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Microchip Technology AT45DB021B-TU
- Part No.:
- AT45DB021B-TU
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-TSSOP (0.465", 11.80mm Width)
- Datasheet:
-
AT45DB021B-TU.pdf
- Description:
- IC FLASH 2MBIT SPI 20MHZ 28TSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,825
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Product details
Overview
AT45DB021B-TU from Microchip Technology (formerly Atmel) is a 2.7V-only serial Flash memory IC with SPI interface, organized as 1024 pages × 264 bytes (2,162,688 bits), featuring dual 264-byte SRAM buffers and hardware page write protection. It supports continuous array read for code shadowing, operates up to 20 MHz, and draws only 4 mA active read current - ideal for embedded firmware storage in space-constrained industrial controllers.
For engineers reviewing the AT45DB021B-TU datasheet, AT45DB021B-TU pinout, AT45DB021B-TU application, or AT45DB021B-TU equivalent, key selection considerations include its 2.7–3.6 V single-supply operation, 5.0 V-tolerant control pins (CS/SCK/SI/WP/RESET), page-erase flexibility, buffer-assisted concurrent I/O, and RoHS-compliant TSOP/SOIC packaging options.
Technical Context
The AT45DB021B-TU implements a dedicated SPI-compatible serial interface supporting Mode 0 and Mode 3, eliminating parallel address/data buses and reducing PCB routing complexity. Its architecture separates main Flash memory (1024 × 264 B pages) from two independent 264-byte SRAM buffers, enabling simultaneous data reception into one buffer while reprogramming the other into nonvolatile memory.
All program and erase operations - including page erase (tPE ≤ 25 ms), block erase (tBE ≤ 40 ms), and buffer-to-page program with built-in erase (tEP ≤ 25 ms) - are self-timed and require no external high-voltage programming supply. The RDY/BUSY open-drain output and status register bit 7 provide real-time busy-state visibility during these operations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 2,162,688 bits (1024 pages × 264 bytes), enabling compact firmware/image storage without external address decoding logic |
| Supply Voltage | 2.7 V – 3.6 V single supply - eliminates need for level shifters in 3.3 V systems and simplifies power design |
| Max Clock Frequency | 20 MHz SPI clock - supports fast sequential reads (e.g., code shadowing) with minimal SCK timing margin constraints |
| Active Read Current | 4 mA typical - reduces thermal load and extends battery life in portable or low-power embedded applications |
| Standby Current | 2 µA typical CMOS standby - enables ultra-low-power sleep modes in always-on monitoring devices |
| Write Protection | Hardware WP pin protects first 256 pages - prevents accidental overwrite of boot code or calibration data in field-deployed units |
| Input Tolerance | 5.0 V-tolerant SI, SCK, CS, RESET, WP - allows direct interfacing with legacy 5 V microcontrollers without external level translation |
Pinout & Package
AT45DB021B-TU is available in an 8-pin SOIC package (JEDEC MS-012AA, 150 mil width) with standard lead finish and RoHS compliance. 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 for SPI command initiation; must remain low during full instruction sequence (opcode + address + data) |
| 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 required |
| SO | Serial Output | Output-only data line for read commands and status register; tri-stated when CS is high |
| WP | Write Protect | Active-low hardware lock for first 256 pages; externally pulled high if unused to prevent unintended protection activation |
| RESET | Chip Reset | Active-low asynchronous reset; terminates ongoing operations and returns state machine to idle; internal POR eliminates external RC network |
| RDY/BUSY | Ready/Busy Indicator | Open-drain output pulled high externally; driven low during self-timed operations (erase/program/transfer) to signal host wait state |
| VCC / GND | Power Supply | Single 2.7–3.6 V supply; decoupling capacitor (0.1 µF) required near VCC pin to suppress switching noise on SPI bus |
Key Features
| Feature | Design Value |
|---|---|
| Dual SRAM Buffers | Two independent 264-byte buffers enable pipelined operation: receive new data into one buffer while programming the other into Flash - critical for uninterrupted firmware updates |
