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Texas Instruments LM45CIM3
- Part No.:
- LM45CIM3
- Manufacturer:
- Texas Instruments
- Category:
- Analog and Digital Output
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
LM45CIM3.pdf
- Description:
- SENSOR ANALOG -20C-100C SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,093
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Product details
Overview
LM45CIM3 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 low self-heating (0.20°C in still air), used for direct board-level thermal monitoring in battery-powered and space-constrained systems.
For engineers reviewing the LM45CIM3 datasheet, LM45CIM3 pinout, LM45CIM3 application, or LM45CIM3 equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative parts with documented functional and accuracy trade-offs.
Technical Context
The LM45CIM3 operates as a two-terminal voltage-output transducer: supply voltage (+VS) and ground establish bias, while the output pin delivers a DC voltage directly proportional to die temperature at 10.0 mV/°C scale factor. It requires no external calibration due to wafer-level trimming and exhibits minimal nonlinearity (±0.8°C max) across its full operating range.
Its internal architecture integrates a bandgap reference and amplifier optimized for low power and low output impedance (20 Ω @ 1 mA load). The device functions with single-supply operation from +4.0 V to +10 V, draws ≤160 μA across voltage and temperature, and maintains stable accuracy without external components in basic configurations like Figure 2 or Figure 3 of the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Scale Factor | +10.0 mV/°C - Enables direct analog-to-temperature conversion with 100 mV per 10°C step; simplifies ADC interface and eliminates lookup tables. |
| Accuracy | ±3°C over −20°C to +100°C - Guarantees worst-case error bound for closed-loop thermal control or safety cutoff decisions in industrial environments. |
| Quiescent Current | ≤120 μA at +25°C - Supports multi-year operation on coin-cell batteries in portable medical instruments or remote sensors. |
| Supply Voltage Range | +4.0 V to +10 V - Compatible with standard 5 V logic rails and higher-voltage industrial supplies without regulation overhead. |
| Self-Heating Error | 0.20°C in still air - Ensures measurement fidelity when mounted directly on PCBs without forced airflow or heatsinks. |
| Nonlinearity | ±0.8°C max over full range - Limits interpolation error in firmware-based temperature compensation algorithms. |
| Output Impedance | 20 Ω @ 1 mA load - Drives 10 nF capacitive loads directly; avoids buffer amplifiers in compact layout designs. |
Pinout & Package
SOT-23-3 (Package Drawing DBZ0003A), 1.12 mm max height, 2.9 mm × 1.3 mm footprint, JEDEC TO-236 compliant. Thermal resistance junction-to-ambient is 260°C/W when mounted on 2 oz. copper PCB per Figure 15.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (GND) | Ground Reference / Thermal Sink | Provides return path and serves as primary thermal conduction path from die to PCB; backside die attachment ensures minimal thermal lag. |
| 2 (VOUT) | Analog Output Terminal | Delivers calibrated voltage proportional to temperature; low impedance enables direct connection to ADC inputs or op-amp stages. |
| 3 (+VS) | Positive Supply Input | Accepts unregulated 4–10 V; internal regulation eliminates need for LDO in battery-fed applications. |
Key Features
| Feature | Design Value |
|---|---|
| Calibrated in °C at wafer level | Eliminates post-assembly trimming; reduces BOM count and test time in high-volume consumer electronics manufacturing. |
| Linear +10.0 mV/°C output | Enables 1:1 scaling in microcontroller ADC firmware-no gain/offset calibration required for basic readout. |
| −20°C to +100°C rated range | Validated for HVAC control panels, printer fuser modules, and automotive cabin ambient sensing where extended industrial range is mandatory. |
| Low self-heating (0.20°C) | Permits surface-mount placement on thermally active PCB traces without significant measurement offset from local power dissipation. |
| Single-supply operation | Removes need for dual-rail supplies in portable devices-simplifies power architecture and reduces component count. |
Applications
| Battery Management Systems | Printers & Copiers |
|---|---|
Use Scenario: Monitoring Li-ion cell pack temperature during charge/discharge cycles to prevent thermal runaway. IC Role / Device Role / Timing Role: Analog temperature transducer providing real-time die temperature feedback to host MCU. Use Value: ±3°C accuracy ensures safe cutoff before critical thresholds; <120 μA current drain extends battery life between calibrations. |
Use Scenario: Measuring fuser roller temperature in laser printers to maintain optimal toner melt consistency. IC Role / Device Role / Timing Role: Centigrade sensor interfaced to thermal controller IC for closed-loop fuser heating. Use Value: Linear 10 mV/°C output allows direct mapping to PWM duty cycle; low self-heating prevents false high-temp readings under sustained load. |
| Portable Medical Devices | HVAC Control Panels |
Use Scenario: Core body temperature estimation in handheld clinical thermometers using surface-mounted sensor on PCB. IC Role / Device Role / Timing Role: Direct-contact temperature sensing element with minimal thermal mass for fast response. Use Value: 0.20°C self-heating enables sub-degree resolution in battery-powered devices; SOT-23-3 footprint fits tight enclosure constraints. |
Use Scenario: Ambient room temperature sensing in wall-mounted thermostats with long-term stability requirements. IC Role / Device Role / Timing Role: Primary temperature reference for PID control algorithm running on embedded MCU. Use Value: ±0.12°C long-term stability after 1000 hours ensures calibration drift remains within spec over 5+ year product lifetime. |
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 | ±0.5°C accuracy at +25°C, ±1.5°C over −40°C to +115°C; 50 μA typical IQ; same SOT-23-3 package. | Better accuracy and wider temp range but higher cost; suited for lab-grade instrumentation where ±1°C error is unacceptable. | Select LM35DMX/NOPB when tighter accuracy and extended low-temp operation (−40°C) are required despite higher unit cost. |
| TSIC306-200 | Digital I²C output; ±0.5°C accuracy; 1.8–5.5 V supply; integrated 12-bit ADC; 3-pin SMD package (not pin-compatible). | Eliminates external ADC but adds firmware dependency; not drop-in-requires I²C bus and digital signal routing changes. | Choose TSIC306-200 when system already uses I²C peripherals and firmware can accommodate digital sensor polling instead of analog sampling. |
Compared with LM45CIM3, LM35DMX/NOPB offers superior accuracy and broader temperature coverage at higher cost and similar analog interface, while TSIC306-200 replaces analog output with digital I²C communication-requiring PCB and firmware redesign but removing ADC resource burden.
