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Microchip Technology AT45DB021B-SI
- Part No.:
- AT45DB021B-SI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 8-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
AT45DB021B-SI.pdf
- Description:
- IC FLASH 2MBIT SPI 20MHZ 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,293
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Product details
Overview
AT45DB021B-SI 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, hardware write protection, and continuous array read for code shadowing in embedded microcontroller systems.
For engineers reviewing the AT45DB021B-SI datasheet, AT45DB021B-SI pinout, AT45DB021B-SI application, or AT45DB021B-SI equivalent, this page delivers verified electrical specs, validated pin functions, confirmed buffer-aided reprogrammability, and real-world use cases in firmware storage, voice logging, and configuration data retention - all grounded in the official 1937J–DFLSH–9/05 datasheet.
Technical Context
The AT45DB021B-SI implements a dedicated SPI-based DataFlash architecture with two independent 264-byte SRAM buffers enabling concurrent data reception and nonvolatile memory reprogramming. It supports SPI Mode 0 and Mode 3, uses MSB-first serial framing, and relies on opcode-driven command sequences (e.g., 52H for page read, 83H for buffer-to-page program with erase).
Its memory hierarchy includes page (264 B), block (8 pages = 2,112 B), and sector-level organization, allowing flexible erase granularity (page or block). All programming and erase operations are self-timed, require no external high-voltage supply, and report status via bit 7 of the 8-bit status register accessible through opcode D7H.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 2,162,688 bits (1024 × 264-byte pages) - provides compact, low-pin-count firmware/data storage without parallel bus overhead. |
| Supply Voltage | 2.7V to 3.6V - single-supply operation compatible with 3.3V logic systems; eliminates level-shifting requirements. |
| Max Clock Frequency | 20 MHz - enables fast sequential reads (e.g., code shadowing) and efficient buffer transfers in time-critical applications. |
| Active Read Current | 4 mA typical - low power consumption during execution-from-Flash scenarios, extending battery life in portable devices. |
| Standby Current | 2 µA typical - ultra-low quiescent draw in sleep modes, critical for always-on sensor nodes and IoT edge devices. |
| Write Protection | Hardware WP pin protects first 256 pages - prevents accidental overwrite of bootloader or calibration data in field-deployed systems. |
| Input Tolerance | 5.0V-tolerant SI, SCK, CS, RESET, WP - simplifies interfacing with mixed-voltage host controllers without external clamping diodes. |
Pinout & Package
AT45DB021B-SI is supplied in an 8-pin SOIC package (Small Outline Integrated Circuit), RoHS-compliant, with 1.27 mm pitch and standard JEDEC MS-012AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-low enable signal; initiates all command sequences and must remain low during opcode/address/data transfer. |
| SCK | Serial Clock | Input-only clock; data latched on rising edge (SI), output shifted on falling edge (SO); supports up to 20 MHz. |
| SI | Serial Input | Input-only data line; carries opcodes, addresses, and buffer data; MSB-first, 8-bit aligned per instruction. |
| SO | Serial Output | Output-only data line; returns read data, status register bits, or compare results; tri-stated when CS is high. |
| WP | Write Protect | Active-low hardware lock; disables programming/erase of pages 0–255 when pulled low - safeguards critical firmware sections. |
| RESET | Chip Reset | Active-low asynchronous reset; terminates ongoing operations and returns internal state machine to idle; internal POR circuitry ensures safe startup. |
| RDY/BUSY | Ready/Busy Indicator | Open-drain output; driven low during self-timed operations (e.g., page program, block erase); requires external 1 kΩ pull-up. |
| VCC / GND | Power Supply | Single 2.7–3.6V supply and ground; decoupling capacitor (0.1 µF) recommended near VCC pin for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Dual SRAM Buffers | Two independent 264-byte buffers enable simultaneous data streaming into one buffer while reprogramming the other into Flash - essential for seamless firmware updates. |
| Continuous Array Read | Opcode 68H/E8H allows uninterrupted sequential read across page boundaries and full memory wraparound - ideal for executing code directly from Flash (XIP) without address management. |
| Self-Timed Page Program | Single-cycle erase-and-program (opcode 83H/86H) completes in ≤20 ms max - eliminates need for external timing control or polling overhead in host firmware. |
| Page/Block Erase Flexibility | Supports discrete page erase (81H) or 8-page block erase (50H) - optimizes endurance and wear leveling in data-logging applications with partial updates. |
| EEPROM Emulation | Three-step Read-Modify-Write via buffers enables byte-level data alteration - satisfies legacy EEPROM replacement requirements without hardware redesign. |
Applications
| Firmware Storage | Voice/Data Logging |
|---|---|
Use Scenario: Storing boot code, application firmware, and configuration parameters for ARM Cortex-M or PIC microcontrollers in industrial gateways. IC Role / Device Role / Timing Role: Nonvolatile serial code storage with continuous array read capability enabling direct execution (XIP) and fast page-level updates. Use Value: Reduces PCB space vs. parallel NOR Flash; eliminates address bus routing; supports in-system firmware upgrades via SPI without external high-voltage circuitry. | Use Scenario: Capturing audio snippets, sensor readings, or event logs in battery-powered environmental monitors. IC Role / Device Role / Timing Role: High-endurance, low-power data sink using block-erase optimization and dual-buffer streaming to avoid data loss during writes. Use Value: 2 µA standby current extends multi-year battery life; page erase granularity minimizes write amplification; 5V-tolerant inputs simplify connection to analog front-end ICs. |
| Configuration Memory | Embedded GUI Assets |
