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Microchip Technology AT45DB321B-CI
- Part No.:
- AT45DB321B-CI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 44-TBGA, CSPBGA
- Datasheet:
-
AT45DB321B-CI.pdf
- Description:
- IC FLASH 32MBIT SPI 20MHZ 44CBGA
- Quantity:
- Payment:
- Shipping:
Inventory:1,930
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Product details
Overview
AT45DB321B-CI from Microchip Technology (formerly Atmel) is a 32-Mbit serial DataFlash memory IC with SPI interface, organized as 8192 pages × 528 bytes, supporting page/block erase, dual 528-byte SRAM buffers, and continuous array read for code shadowing in embedded systems.
For engineers reviewing the AT45DB321B-CI datasheet, AT45DB321B-CI pinout, AT45DB321B-CI application, or AT45DB321B-CI equivalent, key selection considerations include 2.7–3.6V single-supply operation, 20 MHz max SPI clock, 5.0V-tolerant control pins, industrial temperature range (–40°C to +85°C), and hardware write protection for first 256 pages.
Technical Context
The AT45DB321B-CI implements a serial Flash architecture with two independent 528-byte SRAM buffers enabling concurrent data reception and nonvolatile memory reprogramming. Its SPI interface supports Mode 0 and Mode 3, with all commands initiated via CS low followed by 8-bit opcodes and address sequences.
Memory operations are internally self-timed: page program with built-in erase completes in ≤20 ms (tEP), block erase in ≤35 ms (tBE), and status register polling enables real-time RDY/BUSY monitoring via bit 7. The device uses MSB-first serial transfer and supports EEPROM emulation via Read-Modify-Write using buffer compare and auto-page-rewrite functions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 32 Mbit (34,603,008 bits), organized as 8192 × 528-byte pages |
| Supply Voltage | 2.7 V to 3.6 V - enables direct integration with 3.3 V logic without level shifters |
| Max SPI Clock | 20 MHz - supports high-throughput streaming in code shadowing and firmware update applications |
| Active Read Current | 4 mA typical - minimizes power draw during active code execution or data retrieval |
| Standby Current | 2 µA typical - critical for battery-powered devices requiring ultra-low quiescent power |
| Temperature Range | –40°C to +85°C - qualified for industrial-grade embedded systems and automotive body electronics |
| Input Tolerance | 5.0 V-tolerant on CS, SCK, SI, RESET, WP - simplifies interfacing with mixed-voltage host controllers |
Pinout & Package
AT45DB321B-CI is packaged in a 28-pin TSOP-I (Type 1) with 0.55 mm pitch, compliant with JEDEC MO-153. Pinout is identical across TSOP, SOIC, and CBGA variants per datasheet Rev. 2223D.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-low enable for command initiation; falling edge starts opcode loading sequence |
| SCK | Serial Clock | Input-only; controls data timing - rising edge clocks data in, falling edge clocks data out |
| SI | Serial Input | Input-only; carries opcodes, addresses, and write data; MSB-first protocol |
| SO | Serial Output | Output-only; returns read data and status register bits; tri-stated when CS high |
| WP | Hardware Write Protect | Active-low; locks first 256 pages against accidental program/erase - internal pull-up allows omission if unused |
| RESET | Asynchronous Reset | Active-low; aborts ongoing operation and resets internal state machine - internal pull-up enables optional connection |
| RDY/BUSY | Open-drain Status Indicator | Drives low during self-timed operations (program/erase/transfer); requires external 1 kΩ pull-up |
| VCC / GND | Power Supply | Single 2.7–3.6 V supply; decoupling capacitor required near VCC pin for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Dual 528-byte SRAM buffers | Enables pipelined operation: receive new data into one buffer while programming the other into Flash |
| Continuous Array Read (CAR) | Supports seamless code shadowing - automatic page-wrap and array-wrap with no latency at boundaries |
| Page-level erase + program | Eliminates need for separate erase cycle; single-cycle reprogram (erase + write) in ≤20 ms per page |
| Hardware write protection | Pin-controlled lock for first 256 pages - prevents corruption of boot code or configuration sectors |
| EEPROM emulation capability | Self-contained Read-Modify-Write via buffer compare and auto-page-rewrite - no external logic needed |
Applications
| Firmware Storage | Code Shadowing |
|---|---|
|
Use Scenario: Storing bootloader, application firmware, and field-upgradable binaries in resource-constrained microcontroller systems. IC Role / Device Role / Timing Role: Nonvolatile storage medium accessed via SPI during boot or OTA update; supports atomic page writes and sector-level erasure. Use Value: Enables reliable in-system reprogramming without high-voltage programming circuitry or external erase controllers. |
Use Scenario: Executing application code directly from external memory by copying to RAM or XIP-capable bus interfaces. IC Role / Device Role / Timing Role: Continuous-read Flash providing uninterrupted 20 MHz serial data stream for instruction fetch pipelines. Use Value: Eliminates wait states during page boundary crossings and array wraparound - critical for deterministic real-time execution. |
| Data Logging | Configuration Storage |
|
Use Scenario: Recording sensor readings, event timestamps, or diagnostic logs in industrial monitoring equipment. IC Role / Device Role / Timing Role: High-endurance serial memory supporting frequent small-block writes with wear leveling via buffer-assisted page management. Use Value: Dual-buffer architecture allows background logging while foreground tasks access stored data - no blocking I/O stalls. |
Use Scenario: Persisting user settings, calibration coefficients, and network parameters across power cycles in smart peripherals. IC Role / Device Role / Timing Role: EEPROM-replacement storage with byte-alterability emulated via Read-Modify-Write using internal buffers. Use Value: Hardware write protect (WP pin) safeguards critical configuration sectors from accidental overwrite during firmware 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 |
|---|---|---|---|
| W25Q32JVSSIQ | 32 Mbit Quad SPI NOR Flash; 4-line I/O mode; no internal SRAM buffers; requires explicit erase before program | Lacks continuous read and pipelined buffer operation; better suited for execute-in-place (XIP) with QSPI controllers | Select when higher random read speed or QSPI interface compatibility is prioritized over streaming efficiency |
| AT45DB321D-CU | Same 32 Mbit density and pinout; updated revision with enhanced reliability, extended endurance (100k cycles vs. 10k), and improved tEP spec | Drop-in replacement with identical command set and timing; supports same industrial temperature range | Prefer for new designs requiring longer data retention and higher program/erase cycle count |
Compared with W25Q32JVSSIQ, AT45DB321B-CI delivers superior streaming throughput and lower software overhead via dual-buffer pipelining; compared with AT45DB321D-CU, it offers legacy compatibility but reduced endurance and tighter timing margins.