| Continuous Array Read | Supports seamless sequential read across page boundaries and full memory wraparound - eliminates address management overhead in bootloaders and audio streaming |
| Self-Timed Page Programming | No external erase cycle needed; "erase-and-program" occurs automatically on single command (e.g., opcode 83H) - simplifies firmware update routines and reduces host CPU intervention |
| EEPROM Emulation | Three-step Read-Modify-Write via buffers allows byte-level alterations without full-page erasure - suitable for parameter logging and configuration storage |
| Industrial Temp Range | –40°C to +85°C operation validated - ensures reliable firmware access in automotive body control modules and factory automation PLCs |
Applications
| Firmware Storage | Audio Data Buffering |
|---|---|
Use Scenario: Storing bootloader, application firmware, and configuration tables in a microcontroller-based motor drive controller. IC Role / Device Role / Timing Role: Nonvolatile serial Flash memory providing SPI-accessible code storage with page-level update capability and hardware write protection for critical boot sectors. Use Value: Enables field-upgradable firmware without requiring external parallel memory or high-voltage programming circuitry; 2.7 V operation matches MCU core voltage rails. |
Use Scenario: Capturing and replaying voice prompts or alarm tones in a smart HVAC thermostat with limited PCB area. IC Role / Device Role / Timing Role: Serial audio data buffer supporting continuous read mode for glitch-free playback and dual-buffer interleaving for record-while-play functionality. Use Value: Eliminates need for external FIFO or DRAM; 20 MHz SPI clock sustains >2.5 MB/s sequential throughput sufficient for 16-bit/44.1 kHz stereo streams. |
| Calibration Data Logging | Industrial Sensor Configuration |
Use Scenario: Recording sensor offset/gain coefficients and environmental calibration points during manufacturing test of precision pressure transducers. IC Role / Device Role / Timing Role: EEPROM-emulating nonvolatile storage using Read-Modify-Write via buffers to alter individual calibration bytes without erasing entire pages. Use Value: Preserves long-term data integrity across 100,000+ write cycles; hardware WP prevents accidental overwrites during field recalibration procedures. |
Use Scenario: Holding device-specific parameters (e.g., Modbus slave ID, baud rate, analog input scaling) in a DIN-rail mounted I/O module. IC Role / Device Role / Timing Role: SPI-configurable persistent memory accessed by host ARM Cortex-M4 during power-up initialization and runtime parameter queries. Use Value: Reduces BOM count by replacing discrete EEPROM + level shifters; 5.0 V-tolerant inputs simplify interface to legacy RS-485 transceivers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial Flash memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT45DB021D-TU | Successor revision with enhanced endurance (100k vs. 10k program/erase cycles) and extended temperature range (–40°C to +105°C) | Better suited for automotive under-hood applications requiring higher reliability and longer data retention | Select AT45DB021D-TU for new designs targeting AEC-Q100 qualification or extended lifetime requirements |
| W25Q20EWUXIE | 2 Mbit Quad SPI Flash (Winbond) with DTR support, faster erase times (typ. 25 ms vs. 25 ms), but lacks dual SRAM buffers and EEPROM emulation mode | Optimized for high-speed XIP code execution; not suitable for buffer-assisted streaming or byte-alterable data storage | Choose W25Q20EWUXIE only when prioritizing raw read speed and quad interface compatibility over concurrent I/O or EEPROM-like behavior |
Compared with AT45DB021B-TU, AT45DB021D-TU offers higher endurance and temperature rating for mission-critical deployments, while W25Q20EWUXIE trades buffer functionality for faster quad-SPI throughput - making AT45DB021B-TU uniquely balanced for mixed-code-and-data embedded storage where concurrent access and byte-level updates matter.
Availability
AT45DB021B-TU is available at Aetrix Electronics and suitable for industrial control firmware storage, audio prompt buffering, calibration data logging, and sensor configuration persistence requiring stable component supply across multi-year production cycles.
