Microchip Technology 24LC04BT-E/OT

Overview

24LC04BT-E/OT from Microchip Technology Inc. is a 4-Kbit I²C-compatible serial EEPROM organized as two 256 × 8-bit blocks, operating from 2.5V to 5.5V with 400 kHz max clock frequency, 5 ms max page write time, and industrial/extended temperature support (–40°C to +125°C). It delivers low-power operation (1 µA standby, 1 mA read), hardware write-protection via WP pin, and 1 million erase/write cycles - used for configuration storage in embedded controllers and sensor modules.

For engineers reviewing the 24LC04BT-E/OT datasheet, 24LC04BT-E/OT pinout, 24LC04BT-E/OT application, or 24LC04BT-E/OT equivalent, key selection criteria include VCC range compatibility (2.5–5.5V), extended-temperature qualification (–40°C to +125°C), SOT-23-5 package footprint, I²C bus timing compliance at 400 kHz, and hardware write-protect functionality.

Technical Context

The 24LC04BT-E/OT implements a two-wire I²C interface with Schmitt-trigger inputs and slope-controlled outputs to suppress noise and eliminate ground bounce. Its internal architecture includes a 16-byte page write buffer, self-timed erase/write cycle, and address pointer logic supporting current-address, random, and sequential read modes.

It uses a fixed 4-bit device identifier (1010) with block-select bit (B0) and R/W bit for addressing two 256-word memory blocks. Write protection is implemented via dedicated WP pin tied to VCC (full-array lock) or VSS (enabled), independent of I²C commands.

Key Specifications

Pinout & Package

24LC04BT-E/OT is packaged in a 5-lead SOT-23 surface-mount package (Microchip drawing C04-057-SN Rev F), with lead pitch 0.95 mm, body size 2.9 mm × 1.6 mm × 1.1 mm, and wettable flank option not applicable. Pin 1 is SCL; pin 2 is VSS; pin 3 is SDA; pin 4 is WP; pin 5 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC04BT-E/OT, the 24LC04B-I/OT sacrifices extended-temperature capability for lower cost, while AT24C04-SSH-T offers broader VCC range and higher speed but requires PCB redesign due to SOIC-8 packaging and distinct pin mapping.

Availability

24LC04BT-E/OT is available at Aetrix Electronics and suitable for automotive body control units, industrial sensor nodes, medical infusion pumps, and smart energy meters requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 24LC04BT-E/OT 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, with global design and manufacturing operations.

The 24LC04B family is designed for reliable, low-power nonvolatile data storage in space-constrained embedded systems where I²C interface simplicity, extended temperature operation, and hardware write protection are essential.

FAQ

What is the maximum clock frequency supported by the 24LC04BT-E/OT?

The 24LC04BT-E/OT supports a maximum I²C clock frequency of 400 kHz when operated within its specified VCC range of 2.5V to 5.5V. This is confirmed in the Device Selection Table and AC Characteristics section of the DS20001708P datasheet. The 24LC04BT-E/OT does not support 1 MHz operation - that capability is exclusive to the 24FC04 variant. Timing margins must be verified per Table 1-2 under worst-case voltage and temperature conditions.

Does the 24LC04BT-E/OT require external pull-up resistors on SDA and SCL lines?

Yes, the 24LC04BT-E/OT requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. The datasheet recommends 2 kΩ for 400 kHz operation. These resistors ensure proper signal rise times and bus contention avoidance. The 24LC04BT-E/OT itself does not integrate internal pull-ups, and omitting external ones will prevent reliable communication. Pull-up placement should be near the 24LC04BT-E/OT's SDA/SCL pins.

How is memory organized inside the 24LC04BT-E/OT?

Inside the 24LC04BT-E/OT, the 4-Kbit memory is organized as two independent blocks of 256 × 8-bit words (total 512 bytes), addressed using a 9-bit word address where bit B0 selects the block. This structure allows the host to access either block separately via the R/W control byte. The 24LC04BT-E/OT does not implement a linear 512-byte address space - block selection is explicit and required for all operations, as defined in Figure 5-1 and Section 5.0 of DS20001708P.

Can the A0, A1, and A2 pins on the 24LC04BT-E/OT be used for device addressing?

No, the A0, A1, and A2 pins on the 24LC04BT-E/OT are not internally connected and serve no addressing function. As stated in Section 2.1 and Table 2-1 of DS20001708P, these pins are "Not Connected" and may be left floating or tied to VSS/VCC without affecting operation. Device addressing relies solely on the fixed 4-bit identifier (1010) and block-select bit (B0) in the I²C control byte - no hardware address pins are implemented in this variant.

Is the 24LC04BT-E/OT pin-compatible with other 24XX04 family members in SOT-23-5 package?

Yes, the 24LC04BT-E/OT is pin-compatible with other 24XX04 family variants offered in the SOT-23-5 package (e.g., 24AA04T-E/OT, 24FC04T-E/OT), sharing identical pinout: Pin 1 = SCL, Pin 2 = VSS, Pin 3 = SDA, Pin 4 = WP, Pin 5 = VCC. However, electrical differences exist - notably VCC range (2.5–5.5V vs. 1.7–5.5V) and max clock (400 kHz vs. 1 MHz) - so direct substitution requires validation of supply and timing constraints in the target design.