Availability
AT45DB321B-CI is available at Aetrix Electronics and suitable for firmware storage, code shadowing, data logging, and configuration storage applications requiring stable component supply, long-term lifecycle support, and industrial temperature qualification.
Supply support for AT45DB321B-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 AT45DB321B-CI belongs to Microchip's legacy DataFlash® serial Flash product line, designed specifically for embedded systems needing high-density, low-pin-count, low-voltage nonvolatile storage with streaming and buffering capabilities.
FAQ
What is the maximum clock frequency supported by the AT45DB321B-CI?
The AT45DB321B-CI supports a maximum SPI clock frequency of 20 MHz for all read, write, and status operations. This specification applies across the full industrial temperature range (–40°C to +85°C) and 2.7–3.6 V supply voltage. The device complies with SPI Mode 0 and Mode 3, and timing parameters such as tCLK (min 50 ns) and tCH/tCL (min 25 ns) are guaranteed under these conditions. AT45DB321B-CI does not support higher frequencies even at reduced temperatures or voltages.
Does the AT45DB321B-CI require a high-voltage programming signal?
No, the AT45DB321B-CI operates entirely from a single 2.7–3.6 V supply for both read and program/erase operations - no external high-voltage generator or charge pump is needed. All programming cycles are self-timed and internally managed. The AT45DB321B-CI achieves this through on-chip charge pumps and optimized Flash cell design, enabling simple in-system reprogrammability in standard 3.3 V environments. AT45DB321B-CI eliminates the complexity and cost of high-voltage programming circuitry.
How does the dual-buffer architecture of the AT45DB321B-CI improve system performance?
The AT45DB321B-CI integrates two independent 528-byte SRAM buffers that operate concurrently with main memory operations. While one buffer receives incoming data via SI, the other can be programmed into Flash - eliminating I/O blocking and enabling true pipelining. This architecture reduces effective write latency by up to 50% in streaming applications and supports seamless code shadowing. AT45DB321B-CI leverages this for continuous array read and auto-page-rewrite without host intervention.
Can the AT45DB321B-CI be used as a direct EEPROM replacement?
Yes, the AT45DB321B-CI supports EEPROM emulation via its built-in Read-Modify-Write capability: users can perform Main Memory Page to Buffer Transfer, modify buffer contents, then execute Buffer to Main Memory Page Program with Built-in Erase. This three-step process emulates byte-level alterability without external logic. However, AT45DB321B-CI requires page-level granularity (528 bytes), so true random byte writes incur overhead - it is best suited for infrequent, block-oriented updates rather than high-frequency single-byte changes.
What is the purpose of the RDY/BUSY pin on the AT45DB321B-CI?
The RDY/BUSY pin on the AT45DB321B-CI is an open-drain output that drives low during any internally self-timed operation - including page program, block erase, buffer transfer, and auto-page-rewrite. It remains high only when the device is idle and ready to accept the next command. Host systems use this signal for hardware polling instead of software-based status register reads, reducing SPI traffic and improving timing predictability. AT45DB321B-CI requires an external 1 kΩ pull-up resistor on this pin for proper operation.
AT45DB321B-CI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 44-TBGA, CSPBGA
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- FLASH
- Technology:
- FLASH
- Memory Size:
- 32Mbit
- Memory Organization:
- 528 Bytes x 8192 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:
- 44-CBGA (6x12)
AT45DB321B-CI FAQ
1.How can I place an order for AT45DB321B-CI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT45DB321B-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 AT45DB321B-CI reliable?
The price and inventory of AT45DB321B-CI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT45DB321B-CI is usually 5 days.
3.What payment methods are accepted for AT45DB321B-CI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT45DB321B-CI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT45DB321B-CI?
AT45DB321B-CI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT45DB321B-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 AT45DB321B-CI?
For technical support, including AT45DB321B-CI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT45DB321B-CI requirements.
6.How does Aetrix verify that AT45DB321B-CI is sourced from the original manufacturer or authorized distributors?
All AT45DB321B-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 AT45DB321B-CI meets industry standards.
7.What is the process for return or replacement of AT45DB321B-CI?
All AT45DB321B-CI units undergo pre-shipment inspection (PSI). If there is an issue with AT45DB321B-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 AT45DB321B-CI part is unused and in its original packaging.
Return procedure for AT45DB321B-CI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT45DB321B-CI Tags
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