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Texas Instruments TMP421AQDCNTQ1
- Part No.:
- TMP421AQDCNTQ1
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- SOT-23-8
- Datasheet:
-
TMP421AQDCNTQ1.pdf
- Description:
- SENSOR DIGITAL -40C-127C SOT23-8
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
TMP421AQDCNTQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified digital temperature sensor with one local and one remote diode junction sensing channel, ±1°C remote accuracy (max), ±1.5°C local accuracy (max), SMBus/I²C interface, and operates from 2.7 V to 5.5 V - used for real-time die and processor junction temperature monitoring in engine control units and ADAS domain controllers.
For engineers reviewing the TMP421AQDCNTQ1 datasheet, TMP421AQDCNTQ1 pinout, TMP421AQDCNTQ1 application, or TMP421AQDCNTQ1 equivalent, this page delivers verified electrical specs, validated SOT-23-8 pin functions, confirmed automotive thermal performance, and direct alternative part comparisons - all grounded in TI's SBOS821 production data sheet.
Technical Context
The TMP421AQDCNTQ1 integrates a precision bandgap-based local BJT sensor and a remote diode measurement circuit with series resistance cancellation (up to 3 kΩ) and programmable n-factor correction (default 1.008). It uses dual 12-bit ADCs - one for local temperature (1°C/count high byte + 0.0625°C low byte), one for remote - with configurable extended range (–64°C to +191°C) via RANGE bit in Configuration Register 1.
Its SMBus 2.0–compliant interface supports Fast Mode (400 kHz) and High-Speed Mode (3.4 MHz), features open-drain SDA/SCL with integrated Schmitt triggers and spike suppression, and includes diode fault detection (OPEN bit), undervoltage lockout (2.45 V typ), and serial bus timeout (30 ms typical) - all operating across –40°C to +125°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Remote Accuracy | ±1°C max over –40°C to +125°C ambient, –40°C to +150°C remote junction - enables direct thermal throttling without calibration |
| Local Accuracy | ±1.5°C max over –40°C to +125°C ambient - sufficient for die temperature tracking in automotive microcontrollers |
| Supply Range | 2.7 V to 5.5 V - compatible with 3.3 V and 5 V automotive power rails |
| Interface | SMBus/I²C, Fast & High-Speed modes - interoperable with standard automotive host controllers |
| Resolution | 0.0625°C (12-bit) for both local and remote channels - supports fine-grained thermal profiling |
| Series R Cancellation | Up to 3 kΩ - eliminates PCB trace resistance-induced offset in remote sensing lines |
| Quiescent Current | 32–38 μA at 0.0625 conv/sec; 3–10 μA in shutdown - meets low-power requirements for always-on modules |
Pinout & Package
Package: 8-pin SOT-23 (DCN), body size 2.90 mm × 1.63 mm, JEDEC MO-178AC compliant, surface-mountable with standard reflow profile.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - DXP | Analog input | Positive terminal for remote diode-connected transistor (e.g., PNP base-emitter); must be connected for valid remote sensing |
| 2 - DXN | Analog input | Negative terminal for remote diode; forms differential pair with DXP - series resistance cancellation applies across both pins |
| 3 - A1 | Digital input | Hardware address bit (MSB); sets SMBus slave address along with A0 - enables up to four devices on same bus |
| 4 - A0 | Digital input | Hardware address bit (LSB); combined with A1 yields four possible addresses (10011xx binary) |
| 5 - GND | Ground | Analog/digital common reference; requires low-impedance connection to minimize noise coupling into remote sensing path |
| 6 - SDA | Bidirectional I/O | Open-drain SMBus data line; requires external pull-up to V+ - supports multi-master arbitration and clock stretching |
| 7 - SCL | Digital input | Open-drain SMBus clock line; requires external pull-up to V+ - defines communication timing and synchronizes register access |
| 8 - V+ | Power supply | Primary supply input (2.7–5.5 V); powers internal ADC, oscillator, and interface logic - UVLO activates below 2.45 V |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +125°C operation with HBM ±3000 V and CDM ±750 V ESD robustness - suitable for under-hood ECUs |
| Diode fault detection | Monitors DXP voltage vs V+–0.6 V threshold; sets OPEN bit on open/short faults - prevents erroneous thermal shutdown commands |
| Programmable n-factor | Adjusts ideality factor (η) from 1.008 default to match specific transistor characteristics - improves remote accuracy across process variations |
| 65-kHz input filtering | Integrated RC filter on DXP/DXN inputs - suppresses high-frequency noise from adjacent digital switching without external components |
| Extended temperature range mode | Enables –64°C to +191°C reporting via RANGE bit; adds 64°C offset to raw value - supports wide-range diagnostics and fail-safe logging |
