Analog Devices Inc. ADM1023ARQ

Overview

ADM1023ARQ from Analog Devices is a dual-channel, ACPI-compliant microprocessor system temperature monitor IC with on-chip and remote diode sensing. It delivers ±0.5°C local channel accuracy at 60°C–100°C, 0.125°C remote resolution, SMBus 2-wire interface, and operates from 3 V to 5.5 V in a 16-lead QSOP package - used for real-time thermal management in Pentium III–based desktops and industrial controllers.

For engineers reviewing the ADM1023ARQ datasheet, ADM1023ARQ pinout, ADM1023ARQ application, or ADM1023ARQ equivalent, key selection criteria include remote sensor ideality factor (n = 1.008 optimized), open-circuit fault detection on D+/D−, programmable conversion rate (0.0625–4 Hz), ALERT interrupt behavior, and offset calibration registers for PCB trace resistance compensation.

Technical Context

The ADM1023ARQ implements a chopper-stabilized, dual-input ADC architecture that measures ΔV_BE across two collector current ratios (I and NI) to eliminate absolute V_BE variation. It supports both on-die PNP thermal diodes (e.g., Pentium III) and discrete NPN/PNP sensors (e.g., 2N3904/2N3906), with internal biasing of D− above GND to reject ground noise.

Its SMBus interface complies with SMBus 2.0 timing (400 kHz max clock, t_SU:STA = 0.6 μs), features address pins ADD0/ADD1 for up to four device addresses, and includes dedicated status register bits for remote open-circuit detection, local/remote over/under-limit flags, and BUSY indication - all latched to ALERT output.

Key Specifications

Pinout & Package

ADM1023ARQ is housed in a 16-lead QSOP (Quarter-size Outline Package) with no exposed thermal pad. Pin 1 is top-left corner (notch-marked), and pins 1, 5, 9, 13, 16 are NC (no connect). The package supports standard IR reflow (220°C peak) and Pb-free soldering (260°C peak).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar temperature monitoring applications.

Compared with ADM1021ARQ and LM94022QDCNT, the ADM1023ARQ uniquely combines dual-channel digital sensing, SMBus-native interrupt signaling, and field-calibratable remote accuracy - making it the only option for robust, high-fidelity CPU thermal management in ACPI-compliant systems.

Availability

ADM1023ARQ is available at Aetrix Electronics and suitable for desktop computers, industrial controllers, and telecom equipment requiring stable component supply and long-term thermal monitoring reliability.

Supply support for ADM1023ARQ 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

Analog Devices is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The ADM1023ARQ belongs to Analog Devices' system thermal management product line, engineered specifically for ACPI-compliant microprocessor platforms requiring accurate, fault-aware, SMBus-integrated temperature supervision.

FAQ

What is the remote temperature sensor compatibility of the ADM1023ARQ?

The ADM1023ARQ supports both on-die PNP thermal diodes (e.g., Pentium III substrate transistors) and discrete NPN/PNP transistors such as the 2N3904/2N3906. Its measurement technique cancels absolute V_BE variation, eliminating need for per-sensor calibration. The device is optimized for ideality factor n = 1.008, with documented error bounds for n = 1.0057–1.0125. D− is internally biased above GND to reject ground noise, and open-circuit detection confirms sensor integrity.

How does the ADM1023ARQ handle power supply variations and undervoltage conditions?

The ADM1023ARQ operates across 3.0 V to 5.5 V, with undervoltage lockout (UVLO) activating at 2.7 V (±0.15 V hysteresis) to disable the ADC and prevent invalid conversions. Power-on reset triggers at 1.7 V (±0.5 V hysteresis), ensuring reliable initialization. At 3.3 V, standby current is 1 μA (typ), and average operating current ranges from 130 μA (0.25 conv/sec) to 370 μA (2 conv/sec). The device remains functional at 5 V by design, though not production-tested at that rail.

Can the ADM1023ARQ be used without SMBus communication?

No - the ADM1023ARQ requires SMBus communication for configuration, limit setting, and data readback. All registers (including temperature values, limits, offsets, and configuration) are accessed exclusively via the 2-wire SMBus interface using SDATA and SCLK. The ALERT output reflects register-based comparisons but cannot be configured or cleared without SMBus interaction. There is no parallel or standalone analog output mode; the device has no autonomous alarm behavior outside SMBus control.

What is the purpose and implementation of the offset registers in the ADM1023ARQ?

The ADM1023ARQ includes two 11-bit two's complement offset registers (addresses 0x11 and 0x12) to compensate for systematic errors on the remote channel - primarily PCB track resistance and clock-induced noise. These registers add a signed correction value (−128.875°C to +127.875°C) to the raw remote temperature reading before limit comparison. They default to zero at power-up and have no effect unless explicitly written. Offset application is automatic and transparent to the host, enabling field calibration without modifying hardware layout.

Does the ADM1023ARQ support negative temperature measurements?

No - the ADM1023ARQ remote channel measures from 0°C to +127.875°C only, with 0.125°C resolution. Its local channel also starts at 0°C in standard operation. While the status register and limit comparators accept negative values (e.g., −55°C low limit), the ADC output format lacks sign extension for sub-zero readings. For applications requiring true negative temperature capability (e.g., −40°C ambient monitoring), Analog Devices specifies the ADM1021 as the appropriate alternative part.