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Microchip Technology AT45DB021B-CI
- Part No.:
- AT45DB021B-CI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 9-TBGA, CSPBGA
- Datasheet:
-
AT45DB021B-CI.pdf
- Description:
- IC FLASH 2MBIT SPI 20MHZ 9CBGA
- Quantity:
- Payment:
- Shipping:
Inventory:3,813
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Product details
Overview
AT45DB021B-CI 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-CI datasheet, AT45DB021B-CI pinout, AT45DB021B-CI application, or AT45DB021B-CI 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), SPI Mode 0/3 compatibility, RDY/BUSY open-drain status signaling, and support for page/block erase without external high-voltage programming.
Technical Context
The AT45DB021B-CI implements a dedicated SPI-based serial Flash architecture with two independent 264-byte SRAM buffers enabling concurrent data reception and nonvolatile memory reprogramming. Its command set includes buffer-to-page program with built-in erase, page/block erase, main memory page-to-buffer transfer/compare, and auto page rewrite - all internally self-timed with status register (bit 7 = RDY/BUSY) polling support.
It uses MSB-first serial framing with opcode-driven instruction execution, supports continuous read across page boundaries without delay, and provides EEPROM emulation via three-step Read-Modify-Write using buffers. The device avoids parallel address/data buses, reducing PCB routing complexity and EMI while maintaining full random-access capability through sequential addressing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 2,162,688 bits (1024 × 264-byte pages) - enables compact firmware/image storage without external address decoding logic |
| Supply Voltage | 2.7 V to 3.6 V - single-supply operation simplifies power design; no charge pump or external VPP required |
| Max Clock Frequency | 20 MHz - supports high-throughput firmware updates and real-time streaming read at up to ~2.5 MB/s theoretical bandwidth |
| Active Read Current | 4 mA typical - low power consumption suitable for battery-backed or energy-sensitive embedded systems |
| Standby Current | 2 µA typical - enables ultra-low-power sleep modes during idle periods in portable or remote devices |
| Interface Standard | SPI Mode 0 and Mode 3 - compatible with most microcontroller SPI peripherals without mode configuration constraints |
| Input Tolerance | 5.0 V-tolerant SI, SCK, CS, RESET, WP - allows direct interfacing with 5 V logic without level shifters |
| Temperature Range | −40°C to +85°C - qualified for industrial-grade operation in harsh environmental conditions |
Pinout & Package
AT45DB021B-CI is available in 8-pin SOIC (Small Outline Integrated Circuit) package per Figure 2-2 of the datasheet, with lead-free, RoHS-compliant finish.
| 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) |
| SI | Serial Input | Input-only data line for opcodes, addresses, and buffer writes; MSB-first framing |
| SO | Serial Output | Output-only data line for read operations and status register; tri-stated when CS is high |
| WP | Hardware Write Protect | Active-low pin protecting first 256 pages; must be high to enable programming of protected region |
| RESET | Chip Reset | Active-low asynchronous reset; aborts ongoing operation and returns state machine to idle |
| RDY/BUSY | Ready/Busy Indicator | Open-drain output pulled high externally; driven low during internal self-timed operations (erase, program, transfer) |
| VCC / GND | Power Supply | 2.7–3.6 V core supply and ground; decoupling capacitor required near VCC pin for stable operation |
Key Features
| Feature | Design Value |
|---|---|
| Dual 264-byte SRAM buffers | Enables simultaneous data streaming into one buffer while reprogramming main memory from the other - eliminates host CPU wait states during flash writes |
| Continuous Array Read | Supports seamless code shadowing: automatic address wrap-around at page and array boundaries with no inter-page delay |
| Page and Block Erase | Flexible granularity: erase individual 264-byte pages or 8-page blocks (2112 bytes) - optimizes wear leveling and update efficiency |
| Self-timed Program/Erase | No external timing control needed; all operations complete autonomously with RDY/BUSY status flagging completion |
| Hardware Page Write Protect | Physical lock for first 256 pages prevents accidental firmware corruption - critical for bootloader partition security |
| EEPROM Emulation Support | Three-step Read-Modify-Write using buffers enables byte-level updates without full-page erasure - extends effective endurance |
Applications
| Firmware Storage | Code Shadowing |
|---|---|
|
Use Scenario: Storing bootloaders and application firmware in microcontroller-based industrial PLCs where field updates are infrequent but mission-critical. IC Role / Device Role / Timing Role: Nonvolatile storage element holding executable code; accessed sequentially during startup or OTA update via SPI. Use Value: Hardware write protection (WP pin) prevents corruption of bootloader pages; 2.7 V operation ensures compatibility with low-voltage MCU I/O domains. |
Use Scenario: Executing application code directly from AT45DB021B-CI memory in resource-constrained audio DSP systems using XIP (execute-in-place). IC Role / Device Role / Timing Role: Serial Flash acting as extended instruction memory; continuous read mode streams instructions without address reinitialization. Use Value: Seamless page-boundary crossing eliminates pipeline stalls; 20 MHz clock supports real-time instruction fetch rates up to 2.5 MB/s. |
| Data Logging | Configuration Storage |
|
Use Scenario: Capturing sensor readings in environmental monitoring nodes powered by coin-cell batteries. IC Role / Device Role / Timing Role: Low-power persistent storage for timestamped measurements; buffers absorb burst writes while flash erases/programs in background. Use Value: 2 µA standby current extends battery life; dual-buffer architecture enables uninterrupted logging during flash maintenance cycles. |
Use Scenario: Retaining calibration parameters and user settings across power cycles in medical diagnostic equipment. IC Role / Device Role / Timing Role: EEPROM-replacement storage for small, frequently updated configuration records. Use Value: Built-in Read-Modify-Write capability emulates byte-alterable EEPROM behavior without external wear-leveling firmware overhead. |
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-CU | Same density and pinout; enhanced reliability with improved data retention (20 years @ 85°C vs. 10 years) and extended temperature range (−40°C to +105°C) | Better suited for automotive under-hood or high-temperature industrial environments requiring longer data retention | Select AT45DB021D-CU if operating above 85°C or requiring >10-year data retention; otherwise AT45DB021B-CI remains cost-optimized for standard industrial use. |
| W25Q20EWUXIE | 2 Mbit Quad SPI Flash (Winbond); smaller 2×3 mm USON-8 package; supports QPI/DTR modes; no integrated SRAM buffers | Lacks dual-buffer concurrency; requires host-managed buffering but offers faster random access and lower package footprint | Choose W25Q20EWUXIE for space-constrained designs needing higher random-read performance; retain AT45DB021B-CI when concurrent buffer streaming is essential for deterministic write latency. |
Compared with AT45DB021D-CU, the AT45DB021B-CI trades extended temperature rating and retention for lower unit cost and proven maturity in legacy industrial designs; versus W25Q20EWUXIE, it prioritizes buffer-assisted streaming over quad-SPI speed and miniaturization - making it optimal for deterministic, low-overhead firmware storage where host CPU resources are limited.
