Microchip Technology 34LC02-E/ST

Overview

34LC02-E/ST from Microchip Technology Inc. is a 2 Kbit I²C-compatible serial EEPROM with hardware and dual software write-protection, 1 MHz clock support (V_CC ≥ 2.5 V), 16-byte page buffer, and operation down to 2.2 V. It serves as nonvolatile configuration storage in automotive infotainment control modules requiring extended temperature reliability.

For engineers reviewing the 34LC02-E/ST datasheet, 34LC02-E/ST pinout, 34LC02-E/ST application, or 34LC02-E/ST equivalent, key selection criteria include its 1 MHz I²C timing compliance, -40°C to +125°C automotive grade rating, SOT-23-6 package footprint, and dual-layer write protection (permanent software + hardware WP pin).

Technical Context

The 34LC02-E/ST implements a 2-wire I²C slave interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its memory array is organized as 256 × 8-bit with internal address pointer auto-increment for sequential reads.

Write protection is enforced via three independent mechanisms: external WP pin (entire array), resettable Software Write-Protect (SWP) command (lower 128 bytes), and Permanent Software Write-Protect (PSWP) command (lower 128 bytes, irreversible). Acknowledge polling enables precise write-cycle completion detection without fixed delays.

Key Specifications

Pinout & Package

34LC02-E/ST is supplied in a Pb-free, RoHS-compliant 6-lead SOT-23 package (JEDEC MO-178AA). Pin 1 is SCL; pin 2 is VSS; pin 3 is SDA; pin 4 is A1; pin 5 is A0; pin 6 is VCC. A2 and WP pins are not bonded in this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C02C-SSHM-T and M95020-DFMN6TP, the 34LC02-E/ST uniquely combines automotive temperature qualification, 1 MHz I²C speed, and permanent software write protection in a space-constrained SOT-23 package-making it optimal for safety-critical calibration storage where data integrity and layout density are paramount.

Availability

34LC02-E/ST is available at Aetrix Electronics and suitable for automotive ECU calibration, ADAS camera module configuration, and electric power steering motor profile storage requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 34LC02-E/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 leading provider of microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona.

The 34LC02-E/ST belongs to Microchip's serial EEPROM product line, designed specifically for automotive and industrial applications demanding high reliability, extended temperature operation, and robust data integrity features including multiple write-protection layers.

FAQ

What is the maximum I²C clock frequency supported by the 34LC02-E/ST?

The 34LC02-E/ST supports up to 1 MHz I²C clock frequency when V_CC is 2.5 V or higher. At lower voltages (2.2–2.4 V), the maximum clock rate drops to 400 kHz per AC specifications in DS22029F. This dual-speed capability allows designers to optimize for speed or low-voltage operation without changing components. The 34LC02-E/ST datasheet explicitly confirms 1 MHz timing for V_CC ≥ 2.5 V in Table 1-2.

Does the 34LC02-E/ST have hardware write protection via the WP pin?

No, the 34LC02-E/ST in SOT-23-6 package does not include a bonded WP pin - it is marked NC (No Connect) in the pin function table (DS22029F, page 14). Write protection is implemented exclusively through software commands: resettable SWP and permanent PSWP. This differs from 8-lead variants like 34LC02-I/P, which do expose WP. The 34LC02-E/ST relies on PSWP for irreversible protection of critical calibration data.

How many devices can be cascaded on a single I²C bus using the 34LC02-E/ST?

Up to four 34LC02-E/ST devices can share one I²C bus. Because the SOT-23 package lacks the A2 pin (NC), only A1 and A0 are available for chip select, yielding 2² = 4 unique slave addresses. This is explicitly stated in Section 3.6 ("Device Addressing") of DS22029F: "Only four 34XX02 SOT-23 packages can be connected to the same bus." The 34LC02-E/ST uses the standard '1010' control code prefix with A1/A0 bits determining address.

What is the purpose of the A0 pin on the 34LC02-E/ST beyond chip addressing?

On the 34LC02-E/ST, the A0 pin serves a dual role: it functions as both a chip select input (A0 bit in slave address) and a high-voltage detection node (VHV) for executing Software Write-Protect (SWP) and Clear Software Write-Protect (CSWP) commands. Per Table 7-1 and Section 7.2, applying VHV (7–10 V) to A0 while issuing the '0110' control code triggers these commands. This dual use is confirmed in the Pin Function Table (DS22029F, page 14) and Figure 7-1.

Is the 34LC02-E/ST compatible with standard I²C protocol implementations?

Yes, the 34LC02-E/ST is fully I²C™-compatible and adheres to standard bus timing, acknowledge behavior, and addressing conventions. It supports standard Start/Stop conditions, 7-bit slave addressing with R/W bit, and acknowledges valid control bytes. Its Schmitt-trigger inputs and slope-controlled outputs meet I²C noise immunity requirements. The 34LC02-E/ST datasheet states "2-Wire Serial Interface Bus, I²C™ Compatible" in Features and details full protocol compliance in Sections 2.0–6.0 of DS22029F.