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AT24C04C-SSHM-B

4Kbit I2C EEPROM, 512x8, 1MHz@2.5V, 1M cycles, 100yr retention, WP pin, SOIC-8, -40~85°C

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Manufacturer Part：

AT24C04C-SSHM-B

Package：

SOIC-8 (4.9 x 3.9 x 1.5 mm, 1.27mm pitch)

Description

The AT24C04C-SSHM-B from Microchip Technology is a 4 Kbit (512 x 8) I2C serial EEPROM in an 8-pin SOIC package. It operates from 1.7 V to 5.5 V with 400 kHz (1.7 V) and 1 MHz (>2.5 V) clock compatibility. Key features include 16-byte page write, 5 ms maximum write cycle time, 1 million erase/write cycle endurance, 100-year data retention, and hardware write-protect pin (WP). The device supports up to 4 devices on the same I2C bus via A0/A1/A2 address pins. The SSHM-B suffix denotes SOIC-8 tube packaging, -40°C to +85°C industrial temperature range.

Product Introduction:AT24C04C-SSHM-B Product Introduction

The AT24C04C from Microchip (originally Atmel) is a 4 Kbit I2C serial EEPROM organized as 512 x 8 bits. The AT24C04C-SSHM-B is the SOIC-8 tube-packaged version for the -40°C to +85°C industrial temperature range. It is part of the AT24CxxC family, which also includes the AT24C01C (1 Kbit), AT24C02C (2 Kbit), and AT24C08C (8 Kbit) with identical pinouts and protocols.

The device supports two I2C speed modes: Standard-mode (400 kHz) at 1.7 V and Fast-mode Plus (1 MHz) at 2.5 V and above. The 16-byte page write buffer allows writing up to 16 bytes in a single I2C transaction, after which the internal write cycle completes in 5 ms maximum. Random and sequential read modes support single-byte and continuous read operations.

The hardware write-protect pin (WP) protects the entire memory array when pulled HIGH, preventing accidental or malicious writes. This is useful for calibration data, serial numbers, and configuration parameters that must not change in the field.

Three address pins (A0, A1, A2) allow up to four AT24C04C devices to share the same I2C bus, providing a total of 16 Kbit of EEPROM on a single bus. The device uses the standard Atmel I2C EEPROM protocol with a 7-bit slave address (1010 + A2A1A0 + R/W).

The 1.7 V minimum supply voltage enables direct operation from single-cell Li-ion batteries (2.7-4.2 V) and 1.8 V logic systems. The 6 µA maximum standby current preserves battery life in always-connected applications.

An automotive-qualified version (AT24C04C-STPD-TVAO, AEC-Q100 Grade 1, -40°C to +125°C) is available for automotive applications.

Working Principle:AT24C04C-SSHM-B Working Principle

**I2C Interface Protocol:** The AT24C04C communicates via the standard I2C protocol. The master initiates communication with a START condition, followed by the 7-bit device address (1010 + A2A1A0) and a R/W bit. The EEPROM acknowledges (ACK) by pulling SDA low on the 9th clock. Data is transferred MSB first, 8 bits per byte, with ACK after each byte.

**Write Operation:** For byte write, the master sends device address + write, then the 8-bit word address, then data byte, then STOP. The EEPROM enters an internal write cycle (5 ms max) during which it does not respond to I2C commands. Page write works similarly but accepts up to 16 data bytes; the lower 4 address bits auto-increment and wrap within the page.

**Read Operation:** Random read requires a dummy write sequence (device address + write, word address, RESTART, device address + read) to set the address counter, then data is clocked out. Current address read starts from the last accessed address + 1. Sequential read continues indefinitely until the master sends NACK + STOP.

**Memory Cell Technology:** The EEPROM uses floating-gate MOS transistors. Write operations inject charge onto the floating gate via Fowler-Nordheim tunneling through a thin oxide layer. Erase removes the charge. The high-quality oxide provides 100-year data retention and 1 million cycle endurance.

Pin Description:AT24C04C-SSHM-B Pin Definition and Functions

Pin	Name	Type	Description
1	A0	I	Address input bit 0; sets slave address bit; connect to VCC or GND; must be defined for proper bus operation; pin also used for chip selection on multi-device bus
2	A1	I	Address input bit 1; same as A0; for AT24C04C, only A2 and A1 are used for address (up to 4 devices); A0 is don’t care
3	A2	I	Address input bit 2; most significant address bit; must connect to VCC or GND; do not leave floating
4	GND	G	Ground; connect to PCB ground plane
5	SDA	I/O	Serial data; open-drain I2C data line; requires external pull-up resistor (typically 4.7kΩ); bidirectional
6	SCL	I	Serial clock; I2C clock from master; up to 400kHz at 1.7V or 1MHz at >2.5V; requires pull-up if master has open-drain output
7	WP	I	Write protect; active HIGH; when HIGH, the entire memory array is write-protected; when LOW or NC, normal read/write operation; connect to GND for normal operation
8	VCC	P	Supply voltage; 1.7V to 5.5V; bypass with 0.1µF ceramic to GND; 6µA max standby current

Application Scenarios:In which products and applications isAT24C04C-SSHM-B used

Application	Description
Embedded System Configuration Storage	Store calibration coefficients, serial numbers, MAC addresses, and configuration parameters; 4Kbit sufficient for dozens of parameters; WP pin protects critical data; 100-year retention ensures data survives product lifetime
Industrial Sensor Calibration	Store sensor offset and gain calibration data written during manufacturing; WP pin locks calibration after test; I2C interface shared with sensor; 1M cycle endurance for periodic recalibration
Consumer Electronics User Settings	Store user preferences, channel presets, volume levels in consumer devices; 1MHz FM+ allows fast read at startup; low standby current for always-connected battery devices

Alternative Models:What chips are recommended as replacements for AT24C04C-SSHM-B

Model	Manufacturer	Compatibility	Key Difference
AT24C04C-SSHM-T	Microchip	Same Part (T&R)	Identical function in tape-and-reel packaging; 4000 units/reel; same SOIC-8 footprint; use for production volume ordering
AT24C08C-SSHM-B	Microchip	Pin-Compatible Upgrade	8 Kbit (1024×8); same SOIC-8 pinout and protocol; double the memory; use when 4Kbit is insufficient
24LC04B-I/SN	Microchip	Family Variant	4Kbit I2C EEPROM; same Microchip family; 400kHz only (no FM+); lower cost; use when 1MHz speed not needed
BR24G04FVT-3AGE2	ROHM	Competitive Alternative	4Kbit I2C EEPROM; SOIC-8; 1MHz; automotive qualified; ROHM-sourced alternative