TMP421AQDCNTQ1 - ±1°C Remote/Local Temp Sensor, AEC-Q100 | TI
Teilenummer: TMP421AQDCNTQ1 ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $2.85 | $2,85 |
| 10 | $2.55 | $25,50 |
| 100 | $2.05 | $205,00 |
| 500 | $1.72 | $860,00 |
| 1.000 | $1.42 | $1.420,00 |
| 3.000 | $1.18 | $3.540,00 |
TMP421AQDCNTQ1 Übersicht
A remote-junction digital temperature sensor is an integrated transducer that converts a diode-connected transistor's forward-voltage drop into a digital temperature code. Unlike analog thermistors, it applies series-resistance cancellation and a programmable non-ideality factor so that layout series resistance and discrete-transistor beta variation do not degrade accuracy. Within the broader system hierarchy this places the TMP421AQDCNTQ1 at the Sensors > Temperature Sensors layer, used alongside power management ICs, supervisors, and fan controllers.
Key features include a 2.7V to 5.5V supply range, diode-fault detection for open/short conditions, configurable conversion rate, and a high-impedance analog input that ignores parallel paths. The SOT-23-8 footprint integrates into tight PCBs such as M.2 modules, server DIMMs, and battery-pack monitors where board area is constrained.
Typical applications include automotive infotainment SoC thermal monitoring, server/SSD controller die-temperature reading, and battery-pack MOSFET thermistor replacement. When designing, place the TMP421AQDCNTQ1 within 10 cm of the remote diode and route the D+/D- traces as a matched differential pair to preserve ±1°C accuracy; this is the same layout rule TI recommends in the TMP42x-Q1 datasheet.
When designing with this device, ensure the external NPN/PNP is the substrate-diode of the monitored device when possible, since that path has the lowest series resistance and the best matched ideality factor. The remote D+/D- traces should be routed symmetrically, not over a split plane, to avoid leakage-induced offset.
Drop-in-Alternativen für TMP421AQDCNTQ1 – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
TMP421AIDCNR
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
TMP421AQDCNRQ1
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
TMP422AQDCNRQ1
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
TMP423AQDCNRQ1
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
EMC1412-1-ACPC
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
TMP421AQDCNTQ1 Grenzwerte & elektrische Eigenschaften
| Sensortyp | Digital, Local/Remote |
| Remote Channels | 1 |
| Local Sensor Accuracy (max) | ±1.5 °C |
| Remote Sensor Accuracy (max) | ±1 °C |
| Local Temperature Range | -40 °C to +127 °C |
| Remote Temperature Range | -40 °C to +150 °C |
| Auflösung | 12 bit |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Schnittstelle | I2C / SMBus (2-wire) |
| I2C Address Options | 9 user-selectable |
| Eigenschaften | Series-resistance cancellation, programmable non-ideality factor, diode fault detection |
| Gehäuse | SOT-23-8 (DCN) |
| Montageart | Surface Mount |
| Betriebstemperaturbereich | -40 °C to +125 °C |
| RoHS-Status | Compliant |
| Automotive Qualification | AEC-Q100 |
| Lead-Free | Yes |
TMP421AQDCNTQ1 Pin-Konfiguration
| Pin 1 | GND — Ground reference |
| Pin 2 | D+ — Positive connection to remote temperature sensor diode |
| Pin 3 | D- — Negative connection to remote temperature sensor diode |
| Pin 4 | V+ — Positive supply voltage (2.7V to 5.5V) |
| Pin 5 | SDA — Serial data line (SMBus/I2C) |
| Pin 6 | SCL — Serial clock line (SMBus/I2C) |
| Pin 7 | ALERT/THERM — SMBus alert / thermal interrupt output |
| Pin 8 | ADD0 — I2C address select bit 0 |
Typische Anwendungen
TMP421AQDCNTQ1 ist geeignet für 6 Anwendungs: Automotive Infotainment SoC Thermal Monitor, Server SSD Controller Die-Temperature Reading, Battery Pack Cell Temperature Monitoring, FPGA/SoC Module Thermal Sensor, Industrial Router / Switch Board Monitor, Automotive LED Headlamp Thermal Management.
Automotive Infotainment SoC Thermal Monitor
The TMP421AQDCNTQ1 is a strong fit for monitoring the junction temperature of an automotive infotainment SoC because its ±1°C remote accuracy and AEC-Q100 qualification meet cabin-temperature reliability targets across a range from -40°C to +85°C. The D+/D- inputs sense the SoC substrate diode at 1.5 ms conversion time, returning a 12-bit code over the SMBus interface to the host MCU. Because of the device's series-resistance cancellation, designers can route the D+/D- pair across a 5-10 cm PCB trace without losing accuracy, which is critical when the SoC sits behind a shielding can. Use this part over a thermistor because it eliminates analog-to-digital conversion overhead in the host firmware.
Empfohlen
Server SSD Controller Die-Temperature Reading
In M.2 NVMe SSD designs the TMP421AQDCNTQ1 monitors the controller die and the NAND package temperature, feeding the thermal-throttling state machine required by the NVMe spec. The remote-diode input handles up to +150°C, well above the +125°C controller thermal-shutdown trip, while the 2.7V to 5.5V supply integrates with the 3.3V rail common in storage designs. Its 9 user-selectable I2C addresses allow up to nine SSDs on a single bus, useful in dense server backplanes. The device's diode-fault detection flags open/short conditions so the controller can fail-safe rather than report an erroneous 0°C code.
