Texas Instruments TMP421AIDCNRG4

Overview

TMP421AIDCNRG4 from Texas Instruments is a dual-channel digital temperature sensor IC with one local die sensor and one remote junction sensor, delivering ±1°C remote accuracy (max) and ±1.5°C local accuracy (max) over –40°C to +125°C, operating from 2.7V to 5.5V, and communicating via SMBus 2-wire interface - used for real-time thermal monitoring in microprocessor and FPGA power domains.

For engineers reviewing the TMP421AIDCNRG4 datasheet, TMP421AIDCNRG4 pinout, TMP421AIDCNRG4 application, or TMP421AIDCNRG4 equivalent, key selection considerations include its SOT23-8 package, 12-bit resolution per channel, series resistance cancellation up to 3 kΩ, diode fault detection, and support for n-factor correction across multiple semiconductor process nodes.

Technical Context

The TMP421AIDCNRG4 integrates a precision bandgap-based local temperature sensor and a remote diode sensor interface optimized for NPN/PNP transistors or diodes embedded in CPUs, GPUs, or FPGAs. It implements hardware-based series resistance cancellation and programmable ideality factor (η = 1.008) to correct non-ideal diode behavior.

Its SMBus interface supports write byte, read byte, send byte, and receive byte commands, with configurable slave address (100 11xx), timeout (25–35 ms), and clock frequency up to 3.4 MHz. Conversion time is fixed at 100–130 ms per channel, and measurement data is stored in dedicated high/low byte registers accessible via pointer addressing.

Key Specifications

Pinout & Package

SOT23-8 package (DCN designation), 2.9 mm × 1.6 mm × 1.0 mm body, gull-wing leads, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TMP422AIDCNR, TMP421AIDCNRG4 saves board space and cost when only one remote channel is needed; compared with LM95235CIMMX/NOPB, it offers higher resolution, SMBus compatibility, and integrated local sensing - critical for modern processor thermal management stacks.

Availability

TMP421AIDCNRG4 is available at Aetrix Electronics and suitable for processor/FPGA thermal monitoring, LCD/DLP projector lamp control, central office telecom equipment, and storage area networks requiring stable component supply across multi-year production cycles.

Supply support for TMP421AIDCNRG4 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, embedded processing, and connectivity technologies, with decades of expertise in precision sensing and power management ICs.

The TMP421AIDCNRG4 belongs to TI's precision temperature sensor product line, designed specifically for high-accuracy, multi-point thermal monitoring in computing, telecom, and projection systems where reliability and calibration-free operation are mandatory.

FAQ

What is the remote temperature accuracy specification for TMP421AIDCNRG4 under typical operating conditions?

The TMP421AIDCNRG4 achieves ±1°C maximum remote temperature error when ambient temperature is +15°C to +85°C, remote junction temperature is –40°C to +150°C, and supply voltage is 3.3V. This accuracy is guaranteed across multiple IC manufacturers' diodes without calibration - a key differentiator for server and telecom thermal designs. The TMP421AIDCNRG4 maintains this performance using hardware-based series resistance cancellation and fixed n-factor correction.

Does TMP421AIDCNRG4 support extended temperature range operation, and how is it enabled?

Yes, TMP421AIDCNRG4 supports an extended temperature range from –64°C to +191°C by setting bit 2 (RANGE) in Configuration Register 1 to high. This reconfigures the data format from standard binary to extended binary, adding a 64°C offset to the raw value. The feature is validated for use in cold-chain logistics and high-temp industrial enclosures, though the device's specified ambient operating range remains –40°C to +125°C.

How does TMP421AIDCNRG4 handle diode faults, and what types of faults are detectable?

TMP421AIDCNRG4 performs automatic diode fault detection on the DXP–DXN connection, identifying open-circuit (infinite resistance), short-circuit (near-zero resistance), and reversed diode polarity. Fault status is reported in the Status Register (pointer 08h, OPEN bit). This capability prevents erroneous thermal shutdowns in mission-critical systems like 5G base stations - a feature absent in basic analog thermistors or lower-cost digital sensors.

What SMBus addresses are supported by TMP421AIDCNRG4, and how are they configured?

TMP421AIDCNRG4 supports four SMBus slave addresses: 100 1100 (0x98), 100 1101 (0x9A), 100 1110 (0x9C), and 100 1111 (0x9E), selected by hardwiring pins A1 and A0 to V+ or GND. This allows up to four TMP421AIDCNRG4 devices on a single SMBus without address collision - essential for multi-socket servers or modular telecom shelves where dense thermal sensing is required.

Is TMP421AIDCNRG4 RoHS compliant and lead-free, and what packaging does it use?

Yes, TMP421AIDCNRG4 is RoHS compliant and free of antimony and bromine (Sb/Br), per TI's SBOS398C datasheet. It is supplied in a Pb-free, halogen-free SOT23-8 package (DCN designation), with JEDEC-standard gull-wing leads and moisture sensitivity level 1 - suitable for standard reflow profiles and long-term industrial deployment without corrosion concerns.