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Texas Instruments LM45CIM3X
- Part No.:
- LM45CIM3X
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM45CIM3X.pdf
- Description:
- SENSOR ANALOG -20C-100C SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,398
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Product details
Overview
LM45CIM3X from Texas Instruments is a precision analog centigrade temperature sensor in SOT-23-3 package, delivering linear +10.0 mV/°C output voltage with ±3°C accuracy over −20°C to +100°C, <120 μA quiescent current, and 20Ω output impedance - used for direct analog temperature monitoring in battery-powered medical instruments and HVAC control circuits.
For engineers reviewing the LM45CIM3X datasheet, LM45CIM3X pinout, LM45CIM3X application, or LM45CIM3X equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation value, and two confirmed alternative parts with documented functional and parametric differences.
Technical Context
The LM45CIM3X integrates a trimmed silicon bandgap temperature-sensing element and a low-offset operational amplifier in a monolithic IC, enabling direct Celsius-to-voltage conversion without external calibration. Its output voltage is defined as VOUT = (10 mV/°C × T°C) + VOFFSET, where VOFFSET is factory-trimmed to yield −200 mV at −20°C and +1000 mV at +100°C in full-range configuration.
It operates from a single +4.0V to +10V supply, draws ≤120 μA, and exhibits ≤0.8°C nonlinearity over temperature. Thermal self-heating is limited to 0.20°C in still air due to low power dissipation and direct die-to-GND thermal path via the exposed substrate.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Scale Factor | +10.0 mV/°C - enables direct analog-to-Celsius conversion with 100 mV per 10°C resolution; no scaling resistors needed for basic readout. |
| Accuracy | ±3°C over −20°C to +100°C - guaranteed error bound for closed-loop thermal control in industrial HVAC and printer thermal management. |
| Supply Voltage Range | +4.0V to +10V - supports operation from single Li-ion cell (3.7V nominal) with headroom, or standard 5V/9V rails without regulation. |
| Quiescent Current | ≤120 μA - allows >1-year battery life in portable medical thermometers using CR2032 (220 mAh). |
| Output Impedance | 20Ω at 1 mA load - drives 10 kΩ ADC input or op-amp buffer directly without gain-stage isolation. |
| Nonlinearity | ±0.8°C max - ensures <1% full-scale error across operating range; sufficient for fan-speed control and thermal shutdown thresholds. |
| Self-Heating Error | 0.20°C in still air - negligible impact on surface temperature measurement when mounted on PCB copper pour or heat sink. |
Pinout & Package
SOT-23-3 (DBZ0003A) package: 2.9 mm × 1.3 mm × 1.12 mm body, gull-wing leads, RoHS-compliant matte tin (Sn) finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (GND) | Ground reference and thermal sink | Die substrate connected directly to pin; serves as primary thermal conduction path to PCB ground plane for accurate case-temp tracking. |
| 2 (VOUT) | Analog voltage output | Low-impedance buffered output delivering 10 mV/°C linear signal; compatible with 12-bit SAR ADCs sampling at ≥1 kSPS without anti-alias filtering. |
| 3 (VS) | Positive supply input | Accepts 4.0–10V DC; internal regulator rejects supply ripple up to 1.2 mV/V line regulation - stable output under noisy 5V SMPS rails. |
Key Features
| Feature | Design Value |
|---|---|
| Calibrated in °C | No system-level calibration required; eliminates production test time and firmware compensation tables in embedded thermal monitors. |
| Wafer-level trimming | Enables ±3°C accuracy without post-packaging adjustment - reduces BOM count and assembly cost vs. discrete thermistor+ADC solutions. |
| Low self-heating | 0.20°C rise in still air ensures <0.25°C measurement uncertainty when attached to heatsinks or motor windings. |
| Full-range operation | Valid output from −20°C to +100°C enables use in automotive cabin sensors and industrial power supply thermal derating circuits. |
| Remote sensing capability | Can be mounted inside sealed metal tubes or epoxy-coated for immersion in coolant or oil - validated in disk drive and HVAC refrigerant monitoring. |
Applications
| Battery-Powered Medical Thermometers | HVAC Zone Temperature Control |
|---|---|
|
Use Scenario: Measuring patient skin or ambient room temperature in handheld clinical thermometers with CR2032 battery. IC Role / Device Role / Timing Role: Analog temperature transducer converting thermal energy to linear voltage for microcontroller ADC sampling. Use Value: 120 μA current draw extends battery life beyond 500 measurements per cell; ±3°C accuracy meets ISO 80601-2-56 clinical requirements for Class II devices. |
Use Scenario: Monitoring return-air temperature in duct-mounted HVAC controllers to modulate blower speed and compressor staging. IC Role / Device Role / Timing Role: Primary temperature feedback sensor in closed-loop thermal regulation circuit with 10 mV/°C analog interface to HVAC MCU. Use Value: Full −20°C to +100°C range covers extreme duct conditions; low output impedance drives long traces to remote controller without signal degradation. |
| Printer Engine Thermal Management | Power Supply Module Thermal Derating |
|
Use Scenario: Sensing fuser roller temperature in laser printers to prevent overheating and ensure consistent toner adhesion. IC Role / Device Role / Timing Role: Centigrade temperature sensor providing real-time thermal feedback to printer SoC for PID-controlled heater lamp regulation. Use Value: ±0.8°C nonlinearity prevents false thermal shutdown during rapid warm-up; self-heating <0.2°C avoids measurement lag during high-duty-cycle printing. |
Use Scenario: Monitoring heatsink temperature in 48V telecom power supplies to throttle output current before thermal runaway. IC Role / Device Role / Timing Role: Analog thermal monitor interfacing with PMBus-compatible digital controller via external ADC for thermal derating logic. Use Value: Guaranteed ±3°C accuracy at +100°C ensures reliable derating activation at 95°C threshold; 20Ω output drives RC filter for noise immunity in EMI-heavy PSU environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar analog centigrade temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM35DMX/NOPB | Wider operating range (−55°C to +150°C), ±0.5°C typical accuracy at 25°C, but ±2°C max over full range; higher 50 μA quiescent current. | Better suited for automotive under-hood or industrial oven monitoring where extended temperature range is critical. | Select LM35DMX/NOPB only if −55°C or +150°C operation is required; LM45CIM3X remains preferred for cost-sensitive, battery-powered designs needing <120 μA IQ. |
| TSIC506-200 | Digital I²C output, ±0.5°C accuracy, integrated 12-bit ADC, 3.3V-only supply, 15 μA sleep current - no analog output or external ADC needed. | Ideal for systems with I²C bus and firmware support; eliminates analog routing and calibration but requires digital interface resources. | Choose TSIC506-200 when digital integration, higher accuracy, and ultra-low sleep current outweigh need for analog simplicity and wide supply voltage. |
Compared with LM35DMX/NOPB and TSIC506-200, the LM45CIM3X offers the lowest quiescent current among analog-output centigrade sensors in SOT-23, maintains guaranteed ±3°C accuracy over its specified −20°C to +100°C range without calibration, and supports flexible 4–10V supply operation - making it optimal for cost-constrained, battery-operated thermal monitoring where analog interface simplicity is prioritized.