Empfohlen
Battery Pack Cell Temperature Monitoring
The TMP421AQDCNTQ1 supports battery-pack designs that use a small NPN transistor (such as MMBT3904) as a remote temperature sensor on each cell or MOSFET heatsink. Its 12-bit resolution provides 0.0625°C LSB resolution, allowing the BMS to detect early thermal-runaway events and trigger balancing. The AEC-Q100 grade matches the automotive battery-management requirements, and the 2.7V-5.5V supply aligns with the 3.3V LDO rail typical in 12V/48V systems. Series-resistance cancellation tolerates the long harness between the cells and the BMS board, while diode-fault detection alerts the BMS to a disconnected sense transistor.
Empfohlen
FPGA/SoC Module Thermal Sensor
The TMP421AQDCNTQ1 reads the substrate diode of an FPGA or high-performance SoC on a system-on-module and reports temperature to the carrier board MCU. The local sensor also measures the module PCB itself, which is useful for detecting cooling-fail conditions before the SoC trips its own thermal diode. Its small SOT-23-8 footprint fits easily beneath BGA packages, and the SMBus interface is already implemented in Linux kernels as a generic hwmon driver, simplifying firmware bring-up. Compared with a thermistor string, this IC cuts calibration time and BOM count.
Empfohlen
Industrial Router / Switch Board Monitor
Industrial routers and switches use the TMP421AQDCNTQ1 to monitor the switch-SoC die temperature and the SFP cage ambient, supporting NEBS thermal-margin reporting required by telecom operators. Its wide -40°C to +125°C operating range covers outdoor cabinet environments, and the 5.5V maximum supply tolerates the loosely-regulated 5V rail found in PoE-powered designs. With 9 I2C addresses and diode-fault detection, a single controller bus can monitor multiple line cards. Compared with NTC thermistors, the digital output eliminates analog calibration in production.
Empfohlen
Automotive LED Headlamp Thermal Management
High-power automotive LED headlamps generate substantial heat that must be monitored to drive the LED driver's thermal-foldback loop. The TMP421AQDCNTQ1 reads a remote diode placed on the LED PCB heatsink with ±1°C accuracy, enabling the driver IC to dim the LEDs before they exceed their junction-temperature rating. Its AEC-Q100 grade matches automotive headlamp requirements, and the SMBus interface is widely supported by automotive LED-driver ICs. The 2.7V-5.5V supply aligns with the 5V or 3.3V rails available in headlamp modules.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für TMP421AQDCNTQ1 – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | TMP421AIDCNR | TMP421AQDCNRQ1 | TMP422AQDCNRQ1 | EMC1412-1-ACPC |
|---|---|---|---|---|---|
| Package | SOT-23-8 (DCN) | SOT-23-8 (DCN) - same | SOT-23-8 (DCN) - same | SOT-23-8 (DCN) - same | SOT-23-8 - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Microchip Technology |
| Remote Channels | 1 | 1 | 1 | 2 | 1 |
| Remote Accuracy (max) | ±1 °C | ±2.5 °C | ±1 °C | ±1 °C | ±1 °C |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 3.0 V to 3.6 V |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 11 bit |
| Diode Fault Detection | Yes | Yes | Yes | Yes | Yes |
| Interface | I2C / SMBus | I2C / SMBus | I2C / SMBus | I2C / SMBus | I2C / SMBus |
Wichtigste Unterscheidungsmerkmale
- Tighter ±1°C remote accuracy vs industrial version (vs. TMP421AIDCNR)
- Pin-to-pin compatible with the two/three-channel siblings (vs. TMP422AQDCNRQ1 / TMP423AQDCNRQ1)
- 9 user-selectable I2C addresses for multi-device buses (vs. EMC1412-1-ACPC)
Designhinweise
Route the D+ and D- traces as a matched differential pair from the TMP421AQDCNTQ1 to the remote diode, keeping the pair within 10 cm and avoiding splits in the ground plane. TI's TMP42x-Q1 datasheet recommends keeping a ground guard trace between D+ and D- to reject leakage currents that would otherwise add 1-2°C of offset error at high temperatures.
Program the non-ideality factor register to match the actual diode in use (typical CPUs: 1.008, small-signal transistors like MMBT3904: 1.010-1.020). Forgetting this register defaults to a generic 1.010 and adds up to 0.5°C error. The TMP421 also requires the series-resistance-cancellation bit to be enabled whenever the layout adds more than 10 ohm of trace resistance.
The SOT-23-8 package has a theta_JA around 200-250 C/W, but the device itself dissipates only a few milliwatts - so the package thermal resistance is rarely the limit. The real thermal limit is the remote diode's self-heating; avoid placing the sense transistor in a region where nearby power components raise its temperature above the die being measured.
Place a 10 nF ceramic bypass capacitor directly at the V+ pin (within 2 mm) and a 100 nF capacitor at the SMBus pull-up rail. The TMP421's SDA/SCL lines tolerate 5V pull-ups even when V+ is 3.3V, but only when the device's maximum ratings are respected - never pull SDA/SCL above 5.5V.
The TMP421AQDCNTQ1 draws around 0.5 mA during conversion and drops to ~10 uA in standby, so a typical always-on ECU sub-system can power it from a low-quiescent LDO. Disable the conversion loop in software between readings to enter the lower-power standby state described in the TMP42x-Q1 datasheet power-management section.
Compliance-Informationen
AEC-Q100 qualified per the TMP42x-Q1 datasheet 'Q1' suffix designation. RoHS and REACH compliance stated on the TI.com product page. Halogen-free status not explicitly stated in the provided data.
