Texas Instruments REF2940AIDBZR

Overview

REF2940AIDBZR from Texas Instruments is a precision CMOS band-gap voltage reference delivering 4.096 V output with ±2% initial accuracy, 100 ppm/°C max temperature drift, 1 mV typical dropout voltage, and 50 µA maximum quiescent current in a 3-pin SOT-23 package-designed for high-accuracy ADC biasing in portable data acquisition systems.

For engineers reviewing the REF2940AIDBZR datasheet, REF2940AIDBZR pinout, REF2940AIDBZR application, or REF2940AIDBZR equivalent, this page delivers verified electrical specs, thermal behavior, load regulation performance, and real-world implementation guidance for low-power, wide-temperature industrial and medical sensing designs.

Technical Context

The REF2940AIDBZR implements a curvature-compensated band-gap topology using two bipolar transistors (Q1, Q2) biased at different current densities to generate a PTAT voltage across R1, which is amplified and summed with a CTAT base-emitter voltage-yielding a stable 4.096 V output over –40°C to 125°C. It operates without mandatory output capacitance but remains stable with any capacitive load.

Its ultra-low dropout (1 mV unloaded, ≤50 mV at 25 mA) enables operation from supplies as low as V_OUT + 50 mV, while its 50 µA max I_Q and 25 mA output current support battery-powered precision signal chains where supply headroom and power budget are constrained.

Key Specifications

Pinout & Package

SOT-23 (DBZ) package: 2.92 mm × 1.30 mm body, 3-pin surface-mount, JEDEC MO-178AA compliant. Thermal resistance R_θJA = 297.3°C/W enables operation up to 125°C ambient with minimal derating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage reference applications.

Compared with ADR3440ARJZ-R7 and MAX6126AASA41+, REF2940AIDBZR offers the smallest footprint and lowest I_Q among 4.096 V references, trading absolute accuracy for integration and power efficiency-making it optimal for space- and energy-constrained embedded systems where ±2% is sufficient post-calibration.

Availability

REF2940AIDBZR is available at Aetrix Electronics and suitable for portable data acquisition, medical vital sign monitors, and industrial sensor transmitters requiring stable component supply with guaranteed long-term manufacturability.

Supply support for REF2940AIDBZR 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 and embedded processing technologies, with over 50 years of innovation in precision analog ICs and power management solutions.

The REF29xx family was engineered specifically for low-power, high-accuracy voltage referencing in battery-operated and wide-temperature industrial systems-prioritizing micro-size packaging, ultra-low dropout, and robust thermal performance without external components.

FAQ

What is the minimum input voltage required for stable operation of REF2940AIDBZR?

The REF2940AIDBZR requires a minimum input voltage of V_OUT + 50 mV (i.e., 4.146 V) under loaded conditions (up to 25 mA), and as low as V_OUT + 1 mV (4.097 V) when unloaded. This ultra-low dropout enables direct use from aging Li-ion cells or low-headroom 5 V rails without pre-regulation. The REF2940AIDBZR datasheet specifies VIN ≥ 4.146 V for full-load operation across –40°C to 125°C.

Does REF2940AIDBZR require an output capacitor for stability?

No, REF2940AIDBZR does not require an output capacitor for stability-it is designed to remain stable with any capacitive load, including 0 µF. However, TI recommends a 0.47 µF ceramic bypass capacitor on the IN pin to maintain PSRR above 60 dB up to 100 kHz. Adding output capacitance may reduce high-frequency noise but is never mandatory for loop stability.

How does the 100 ppm/°C temperature drift of REF2940AIDBZR impact 12-bit ADC accuracy?

Over the full –40°C to 125°C range, the 100 ppm/°C drift introduces up to ±49 ppm (≈±0.2 mV) error in the 4.096 V output-equivalent to ±0.49 LSB for a 12-bit ADC with 4.096 V full scale. This remains within the ±0.5 LSB total unadjusted error budget for many industrial sensors, especially when combined with one-time factory calibration at 25°C.

Can REF2940AIDBZR drive a 24-bit delta-sigma ADC like the ADS1262?

Yes, REF2940AIDBZR can directly drive the ADS1262's reference input, which draws ≤100 µA typical. With 25 mA max output current and 3–100 µV/mA load regulation, REF2940AIDBZR maintains <±1 mV shift across the ADS1262's dynamic current profile. Its 45 µV_PP (0.1–10 Hz) noise also supports >100 dB SNR in low-speed precision measurements.

What is the long-term stability specification for REF2940AIDBZR?

REF2940AIDBZR exhibits 24 ppm drift over the first 1000 hours and an additional 15 ppm from 1000 to 2000 hours-totaling 39 ppm over 2000 hours (≈3 months). This corresponds to ~0.16 mV drift at 4.096 V, making it suitable for field-deployed equipment requiring recalibration intervals longer than 1 year.