Microchip Technology MCP98242-BE/ST

Overview

MCP98242-BE/ST from Microchip Technology is a JEDEC JC42.4-compliant digital temperature sensor with integrated 256-byte serial EEPROM, designed for DDR memory module thermal monitoring. It delivers ±0.5°C typical accuracy from +75°C to +95°C, operates from 3.0V to 3.6V, draws 200 µA typical active current and 3 µA max shutdown current, and interfaces via I²C/SMBus-compatible 2-wire bus - enabling DIMM SPD data storage and real-time thermal event signaling in server memory subsystems.

For engineers reviewing the MCP98242-BE/ST datasheet, MCP98242-BE/ST pinout, MCP98242-BE/ST application, or MCP98242-BE/ST equivalent, key selection considerations include its JEDEC JC42.4 compliance, user-programmable TUPPER/TLOWER/TCRIT trip registers, permanent/software write-protect EEPROM architecture, open-drain Event output polarity configuration, and DFN-8 package thermal performance (θJA = 84.5°C/W).

Technical Context

The MCP98242-BE/ST integrates a band-gap temperature sensor and delta-sigma ADC with programmable resolution (0.0625°C to 0.5°C), supporting continuous conversion or shutdown mode via CONFIG register bit 8. Its dual-function EEPROM is partitioned: lower 128 bytes (00h–7Fh) support permanent or reversible software write-protection for SPD vendor data, while upper 128 bytes (80h–FFh) are freely writable for general-purpose storage.

Communication uses standard-mode I²C/SMBus at up to 100 kHz with tOUT = 40 ms timeout; device addressing uses 7-bit slave address 0011xxx (A2/A1/A0 configurable), with separate address codes for sensor (0011xxx), EEPROM (1010xxx), and write-protect control (0110xxx). The open-drain Event pin supports comparator (active-high/low) or interrupt modes, configurable via CONFIG register bits 1–0.

Key Specifications

Pinout & Package

Package: 8-pin DFN (2 mm × 3 mm, exposed thermal pad), RoHS-compliant, moisture sensitivity level 3. Thermal resistance θJA = 84.5°C/W enables reliable operation on dense DIMM PCBs without forced airflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar temperature sensor + SPD EEPROM applications.

Compared with AT30TS74-MA8Y and MCP9808-E/MS, the MCP98242-BE/ST uniquely combines JEDEC JC42.4 thermal accuracy with SPD-compliant EEPROM in a single die - eliminating board space, interconnect complexity, and qualification overhead for DDR memory thermal solutions.

Availability

MCP98242-BE/ST is available at Aetrix Electronics and suitable for server memory modules, laptop DDR SODIMMs, industrial embedded memory systems, and network equipment DIMMs requiring stable component supply, long-term lifecycle assurance, and JEDEC-compliant thermal monitoring.

Supply support for MCP98242-BE/ST 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 leading provider of microcontrollers, analog components, and memory solutions, with core expertise in embedded control and thermal management ICs.

The MCP98242-BE/ST belongs to Microchip's JEDEC-compliant thermal sensor family, engineered specifically for DDR memory module SPD and real-time thermal event detection in high-reliability computing platforms.

FAQ

What is the primary application purpose of the MCP98242-BE/ST?

The MCP98242-BE/ST is purpose-built for JEDEC JC42.4-compliant thermal monitoring and Serial Presence Detect (SPD) data storage in DDR3/DDR4 memory modules. Its integrated 256-byte EEPROM stores vendor-specific SPD information, while its ±0.5°C accurate temperature sensor enables real-time thermal event signaling via the programmable Event output - making it essential for server, laptop, and industrial DIMM designs requiring on-die thermal intelligence and SPD compliance.

Does the MCP98242-BE/ST support I²C standard-mode or fast-mode communication?

The MCP98242-BE/ST supports I²C standard-mode operation at 10–100 kHz, fully compliant with SMBus 1.1 timing specifications. It does not support I²C fast-mode (400 kHz) or high-speed mode. Its 40 ms bus timeout (tOUT) and strict adherence to tSU-DATA (250 ns), tH-DATA (300 ns), and tLOW (4.7 µs) ensure robust communication in noisy DIMM environments where signal integrity is constrained by trace length and stub loading.

How is EEPROM write protection implemented on the MCP98242-BE/ST?

The MCP98242-BE/ST implements dual-layer EEPROM write protection: the lower 128 bytes (addresses 00h–7Fh) support either permanent write-protection (PWP) or software-reversible write-protection (SWP) activated by applying 8–12 V to the A0 pin; the upper 128 bytes (80h–FFh) remain fully writable. This architecture ensures SPD-critical vendor data remains tamper-proof while allowing runtime logging in the upper block - a requirement for JEDEC JC42.4 SPD compliance.

Can the Event output of the MCP98242-BE/ST be configured as an active-high signal?

Yes, the Event output of the MCP98242-BE/ST can be configured as active-high via the CONFIG register (bit 0, Event Polarity). When set to '1', the open-drain Event pin asserts by pulling high through an external pull-up resistor - enabling direct connection to microcontroller GPIOs expecting active-high interrupts. This configuration, combined with Event Mode selection (bit 1), allows flexible thermostat or interrupt behavior without external logic.

What is the thermal performance difference between the DFN-8 and TSSOP-8 packages of the MCP98242?

The MCP98242-BE/ST in DFN-8 package has θJA = 84.5°C/W, while the TSSOP-8 variant measures θJA = 139°C/W - a 39% higher thermal resistance. This means the DFN-8 version runs cooler under identical power dissipation and PCB layout, making it preferred for thermally dense DIMM applications where junction temperature must stay below +150°C across -40°C to +125°C ambient. The exposed thermal pad (EP) in DFN-8 is internally connected to GND and must be soldered to a thermal plane.