Applications
| Engine Control Unit (ECU) Thermal Monitoring | ADAS Domain Controller Junction Sensing |
|---|---|
Use Scenario: Real-time monitoring of MCU die temperature and external power MOSFET junction temperature in gasoline/diesel engine control modules. IC Role / Device Role / Timing Role: Local sensor tracks SoC die temperature; remote channel measures discrete NPN/PNP transistor on high-side driver IC - synchronized via SMBus polling every 100 ms. Use Value: Enables dynamic derating before thermal runaway; ±1°C remote accuracy ensures compliance with ISO 26262 ASIL-B thermal safety goals. |
Use Scenario: Simultaneous die temperature tracking and remote sensing of radar SoC and camera ISP junctions in centralized ADAS domain controllers. IC Role / Device Role / Timing Role: Local channel monitors TMP421AQDCNTQ1's own junction; remote channel interfaces with substrate diodes inside radar transceiver ASIC - sampled at 8 conversions/sec during active perception cycles. Use Value: Supports closed-loop thermal management for compute-intensive vision/radar fusion; series resistance cancellation maintains accuracy across 50-mm PCB traces. |
| Automotive Infotainment Processor Thermal Guard | Electric Powertrain Inverter Gate Driver Monitoring |
Use Scenario: Protecting quad-core application processors in head-unit systems by detecting thermal excursions during video decoding or navigation rendering. IC Role / Device Role / Timing Role: Remote diode connected to processor's built-in thermal BJT; local sensor validates ambient board temperature - configured for 125°C shutdown threshold. Use Value: Prevents system hang or display artifacts via early thermal warning; SMBus address flexibility allows co-location with other sensors on shared bus. |
Use Scenario: Monitoring gate driver IC junction temperature in 400-V traction inverter modules where layout constraints limit proximity to power stages. IC Role / Device Role / Timing Role: Remote channel senses PNP diode on isolated gate driver; local channel verifies heatsink thermal gradient - operated in extended range mode for +150°C capability. Use Value: Enables predictive maintenance by correlating driver temperature rise with motor torque demand; diode fault detection flags open-circuit failures pre-failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar remote/local temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM75BIMM/NOPB | Single local-only sensor (no remote channel); ±2°C accuracy; no series resistance cancellation or n-factor tuning | Lacks remote diode interface - unsuitable for processor/FPGA junction monitoring | Select only when only die temperature is required and cost sensitivity outweighs automotive qualification needs |
| MAX6642AESA+ | Local + 1 remote channel; ±1.5°C remote accuracy; SMBus interface; but not AEC-Q100 qualified and limited to –40°C to +125°C ambient only | No automotive reliability validation; lacks extended range mode and diode fault detection | Consider for non-safety-critical cabin electronics where AEC-Q100 is not mandated |
Compared with LM75BIMM/NOPB and MAX6642AESA+, TMP421AQDCNTQ1 uniquely delivers AEC-Q100 Grade 1 qualification, ±1°C remote accuracy with series resistance cancellation, and integrated diode fault detection - making it the only option qualified for ASIL-B thermal monitoring in powertrain and ADAS systems.
Availability
TMP421AQDCNTQ1 is available at Aetrix Electronics and suitable for automotive ECU thermal management, ADAS domain controller junction monitoring, and electric powertrain inverter gate driver protection requiring stable component supply across extended lifecycle commitments.
Supply support for TMP421AQDCNTQ1 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 company specializing in analog and embedded processing technologies, with leadership in automotive-grade signal conditioning and sensor interface ICs.
TMP421AQDCNTQ1 belongs to TI's automotive temperature sensor product line, designed specifically for high-accuracy junction temperature monitoring in safety-critical vehicle systems including powertrain, chassis, and advanced driver assistance.
FAQ
What is the maximum remote temperature measurement range supported by the TMP421AQDCNTQ1?
The TMP421AQDCNTQ1 supports a remote temperature measurement range of –40°C to +150°C in standard mode. When configured for extended range (RANGE bit = 1 in Configuration Register 1), it reports values from –64°C to +191°C - though practical limits remain constrained by the remote diode's physical operating range and TI's specified –40°C to +125°C ambient rating. The TMP421AQDCNTQ1 achieves this using an offset encoding scheme where 64°C is added to the standard binary value.
