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Microchip Technology AT45DB021B-RI
- Part No.:
- AT45DB021B-RI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.342", 8.69mm Width)
- Datasheet:
-
AT45DB021B-RI.pdf
- Description:
- IC FLASH 2MBIT SPI 20MHZ 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,776
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Product details
Overview
AT45DB021B-RI from Microchip Technology (formerly Atmel) is a 2.7V-only serial Flash memory IC with SPI interface, 2 Mbit (2,162,688-bit) capacity organized as 1024 pages × 264 bytes, integrated dual 264-byte SRAM buffers, and hardware page write protection. It enables code shadowing, firmware storage, and data logging in space-constrained embedded systems.
For engineers reviewing the AT45DB021B-RI datasheet, AT45DB021B-RI pinout, AT45DB021B-RI application, or AT45DB021B-RI equivalent, key selection considerations include its 20 MHz SPI clock support, single 2.7–3.6 V supply, continuous array read capability, 4 mA active read current, and 2 µA standby current - all critical for low-power, high-reliability serial memory integration.
Technical Context
The AT45DB021B-RI implements a dedicated SPI-based serial Flash architecture with two independent 264-byte SRAM buffers enabling concurrent buffer loading and main memory reprogramming. Its command set supports page/block erase, buffer-to-page program with built-in erase, and auto page rewrite - eliminating external erase cycles.
It operates in SPI Mode 0 and Mode 3, uses MSB-first data transfer, and features a status register (bit 7 = RDY/BUSY) for polling. The RDY/BUSY open-drain output signals internal self-timed operations including page program (tEP max), block erase (tBE max), and buffer transfers (tXFR).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 2,162,688 bits (1024 pages × 264 bytes) - provides compact nonvolatile storage for boot code or configuration data without parallel bus overhead. |
| Supply Voltage | 2.7 V to 3.6 V - single-supply operation simplifies power design and eliminates level-shifting for 3.3 V microcontrollers. |
| SPI Clock Frequency | Up to 20 MHz - enables fast sequential reads (e.g., code shadowing) and reduces firmware update time. |
| Active Read Current | 4 mA typical - low dynamic power supports battery-powered or thermally constrained applications. |
| Standby Current | 2 µA typical - ultra-low quiescent draw extends system sleep-mode battery life. |
| Page Erase Time | tPE ≤ 25 ms - deterministic erase latency allows predictable timing in real-time firmware update sequences. |
| Hardware Write Protect | WP pin protects first 256 pages - prevents accidental overwrite of critical bootloader or calibration data. |
Pinout & Package
AT45DB021B-RI is available in 8-pin SOIC (Small Outline Integrated Circuit) package per Figure 2-2, with lead-free, RoHS-compliant finish. Pin functions are electrically defined and validated per Atmel datasheet 1937J–DFLSH–9/05.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-low enable signal; initiates command sequence on falling edge and terminates operation on rising edge. |
| SCK | Serial Clock | Input-only clock; data latched on rising edge (SI), output shifted on falling edge (SO); supports SPI Mode 0/3. |
| SI | Serial Input | Input-only data line for opcodes, addresses, and buffer writes; MSB-first protocol. |
| SO | Serial Output | Output-only data line for read data and status register; tri-stated when CS is high. |
| WP | Write Protect | Active-low hardware lock for first 256 pages; prevents inadvertent programming during field updates. |
| RESET | Chip Reset | Active-low asynchronous reset; halts ongoing operation and returns state machine to idle. |
| RDY/BUSY | Ready/Busy Indicator | Open-drain output pulled high externally; driven low during self-timed operations (erase, program, transfer). |
| VCC / GND | Power Supply | Single 2.7–3.6 V supply; 5.0 V-tolerant inputs (CS, SI, SCK, WP, RESET) simplify interface with mixed-voltage systems. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 264-byte SRAM buffers | Enables pipelined operation: receive new data into one buffer while reprogramming main memory from the other - no CPU wait states during flash writes. |
