Texas Instruments LM4040C50QDBZR

Overview

LM4040C50QDBZR from Texas Instruments is a precision micropower shunt voltage reference with 5.0V nominal output, ±0.5% initial accuracy (C grade), 100ppm/°C temperature coefficient, 35μVRMS wideband noise, and operation across –40°C to 125°C. It serves as a stable voltage reference in high-accuracy analog signal chains for industrial sensor interfaces and automotive control modules.

For engineers reviewing the LM4040C50QDBZR datasheet, LM4040C50QDBZR pinout, LM4040C50QDBZR application, or LM4040C50QDBZR equivalent, key selection criteria include guaranteed 5.0V output tolerance over extended temperature, low 45μA minimum cathode current, stability with all capacitive loads, and SOT-23-3 package compatibility with space-constrained PCB layouts.

Technical Context

The LM4040C50QDBZR operates as a two-terminal shunt reference, sinking cathode current (IZ) to maintain a precise 5.0V reverse breakdown voltage (VZ) across its terminals. Its Zener-zap trimmed silicon design delivers tight initial tolerance and low thermal drift without requiring external compensation components.

It exhibits low dynamic impedance (0.9Ω typical at 1mA), enabling stable regulation under varying load conditions, and achieves 35μVRMS noise performance over 10Hz–10kHz - critical for high-resolution ADC biasing and precision DAC references in harsh thermal environments.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: compact 2.92mm × 1.30mm footprint with gull-wing leads, optimized for automated assembly and thermal dissipation in dense layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM4040C50IDBZR, the LM4040C50QDBZR adds 125°C operation for automotive/industrial edge cases; versus REF3050AIDBZR, it offers simpler 2-pin shunt topology and lower minimum current, trading off some noise and tempco performance for robustness and layout simplicity.

Availability

LM4040C50QDBZR is available at Aetrix Electronics and suitable for industrial sensor transmitters, automotive engine control units, and portable data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM4040C50QDBZR 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 decades of expertise in precision reference design and automotive-grade qualification.

The LM4040 family was engineered for high-accuracy, low-power shunt referencing in mission-critical analog signal chains - targeting applications where stability, noise, and thermal resilience outweigh cost or feature density.

FAQ

What is the maximum operating temperature for LM4040C50QDBZR?

The LM4040C50QDBZR is characterized for continuous operation from –40°C to +125°C ambient temperature, making it suitable for under-hood automotive applications and industrial equipment deployed in hot environments. This extended rating is confirmed in Section 4 (Device Comparison Table) and Section 6.7 of the TI datasheet SLOS456Q.

Does LM4040C50QDBZR require an output capacitor?

No, the LM4040C50QDBZR is stable with all capacitive loads and does not require an external output capacitor - a key advantage over many series references. This simplifies layout, reduces component count, and improves reliability in high-noise or space-constrained designs, as explicitly stated in the Features section and Section 3 (Description) of the datasheet.

What is the minimum cathode current needed for LM4040C50QDBZR to regulate properly?

The LM4040C50QDBZR requires a minimum cathode current of 45μA (typical) at 25°C to maintain regulation, rising to 80μA across the full –40°C to 125°C range. This ultra-low requirement enables use in micropower systems such as battery-backed sensors and energy-harvesting nodes, per Electrical Characteristics Table 6.18.

How does the 0.5% initial accuracy of LM4040C50QDBZR translate to actual voltage tolerance at 5.0V?

At 25°C, the LM4040C50QDBZR's ±0.5% initial accuracy corresponds to a guaranteed output voltage range of 4.975V to 5.025V. When combined with its 100ppm/°C temperature coefficient and full-range operation, total tolerance remains within ±1.5% (±75mV) over –40°C to 125°C, as calculated in footnote (2) of Section 6.7.

Is LM4040C50QDBZR pin-compatible with other LM4040 variants in SOT-23-3?

Yes, all LM4040 variants in the DBZ (SOT-23-3) package - including LM4040A/B/C/D grades and 2.048V–10V versions - share identical pinout: Pin 1 = Cathode, Pin 2 = Anode, Pin 3 = NC. This allows drop-in replacement across voltage and accuracy grades without PCB modification, as shown in Figure 5-1 and Table 5-1 of the datasheet.