Supply support for AT45DB021B-TU 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 technical and supply chain responsibility for the AT45DB series. The company specializes in secure, low-power microcontrollers and nonvolatile memory solutions for industrial and automotive markets.
The AT45DB product line was designed specifically for embedded systems needing SPI-based Flash with integrated SRAM buffers and EEPROM emulation - addressing limitations of standard NOR/NAND Flash in resource-constrained, real-time applications.
FAQ
What is the maximum clock frequency supported by the AT45DB021B-TU during continuous array read?
The AT45DB021B-TU supports up to 20 MHz for continuous array read operations, as specified in the datasheet's fCAR parameter. This allows sustained sequential data transfer rates exceeding 2.5 MB/s, making it suitable for code shadowing and audio streaming applications where latency and throughput are critical. The AT45DB021B-TU maintains this performance across its full operating voltage range (2.7–3.6 V) and temperature range (–40°C to +85°C).
Does the AT45DB021B-TU require a high-voltage programming supply?
No, the AT45DB021B-TU operates entirely from a single 2.7–3.6 V supply for both read and program/erase operations. All internal high-voltage generation is handled on-chip, eliminating the need for external charge pumps or 5 V/12 V programming supplies. This simplifies system power design and enhances reliability in battery-powered or low-voltage embedded systems using the AT45DB021B-TU.
How does the dual-buffer architecture of the AT45DB021B-TU improve system responsiveness?
The AT45DB021B-TU's two independent 264-byte SRAM buffers allow overlapping operations: while one buffer is being written to via SPI, the other can be programmed into Flash memory - or vice versa. This pipelining reduces effective write latency and enables uninterrupted data acquisition during firmware updates. In practice, this means the host processor spends less time waiting for AT45DB021B-TU operations to complete.
Can the AT45DB021B-TU emulate EEPROM functionality for small parameter updates?
Yes, the AT45DB021B-TU supports true EEPROM emulation through a three-step Read-Modify-Write sequence using its SRAM buffers. This allows individual bytes or words to be altered without erasing entire pages - preserving data integrity and extending memory lifetime. Unlike basic Flash parts, this capability is natively implemented in the AT45DB021B-TU's command set and requires no external wear-leveling firmware.
What is the purpose of the RDY/BUSY pin on the AT45DB021B-TU?
The RDY/BUSY pin on the AT45DB021B-TU is an open-drain output that signals active self-timed operations (e.g., page erase, buffer-to-Flash program, page compare). It is driven low during these operations and returns high when complete. This allows the host microcontroller to poll status efficiently instead of relying solely on fixed delay timers - improving system determinism and reducing unnecessary SPI traffic when verifying AT45DB021B-TU readiness.
AT45DB021B-TU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 28-TSSOP (0.465", 11.80mm Width)
- Packaging:
- Tray
- 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-TSOP
AT45DB021B-TU FAQ
1.How can I place an order for AT45DB021B-TU through Aetrix?
Please submit a Request for Quotation (RFQ) for AT45DB021B-TU 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-TU reliable?
The price and inventory of AT45DB021B-TU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT45DB021B-TU is usually 5 days.
3.What payment methods are accepted for AT45DB021B-TU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT45DB021B-TU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT45DB021B-TU?
AT45DB021B-TU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT45DB021B-TU 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-TU?
For technical support, including AT45DB021B-TU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT45DB021B-TU requirements.
6.How does Aetrix verify that AT45DB021B-TU is sourced from the original manufacturer or authorized distributors?
All AT45DB021B-TU 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-TU meets industry standards.
7.What is the process for return or replacement of AT45DB021B-TU?
All AT45DB021B-TU units undergo pre-shipment inspection (PSI). If there is an issue with AT45DB021B-TU, 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-TU part is unused and in its original packaging.
Return procedure for AT45DB021B-TU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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