Use Scenario: Retaining user preferences, calibration tables, and network settings in smart home hubs after power cycles. IC Role / Device Role / Timing Role: EEPROM-replacement storage using Read-Modify-Write buffer operations to alter individual bytes without full-page rewrites. Use Value: Eliminates need for separate EEPROM; avoids wear-out limitations of single-page Flash by distributing updates across sectors per 10,000-cycle rule. | Use Scenario: Hosting bitmap fonts, icons, and UI strings for LCD-based HMIs in medical devices and test equipment. IC Role / Device Role / Timing Role: High-bandwidth serial asset repository supporting burst reads at 20 MHz for rapid screen refreshes. Use Value: Continuous read mode delivers deterministic latency; 264-byte page size aligns with common glyph/asset chunking; SO pin drive strength supports direct LCD controller interfacing. |
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-SU | Same density and pinout; updated revision with enhanced ESD robustness and extended temperature range (–40°C to +85°C vs. 0°C to +70°C for -SI). | Preferred for industrial environments requiring wider thermal stability and higher reliability under electrostatic stress. | Select AT45DB021D-SU when operating beyond commercial temperature limits or in high-noise factory-floor deployments. |
| W25Q20EWUXIE | 2 Mbit Quad SPI Flash (Winbond); smaller 4×3 mm WSON package; supports QPI/DTR modes but lacks dual buffers and continuous array read. | Better suited for space-constrained designs needing faster random access, but not for buffer-assisted streaming or XIP code shadowing. | Choose W25Q20EWUXIE only if board layout demands minimal footprint and host supports Quad SPI; avoid where buffer concurrency or seamless read wraparound is required. |
Compared with AT45DB021D-SU, the AT45DB021B-SI offers identical core functionality but narrower temperature rating and older ESD spec; versus W25Q20EWUXIE, it trades package size and interface speed for unique dual-buffer concurrency and continuous-read determinism - making it irreplaceable in streaming-centric embedded firmware architectures.
Availability
AT45DB021B-SI is available at Aetrix Electronics and suitable for firmware storage, voice/data logging, and configuration memory applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for AT45DB021B-SI 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-SI belongs to Microchip's DataFlash family - designed specifically for embedded systems needing reliable, low-pin-count serial Flash with integrated SRAM buffers to enable concurrent data handling and seamless code execution.
FAQ
What is the maximum clock frequency supported by the AT45DB021B-SI during continuous array read?
The AT45DB021B-SI supports up to 20 MHz for continuous array read (CAR) operations using opcodes 68H or E8H. This timing is defined by the fCAR parameter in the datasheet and ensures deterministic streaming performance for code shadowing. Exceeding 20 MHz may cause read corruption or timing violations, as the internal logic is characterized and guaranteed only up to this frequency. The AT45DB021B-SI does not support overclocking beyond its rated specification.
Does the AT45DB021B-SI require a high-voltage programming supply?
No, the AT45DB021B-SI operates entirely from a single 2.7V–3.6V supply for both read and program/erase operations. All internal high-voltage generation is handled on-chip, eliminating the need for external VPP pins or charge pumps. This simplifies power design and enables true single-supply in-system reprogrammability - a defining feature of the AT45DB021B-SI architecture.
How does the dual-buffer architecture of the AT45DB021B-SI improve system throughput?
The AT45DB021B-SI's two independent 264-byte SRAM buffers allow overlapping operations: while one buffer streams data into Flash (e.g., via opcode 83H), the other can simultaneously accept new data via SI. This concurrency eliminates idle time between writes, increasing effective data throughput by up to 2× in streaming applications. The AT45DB021B-SI leverages this to sustain continuous logging or firmware patching without host CPU stalls.
Can the AT45DB021B-SI be used as a direct EEPROM replacement?
Yes, the AT45DB021B-SI supports EEPROM emulation via its built-in Read-Modify-Write sequence using the buffers - enabling byte- or bit-level alterations without full-page erases. However, unlike true EEPROM, it requires explicit host firmware management of wear leveling and sector rotation per the 10,000-cycle rule. The AT45DB021B-SI is functionally suitable but demands careful software implementation to match EEPROM endurance behavior.
What happens when the AT45DB021B-SI reaches the end of memory during a continuous array read?
During continuous array read (opcode 68H/E8H), the AT45DB021B-SI automatically wraps around from the last bit of page 1023 back to the first bit of page 0 with zero delay - no additional addressing or host intervention is needed. This seamless wraparound is hardware-implemented and guarantees uninterrupted data flow, making the AT45DB021B-SI ideal for circular buffer implementations and infinite-loop audio playback.
AT45DB021B-SI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-SOIC (0.209", 5.30mm 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:
- 8-SOIC
AT45DB021B-SI FAQ
1.How can I place an order for AT45DB021B-SI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT45DB021B-SI 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-SI reliable?
The price and inventory of AT45DB021B-SI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT45DB021B-SI is usually 5 days.
3.What payment methods are accepted for AT45DB021B-SI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT45DB021B-SI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT45DB021B-SI?
AT45DB021B-SI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT45DB021B-SI 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-SI?
For technical support, including AT45DB021B-SI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT45DB021B-SI requirements.
6.How does Aetrix verify that AT45DB021B-SI is sourced from the original manufacturer or authorized distributors?
All AT45DB021B-SI 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-SI meets industry standards.
7.What is the process for return or replacement of AT45DB021B-SI?
All AT45DB021B-SI units undergo pre-shipment inspection (PSI). If there is an issue with AT45DB021B-SI, 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-SI part is unused and in its original packaging.
Return procedure for AT45DB021B-SI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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