Texas Instruments LM20CIM7X

Overview

LM20CIM7X from Texas Instruments (formerly National Semiconductor) is a precision analog-output CMOS temperature sensor in SC70-5 package, operating from +2.4 V to +5.5 V with ±5°C accuracy at −55°C to +130°C, 10 μA max quiescent current, and parabolic transfer function VO = (−3.88×10⁻⁶×T²) + (−1.15×10⁻²×T) + 1.8639 V - used for battery-powered thermal monitoring in portable electronics.

For engineers reviewing the LM20CIM7X datasheet, LM20CIM7X pinout, LM20CIM7X application, or LM20CIM7X equivalent, key selection criteria include supply voltage-dependent temperature range (−30°C min at 2.4 V), output impedance ≤160 Ω, load regulation ≤−2.5 mV, nonlinearity ±0.4% typ, and SC70-5 thermal resistance of 415°C/W - all critical for low-power, space-constrained thermal sensing designs.

Technical Context

The LM20CIM7X implements a monolithic CMOS temperature-to-voltage transducer with predictable parabolic curvature, enabling high-accuracy linearization over wide ranges using its published second-order equation. Its output voltage varies from +2485 mV at −55°C to +303 mV at +130°C, with sensor gain of −11.77 mV/°C (min) across −30°C to +100°C.

Thermal self-heating is limited to <0.02°C in still air due to sub-10 μA quiescent current; GND pin (Pin 2) serves as thermal conduction path to PCB ground plane, while NC pin (Pin 1) must remain floating or grounded - no signal routing permitted. The device requires no shutdown circuitry owing to intrinsic ultra-low power operation.

Key Specifications

Pinout & Package

LM20CIM7X uses the SC70-5 molded package (NS Package Number MAA05A), 5-pin surface-mount with 0.65 mm pitch, 2.0 × 1.25 × 0.9 mm body dimensions, and thermal pad on Pin 2 (GND) for board-level heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar analog-output temperature sensor applications.

Compared with LM20BIM7X, LM20CIM7X trades ±2.5°C mid-range accuracy for lower unit cost while retaining identical packaging, supply range, and full −55°C to +130°C operability above 2.7 V; versus TS2012-1.8, LM20CIM7X provides superior low-temperature coverage and user-selectable linearization but requires external ADC and reference.

Availability

LM20CIM7X is available at Aetrix Electronics and suitable for cellular phones, power supply modules, and battery management systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant SC70 packaging.

Supply support for LM20CIM7X 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 acquired National Semiconductor in 2011 and maintains its precision analog portfolio, including high-accuracy temperature sensors, voltage references, and data converters for industrial and portable applications.

The LM20CIM7X belongs to TI's legacy analog temperature sensor product line, designed specifically for ultra-low-power, space-constrained thermal monitoring in battery-operated and thermally sensitive systems.

FAQ

What is the guaranteed temperature measurement accuracy of the LM20CIM7X across its full operating range?

The LM20CIM7X guarantees ±5°C maximum accuracy at both −55°C and +130°C extremes when powered at ≥2.7 V, and ±5°C at +30°C ambient. At 2.4 V supply, the lower limit shifts to −30°C with same ±5°C error bound. This specification is validated per National Semiconductor's AOQL testing and applies under specified load and thermal conditions.

Can the LM20CIM7X operate directly from a single Li-ion battery without regulation?

Yes, the LM20CIM7X operates over +2.4 V to +5.5 V, fully covering the discharge curve of a single Li-ion cell (typically 4.2 V down to 2.7 V). At 2.4 V, it retains functionality from −30°C to +130°C, making it suitable for direct battery connection in portable devices without LDO or regulator overhead.

What is the purpose of the NC pin (Pin 1) on the LM20CIM7X SC70-5 package?

Pin 1 of the LM20CIM7X is designated NC (No Connect) and is not bonded internally. It must be left floating or tied to GND - no signal traces may be routed to it. This pin has no electrical function but maintains mechanical symmetry in the SC70-5 footprint; violating this rule risks thermal or electrical interference with adjacent pins.

How does the LM20CIM7X's parabolic transfer function improve measurement accuracy compared to linear sensors?

The LM20CIM7X's published parabolic equation VO = (−3.88×10⁻⁶×T²) + (−1.15×10⁻²×T) + 1.8639 V reduces linearization error to ±1.41°C over −55°C to +130°C, versus >±5°C for first-order approximations. This enables higher fidelity thermal control in applications like battery management where curvature-induced drift must be minimized.

Is the LM20CIM7X susceptible to optical interference, and how should it be mitigated?

Yes - the LM20CIM7X in micro SMD package exhibits up to 1.5 V output drop under bright sunlight, though SC70-5 variants like LM20CIM7X are not light-sensitive. For LM20CIM7X, no optical shielding is required; however, if used alongside micro SMD variants in same design, enclosure-based light blocking is recommended to ensure consistent behavior across sensor types.