrupts or BUSY, no battery backup | Cost-optimized general-purpose SRAM; lacks dual-port concurrency and arbitration | Use only when dual-port functionality is unnecessary - requires redesign for software-managed sharing and no power-loss data hold |
Compared with CY7C1371DV33-200BZI and IS61WV20488BLL-20MLI, the IDT71421LA20PF8 uniquely combines 5V-compatible dual-port operation, hardware BUSY-based arbitration, 2V data retention, and interrupt mailboxes - making it irreplaceable in deterministic, fault-resilient interprocessor memory systems.
Availability
IDT71421LA20PF8 is available at Aetrix Electronics and suitable for real-time interprocessor communication, redundant control system memory, and embedded data acquisition buffering requiring stable component supply, long-term lifecycle support, and industrial-temperature reliability.
Supply support for IDT71421LA20PF8 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 power management ICs for communications, computing, and industrial markets.
The IDT71421LA20PF8 belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic, low-latency interprocessor communication in safety-critical and industrial embedded systems requiring hardware arbitration and battery-backed data integrity.
FAQ
What is the function of BUSYL and BUSYR on the IDT71421LA20PF8?
On the IDT71421LA20PF8, BUSYL and BUSYR are dedicated input terminals - not outputs - used exclusively to receive BUSY signals from a MASTER IDT71321 device. When either signal is driven low, the corresponding port's write operations are internally inhibited, preventing memory contention. This SLAVE-only BUSY input behavior is fundamental to the device's role in MASTER/SLAVE memory expansion architectures.
Does the IDT71421LA20PF8 support battery backup, and what voltage is required?
Yes, the IDT71421LA20PF8 supports battery backup data retention at 2.0 V minimum (VDR), as specified in its LA variant designation. At this voltage and +25°C, data retention current (ICCDR) is guaranteed ≤1500 µA for commercial grade. The device retains stored data indefinitely under these conditions, enabling use in systems requiring nonvolatile memory without EEPROM or Flash.
How do the interrupt flags INTL and INTR operate on the IDT71421LA20PF8?
The IDT71421LA20PF8 uses fixed address locations to control interrupts: writing to address 7FEh (hex) on the right port asserts INTL (left port flag), and writing to 7FFh on the left port asserts INTR (right port flag). Each flag is cleared by reading its respective address with CE and OE active. These open-drain outputs require external pull-up resistors and provide hardware-synchronized cross-port signaling without CPU polling.
What package type and pin count does the IDT71421LA20PF8 use?
The IDT71421LA20PF8 is packaged in a 64-pin TQFP (Thin Quad Flat Package), designated PNG64 per IDT documentation. Its body measures 14 mm × 14 mm × 1.4 mm, with 0.5 mm lead pitch. This RoHS-compliant, lead-free package supports automated surface-mount assembly and provides thermal and electrical performance suited for industrial-density PCB layouts.
Can the IDT71421LA20PF8 be used as a standalone dual-port RAM without a MASTER device?
No - the IDT71421LA20PF8 is designed strictly as a SLAVE device and lacks on-chip port arbitration logic. It requires an external MASTER (e.g., IDT71321) to generate BUSY signals for write coordination. Using it standalone risks memory corruption during simultaneous port accesses. For autonomous dual-port operation, the IDT71321SA/LA MASTER variant must be selected instead.
71421LA20PF8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- -
- Package/Case:
- 64-LQFP
- Packaging:
- Tape & Reel (TR)
- 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:
- 20ns
- Access Time:
- 20 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)
71421LA20PF8 FAQ
1.How can I place an order for 71421LA20PF8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 71421LA20PF8 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 71421LA20PF8 reliable?
The price and inventory of 71421LA20PF8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 71421LA20PF8 is usually 5 days.
3.What payment methods are accepted for 71421LA20PF8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 71421LA20PF8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 71421LA20PF8?
71421LA20PF8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 71421LA20PF8 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 71421LA20PF8?
For technical support, including 71421LA20PF8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 71421LA20PF8 requirements.
6.How does Aetrix verify that 71421LA20PF8 is sourced from the original manufacturer or authorized distributors?
All 71421LA20PF8 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 71421LA20PF8 meets industry standards.
7.What is the process for return or replacement of 71421LA20PF8?
All 71421LA20PF8 units undergo pre-shipment inspection (PSI). If there is an issue with 71421LA20PF8, 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 71421LA20PF8 part is unused and in its original packaging.
Return procedure for 71421LA20PF8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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