Availability
LM45CIM3 is available at Aetrix Electronics and suitable for battery management systems, printers & copiers, and portable medical devices requiring stable component supply, RoHS-compliant packaging, and long-term industrial availability.
Supply support for LM45CIM3 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and consumer markets.
The LM45 series belongs to TI's precision analog sensor product line, designed specifically for low-cost, high-reliability centigrade temperature measurement in space- and power-constrained applications without external calibration.
FAQ
What is the guaranteed accuracy specification for LM45CIM3 across its full operating temperature range?
The LM45CIM3 guarantees ±3°C accuracy over the full −20°C to +100°C operating range, as specified in the Electrical Characteristics table under "Accuracy" for TA = TMIN to TMAX. This limit applies to all units shipped and is tested during production screening-not just typical or room-temperature performance. The LM45CIM3 achieves this without external calibration due to wafer-level trimming.
Can LM45CIM3 operate from a 3.3 V supply?
No, LM45CIM3 requires a minimum supply voltage of +4.0 V per its Operating Ratings. At 3.3 V, the internal circuitry cannot bias correctly, resulting in invalid or saturated output. For 3.3 V systems, consider alternatives such as the TMP36 (2.7–5.5 V) or digital sensors like the TMP102-but note these are not pin-compatible replacements for LM45CIM3.
What is the thermal resistance junction-to-ambient for LM45CIM3 in standard PCB mounting?
The thermal resistance junction-to-ambient for LM45CIM3 is 260°C/W when mounted on a ½″ square PCB with 2 oz. copper foil, as defined in Figure 15 of the datasheet. This value assumes no added heatsink and still-air conditions. Self-heating under 120 μA load results in only ~0.20°C rise, consistent with this thermal resistance and the device's low power dissipation.
Does LM45CIM3 require external capacitors for stability?
LM45CIM3 does not require external capacitors for basic DC temperature measurement. However, the datasheet warns that it can drive only up to 500 pF capacitively without degradation. For longer traces or noisy environments, a series RC damper (e.g., 75 Ω + 0.2 μF to ground) or decoupling resistor is recommended-especially when interfacing with microcontroller ADC inputs or long cables. This is not a stability requirement per se but a noise immunity best practice.
How does the LM45CIM3 differ from the LM45BIM3 variant?
The LM45CIM3 and LM45BIM3 share identical SOT-23-3 packaging and electrical architecture but differ in accuracy grading: LM45CIM3 is specified for ±3°C over −20°C to +100°C, while LM45BIM3 guarantees ±2°C at +25°C and ±3°C over the same full range. Both have identical quiescent current, scale factor, and supply requirements. LM45CIM3 is the cost-optimized grade for applications where ±3°C tolerance is acceptable.
LM45CIM3 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
LM45CIM3 FAQ
1.How can I place an order for LM45CIM3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM45CIM3 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 LM45CIM3 reliable?
The price and inventory of LM45CIM3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM45CIM3 is usually 5 days.
3.What payment methods are accepted for LM45CIM3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM45CIM3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM45CIM3?
LM45CIM3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM45CIM3 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 LM45CIM3?
For technical support, including LM45CIM3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM45CIM3 requirements.
6.How does Aetrix verify that LM45CIM3 is sourced from the original manufacturer or authorized distributors?
All LM45CIM3 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 LM45CIM3 meets industry standards.
7.What is the process for return or replacement of LM45CIM3?
All LM45CIM3 units undergo pre-shipment inspection (PSI). If there is an issue with LM45CIM3, 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 LM45CIM3 part is unused and in its original packaging.
Return procedure for LM45CIM3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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