| Continuous Array Read | Supports seamless streaming from address 0x000000 through full memory with automatic page-wrap - ideal for executing code directly from flash (XIP-like behavior). |
| Self-timed Page Program with Erase | Single-command (e.g., 0x83/0x86) erases and programs a page in ≤ tEP; eliminates need for separate erase cycle and host timing management. |
| EEPROM Emulation Support | Three-step Read-Modify-Write via buffers enables byte-level updates without full-page erase - suitable for parameter storage with frequent small changes. |
| 5.0 V-tolerant control pins | CS, SI, SCK, WP, and RESET accept 5 V logic levels while operating at 2.7–3.6 V - avoids level shifters in legacy 5 V MCU designs. |
Applications
| Firmware Storage | Audio Data Logging |
|---|---|
|
Use Scenario: Storing boot firmware, application binaries, and field-upgrade images in microcontroller-based IoT edge nodes. IC Role / Device Role / Timing Role: Nonvolatile serial code storage with fast continuous read and in-system reprogrammability via SPI. Use Value: Eliminates external parallel NOR/NAND, reduces PCB footprint and BOM count, and enables secure over-the-air (OTA) updates using page-erase granularity. |
Use Scenario: Capturing voice memos or sensor-triggered audio clips in portable medical or industrial recorders. IC Role / Device Role / Timing Role: High-reliability, low-power sequential data sink with dual-buffer streaming to avoid dropouts during flash write latency. Use Value: 4 mA active current and 2 µA standby allow >1-year battery life in always-on recorders; 20 MHz SPI sustains 2.5 MB/s sustained read throughput. |
| Configuration Parameter Storage | Industrial HMI Display Cache |
|
Use Scenario: Retaining user settings, calibration coefficients, and device-specific IDs across power cycles in PLC modules and motor drives. IC Role / Device Role / Timing Role: EEPROM-emulating nonvolatile storage using Read-Modify-Write with SRAM buffers. Use Value: Supports bit/byte alteration without full-page erase wear; hardware WP pin safeguards factory defaults from accidental overwrite. |
Use Scenario: Caching GUI assets (fonts, icons, bitmaps) for TFT LCD displays in factory HMIs where fast display refresh is required. IC Role / Device Role / Timing Role: High-speed serial memory accessed via continuous array read to feed display controller DMA engines. Use Value: 20 MHz SPI clock and zero-gap page boundary crossing enable uninterrupted pixel stream delivery - no visible tearing or stutter during screen updates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| W25Q20EW | 2 Mbit Quad SPI (QSPI) interface, 104 MHz clock, 1.65–1.95 V supply - higher speed but narrower voltage range. | Requires QSPI-capable host; unsuitable for legacy SPI-only controllers or 2.7–3.6 V systems. | Select W25Q20EW only if host supports QSPI and system operates at 1.8 V; otherwise AT45DB021B-RI offers broader voltage compatibility and simpler interface. |
| MX25L2006E | 2 Mbit standard SPI, 80 MHz max clock, 2.7–3.6 V supply, but no integrated SRAM buffers or continuous array read mode. | Lacks pipelined buffer operation - host must manage erase-before-write and cannot stream reads across page boundaries. | Choose MX25L2006E for cost-sensitive, non-streaming applications; AT45DB021B-RI is preferred when continuous read or concurrent buffer access is required. |
Compared with W25Q20EW and MX25L2006E, the AT45DB021B-RI uniquely delivers dual-SRAM-buffer concurrency and gapless continuous array read within its 2.7–3.6 V operating range - making it optimal for real-time streaming and low-voltage embedded firmware storage where interface simplicity and deterministic latency matter.
Availability
AT45DB021B-RI is available at Aetrix Electronics and suitable for firmware storage, audio data logging, configuration parameter retention, and industrial HMI display caching requiring stable component supply and long-term obsolescence planning.
