Renesas RM24C32DS-LSNI-B

Overview

RM24C32DS-LSNI-B from Adesto Technologies is a 32-Kbit non-volatile serial EEPROM based on CBRAM® resistive memory technology, operating from 1.65V to 3.6V with I²C interface up to 1 MHz, featuring 32-byte page write, 128-byte OTP security register, and 100,000 write cycles. It serves as a low-energy, high-endurance data storage element in space-constrained industrial and IoT edge nodes requiring secure configuration storage.

For engineers reviewing the RM24C32DS-LSNI-B datasheet, RM24C32DS-LSNI-B pinout, RM24C32DS-LSNI-B application, or RM24C32DS-LSNI-B equivalent, key selection criteria include its 50 nJ byte-write energy, 1.5 ms page-write latency, -40°C to +85°C operation, OTP security register partitioning, and compatibility with standard I²C masters across 100 kHz/400 kHz/1 MHz modes.

Technical Context

The RM24C32DS-LSNI-B implements a slave-only 2-wire I²C interface with SDA (open-drain) and SCL (input-only), supporting device addressing via three external enable pins (E0–E2) for up to eight devices on one bus. Its internal architecture uses a 256 Kb resistive memory array organized as 4,096 × 8 bits, with separate address pointer logic shared between main EEPROM and OTP registers.

Write operations are initiated by STOP condition and validated via acknowledge polling; byte and page writes share identical endurance (100,000 cycles) and retention (>40 years at 125°C) due to CBRAM's direct-write mechanism-eliminating read-modify-write overhead and temperature-dependent degradation seen in floating-gate EEPROMs.

Key Specifications

Pinout & Package

RM24C32DS-LSNI-B is supplied in an 8-lead SOIC package (3.9 mm × 4.9 mm, 1.27 mm pitch), RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C32D-SSHM-T and FM24V10-G, RM24C32DS-LSNI-B uniquely delivers I²C-compatible CBRAM performance with integrated OTP security, sub-1V write capability, and temperature-stable endurance - making it optimal for secure, low-power, thermally demanding embedded systems where pin count and interface consistency are constraints.

Availability

RM24C32DS-LSNI-B is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration lock, IoT edge node identity binding, and automotive body control module NVM applications requiring stable component supply, long-life data retention, and secure programmable storage.

Supply support for RM24C32DS-LSNI-B 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

Adesto Technologies (acquired by Dialog Semiconductor in 2020, now part of Renesas Electronics) specialized in low-power, high-reliability non-volatile memory solutions for constrained-edge applications.

The RM24C32DS product line was designed specifically for secure, energy-efficient configuration and identity storage in battery-powered and thermally aggressive environments - leveraging CBRAM to overcome endurance and voltage limitations of traditional EEPROM.

FAQ

What is the maximum I²C clock frequency supported by RM24C32DS-LSNI-B?

The RM24C32DS-LSNI-B supports I²C clock frequencies up to 1 MHz under recommended operating conditions (VCC = 1.65V–3.6V, TA = -40°C to +85°C). This is confirmed in the AC characteristics table of the DS-RM24C32DS–117B–11/2016 datasheet, where fCLK is specified as 0–1 MHz. The device maintains full functionality across all standard I²C modes: 100 kHz (standard), 400 kHz (fast), and 1 MHz (fast-plus).

Does RM24C32DS-LSNI-B require external pull-up resistors on SDA and SCL lines?

Yes, RM24C32DS-LSNI-B requires external pull-up resistors on both SDA and SCL lines because SDA is open-drain and SCL is input-only. The datasheet specifies typical values of 10 kΩ for 100 kHz operation and 2 kΩ for 400 kHz or 1 MHz operation. These values ensure proper rise times (tRI ≤ 300 ns) and bus capacitance compliance (<400 pF), preventing signal integrity issues during high-speed I²C transactions.

How is the 128-byte OTP Security Register structured in RM24C32DS-LSNI-B?

The 128-byte OTP Security Register in RM24C32DS-LSNI-B is split into two 64-byte sections: bytes 0–63 are user-programmable (one-time only), and bytes 64–127 are factory-programmed by Adesto with a unique identifier. Access uses I²C control code "1011" (vs. "1010" for main memory), and address bits above A5 are masked - ensuring only the lower 6 bits determine the target location within the OTP space.

Can RM24C32DS-LSNI-B operate reliably at 1.65V supply voltage?

Yes, RM24C32DS-LSNI-B is fully specified to operate at 1.65V minimum VCC, including all I²C timing parameters, write endurance (100,000 cycles), and data retention (>40 years at 125°C). The DC characteristics table explicitly lists VCC = 1.65V to 3.6V, and AC specs (e.g., tSCLH, tSCLL) are guaranteed across this full range - enabling direct use with 1.8V microcontrollers without level shifters or voltage boosters.

What happens if the WP pin is held high during a write command to RM24C32DS-LSNI-B?

When WP is held high during a write command (Byte/Page/OTP), RM24C32DS-LSNI-B acknowledges the control byte, address, and data bytes normally, but inhibits the internal write cycle after the STOP condition. No data is written to memory or OTP registers; however, the internal address pointer increments as if the write succeeded - requiring firmware to validate write completion via acknowledge polling rather than relying solely on WP state.