Microchip Technology AT24C08B-TH-T

Overview

AT24C08B-TH-T from Microchip Technology is an 8-Kbit (1024 × 8) two-wire serial EEPROM with 1.8 V to 5.5 V operation, 400 kHz I²C interface at 1.8 V/2.5 V/2.7 V, hardware write protection via WP pin, and 16-byte page write capability. It delivers high reliability with 1 million write cycles and 100-year data retention, deployed in industrial sensor nodes for nonvolatile configuration storage.

For engineers reviewing the AT24C08B-TH-T datasheet, AT24C08B-TH-T pinout, AT24C08B-TH-T application, or AT24C08B-TH-T equivalent, key selection criteria include voltage range compatibility (1.8–5.5 V), TSSOP-8 package footprint, I²C timing compliance at low voltage, hardware write protect functionality, and endurance requirements for field-updatable firmware parameters.

Technical Context

The AT24C08B-TH-T implements a standard two-wire (I²C-compatible) serial interface with Schmitt-triggered, noise-filtered SCL and SDA inputs. It uses a 10-bit internal word address counter for random access across its 1024-word memory array organized in 64 pages of 16 bytes each.

Device addressing employs a fixed 4-bit prefix (1010) followed by a single hardware-selectable A2 bit - A0 and A1 are no-connects - enabling up to two AT24C08B devices on one bus. Write operations support byte and page modes, with self-timed internal write cycles completing in ≤5 ms.

Key Specifications

Pinout & Package

AT24C08B-TH-T is housed in an 8-lead Plastic Thin Shrink Small Outline Package (TSSOP), 4.4 mm body width, lead-free/halogen-free, with JEDEC-compliant pinout and 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M24C08-RMN6TP and CAT24C08HU4IGT3, AT24C08B-TH-T uniquely balances dual-device bus support (via A2 only), industrial temperature compliance, and minimal pin count - simplifying layout while retaining scalability where needed.

Availability

AT24C08B-TH-T is available at Aetrix Electronics and suitable for industrial sensor nodes, smart energy meters, and automotive body control units requiring stable component supply across long production lifecycles.

Supply support for AT24C08B-TH-T 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 is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with broad industrial and automotive qualification coverage.

The AT24C08B belongs to Microchip's legacy serial EEPROM product line, designed specifically for cost-sensitive, low-power embedded systems requiring robust nonvolatile storage with minimal external components.

FAQ

What is the maximum I²C clock frequency supported by AT24C08B-TH-T at 1.8 V?

AT24C08B-TH-T supports up to 400 kHz I²C clock frequency at 1.8 V, as specified in Table 4 of the official datasheet. This is lower than its 1 MHz capability at 5 V, reflecting timing constraints under reduced supply voltage. The device maintains full functionality and noise immunity at this rate due to integrated Schmitt triggers and input filtering - critical for stable operation in battery-powered or low-voltage industrial sensors using AT24C08B-TH-T.

How many devices can share the same I²C bus when using AT24C08B-TH-T?

Up to two AT24C08B-TH-T devices can operate on a single I²C bus. This is enabled by the A2 hardware address pin, which selects between device addresses 10100xx and 10101xx (where xx are fixed page bits). Pins A0 and A1 are no-connects and must be grounded or left unconnected - they do not contribute to addressing. This dual-device limit is a defined architectural constraint of the AT24C08B-TH-T, distinct from variants like CAT24C08HU4IGT3 that support three address bits.

Does AT24C08B-TH-T require external pull-up resistors on SDA and SCL lines?

Yes, AT24C08B-TH-T requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. Typical values range from 2.2 kΩ to 10 kΩ depending on bus capacitance and target clock speed - e.g., 4.7 kΩ is common for 400 kHz operation with ≤400 pF total capacitance. Failure to install pull-ups will prevent proper signal high-level establishment and cause communication failure. This requirement applies identically across all AT24C08B-TH-T implementations regardless of host MCU.

What is the purpose of the WP pin on AT24C08B-TH-T, and how should it be used?

The WP (Write Protect) pin on AT24C08B-TH-T provides hardware-level write inhibition: when pulled high (to VCC), it locks the entire memory array against writes; when pulled low (to GND), normal read/write operations resume. Unlike software-based protection, WP operates independently of firmware state - preventing corruption during power loss, reset, or code faults. For most industrial designs using AT24C08B-TH-T, WP is tied to a controlled GPIO or hardwired to GND during programming and to VCC during normal operation.

Is AT24C08B-TH-T compatible with standard I²C protocol stacks and drivers?

Yes, AT24C08B-TH-T is fully compatible with standard I²C protocol stacks and drivers, implementing standard START/STOP, ACK/NACK, and 7-bit addressing (with R/W bit) as defined in the NXP I²C specification. It responds to device address 1010xxx (where xxx = A2 + two page bits) and supports all three read modes (current address, random, sequential) and byte/page write protocols. No custom driver modifications are needed - existing MCU HAL libraries for STM32, PIC, or ESP32 work out-of-the-box with AT24C08B-TH-T when configured for 400 kHz or 1 MHz timing.