Microchip Technology 24C65/P

Overview

24C65/P from Microchip Technology Inc. is a 64 Kbit (8K × 8) I²C-compatible serial EEPROM with programmable high-endurance memory blocks, 64-byte input cache, and dual-speed I²C interface (100 kHz at 1.8–4.5 V, 400 kHz at 4.5–6.0 V). It features 10 million write/erase cycles in its dedicated 4K-bit high-endurance block, 1 μA typical standby current, and operates across industrial temperature range (−40°C to +85°C) in 8-pin PDIP package. Used for firmware parameter storage in industrial controllers.

For engineers reviewing the 24C65/P datasheet, 24C65/P pinout, 24C65/P application, or 24C65/P equivalent, key selection criteria include its 4.5–6.0 V supply range, page-write capability with 64-byte cache, Schmitt-triggered noise-immune I²C inputs, programmable security blocks, and support for up to eight devices on one bus via A0–A2 addressing.

Technical Context

The 24C65/P implements a two-wire I²C slave interface with hardware-addressable device select lines (A0–A2), supporting standard (100 kHz) and fast (400 kHz) modes depending on VCC. Its internal architecture includes an 8-page × 8-byte FIFO cache, address pointer auto-increment logic, and separate high-endurance (10M cycle) and standard (1M cycle) memory blocks mapped within the same 64Kbit array.

It integrates VDD monitor circuitry for power-on/off data protection, self-timed erase/write cycles, and programmable security configuration that locks up to 15 contiguous 4K blocks. All I/O pins feature Schmitt-trigger inputs and output slope control to suppress ground bounce and EMI-induced glitches on noisy industrial buses.

Key Specifications

Pinout & Package

8-pin Plastic Dual In-line Package (PDIP), through-hole mounting, RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC65/P and AT24C64D-PU, the 24C65/P delivers superior endurance differentiation and security configurability within its 4.5–6.0 V window, making it optimal for industrial systems where parameter volatility and data integrity are critical - but not a drop-in replacement due to narrower voltage range and unique feature set.

Availability

24C65/P is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics equipment, automotive body control modules, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for 24C65/P 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 memory products for embedded control applications.

The 24C65/P belongs to Microchip's "Smart Serial EEPROM" family, designed specifically for systems needing differentiated endurance, configurable security, and robust I²C performance in harsh industrial and automotive environments.

FAQ

What is the maximum I²C clock frequency supported by the 24C65/P?

At VCC = 4.5–6.0 V, the 24C65/P supports Fast Mode I²C up to 400 kHz. Below 4.5 V, it defaults to Standard Mode (100 kHz). This voltage-dependent speed scaling is hardwired - no software configuration is needed. The 24C65/P will not operate reliably above 400 kHz, even with valid timing margins, because its internal timing generator is calibrated for this ceiling. Always verify VCC stability during high-speed transfers.

Does the 24C65/P have built-in write protection, and how is it configured?

Yes, the 24C65/P includes programmable write protection for up to 15 contiguous 4K blocks. Protection is enabled by sending a specific three-byte command sequence that sets both the starting block number and count. Once configured with a non-zero length, the security option is permanent and irreversible. The 24C65/P does not support volatile or password-based protection - only one-time hardware-enforced locking.

How does the 64-byte input cache improve write performance in the 24C65/P?

The 64-byte cache allows the host to stream up to 64 bytes of data over I²C at bus speed before triggering the internal write cycle. This eliminates the need to wait for each byte to commit individually. For example, writing eight full pages (64 bytes) takes the same ~5 ms total write time as writing one page - dramatically improving throughput versus byte-by-byte writes. Cache contents are lost if power fails before the Stop condition initiates the write.

Can multiple 24C65/P devices share the same I²C bus, and how are they addressed?

Yes, up to eight 24C65/P devices can share one I²C bus using hardware address lines A0, A1, and A2. Each device's 7-bit slave address is formed as 1010xxx, where xxx corresponds to the binary state of A2–A0. All three pins must be hardwired to VSS or VCC on the PCB - no pull-up/pull-down resistors are allowed. The 24C65/P does not support software-configurable addresses or dynamic addressing.

What is the purpose of the NC pin on the 24C65/P PDIP package?

The NC (No Connection) pin on the 24C65/P PDIP package is internally unconnected and serves no electrical function. It must be left floating on the PCB - tying it to VCC or VSS is not recommended and may cause mechanical stress or unintended coupling. Its presence maintains pin compatibility with other members of the 24XX65 family (e.g., 24AA65) that use the same physical package footprint but different internal pin mappings.