Texas Instruments TMP400AIDBQT

Overview

TMP400AIDBQT from Texas Instruments is a dual-channel digital temperature sensor IC with integrated local die sensor and remote diode junction sensing capability. It delivers ±1°C accuracy for both local (–40°C to +125°C) and remote (–40°C to +125°C) measurements, supports SMBus 2.0 interface, offers programmable 9–12-bit resolution, and operates from 2.7V to 5.5V supply - used in server CPU thermal monitoring and FPGA junction temperature control.

For engineers reviewing the TMP400AIDBQT datasheet, TMP400AIDBQT pinout, TMP400AIDBQT application, or TMP400AIDBQT equivalent, this page provides verified technical context, validated register-level functionality, confirmed QSSOP-16 package mapping, and real-world thermal monitoring use cases - all derived from TI SBOS404 production data.

Technical Context

The TMP400AIDBQT implements dual-sensor architecture: a precision bandgap-based local sensor and a remote channel using sequential current excitation across D+/D– to measure ΔV_BE of external PNP/NPN transistors or diodes. Its internal ADC performs 12-bit remote conversions and programmable 9–12-bit local conversions, with conversion time ranging from 12.5 ms (9-bit) to 100 ms (12-bit).

It features on-chip series resistance cancellation (up to 3 kΩ), programmable non-ideality factor (η = 1.008 default, adjustable via N-factor register), and SMBus-compliant interface supporting write byte, read byte, send byte, and receive byte commands. Alert logic latches comparator events (LHIGH/LLOW/RHIGH/RLOW/OPEN) and drives open-drain ALERT pin under configurable conditions.

Key Specifications

Pinout & Package

Package: QSSOP-16 (DBQ), 3.9 mm × 4.9 mm × 1.5 mm body, 0.65 mm pitch, exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar remote/local temperature sensing applications.

Compared with TMP400AIDBQT, LM95235CIMM/NOPB lacks local sensing and SMBus compatibility, while MAX6642AESA+ omits series resistance cancellation and fails to meet ±1°C accuracy - making TMP400AIDBQT the sole option supporting simultaneous high-accuracy local/remote monitoring with full SMBus integration and PCB trace compensation.

Availability

TMP400AIDBQT is available at Aetrix Electronics and suitable for server thermal management, industrial PLC controller design, and medical imaging power module development requiring stable component supply and long-term lifecycle support.

Supply support for TMP400AIDBQT 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

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision sensing and thermal management ICs.

The TMP400AIDBQT belongs to TI's high-accuracy temperature sensor product line, designed specifically for dual-point thermal monitoring in computing, telecom, and industrial systems where local die and remote junction temperatures must be tracked with minimal calibration and robust fault handling.

FAQ

What is the remote temperature accuracy specification for TMP400AIDBQT?

The TMP400AIDBQT achieves ±0.0625°C typical remote temperature accuracy over +15°C to +75°C ambient and ±1°C maximum over –40°C to +100°C ambient, as specified in TI SBOS404. This accuracy holds with series resistance cancellation enabled and uses a 2N3906 PNP transistor as the remote sensor. The device does not require factory calibration to meet these specs across multiple IC manufacturers.

Does TMP400AIDBQT support both local and remote temperature measurement simultaneously?

Yes, TMP400AIDBQT performs concurrent local die temperature sensing and remote junction temperature measurement using external diode-connected transistors. Both channels update independently: local resolution is programmable (9–12-bit), while remote is fixed at 12-bit (0.0625°C step). Conversion timing is synchronized internally, and results are stored in separate high/low byte registers accessible via SMBus.

How does the series resistance cancellation feature work in TMP400AIDBQT?

TMP400AIDBQT cancels up to 3 kΩ of series resistance in the remote D+/D– path by enabling the RC bit in the Resolution Register (address 1Ah). When RC = 1, the device applies correction during ΔV_BE measurement to eliminate offset caused by PCB trace resistance and connector impedance - eliminating need for board-level characterization or manual compensation algorithms.

What SMBus commands are supported by TMP400AIDBQT?

TMP400AIDBQT supports SMBus 2.0 standard commands: Write Byte, Read Byte, Send Byte, and Receive Byte. It does not support Block Write/Read or Process Call. All register access uses the 8-bit Pointer Register (address 00h) to select target registers before read/write operations, and the device responds to 7-bit slave addresses (10010xx) determined by A0/A1 pins.

Can TMP400AIDBQT detect an open remote sensor connection?

Yes, TMP400AIDBQT includes dedicated diode fault detection that sets the OPEN bit in the Status Register (address 02h) when the remote sensor is disconnected or exhibits excessive leakage. This condition is latched until the Status Register is read, and it triggers the ALERT pin if MASK = 0 - enabling fail-safe thermal monitoring in mission-critical systems.