Texas Instruments LM94021BIMG

Overview

LM94021BIMG from Texas Instruments is a precision analog-output CMOS temperature sensor with four selectable gain settings (−5.5, −8.2, −10.9, −13.6 mV/°C), operating from 1.5V to 5.5V supply over −50°C to +150°C. It delivers inverse-proportional voltage output, features 9 μA typical supply current, short-circuit protected analog output, and is housed in an ultra-small 5-pin SC70 package. It is widely used in battery-powered thermal monitoring for automotive and portable electronics.

For engineers reviewing the LM94021BIMG datasheet, LM94021BIMG pinout, LM94021BIMG application, or LM94021BIMG equivalent, key selection criteria include its multi-gain flexibility, low-voltage operation down to 1.5V, ±1.5°C accuracy from 20°C to 40°C, SC70 footprint compatibility with LM20, and direct logic-level gain control without external resistors.

Technical Context

The LM94021BIMG implements a CMOS-based bandgap-derived temperature-to-voltage transducer with digitally selectable gain via two logic inputs (GS1, GS0). Its output is inherently inverse-proportional to temperature and exhibits parabolic nonlinearity compensated by factory-characterized transfer tables.

It uses rail-to-rail NMOS/PMOS output buffering, enabling stable operation across full supply range (1.5V–5.5V) while maintaining monotonicity. Self-heating error is minimized by ultra-low 9 μA quiescent current and 415°C/W θ_JA, yielding <0.025°C junction rise under typical load conditions.

Key Specifications

Pinout & Package

The LM94021BIMG is packaged in a 5-pin SC70 (DCK0005A) with exposed pad not connected internally; GND pin (Pin 2) serves as thermal reference and die backside connection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM20BIM7/NOPB and TSI202YFDT, the LM94021BIMG uniquely supports real-time gain switching for adaptive noise performance and extended low-voltage operation - critical for battery-constrained and high-SNR thermal sensing designs.

Availability

LM94021BIMG is available at Aetrix Electronics and suitable for automotive cabin control, battery pack thermal monitoring, and industrial motor protection requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM94021BIMG 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 delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The LM94021BIMG belongs to TI's precision analog temperature sensor product line, designed specifically for applications demanding wide operating range, low-power analog output, and configurable sensitivity without external components.

FAQ

What is the operating temperature range of the LM94021BIMG?

The LM94021BIMG operates from −50°C to +150°C. This full industrial and automotive-grade range is validated across all four gain configurations and supply voltages from 1.5V to 5.5V. The device maintains specified accuracy limits within this range, with ±2.7°C maximum error over the entire span - making it suitable for under-hood, motor, and power electronics thermal monitoring where extreme ambient conditions occur.

How does the LM94021BIMG achieve selectable gain without external components?

The LM94021BIMG uses two dedicated logic inputs - GS0 (Pin 1) and GS1 (Pin 5) - to select one of four factory-trimmed gain slopes: −5.5, −8.2, −10.9, or −13.6 mV/°C. These inputs accept direct connection to VDD or GND, or can be driven by microcontroller GPIO pins. No pull-up or pull-down resistors are required because internal threshold logic (VIL ≤0.5V, VIH ≥VDD−0.5V) ensures reliable recognition across the full 1.5V–5.5V supply range.

Is the LM94021BIMG pin-compatible with the LM20 temperature sensor?

Yes, the LM94021BIMG is footprint-compatible with the LM20 in the SC70-5 package. Pin assignments match exactly: GS0 = LM20's V_OUT, GND = GND, OUT = V_OUT, VDD = V_CC, GS1 = unused (NC on LM20). This allows mechanical drop-in replacement in existing layouts, though firmware must be updated to configure gain select lines and interpret the inverse-proportional output polarity.

What is the maximum capacitive load the LM94021BIMG can drive directly?

The LM94021BIMG can drive up to 1100 pF of capacitive load directly without oscillation or settling degradation, as confirmed in the datasheet's Figure 14 and Electrical Characteristics table. For loads exceeding 1100 pF - such as long traces or high-input-capacitance ADCs - a small series resistor (e.g., 10–100 Ω) should be added at the output per Figure 15 to maintain stability and minimize noise coupling.

Does the LM94021BIMG require a bypass capacitor on its VDD pin?

No, the LM94021BIMG does not require a bypass capacitor on VDD. Its CMOS architecture draws only 9 μA quiescent current with no significant transient current spikes, eliminating the need for local decoupling. Bench testing confirms stable operation even with bypass capacitance located up to 6 inches away - enabling simplified layout and reduced component count in space-constrained designs.