Analog Devices Inc. ADT7468ARQZ

Overview

ADT7468ARQZ from onsemi is a dBCool® remote thermal controller and voltage monitor IC designed for active cooling management in noise- and power-sensitive systems. It monitors up to five voltages (including +12V, +5V, +2.5V, VCCP, and VCC), controls four PWM fan outputs with selectable high/low-frequency drive (22.5 kHz or 10–100 Hz), and integrates one on-chip and two remote temperature sensors with series resistance cancellation - enabling precise thermal supervision up to 191°C in Intel Pentium 4–based server and desktop platforms.

For engineers reviewing the ADT7468ARQZ datasheet, ADT7468ARQZ pinout, ADT7468ARQZ application, or ADT7468ARQZ equivalent, key selection considerations include its SMBus 2.0 compliance, dynamic TMIN control mode for acoustic optimization, fail-safe full-speed fan activation at 100°C THERM threshold, and VID0–VID5 CPU voltage monitoring capability for VRM10-compatible systems.

Technical Context

The ADT7468ARQZ implements a 10-bit ADC with multiplexed analog inputs for simultaneous voltage and temperature measurement, featuring ±2% total unadjusted error on 12 V/5 V channels and 0.25°C resolution for both local and remote temperature sensing. Its dual-diode remote channel supports series resistance cancellation (SRC) to eliminate PCB trace resistance-induced offset, critical for accurate CPU die temperature tracking.

It embeds three independent PWM controllers (PWM1–PWM3, with PWM3 supporting dual-fan control), configurable TACH input logic for 2-/3-/4-wire fan speed measurement, and a bidirectional THERM pin that functions as both PROCHOT input (for Intel processor thermal throttling monitoring) and overtemperature output - all coordinated via automatic fan speed control loops with programmable PWMMIN/PWMMAX, TRANGE, and TTHERM thresholds.

Key Specifications

Pinout & Package

ADT7468ARQZ is housed in a 24-lead QSOP package (5.3 mm × 7.6 mm, 0.635 mm pitch) with exposed pad for thermal dissipation. Pin functions are validated per onsemi Rev. 3 datasheet Figure 3 and Table 3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar thermal monitoring and fan control applications.

Compared with ADT7463ARQZ and LM96163CISD/NOPB, the ADT7468ARQZ uniquely combines VRM10-compliant VID5 support, bidirectional THERM for Intel PROCHOT integration, series resistance cancellation for precision CPU die sensing, and fail-safe cooling activation - making it the only choice for modern x86 server/desktop thermal management requiring guaranteed interoperability with Intel thermal architecture.

Availability

ADT7468ARQZ is available at Aetrix Electronics and suitable for server thermal management, desktop PC cooling control, VRM10-compliant power monitoring, and industrial embedded controller cooling requiring stable component supply across long-life production cycles.

Supply support for ADT7468ARQZ 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient silicon solutions for automotive, industrial, cloud, and IoT applications - with leadership in thermal management, power conversion, and sensor signal conditioning.

The ADT7468ARQZ belongs to onsemi's dBCool® family of thermal controllers, engineered specifically for intelligent, low-noise active cooling in x86-based computing platforms where acoustic performance, thermal reliability, and Intel processor compatibility are mandatory design requirements.

FAQ

What is the primary function of the ADT7468ARQZ in a computer system?

The ADT7468ARQZ serves as a centralized thermal and power supervisor - monitoring up to five voltage rails, measuring temperatures from one on-chip sensor and two remote diodes, and controlling four fans via three PWM outputs. Its core function is to maintain safe operating temperatures while minimizing acoustic noise through dynamic fan speed algorithms, especially in Intel Pentium 4–compatible platforms where PROCHOT and VID monitoring are essential. The ADT7468ARQZ enables this via SMBus 2.0 communication and fail-safe full-speed fan activation.

Does the ADT7468ARQZ support Intel PROCHOT protocol, and how is it implemented?

Yes, the ADT7468ARQZ supports Intel PROCHOT protocol through its bidirectional THERM pin - which can be configured as an input to monitor the CPU's PROCHOT assertion (e.g., from Pentium 4 or compatible processors) or as an output to signal system overtemperature. When used as input, the ADT7468ARQZ times PROCHOT assertions and triggers automatic fan speed increases; when used as output, it asserts THERM at 100°C to force CPU throttling. This dual-mode operation is integral to the ADT7468ARQZ's role in x86 thermal management.

How does series resistance cancellation (SRC) improve temperature accuracy in the ADT7468ARQZ?

Series resistance cancellation (SRC) in the ADT7468ARQZ compensates for voltage drop caused by PCB trace resistance between the remote thermal diode (e.g., CPU die) and the ADT7468ARQZ's D1+/D1− or D2+/D2− inputs. By applying three different bias currents (6 µA, 36 µA, 96 µA) and calculating the resulting voltage differences, the ADT7468ARQZ mathematically removes linear offset error - improving remote temperature accuracy to ±1.5°C over 0°C–70°C. This ensures the ADT7468ARQZ delivers true die temperature rather than a PCB-trace-degraded reading.

Can the ADT7468ARQZ monitor CPU core voltage (VCCP), and why is this important?

Yes, the ADT7468ARQZ monitors CPU core voltage (VCCP) on Pin 23 with 0 V to 3 V input range and uses it to dynamically set the THERM trip threshold at 2/3 × VCCP - matching Intel's PROCHOT specification. This ensures accurate thermal throttling coordination between CPU and system controller. Additionally, VCCP measurement validates VRM regulation stability and enables BIOS-level voltage droop detection. For VRM10 compliance, the ADT7468ARQZ also reads VID0–VID5 bits to cross-check commanded vs. actual core voltage - a capability central to the ADT7468ARQZ's value in high-reliability platforms.

What fan control modes does the ADT7468ARQZ support, and how do they differ?

The ADT7468ARQZ supports two PWM drive modes: high-frequency (22.5 kHz default) and low-frequency (10–100 Hz, programmable). HF mode eliminates audible whine from fan coils but may increase EMI; LF mode reduces EMI and improves fan compatibility with older motors but risks audible buzz below 25 Hz. Both modes operate within the ADT7468ARQZ's automatic fan speed control loop, which adjusts duty cycle based on temperature vs. programmable operating points (TMIN, TTHERM, THYST). The ADT7468ARQZ also provides enhanced acoustic mode to smooth transitions between duty cycles - reducing perceived noise.