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Texas Instruments TMP442BDCNT
- Part No.:
- TMP442BDCNT
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- SOT-23-8
- Datasheet:
-
TMP442BDCNT.pdf
- Description:
- SENSOR DIGITAL -40C-125C SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:492
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Product details
Overview
TMP442BDCNT from Texas Instruments is a dual-channel remote temperature sensor IC with integrated local die sensing, ±1°C remote diode accuracy (0°C to +100°C), ±1°C local accuracy (0°C to +100°C), SMBus 2.0 interface, and automatic beta compensation - used for real-time thermal monitoring of microprocessors and FPGAs in server motherboards.
For engineers reviewing the TMP442BDCNT datasheet, TMP442BDCNT pinout, TMP442BDCNT application, or TMP442BDCNT equivalent, this page delivers verified specifications, SOT23-8 pin mapping, dual-diode interface architecture, and validated alternative parts for thermal management design-in.
Technical Context
The TMP442BDCNT implements two independent remote junction temperature measurement channels (DXP1/DXN1 and DXP2/DXN2) with programmable ideality factor (η = 1.000–1.008), series resistance cancellation (up to 300 Ω with beta correction enabled), and auto-ranging beta compensation across 0.1–27 β range. It uses collector-current-controlled sensing instead of emitter-current control to maintain accuracy on low-beta transistors found in modern 90nm+ processors.
Its SMBus interface supports write byte, read byte, send byte, and receive byte commands at up to 3.4 MHz clock frequency, with 25–35 ms timeout and 1 µs SCL-to-SDA timing compliance. Configuration registers (e.g., pointer address 09h for RANGE/SD control, 0Ah for REN2/REN/RC bits) enable per-channel remote enable, conversion rate selection (0.0625–8 conversions/s), and shutdown mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Remote Accuracy | ±1°C max over 0°C to +100°C ambient and –40°C to +150°C diode temp - enables direct thermal throttling without calibration. |
| Local Accuracy | ±1°C max over 0°C to +100°C - provides precise die temperature reference for system-level thermal margining. |
| Interface | SMBus 2.0 compliant (3.4 MHz max) - interoperates with standard motherboard baseboard management controllers (BMCs). |
| Supply Range | 2.7 V to 5.5 V - compatible with 3.3 V and 5 V system rails without level-shifting. |
| Quiescent Current | 45 µA typical at 0.0625 conv/s - supports always-on thermal monitoring in low-power states. |
| Package | SOT23-8 (DCN) - 2.9 mm × 2.8 mm footprint ideal for space-constrained CPU/FPGA proximity placement. |
| Temperature Range | –40°C to +125°C operating - rated for industrial and enterprise server ambient conditions. |
Pinout & Package
SOT23-8 package (DCN marking), 2.9 mm × 2.8 mm body, 0.95 mm height, gull-wing leads, JEDEC MO-178AC compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - DXP1 | Channel 1 remote sensor positive input | Connects to collector (PNP) or anode (diode) of first external transistor/diode; requires <5 Ω series resistance for full accuracy. |
| 2 - DXN1 | Channel 1 remote sensor negative input | Connects to emitter (PNP) or cathode (diode); differential pair rejects common-mode noise on long PCB traces. |
| 3 - DXP2 | Channel 2 remote sensor positive input | Dedicated second channel for dual-core CPU or FPGA + ASIC thermal pairing - no shared bias or timing constraints. |
| 4 - DXN2 | Channel 2 remote sensor negative input | Independent differential input; allows simultaneous measurement of two thermally distinct zones without multiplexing delay. |
| 5 - GND | Analog and digital ground reference | Single ground pin serves both ADC and SMBus I/O; requires low-inductance connection to system ground plane. |
| 6 - SDA | SMBus serial data line (open-drain) | Requires external pull-up to V+; supports multi-drop bus with other SMBus devices (e.g., power monitors, fan controllers). |
| 7 - SCL | SMBus serial clock line (open-drain) | Driven by host controller; 3.4 MHz max clock enables sub-100 ms full 2-channel read cycle including command overhead. |
| 8 - V+ | Positive supply input (2.7–5.5 V) | Decoupled via 0.1 µF ceramic capacitor placed ≤2 mm from pin; powers internal bandgap, ADC, and SMBus logic. |
Key Features
| Feature | Design Value |
|---|---|
| Dual remote + local sensing | Simultaneous monitoring of CPU core, GPU junction, and SoC die temperature in one IC - eliminates need for discrete sensors and reduces BOM count. |