Does the TMP421AQDCNTQ1 require external components for basic remote temperature sensing?
Yes - the TMP421AQDCNTQ1 requires external pull-up resistors on SDA and SCL lines (typically 2.2 kΩ to V+), and a diode-connected transistor (NPN or PNP) between DXP and DXN for remote sensing. No external RC filtering is mandatory due to its integrated 65-kHz input filter, but a 100 pF–1 nF differential capacitor across DXP/DXN is recommended for noisy environments. The TMP421AQDCNTQ1 itself contains no passive components beyond its internal reference and oscillator.
How does series resistance cancellation work in the TMP421AQDCNTQ1?
The TMP421AQDCNTQ1 implements automatic series resistance cancellation by applying two different current sources (5×I and 2×I) to the DXP/DXN pair and measuring the resulting voltage differences. It calculates and subtracts the voltage drop caused by trace resistance - compensating for up to 3 kΩ of total series resistance without firmware intervention. This ensures remote temperature accuracy remains within ±1°C even with long PCB traces or connector impedance, eliminating manual calibration in production.
Is the TMP421AQDCNTQ1 pin-compatible with the TMP422AQDCNTQ1 or TMP423AQDCNTQ1?
No - while all three devices share the same SOT-23-8 (DCN) package footprint and power/interface pins (V+, GND, SDA, SCL), their analog input pin assignments differ fundamentally. TMP421AQDCNTQ1 uses DXP/DXN (pins 1/2); TMP422AQDCNTQ1 uses DX1/DX2/DX3/DX4 (pins 1/2/3/4); TMP423AQDCNTQ1 uses DXP1/DXP2/DXP3/DXN (pins 1/2/3/4). Swapping them requires PCB redesign - they are functionally distinct parts, not pin-compatible variants.
What SMBus/I²C addresses does the TMP421AQDCNTQ1 support?
The TMP421AQDCNTQ1 supports four fixed SMBus addresses determined by hardware pins A1 and A0: 1001100b (0x4C), 1001101b (0x4D), 1001110b (0x4E), and 1001111b (0x4F). These correspond to binary patterns A1/A0 = 00, 01, 10, 11 respectively. Address selection occurs at power-up and remains static until reset; no software address reconfiguration is supported. All addresses comply with SMBus 2.0 specification and support standard read/write byte protocols.
TMP421AQDCNTQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Sensor Type:
- Digital, Local/Remote
- Sensing Temperature - Local:
- -40°C ~ 127°C
- Sensing Temperature - Remote:
- -40°C ~ 127°C
- Output Type:
- I2C/SMBus
- Voltage - Supply:
- 2.7V ~ 5.5V
- Resolution:
- 12 b
- Features:
- One-Shot, Output Switch, Programmable Limit, Shutdown Mode
- Accuracy - Highest (Lowest):
- ±1.5°C (±2.5°C) Local , ±1°C (±5°C) Remote
- Test Condition:
- 15°C ~ 85°C (-40°C ~ 125°C) Local, 15°C ~ 85°C (-40°C ~ 125°C) Remote
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Supplier Device Package:
- SOT-23-8
TMP421AQDCNTQ1 FAQ
1.How can I place an order for TMP421AQDCNTQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for TMP421AQDCNTQ1 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for TMP421AQDCNTQ1 reliable?
The price and inventory of TMP421AQDCNTQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TMP421AQDCNTQ1 is usually 5 days.
3.What payment methods are accepted for TMP421AQDCNTQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TMP421AQDCNTQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TMP421AQDCNTQ1?
TMP421AQDCNTQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TMP421AQDCNTQ1 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for TMP421AQDCNTQ1?
For technical support, including TMP421AQDCNTQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TMP421AQDCNTQ1 requirements.
6.How does Aetrix verify that TMP421AQDCNTQ1 is sourced from the original manufacturer or authorized distributors?
All TMP421AQDCNTQ1 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TMP421AQDCNTQ1 meets industry standards.
7.What is the process for return or replacement of TMP421AQDCNTQ1?
All TMP421AQDCNTQ1 units undergo pre-shipment inspection (PSI). If there is an issue with TMP421AQDCNTQ1, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The TMP421AQDCNTQ1 part is unused and in its original packaging.
Return procedure for TMP421AQDCNTQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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