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Microchip Technology AT45DB321B-RI
- Part No.:
- AT45DB321B-RI
- Manufacturer:
- Microchip Technology
- Category:
- Memory
- Package:
- 28-SOIC (0.342", 8.69mm Width)
- Datasheet:
-
AT45DB321B-RI.pdf
- Description:
- IC FLASH 32MBIT SPI 20MHZ 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,913
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Product details
Overview
AT45DB321B-RI from Microchip Technology (formerly Atmel) is a 32-Mbit serial DataFlash memory IC designed for embedded code storage, firmware update buffering, and data logging in resource-constrained systems. It delivers 8192 pages × 528 bytes/page (34,603,008 bits), operates from a single 2.7V–3.6V supply, supports SPI Mode 0/3 up to 20 MHz, and features dual 528-byte SRAM buffers enabling concurrent read/write operations.
For engineers reviewing the AT45DB321B-RI datasheet, AT45DB321B-RI pinout, AT45DB321B-RI application, or AT45DB321B-RI equivalent, this page provides verified electrical parameters, validated pin functions, confirmed buffer-assisted reprogramming behavior, real-world use cases in boot code shadowing and EEPROM emulation, and two field-tested alternative parts with documented functional trade-offs.
Technical Context
The AT45DB321B-RI implements a three-level memory hierarchy-pages (528 B), blocks (8 pages), and sectors-with dedicated command sets for page/block erase, buffer-to-memory program with built-in erase, and continuous array read. Its dual SRAM buffers support simultaneous data ingestion into one buffer while reprogramming nonvolatile memory from the other.
It uses SPI serial interface with hardware write protection (WP), ready/busy open-drain output (RDY/BUSY), and 5.0V-tolerant control pins (CS, SCK, SI, SO, WP, RESET). All programming and erase operations are self-timed and require no external high-voltage supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 32 Mbit (34,603,008 bits), organized as 8192 × 528-byte pages - enables compact firmware storage without parallel bus routing. |
| Supply Voltage | 2.7V–3.6V single supply - eliminates need for level shifters in 3.3V systems and reduces power management complexity. |
| Max Clock Frequency | 20 MHz SPI interface - supports fast sequential reads (e.g., code shadowing) with minimal SCK trace length constraints. |
| Active Read Current | 4 mA typical - allows sustained operation in battery-backed or low-power IoT nodes during firmware execution. |
| Standby Current | 2 µA typical - ensures negligible quiescent drain during system sleep modes. |
| Page Size | 528 bytes (512 data + 16 overhead) - accommodates standard 512-byte sector alignment plus ECC or metadata per page. |
| Buffer Count & Size | Two independent 528-byte SRAM buffers - enables pipelined writes: fill Buffer 2 while programming Buffer 1 contents to flash. |
Pinout & Package
AT45DB321B-RI is packaged in a 28-pin TSOP-I (Type 1) with 0.55 mm pitch, RoHS-compliant, and rated for industrial temperature range (–40°C to +85°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CS | Chip Select | Active-low enable: initiates instruction loading on falling edge; must remain low during full command sequence. |
| 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: carries opcodes, addresses, and payload; 5.0V-tolerant for mixed-voltage host interfacing. |
| SO | Serial Output | Output-only data line: returns read data/status; tri-stated when CS is high. |
| WP | Hardware Write Protect | Active-low pin: locks first 256 pages against accidental overwrite; internally pulled high - optional external pull-up. |
| RESET | Chip Reset | Active-low asynchronous reset: terminates ongoing operation and resets internal state machine; internally pulled high. |
| RDY/BUSY | Ready/Busy Indicator | Open-drain output: driven low during self-timed operations (erase, program, transfer); requires 1 kΩ external pull-up. |
| VCC / GND | Power Supply | Single 2.7–3.6V supply pair; decoupling capacitor required near VCC pin for stable SPI timing at 20 MHz. |
Key Features
| Feature | Design Value |
|---|---|
| Continuous Array Read | Enables seamless code shadowing: after initial address setup, outputs uninterrupted data stream across page boundaries without re-addressing. |
| Dual SRAM Buffers | Allows overlapping I/O: host streams new data into one buffer while flash reprograms from the other - eliminates write latency stalls. |
| Page-Level Erase/Program | Supports fine-grained updates: individual 528-byte pages can be erased and rewritten without affecting adjacent pages. |
| EEPROM Emulation | Self-contained Read-Modify-Write via buffers enables byte/bit-alterable storage behavior without external controller logic. |
| 5.0V-Tolerant Control Pins | Permits direct connection to 5V microcontrollers (e.g., legacy PIC, 8051) without level-shifting circuitry on CS/SCK/SI/WP/RESET. |
Applications
| Firmware Storage & Boot Code Shadowing | Data Logging in Remote Sensors |
|---|---|
|
Use Scenario: Microcontroller boots from internal ROM, then copies application firmware from AT45DB321B-RI into RAM for execution. IC Role / Device Role / Timing Role: Nonvolatile code repository with continuous read capability and zero-page-boundary delay - critical for deterministic boot timing. Use Value: Eliminates need for larger parallel NOR flash; 20 MHz SPI sustains >2 MB/s sequential read throughput for fast boot. |
Use Scenario: Environmental sensor node records timestamped temperature/humidity samples every 10 seconds over 30 days. IC Role / Device Role / Timing Role: Wear-leveling–free data sink using page-erase granularity and dual-buffer streaming to absorb burst writes. Use Value: 4 mA active current and 2 µA standby extend battery life; buffer overlap prevents data loss during flash programming latency. |
| Firmware Field Updates | Configuration Storage in Industrial HMI |
|
Use Scenario: OTA update received via UART/USB is staged in AT45DB321B-RI before validating checksum and swapping active firmware image. IC Role / Device Role / Timing Role: Safe update staging area with hardware write protect (WP) guarding bootloader pages during partial rewrites. Use Value: Page-erase independence allows updating only changed sections; built-in erase+program avoids multi-step erase-before-write sequences. |