| Automatic beta compensation | Adapts to β drift in PNP transistors (0.1–27 range) across temperature and process variation - maintains ±1°C accuracy without factory calibration or software tuning. |
| Series resistance cancellation | Compensates up to 300 Ω trace resistance (with beta correction enabled) - enables reliable sensing over >10 cm PCB runs without error correction firmware. |
| η-factor correction | Programmable ideality factor (1.000–1.008) matches physical characteristics of 2N3906, BC847, or integrated diodes - eliminates diode model mismatch errors. |
| Diode fault detection | Flags open-circuit, short-circuit, and reverse-bias conditions on either remote channel - prevents false thermal shutdown due to sensor wiring faults. |
Applications
| Processor Thermal Monitoring | FPGA Junction Sensing |
|---|---|
Use Scenario: Real-time temperature tracking of dual-core x86 CPU under variable workload in 1U rack server. IC Role / Device Role / Timing Role: TMP442BDCNT measures local die temperature and remote junctions of each core's integrated PNP transistor via DXP1/DXN1 and DXP2/DXN2. Use Value: Enables dynamic frequency scaling and fan speed control with ±1°C resolution - avoids thermal throttling latency seen with slower single-channel sensors. |
Use Scenario: Thermal profiling of high-density FPGA fabric and I/O banks during bitstream validation in telecom baseband unit. IC Role / Device Role / Timing Role: TMP442BDCNT interfaces with two on-die diodes (one per bank) using dedicated differential inputs, reporting concurrent readings via SMBus burst read. Use Value: Detects localized hotspots exceeding 100°C before configuration lockup - triggers graceful reconfiguration instead of hard reset. |
| LCD Projector Lamp Control | Central Office Telecom Shelf |
Use Scenario: Closed-loop thermal management of UHP lamp driver MOSFETs in DLP® projector light engine. IC Role / Device Role / Timing Role: TMP442BDCNT monitors local IC temperature and remote diodes on two parallel lamp driver stages (DXP1/DXN1 and DXP2/DXN2). Use Value: Maintains lamp color stability by limiting driver duty cycle when either stage exceeds 95°C - extends lamp life by 35% vs fixed-threshold schemes. |
Use Scenario: Ambient and component-level thermal supervision across 14-slot telecom shelf with mixed ASIC/FPGA line cards. IC Role / Device Role / Timing Role: TMP442BDCNT deployed per card (local + 2 remote) feeds temperature data to shelf controller via shared SMBus; A0/A1 pins set unique addresses. Use Value: Enables per-card thermal derating and predictive fan control - reduces shelf-wide cooling power by 22% while meeting GR-63-CORE airflow requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-channel remote temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6642AESA+ | Single remote + local channel; SMBus interface; ±2°C remote accuracy (0°C to +85°C); no beta compensation. | Limited to single-point monitoring; requires external calibration for processor diodes; no support for low-beta transistors. | Select when only one remote zone is needed and cost sensitivity outweighs accuracy requirements. |
| LM95235CIMM/NOPB | Dual remote + local; SPI interface only; ±1.5°C remote accuracy; no automatic beta compensation; 10-bit resolution. | Requires SPI host resource; lacks SMBus compatibility with standard BMCs; lower resolution increases quantization error in fine-grained control loops. | Choose for SPI-based embedded controllers where SMBus is unavailable and ±1.5°C tolerance is acceptable. |
Compared with MAX6642AESA+ and LM95235CIMM/NOPB, the TMP442BDCNT uniquely delivers dual remote sensing with ±1°C accuracy, automatic beta compensation, and native SMBus integration - making it the only option qualified for uncalibrated, high-accuracy thermal management in modern multi-core servers and telecom systems.
Availability
TMP442BDCNT is available at Aetrix Electronics and suitable for server thermal management, FPGA-based industrial controllers, LCD/DLP projector lamp regulation, and central office telecom equipment requiring stable component supply across extended product lifecycles.
Supply support for TMP442BDCNT 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 leadership in precision temperature sensing.
The TMP442BDCNT belongs to TI's high-accuracy remote diode sensor product line, designed specifically for thermal monitoring of microprocessors, FPGAs, and ASICs in enterprise, telecom, and projection systems where calibration-free operation and SMBus interoperability are critical.
FAQ
What is the remote temperature accuracy specification for TMP442BDCNT?
