Texas Instruments LM4040D50IDBZR

Overview

LM4040D50IDBZR from Texas Instruments is a precision micropower shunt voltage reference with 5.0V nominal output, ±1.0% initial accuracy (D grade), 150ppm/°C temperature coefficient, 35μVRMS wideband noise, and stable operation from 45μA to 15mA cathode current. It serves as a compact, capacitor-free reference in analog signal chains for industrial data acquisition and field transmitters.

For engineers reviewing the LM4040D50IDBZR datasheet, LM4040D50IDBZR pinout, LM4040D50IDBZR application, or LM4040D50IDBZR equivalent, this page delivers verified specifications, package-confirmed pin functions, real-world use cases, and validated alternative options for cost–performance trade-off analysis in precision analog designs.

Technical Context

The LM4040D50IDBZR operates as a two-terminal shunt reference, sinking cathode current (IZ) to maintain a stable 5.0V reverse breakdown voltage across its terminals. Its Zener-zap trimmed silicon design achieves D-grade tolerance (±1.0% at 25°C) and supports operation over –40°C to 85°C ambient temperature.

It features low dynamic impedance (≤1.1Ω at 1mA), thermal hysteresis of 0.08%, and long-term stability of 120ppm after 1000 hours. No external capacitor is required-stable with all capacitive loads due to inherent compensation.

Key Specifications

Pinout & Package

LM4040D50IDBZR is packaged in SOT-23-3 (DBZ) - a 2.92mm × 1.30mm surface-mount package with gull-wing leads. Pin 1 is Cathode, Pin 2 is Anode, and Pin 3 is the NC (No Connection) terminal, which must be left floating or tied to Anode per TI layout guidance for EMI-sensitive environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL4050C50IDBZR and MAX6005EUR+T, the LM4040D50IDBZR offers the lowest cost and broadest distributor availability for non-critical 5V reference needs, trading accuracy and TC for production scalability and legacy design compatibility.

Availability

LM4040D50IDBZR is available at Aetrix Electronics and suitable for data-acquisition systems, field transmitters, and analog input modules requiring stable component supply with consistent parametric performance across production lots.

Supply support for LM4040D50IDBZR 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 high-volume manufacturing.

The LM4040 series was developed for cost-sensitive, space-constrained applications demanding stable voltage references without external components - targeting industrial automation, energy metering, and portable instrumentation markets.

FAQ

What is the minimum cathode current required for LM4040D50IDBZR to regulate properly?

The LM4040D50IDBZR requires a minimum cathode current of 45μA at 25°C to maintain regulation within specification. At full temperature range (–40°C to 85°C), the minimum increases to 80μA. Below this threshold, output voltage deviates beyond the ±1.0% initial accuracy band. Designers must size the series current-limiting resistor accordingly to guarantee this minimum under worst-case input voltage and load conditions. The LM4040D50IDBZR datasheet specifies these values in Section 6.5–6.9.

Can LM4040D50IDBZR be used without an output capacitor?

Yes - the LM4040D50IDBZR is explicitly designed to be stable with all capacitive loads and requires no output capacitor for proper operation. This is confirmed in the device description and "Features" section of the TI datasheet (SLOS456Q). Unlike many shunt references, its internal compensation ensures stability even when driving large bypass caps (e.g., 10μF ceramic) directly at the cathode node, simplifying layout and reducing BOM count. The LM4040D50IDBZR maintains regulation integrity regardless of downstream capacitance.

What does the 'D' in LM4040D50IDBZR indicate?

The 'D' in LM4040D50IDBZR denotes the device grade: D grade specifies ±1.0% initial output voltage tolerance at 25°C and a maximum temperature coefficient of 150ppm/°C. This grade targets cost-sensitive applications where moderate accuracy suffices - such as non-critical sensor biasing or mid-resolution ADC references. It contrasts with A (±0.1%), B (±0.2%), and C (±0.5%) grades. All grades share identical pinout, package, and functional behavior; only accuracy and TC differ. The LM4040D50IDBZR is the D-grade, 5.0V, industrial-temp, SOT-23 variant.

Is LM4040D50IDBZR suitable for automotive applications?

The LM4040D50IDBZR is qualified for the industrial temperature range (–40°C to +85°C), not the full automotive AEC-Q100 Grade 1 (–40°C to +125°C) range. While it may function in some under-dash environments, TI does not characterize or warrant it for automotive safety-critical systems. For automotive use, consider the LM4040Q series (e.g., LM4040D50QDBZR), which is AEC-Q100 qualified and specified from –40°C to +125°C. The LM4040D50IDBZR remains appropriate for industrial control panels, factory-floor equipment, and commercial energy meters.

How does the NC pin (Pin 3) affect LM4040D50IDBZR performance?

Pin 3 of the LM4040D50IDBZR is a no-connect terminal with no internal bond wire. TI recommends leaving it floating or connecting it directly to the Anode (Pin 2) - especially in high-EMI environments (e.g., near transformers or switching regulators) - to reduce noise coupling into the reference node. This connection does not alter regulation performance but improves immunity to high-frequency interference. The LM4040D50IDBZR's electrical characteristics remain unchanged whether Pin 3 is floated or tied to Anode, as confirmed in the Pin Functions table (Section 5) of the datasheet.