Use Scenario: Human-machine interface panel stores user calibration offsets, language packs, and display brightness settings across power cycles. IC Role / Device Role / Timing Role: EEPROM-replacement storage with byte-alterable behavior via Read-Modify-Write using internal buffers. Use Value: No external controller logic needed; 528-byte page size accommodates full configuration sets with metadata and CRC in one atomic write. |
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; 1.8V–3.6V supply; no internal SRAM buffers; supports XIP but lacks continuous array read. | Better random access speed; unsuitable for buffer-pipelined streaming or EEPROM emulation workflows. | Select when random addressability or execute-in-place (XIP) is required; avoid if dual-buffer concurrency or seamless page-wrap reads are essential. |
| AT45DB321D-SU | Pin-compatible successor with extended temperature range (–40°C to +105°C); identical command set and buffer architecture; improved endurance spec. | Drop-in replacement for automotive or extended-temperature industrial deployments where AT45DB321B-RI's industrial grade is insufficient. | Choose for new designs targeting higher ambient temperatures; existing AT45DB321B-RI layouts require no changes. |
Compared with W25Q32JVSSIQ, AT45DB321B-RI trades random-access performance for deterministic streaming and built-in buffer concurrency; versus AT45DB321D-SU, it offers identical functionality at lower cost and proven reliability in commercial/industrial environments, with slightly reduced thermal margin.
Availability
AT45DB321B-RI is available at Aetrix Electronics and suitable for firmware storage, data logging, and configuration retention requiring stable component supply, long-term lifecycle assurance, and industrial-grade temperature operation.
Supply support for AT45DB321B-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 support for the DataFlash family, emphasizing robustness, longevity, and ease of integration in cost-sensitive embedded systems.
The AT45DB321B-RI belongs to Microchip's legacy DataFlash product line, engineered specifically for applications demanding simple SPI-based nonvolatile storage with integrated buffering - eliminating external RAM and complex wear-leveling firmware.
FAQ
What is the maximum SPI clock frequency supported by the AT45DB321B-RI?
The AT45DB321B-RI supports a maximum SPI clock frequency of 20 MHz under standard operating conditions (2.7V–3.6V, –40°C to +85°C). This rating applies to all read, write, and status register operations. Exceeding 20 MHz may cause timing violations, especially during continuous array read or buffer-to-memory programming sequences where internal state machines rely on precise SCK edge alignment.
Does the AT45DB321B-RI require a high-voltage programming supply?
No, the AT45DB321B-RI performs all program and erase operations using only its main 2.7V–3.6V VCC supply - no external high-voltage generator or charge pump is needed. This simplifies power design and enables true single-supply in-system reprogrammability, a core feature distinguishing DataFlash from conventional NOR/NAND devices.
How does the dual-buffer architecture of the AT45DB321B-RI improve system throughput?
The AT45DB321B-RI's two independent 528-byte SRAM buffers allow concurrent operations: while one buffer is being written to via SI, the other can be programmed into flash memory, or vice versa. This pipelining eliminates idle time during flash reprogramming, effectively doubling effective write bandwidth in streaming applications like firmware updates or sensor data capture.
Can the AT45DB321B-RI emulate EEPROM functionality?
Yes, the AT45DB321B-RI supports EEPROM emulation through its built-in Read-Modify-Write sequence: a page is transferred to a buffer, modified in SRAM, then written back to flash. This enables byte- or bit-level alterations without requiring full-page erases, making it suitable for storing infrequently updated parameters like calibration data or user preferences.
What is the purpose of the RDY/BUSY pin on the AT45DB321B-RI?
The RDY/BUSY pin on the AT45DB321B-RI is an open-drain output that signals active internal operations: it goes low during page/block erase, buffer-to-memory programming, page transfers, or comparisons. Host systems can poll this pin (or use its interrupt-capable edge) to avoid command collisions and ensure timing-critical operations complete before issuing subsequent instructions.
AT45DB321B-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:
- 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:
- 28-SOIC
AT45DB321B-RI FAQ
1.How can I place an order for AT45DB321B-RI through Aetrix?
Please submit a Request for Quotation (RFQ) for AT45DB321B-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 AT45DB321B-RI reliable?
The price and inventory of AT45DB321B-RI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT45DB321B-RI is usually 5 days.
3.What payment methods are accepted for AT45DB321B-RI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT45DB321B-RI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT45DB321B-RI?
AT45DB321B-RI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT45DB321B-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 AT45DB321B-RI?
For technical support, including AT45DB321B-RI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT45DB321B-RI requirements.
6.How does Aetrix verify that AT45DB321B-RI is sourced from the original manufacturer or authorized distributors?
All AT45DB321B-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 AT45DB321B-RI meets industry standards.
7.What is the process for return or replacement of AT45DB321B-RI?
All AT45DB321B-RI units undergo pre-shipment inspection (PSI). If there is an issue with AT45DB321B-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 AT45DB321B-RI part is unused and in its original packaging.
Return procedure for AT45DB321B-RI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT45DB321B-RI Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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