The TMP442BDCNT achieves ±1°C maximum remote temperature error over 0°C to +100°C ambient temperature and –40°C to +150°C diode temperature, as specified in the Electrical Characteristics table under TEREMOTE condition. This accuracy holds across multiple IC manufacturers' transistors without calibration, thanks to automatic beta compensation and η-factor correction. The TMP442BDCNT maintains this performance using its dual-channel DXP1/DXN1 and DXP2/DXN2 inputs with series resistance cancellation.
Does TMP442BDCNT support SMBus 2.0 or only SMBus 1.1?
The TMP442BDCNT fully supports SMBus 2.0, including write byte, read byte, send byte, and receive byte commands, with a maximum clock frequency of 3.4 MHz and 25–35 ms timeout. Its electrical interface meets SMBus 2.0 voltage thresholds (VIH ≥ 2.1 V, VIL ≤ 0.8 V) and timing requirements (SCL falling edge to SDA valid ≤ 1 µs). The TMP442BDCNT operates reliably on standard motherboard SMBus buses alongside other TI and third-party SMBus peripherals.
How does TMP442BDCNT handle low-beta transistors in modern processors?
The TMP442BDCNT uses collector-current-controlled sensing and automatic beta compensation to maintain ±1°C accuracy with transistors having β as low as 0.1 - common in 90nm and smaller process nodes. It detects β range dynamically at the start of each conversion and selects optimal bias current (120 µA high / 6 µA low) and series resistance cancellation (up to 300 Ω). This eliminates manual calibration required by legacy sensors and ensures consistent performance across CPU generations. The TMP442BDCNT implements this via its Beta Compensation Register (pointer 0Ch) and RC bit in Configuration Register 2.
What is the function of pins A0 and A1 on TMP442BDCNT?
The TMP442BDCNT does not include A0 or A1 pins - those are present on the TMP441 variant (single remote channel) for SMBus address selection. The TMP442BDCNT uses fixed SMBus addresses: TMP442A = 100 1100b (0x4C), TMP442B = 100 1101b (0x4D). Its SOT23-8 pinout is DXP1, DXN1, DXP2, DXN2, GND, SDA, SCL, V+. Confusion may arise from the TMP441 datasheet excerpt; the TMP442BDCNT pin assignment is confirmed in Figure 6 and Table "TMP442 PIN ASSIGNMENTS" of SBOS425A.
Can TMP442BDCNT measure temperatures beyond +125°C ambient?
Yes - the TMP442BDCNT is rated for operation from –40°C to +125°C ambient, but its remote diode channel measures up to +150°C, and its extended temperature mode (RANGE bit = 1 in Configuration Register 1) supports remote readings from –64°C to +191°C. Local die temperature measurement also extends to +127°C in default mode and +191°C in extended mode. However, absolute maximum junction temperature remains +150°C, so sustained operation above +125°C ambient requires thermal design verification to ensure TJ < +150°C. The TMP442BDCNT's thermal resistance (θJA = 170°C/W) must be considered in PCB layout.
TMP442BDCNT 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 ~ 125°C
- Sensing Temperature - Remote:
- -64°C ~ 191°C
- Output Type:
- SMBus
- Voltage - Supply:
- 2.7V ~ 5.5V
- Resolution:
- 11 b
- Features:
- One-Shot, Shutdown Mode
- Accuracy - Highest (Lowest):
- ±1°C (±2.5°C)
- Test Condition:
- 0°C ~ 100°C (-40°C ~ 125°C)
- Operating Temperature:
- -55°C ~ 127°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- SOT-23-8
TMP442BDCNT FAQ
1.How can I place an order for TMP442BDCNT through Aetrix?
Please submit a Request for Quotation (RFQ) for TMP442BDCNT 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 TMP442BDCNT reliable?
The price and inventory of TMP442BDCNT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TMP442BDCNT is usually 5 days.
3.What payment methods are accepted for TMP442BDCNT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TMP442BDCNT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TMP442BDCNT?
TMP442BDCNT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TMP442BDCNT 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 TMP442BDCNT?
For technical support, including TMP442BDCNT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TMP442BDCNT requirements.
6.How does Aetrix verify that TMP442BDCNT is sourced from the original manufacturer or authorized distributors?
All TMP442BDCNT 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 TMP442BDCNT meets industry standards.
7.What is the process for return or replacement of TMP442BDCNT?
All TMP442BDCNT units undergo pre-shipment inspection (PSI). If there is an issue with TMP442BDCNT, 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 TMP442BDCNT part is unused and in its original packaging.
Return procedure for TMP442BDCNT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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