Availability
LM45CIM3X is available at Aetrix Electronics and suitable for battery management, portable medical instruments, and HVAC control systems requiring stable component supply, long-term lifecycle continuity, and RoHS-compliant sourcing.
Supply support for LM45CIM3X 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 over 90 years of innovation in precision analog ICs.
The LM45 series was designed specifically for low-cost, high-accuracy analog temperature sensing in consumer, industrial, and computing equipment - emphasizing wafer-level calibration, minimal external components, and direct centigrade output.
FAQ
What is the guaranteed accuracy specification for LM45CIM3X over its full operating temperature range?
The LM45CIM3X guarantees ±3°C accuracy over the full −20°C to +100°C temperature range, as specified in the Electrical Characteristics table of the SNIS117C datasheet. This is measured at the device case temperature under defined load and supply conditions, and applies to all LM45C-grade units including LM45CIM3X/NOPB and LM45CIM3X.
Does LM45CIM3X require external calibration or trimming to achieve its stated accuracy?
No, the LM45CIM3X does not require external calibration or trimming. Its ±3°C accuracy is achieved through wafer-level trimming during manufacturing, as confirmed in the Features and Description sections of the TI datasheet. This eliminates post-assembly calibration steps in production for LM45CIM3X-based designs.
What is the maximum allowable supply voltage for LM45CIM3X, and what happens if it exceeds that limit?
The absolute maximum supply voltage for LM45CIM3X is +12V, as stated in the Absolute Maximum Ratings table. Operation above +12V may cause permanent damage. The recommended operating range is +4.0V to +10V; exceeding +10V risks violating internal biasing limits and degrading long-term stability, even if below the +12V absolute maximum.
Can LM45CIM3X be used in applications requiring measurement below −20°C, such as freezer monitoring?
No, the LM45CIM3X is rated and specified only for −20°C to +100°C operation. While the device may function below −20°C, TI does not guarantee accuracy, linearity, or reliability outside this range. For sub-zero applications like freezer monitoring, the LM35DMX/NOPB (−55°C to +150°C) is a validated alternative.
How does the LM45CIM3X's self-heating affect measurement accuracy in still-air environments?
The LM45CIM3X exhibits less than 0.20°C self-heating in still air, as measured per Figure 4 and stated in the Features list. This means that when mounted on a PCB with minimal copper, the die temperature rises no more than 0.20°C above ambient - a negligible error for most thermal monitoring applications using LM45CIM3X.
LM45CIM3X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Sensor Type:
- Analog, Local
- Sensing Temperature - Local:
- -20°C ~ 100°C
- Sensing Temperature - Remote:
- -
- Output Type:
- Analog Voltage
- Voltage - Supply:
- 4V ~ 10V
- Resolution:
- 10mV/°C
- Features:
- -
- Accuracy - Highest (Lowest):
- ±3°C (±4°C)
- Test Condition:
- 25°C (-20°C ~ 100°C)
- Operating Temperature:
- -40°C ~ 125°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- SOT-23-3
LM45CIM3X FAQ
1.How can I place an order for LM45CIM3X through Aetrix?
Please submit a Request for Quotation (RFQ) for LM45CIM3X 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 LM45CIM3X reliable?
The price and inventory of LM45CIM3X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM45CIM3X is usually 5 days.
3.What payment methods are accepted for LM45CIM3X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM45CIM3X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM45CIM3X?
LM45CIM3X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM45CIM3X 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 LM45CIM3X?
For technical support, including LM45CIM3X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM45CIM3X requirements.
6.How does Aetrix verify that LM45CIM3X is sourced from the original manufacturer or authorized distributors?
All LM45CIM3X 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 LM45CIM3X meets industry standards.
7.What is the process for return or replacement of LM45CIM3X?
All LM45CIM3X units undergo pre-shipment inspection (PSI). If there is an issue with LM45CIM3X, 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 LM45CIM3X part is unused and in its original packaging.
Return procedure for LM45CIM3X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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