Availability
AT45DB021B-CI is available at Aetrix Electronics and suitable for firmware storage, code shadowing, data logging, and configuration storage requiring stable component supply across long-lifecycle industrial programs.
Supply support for AT45DB021B-CI 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 DataFlash family.
The AT45DB021B-CI belongs to Microchip's legacy DataFlash® serial Flash product line, designed specifically for embedded systems requiring SPI-based nonvolatile storage with integrated buffering and EEPROM-like flexibility.
FAQ
What is the maximum clock frequency supported by the AT45DB021B-CI?
The AT45DB021B-CI supports a maximum serial clock (SCK) frequency of 20 MHz for all read, write, and command operations. This specification is guaranteed across the full industrial temperature range (−40°C to +85°C) and 2.7–3.6 V supply voltage. Exceeding 20 MHz may result in unreliable opcode recognition or data corruption during transfers. The AT45DB021B-CI does not require external clock dividers or timing adjustments - the internal state machine handles all setup/hold timing automatically.
Does the AT45DB021B-CI require high-voltage programming?
No, the AT45DB021B-CI does not require high-voltage programming. All program and erase operations execute from the same 2.7–3.6 V supply used for read operations - no external VPP pin or charge pump circuitry is needed. The AT45DB021B-CI achieves this through internal voltage multiplication and self-timed algorithms, simplifying system design and eliminating risk of accidental overvoltage damage. This feature is intrinsic to the AT45DB021B-CI architecture and documented in Section 2 of the official datasheet.
How does the RDY/BUSY pin function on the AT45DB021B-CI?
The RDY/BUSY pin on the AT45DB021B-CI is an open-drain output that sinks current when the device is executing any internally self-timed operation - including page/block erase, buffer-to-memory programming, page transfer, or compare. It remains high (via external 1 kΩ pull-up) when idle or ready. The AT45DB021B-CI asserts RDY/BUSY low synchronously with command initiation and releases it only after full completion, including internal verification. Status register bit 7 mirrors this signal for software polling.
Can the AT45DB021B-CI emulate EEPROM functionality?
Yes, the AT45DB021B-CI supports EEPROM emulation via a three-step Read-Modify-Write sequence using its dual SRAM buffers. First, a page is transferred from main memory to a buffer; second, the desired byte(s) are modified in the buffer; third, the updated buffer contents are programmed back to the same page. This avoids full-page erasure for single-byte changes. The AT45DB021B-CI implements this natively - no external controller logic is required beyond issuing the standard opcodes (53H/55H, then 83H/86H).
What packages are available for the AT45DB021B-CI?
The AT45DB021B-CI is offered in an 8-pin SOIC (Small Outline Integrated Circuit) package, designated "CI" in the part number suffix. This is the standard commercial/industrial variant with gull-wing leads, RoHS-compliant finish, and JEDEC MS-012AC footprint. Other variants like CBGA or 28-SOIC exist for the AT45DB021B family but are not applicable to the -CI suffix - the AT45DB021B-CI specifically maps to the 8-pin SOIC configuration shown in Figure 2-2 of the datasheet.
AT45DB021B-CI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 9-TBGA, CSPBGA
- 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:
- 9-CBGA (5x5)
AT45DB021B-CI FAQ
1.How can I place an order for AT45DB021B-CI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT45DB021B-CI 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-CI reliable?
The price and inventory of AT45DB021B-CI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT45DB021B-CI is usually 5 days.
3.What payment methods are accepted for AT45DB021B-CI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT45DB021B-CI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT45DB021B-CI?
AT45DB021B-CI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT45DB021B-CI 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-CI?
For technical support, including AT45DB021B-CI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT45DB021B-CI requirements.
6.How does Aetrix verify that AT45DB021B-CI is sourced from the original manufacturer or authorized distributors?
All AT45DB021B-CI 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-CI meets industry standards.
7.What is the process for return or replacement of AT45DB021B-CI?
All AT45DB021B-CI units undergo pre-shipment inspection (PSI). If there is an issue with AT45DB021B-CI, 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-CI part is unused and in its original packaging.
Return procedure for AT45DB021B-CI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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