Analog Devices Inc. ADT7461AR

Overview

ADT7461AR from onsemi is a dual-channel SMBus-compatible digital temperature monitor IC with local/remote sensing, series resistance cancellation (up to 3 kΩ), programmable over/under-temperature alarms, and dual open-drain THERM outputs - used in PC thermal management, industrial controllers, and embedded systems for ±1°C remote and ±3°C local accuracy.

For engineers reviewing the ADT7461AR datasheet, ADT7461AR pinout, ADT7461AR application, or ADT7461AR equivalent, this page delivers verified technical context, real-world design meaning of key specs (e.g., 0.25°C remote resolution, 0°C–+127°C default range, 8-lead SOIC package), and actionable selection guidance against alternatives.

Technical Context

The ADT7461AR uses a three-current V_BE measurement method to cancel series resistance up to 3 kΩ across D+ and D−, enabling accurate remote diode readings in noisy PCB environments. Its ADC alternates between on-chip and external sensor inputs, storing results in dedicated registers (0x00 local, 0x01/0x10 remote high/low byte) with 0.25°C resolution on the remote channel.

It implements SMBus-compliant alert signaling (address 0x4C), configurable ALERT/THERM2 pin behavior via Bit 5 of the configuration register (0x03), and switchable temperature ranges (0°C to +127°C default or −55°C to +150°C extended) controlled by Bit 2 - requiring manual reprogramming of limit registers upon range change due to offset-binary data format shift.

Key Specifications

Pinout & Package

ADT7461AR is housed in an 8-lead SOIC package (Case 751), Pb-free, with 1.27 mm lead pitch and JEDEC MS-012AC outline. Thermal resistance θ_JA = 121°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM1032ARQ and LM95235CIMM, the ADT7461AR uniquely combines SMBus compatibility, hardware-based series resistance cancellation, and dual THERM outputs in a single 8-pin SOIC - making it optimal for cost-sensitive, noise-prone PC and industrial thermal designs requiring minimal firmware overhead.

Availability

ADT7461AR is available at Aetrix Electronics and suitable for desktop PCs, industrial controllers, and smart batteries requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for ADT7461AR 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 power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The ADT7461AR belongs to onsemi's precision analog temperature sensor product line, designed specifically for SMBus-based thermal management in computing and embedded systems where reliability, noise immunity, and dual-channel capability are essential.

FAQ

What is the SMBus address of the ADT7461AR?

The ADT7461AR has a fixed SMBus slave address of 0x4C. This address is hardwired and cannot be changed via pins or registers. The ADT7461AR-2 variant uses 0x4D, but the ADT7461AR itself operates exclusively at 0x4C. This ensures deterministic bus arbitration in multi-sensor systems and simplifies host driver implementation for the ADT7461AR.

Does the ADT7461AR support remote temperature sensing with series resistance compensation?

Yes, the ADT7461AR supports automatic series resistance cancellation of up to 3.0 kΩ (typical), split evenly across D+ and D− inputs. This feature uses a three-current V_BE measurement technique to eliminate offset errors caused by PCB trace resistance or connector contact resistance. It is enabled by default and requires no user calibration - a core differentiator of the ADT7461AR versus earlier thermal monitors like the ADM1032.

Can the ADT7461AR operate in the −55°C to +150°C temperature range?

Yes, the ADT7461AR supports an extended temperature measurement range of −55°C to +150°C when Bit 2 of the Configuration Register (0x03) is set to 1. However, this mode switches the data format to offset binary (64°C offset), and all limit registers must be manually reprogrammed in the new format. The ADT7461AR itself remains rated for operation from −40°C to +120°C ambient.

How does the ALERT/THERM2 pin function on the ADT7461AR?

The ALERT/THERM2 pin (Pin 6) on the ADT7461AR defaults to SMBus Alert output but can be reconfigured as a second THERM output via Bit 5 of the Configuration Register (0x03). When configured as THERM2, it asserts low only on high-limit violations (not low-limit), mirroring the behavior of the primary THERM pin (Pin 4). Both outputs are open-drain and require external pull-up resistors to VDD.

What is the resolution and accuracy of the remote temperature channel on the ADT7461AR?

The remote temperature channel of the ADT7461AR provides 0.25°C resolution (using upper byte at 0x01 and lower byte at 0x10) and ±1.0°C accuracy over +60°C to +100°C with a 3.0–3.6 V supply. Accuracy degrades to ±3.0°C across the full −55°C to +150°C extended range. This resolution enables precise fan ramping and thermal event logging in applications such as the ADT7461AR-based notebook thermal subsystems.