Renesas RM25C128A-BTAC-T

Overview

RM25C128A-BTAC-T from Adesto Technologies is a 128Kbit CBRAM-based non-volatile boot memory IC with SPI interface, operating from 2.7V to 3.6V, supporting 5MHz fast read and 64-byte page write in ≤1ms, used for firmware storage and configuration retention in microcontroller-based embedded systems.

For engineers reviewing the RM25C128A-BTAC-T datasheet, RM25C128A-BTAC-T pinout, RM25C128A-BTAC-T application, or RM25C128A-BTAC-T equivalent, key selection criteria include SPI mode 0/3 compatibility, 10-year data retention at 70°C, 5µA power-down current, JEDEC TSSOP-8 package footprint, and byte/page erase capability without external high voltage.

Technical Context

The RM25C128A-BTAC-T implements a serial peripheral interface with four dedicated pins (CS, SCK, SDI, SDO) and two control terminals (WP, HOLD), supporting both SPI Mode 0 (CPOL=0, CPHA=0) and Mode 3 (CPOL=1, CPHA=1). It uses conductive-bridge RAM (CBRAM) technology instead of floating-gate EEPROM, enabling lower energy per byte write (10% of comparable EEPROM) and single-supply operation.

Internal architecture includes a 128Kb memory array organized as 2048 pages × 64 bytes, a status register with WIP/WEL flags, and self-timed erase/write cycles managed by on-chip control logic. All instructions-including READ (03h), FREAD (0Bh), WR (02h), PERS (42h), and CERS (60h/C7h)-are 8-bit opcodes transmitted MSB-first after CS assertion.

Key Specifications

Pinout & Package

RM25C128A-BTAC-T is packaged in an 8-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 3.0mm × 4.4mm body, 0.65mm lead pitch, with gull-wing leads and exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-volatile serial memory applications.

Compared with AT25DF041A-SHN-T and M95M02-DRMN6TP/K, RM25C128A-BTAC-T uniquely combines CBRAM's low-energy byte writes, hardware WP, and 5MHz fast read in a TSSOP-8 package - optimizing for boot-time-critical, power-sensitive embedded systems requiring robust configuration storage.

Availability

RM25C128A-BTAC-T is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostics, smart metering, and automotive body control modules requiring stable component supply, long-term data retention, and low-power non-volatile memory.

Supply support for RM25C128A-BTAC-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

Adesto Technologies was a fabless semiconductor company specializing in low-power, non-volatile memory solutions, acquired by Dialog Semiconductor in 2020 and now part of Renesas Electronics.

The RM25C128A-BTAC-T belongs to Adesto's CBRAM-based serial memory product line, designed specifically for boot code and configuration storage in space- and power-constrained embedded systems where traditional EEPROM or flash fails to meet performance or reliability targets.

FAQ

What is the maximum clock frequency supported by RM25C128A-BTAC-T in fast read mode?

The RM25C128A-BTAC-T supports a maximum SCK clock frequency of 5MHz in fast read mode (FREAD command, 0Bh), enabling sub-200ns effective access time. This is double the 1.6MHz limit of normal read mode (READ command, 03h) and critical for reducing boot latency in time-sensitive applications. The device maintains full timing compliance across its 0°C to +70°C commercial temperature range.

Does RM25C128A-BTAC-T require external high voltage for write or erase operations?

No, RM25C128A-BTAC-T does not require external high voltage. It uses conductive-bridge RAM (CBRAM) technology with integrated charge-pump-free circuitry, enabling all write and erase functions - including byte, page, and chip erase - using only the standard 2.7V–3.6V VCC supply. This eliminates external HV generation components and associated layout complexity, unlike traditional EEPROM or flash devices.

How is hardware write protection implemented on RM25C128A-BTAC-T?

RM25C128A-BTAC-T implements hardware write protection via the WP (Write Protect) pin (Pin 3). When WP is driven low, all write, page erase, and chip erase commands (WR, PERS, CERS) are blocked regardless of the Write Enable Latch (WEL) status in the status register. This provides fail-safe protection against accidental or malicious overwrites during system operation, independent of software state.

What package type is used for RM25C128A-BTAC-T and what are its key mechanical dimensions?

RM25C128A-BTAC-T uses an 8-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant. Its body measures 3.0mm × 4.4mm with 0.65mm lead pitch, gull-wing leads, and no exposed thermal pad. The "TA" in the part number explicitly denotes this TSSOP variant, distinguishing it from the SOIC-8 ("SN") version RM25C128A-BSNC-T.

Can RM25C128A-BTAC-T be used as a direct replacement for standard SPI EEPROMs in existing designs?

RM25C128A-BTAC-T is pin-compatible and functionally interoperable with standard SPI EEPROMs (e.g., AT25xxx series) sharing the same 8-pin TSSOP footprint and command set structure, but it is not a drop-in replacement due to differences in erase granularity, timing, and status register behavior. Designers must verify HOLD/CS timing margins, update firmware to handle CBRAM-specific endurance and retention characteristics, and confirm WP pin usage aligns with system-level protection requirements.