Supply support for AT45DB021B-RI 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
Microchip Technology acquired Atmel in 2016 and maintains full product support, documentation, and manufacturing continuity for the AT45DB series.
The AT45DB021B-RI belongs to the DataFlash® family - designed specifically for embedded systems needing SPI-based serial Flash with integrated buffers to replace parallel EEPROM/NOR and simplify code shadowing and data logging.
FAQ
What is the maximum SPI clock frequency supported by the AT45DB021B-RI?
The AT45DB021B-RI supports up to 20 MHz SPI clock frequency for all read and write operations, including continuous array read and buffer transfers. This timing is validated across commercial and industrial temperature ranges and enables high-throughput firmware loading and streaming applications without requiring external clock dividers or timing compensation.
Does the AT45DB021B-RI require a high-voltage programming supply?
No, the AT45DB021B-RI operates entirely from a single 2.7–3.6 V supply for both read and program/erase operations. All programming cycles are self-timed and internally generated - no external 12 V or 5 V programming voltage is needed, simplifying power design and enabling direct connection to 3.3 V microcontrollers.
How does the dual-buffer architecture of the AT45DB021B-RI improve system performance?
The AT45DB021B-RI's two independent 264-byte SRAM buffers allow simultaneous operations: while one buffer streams data to main memory (e.g., during Buffer-to-Page Program), the other can accept new incoming data via SI. This pipelining eliminates CPU idle time during flash write latency and enables true continuous data acquisition - a capability not present in standard SPI Flash devices.
Can the AT45DB021B-RI be used for EEPROM emulation, and how is it implemented?
Yes, the AT45DB021B-RI supports EEPROM emulation via a self-contained three-step Read-Modify-Write process using its SRAM buffers. A page is first transferred to a buffer (Main Memory Page to Buffer), modified in RAM, then written back with built-in erase (Buffer to Main Memory Page Program). This avoids external wear-leveling firmware and enables reliable byte-level updates in parameter storage applications.
What is the function of the RDY/BUSY pin on the AT45DB021B-RI, and how should it be used?
The RDY/BUSY pin on the AT45DB021B-RI is an open-drain output that goes low during any self-timed operation (page program, block erase, buffer transfer, or compare). It must be externally pulled up (~1 kΩ) and monitored either by polling bit 7 of the status register or directly via GPIO. Using RDY/BUSY avoids fixed delay loops and ensures precise synchronization with internal flash timing - critical for deterministic real-time firmware updates.
AT45DB021B-RI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-SOIC (0.342", 8.69mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- FLASH
- Technology:
- FLASH
- Memory Size:
- 2Mbit
- Memory Organization:
- 264 Bytes x 1024 pages
- Memory Interface:
- SPI
- Clock Frequency:
- 20 MHz
- Write Cycle Time - Word, Page:
- 14ms
- Access Time:
- -
- Voltage - Supply:
- 2.7V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TC)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
AT45DB021B-RI FAQ
1.How can I place an order for AT45DB021B-RI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT45DB021B-RI 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 AT45DB021B-RI reliable?
The price and inventory of AT45DB021B-RI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT45DB021B-RI is usually 5 days.
3.What payment methods are accepted for AT45DB021B-RI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT45DB021B-RI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT45DB021B-RI?
AT45DB021B-RI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT45DB021B-RI 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 AT45DB021B-RI?
For technical support, including AT45DB021B-RI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT45DB021B-RI requirements.
6.How does Aetrix verify that AT45DB021B-RI is sourced from the original manufacturer or authorized distributors?
All AT45DB021B-RI 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 AT45DB021B-RI meets industry standards.
7.What is the process for return or replacement of AT45DB021B-RI?
All AT45DB021B-RI units undergo pre-shipment inspection (PSI). If there is an issue with AT45DB021B-RI, 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 AT45DB021B-RI part is unused and in its original packaging.
Return procedure for AT45DB021B-RI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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