Microchip Technology 25AA160AT-I/MS

Overview

25AA160AT-I/MS from Microchip Technology Inc. is a 16 Kbit (2048 × 8) SPI Serial EEPROM with 1.8–5.5 V supply range, 16-byte page size, and industrial temperature rating (–40°C to +85°C), housed in an 8-lead MSOP package. It features hardware write protection via WP pin, HOLD functionality for bus arbitration, and self-timed 5 ms max write cycles - used for nonvolatile parameter storage in embedded controllers, sensor calibration data retention, and firmware configuration backup.

For engineers reviewing the 25AA160AT-I/MS datasheet, 25AA160AT-I/MS pinout, 25AA160AT-I/MS application, or 25AA160AT-I/MS equivalent, key selection criteria include V_CC compatibility down to 1.8 V, 16-byte page write constraint, WPEN-controlled hardware write protection, and MSOP-8 thermal and layout suitability for space-constrained industrial PCBs.

Technical Context

The 25AA160AT-I/MS implements a standard SPI Mode 0,0 or Mode 1,1 interface with separate SI and SO lines, requiring CS low, SCK synchronized clocking, and rising-edge sampling of input data. Its internal architecture includes a status register with WIP, WEL, BP0/BP1, and WPEN bits, enabling configurable block-level write protection (none, 1/4, 1/2, or full array).

It supports sequential read with automatic address increment, byte/page write with CS-high-triggered internal write cycle, and HOLD pin suspension of ongoing transfers without sequence reset. Write enable latch (WEL) must be set via WREN instruction before any WRITE or WRSR operation, and resets automatically after power-up, WRDI, WRSR, or successful WRITE.

Key Specifications

Pinout & Package

8-lead MSOP (Mini Small Outline Package), 3.0 mm × 3.0 mm body, 0.65 mm lead pitch, exposed pad optional per design - optimized for thermal dissipation and high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA160AT-I/MS, the SOIC variant offers mechanical robustness and ease of rework but sacrifices board area and thermal performance, while the AT25160B demands driver-level changes due to divergent protection architecture and timing behavior - making 25AA160AT-I/MS optimal for compact, low-voltage, and WP-secured industrial designs.

Availability

25AA160AT-I/MS is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and smart energy metering applications requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for 25AA160AT-I/MS 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 Inc. is a leading provider of microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25AA160A/B family was designed specifically for reliable, low-voltage SPI EEPROM storage in space- and power-constrained embedded systems - emphasizing write-protection flexibility, wide V_CC tolerance, and industrial-grade endurance.

FAQ

What is the maximum clock frequency supported by the 25AA160AT-I/MS across its full voltage range?

The 25AA160AT-I/MS supports up to 10 MHz at V_CC ≥ 4.5 V, 5 MHz at 2.5 V ≤ V_CC < 4.5 V, and 3 MHz at 1.8 V ≤ V_CC < 2.5 V. These limits are defined in Table 1-2 AC Characteristics and must be observed to ensure setup/hold timing compliance - exceeding them risks read corruption or failed write latching. The 25AA160AT-I/MS does not auto-negotiate clock rate; host MCU must configure SCK accordingly.

How does the 25AA160AT-I/MS handle page boundary crossings during a page write operation?

The 25AA160AT-I/MS enforces strict 16-byte page alignment: if a page write command attempts to cross a physical page boundary (e.g., writing 16 bytes starting at address 0x05F8), data wraps to the start of the same page (0x05F8 → 0x05FF, then 0x05F8 again), overwriting prior bytes. This behavior is documented in Section 2.3 and requires application firmware to split writes at 0x0000, 0x0010, ..., 0x07F0 boundaries - the 25AA160AT-I/MS provides no automatic page rollover.

Can the WP pin of the 25AA160AT-I/MS protect memory array writes, or only the STATUS register?

The WP pin of the 25AA160AT-I/MS protects only the nonvolatile bits in the STATUS register (BP0, BP1, WPEN) - not the main memory array. Array protection is controlled exclusively by the BP0/BP1 bits in the STATUS register. Hardware write protection is active only when both WP = low and WPEN = 1; if WPEN = 0, the WP pin has no effect. This separation allows safe WP-grounded PCB layouts while retaining full array write capability.

What happens to the 25AA160AT-I/MS during power-up, and how is write safety ensured?

At power-up, the 25AA160AT-I/MS enters Standby mode with CS high, SO in high-impedance, and the write enable latch (WEL) reset to 0 - disabling all writes until WREN is issued. This prevents spurious writes during V_CC ramp-up. The 25AA160AT-I/MS also includes built-in power-on/off data protection circuitry and a write-enable latch that resets after every successful WRITE, WRSR, or WRDI command, enforcing explicit write enable for each operation.

Is the HOLD function of the 25AA160AT-I/MS compatible with all SPI modes, and what are the timing constraints?

Yes, the HOLD function of the 25AA160AT-I/MS operates independently of SPI mode (0,0 or 1,1) and suspends ongoing transfers regardless of instruction phase. However, HOLD must be asserted only when SCK is low; asserting it during SCK high delays activation until the next SCK high-to-low transition. To resume, HOLD must be deasserted while SCK remains low - violating this causes undefined behavior. Timing values (THS, THH, THZ, THV) scale with V_CC and are specified in Table 1-2.