Microchip Technology 34AA02-I/ST

Overview

34AA02-I/ST from Microchip Technology is a 2 Kbit I²C-compatible serial EEPROM with permanent and resettable software write-protection for the lower 128 bytes (00h–7Fh), hardware write-protection via WP pin, 1.7V to 5.5V single-supply operation, and 400 kHz max clock frequency at V_CC ≥ 1.8V. It supports page writes of up to 16 bytes and delivers 100 nA typical standby current, enabling use in battery-backed industrial sensors and embedded configuration storage.

For engineers reviewing the 34AA02-I/ST datasheet, 34AA02-I/ST pinout, 34AA02-I/ST application, or 34AA02-I/ST equivalent, key selection criteria include its dual software write-protect modes, extended temperature range (–40°C to +85°C), TSSOP-8 package compatibility, and I²C bus noise immunity via Schmitt-trigger inputs and output slope control.

Technical Context

The 34AA02-I/ST implements a 256 × 8-bit memory array organized as a single block, accessed via a bidirectional 2-wire I²C interface where it operates exclusively as a slave device. Its address decoding uses three chip-select pins (A0–A2) to support up to eight devices on one bus - though A2 is unconnected in SOT-23 variants, limiting that package to four devices.

Write protection is implemented through three independent mechanisms: hardware-level protection via the WP pin (V_CC/V_SS), resettable software write-protect (SWP/CSWP), and permanent software write-protect (PSWP), each with distinct command protocols requiring specific voltage levels on A0 and matching chip-select bits. Internal high-voltage generation enables PSWP programming without external HV supply.

Key Specifications

Pinout & Package

34AA02-I/ST is packaged in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, RoHS-compliant matte tin plating, and moisture sensitivity level (MSL) 1. The package footprint matches industry-standard SOIC-8 but with 30% smaller area and improved thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C02C-SSHM-T and BR24G02NUX-5TR, the 34AA02-I/ST uniquely provides irreversible PSWP for calibration-critical applications, while maintaining identical TSSOP-8 footprint and I²C timing compatibility - making it the only option for designs requiring guaranteed immutability of lower-array contents.

Availability

34AA02-I/ST is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration memory, and automotive body control module ID storage requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 34AA02-I/ST 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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and nonvolatile memory solutions for embedded control applications.

The 34AA02-I/ST belongs to Microchip's 34XX02 family of I²C serial EEPROMs designed specifically for secure, low-voltage, and extended-temperature industrial and automotive configuration storage with multi-layer write protection.

FAQ

What is the maximum I²C clock frequency supported by the 34AA02-I/ST?

The 34AA02-I/ST supports up to 400 kHz I²C clock frequency when V_CC is 1.8V or higher. At V_CC < 1.8V, the maximum clock frequency drops to 100 kHz to ensure reliable timing margins. This dual-speed behavior is explicitly defined in the device's AC specifications table and applies regardless of temperature grade or package type.

How does the Permanent Software Write-Protect (PSWP) feature work on the 34AA02-I/ST?

The PSWP feature on the 34AA02-I/ST irreversibly locks the lower 128 bytes (addresses 00h–7Fh) against all write operations. Once executed, PSWP cannot be cleared by power cycling, reset, WP pin state, or any software command. The 34AA02-I/ST will no longer acknowledge the '0110' device identifier used for SWP/CSWP commands after PSWP activation.

Can the 34AA02-I/ST be used with a 1.8V I/O system?

Yes, the 34AA02-I/ST is fully compatible with 1.8V I/O systems. Its V_CC operating range starts at 1.7V, and its I²C interface meets standard 1.8V logic thresholds: VIH = 0.7 × V_CC (≥1.26V) and VIL = 0.3 × V_CC (≤0.54V). Schmitt-trigger inputs further enhance noise immunity at this voltage level.

What package type is used for the 34AA02-I/ST part number?

The 34AA02-I/ST uses an 8-lead TSSOP (Thin Shrink Small Outline Package) with 4.4 mm width, 3.0 mm length, and 0.65 mm lead pitch. The 'ST' suffix in the part number explicitly denotes the TSSOP package, distinguishing it from PDIP ('P'), SOIC ('SN'), MSOP ('MT'), or SOT-23 ('E') variants.

Does the 34AA02-I/ST support page write operations, and what is the buffer size?

Yes, the 34AA02-I/ST supports page write operations with a 16-byte internal buffer. A single I²C transaction can write up to 16 contiguous bytes within the same physical page (aligned to 16-byte boundaries), reducing bus overhead versus individual byte writes. Page wraparound occurs if more than 16 bytes are sent before the Stop condition.