Microchip Technology AT45DB161B-CI

Overview

AT45DB161B-CI from Microchip Technology (formerly Atmel) is a 16-Mbit serial DataFlash memory IC with SPI interface, organized as 4096 pages × 528 bytes, featuring dual 528-byte SRAM buffers and hardware write protection. It operates from a single 2.5V–3.6V or 2.7V–3.6V supply, supports up to 20 MHz clock frequency, and enables continuous array read for code shadowing in embedded microcontroller systems.

For engineers reviewing the AT45DB161B-CI datasheet, AT45DB161B-CI pinout, AT45DB161B-CI application, or AT45DB161B-CI equivalent, key selection considerations include its page-erase flexibility, buffer-assisted streaming write capability, 5.0V-tolerant control inputs (CS, SCK, SI, WP, RESET), RDY/BUSY open-drain status signaling, and industrial temperature range support (–40°C to +85°C).

Technical Context

The AT45DB161B-CI implements a dedicated SPI-based serial Flash architecture with two independent 528-byte SRAM buffers enabling concurrent data reception and nonvolatile memory reprogramming. Its command set includes page/block erase, buffer-to-main-memory program with or without built-in erase, and main memory page-to-buffer transfer/compare - all internally self-timed and controlled via 8-bit opcodes.

It supports SPI Mode 0 and Mode 3 (clock polarity/idle state configurable per CS edge), features 5.0V-tolerant SI, SCK, CS, RESET, and WP pins, and uses an internal address counter for seamless continuous array read across page boundaries without latency penalties or external address management.

Key Specifications

Pinout & Package

AT45DB161B-CI is packaged in a 28-pin SOIC (Small Outline Integrated Circuit) with 300-mil body width, compliant with JEDEC MS-012AC. Pin functions are electrically identical across SOIC, TSOP, and CBGA variants per datasheet Rev. 2224G.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial Flash memory applications.

Compared with W25Q16JVSSIQ, AT45DB161B-CI delivers deterministic streaming write performance via dual buffers and eliminates erase-before-write constraints, while AT45DB161D-CU offers measurable reliability gains without changing PCB layout or firmware logic.

Availability

AT45DB161B-CI is available at Aetrix Electronics and suitable for embedded firmware storage, audio data logging, and industrial HMI configuration requiring stable component supply, long-term manufacturability, and industrial temperature compliance.

Supply support for AT45DB161B-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 support for the legacy DataFlash product family, including documentation, validation, and long-term supply commitments.

The AT45DB161B-CI belongs to the DataFlash® serial Flash memory product line, designed specifically for embedded systems needing high-density, low-pin-count, low-voltage nonvolatile storage with streaming data handling capabilities - bridging the gap between traditional NOR Flash and EEPROM.

FAQ

What is the maximum clock frequency supported by the AT45DB161B-CI?

The AT45DB161B-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 2.5V–3.6V supply voltage. The device uses edge-triggered SPI timing with data sampled on the rising edge of SCK for input and output on the falling edge, ensuring robust timing margins in noise-prone environments. AT45DB161B-CI maintains this speed without requiring external wait states or clock dividers.

Does the AT45DB161B-CI require a high-voltage programming supply?

No, the AT45DB161B-CI does not require a high-voltage programming supply. It operates entirely from a single 2.5V–3.6V or 2.7V–3.6V supply for both read and program/erase operations. All internal programming voltages are generated on-chip using charge pump circuitry, eliminating the need for external VPP pins or external high-voltage sources. This simplifies power design and enables direct connection to standard 3.3V MCU I/O rails. AT45DB161B-CI achieves full functionality - including page erase and buffer-to-memory programming - within this low-voltage envelope.

How does the RDY/BUSY pin function on the AT45DB161B-CI?

The RDY/BUSY pin on the AT45DB161B-CI is an open-drain output that drives low during any internally self-timed operation - including page erase, block erase, buffer-to-memory programming, main memory page-to-buffer transfer, and compare operations. It remains high otherwise, indicating readiness to accept the next command. A 1 kΩ external pull-up resistor is required. Host firmware can poll this pin or configure an interrupt to detect completion. AT45DB161B-CI guarantees that RDY/BUSY reflects true internal state - no additional software delays are needed after asserting CS high.

Can the AT45DB161B-CI be used for EEPROM emulation?

Yes, the AT45DB161B-CI supports EEPROM emulation through its three-step Read-Modify-Write operation, enabled by the dual SRAM buffers and page-level erase capability. A typical implementation reads a page into Buffer 1, modifies specific bytes, then writes the updated buffer back to the same or another page. The AT45DB161B-CI's Auto Page Rewrite command (58H/59H) automates this process. Unlike true EEPROM, byte-level writes require full-page handling, but the architecture provides predictable latency and wear-leveling flexibility. AT45DB161B-CI is widely deployed in this mode for storing configuration parameters and calibration data.

Is the AT45DB161B-CI pin-compatible with the AT45DB161D-CU?

Yes, the AT45DB161B-CI is pin-compatible and functionally compatible with the AT45DB161D-CU. Both share identical SOIC-28 packaging, pinout, electrical characteristics, command set, and timing specifications. The AT45DB161D-CU is a revised version with enhanced endurance (100,000 erase/write cycles vs. 10,000), improved data retention, and updated process technology - but requires no PCB or firmware changes. AT45DB161B-CI remains fully supported for legacy designs, while AT45DB161D-CU is recommended for new production where extended reliability is prioritized.