Texas Instruments LM4040C20IDBZT

Overview

LM4040C20IDBZT from Texas Instruments is a precision micropower shunt voltage reference delivering a fixed 2.048 V output with ±10 mV (±0.5%) initial tolerance at 25°C, 100 ppm/°C temperature coefficient, 35 μV_RMS wideband noise, and stable operation from 45 μA to 15 mA cathode current. It serves as a compact, low-drift reference in high-resolution ADC/DAC biasing and sensor signal conditioning circuits.

For engineers reviewing the LM4040C20IDBZT datasheet, LM4040C20IDBZT pinout, LM4040C20IDBZT application, or LM4040C20IDBZT equivalent, key selection considerations include its C-grade accuracy over –40°C to 85°C, SOT-23-3 (DBZ) package compatibility, cathode/anode terminal configuration, and absence of required output capacitance in portable or space-constrained analog designs.

Technical Context

The LM4040C20IDBZT operates as a two-terminal shunt reference, sinking cathode current to maintain a precise reverse breakdown voltage across its terminals. Its Zener-zap trimmed silicon design achieves 0.5% initial accuracy without external components and remains stable under all capacitive loads - eliminating need for output bypass capacitors.

It features low dynamic impedance (0.9 Ω typical at 1 mA), thermal hysteresis of 0.08%, and long-term stability of 120 ppm over 1000 hours. The device is characterized for industrial temperature range (–40°C to 85°C) and uses fuse-based wafer-level trimming to meet C-grade specifications.

Key Specifications

Pinout & Package

SOT-23-3 (DBZ) package: 2.92 mm × 1.30 mm footprint, surface-mount, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL4050C20IDBZR, LM4040C20IDBZT offers tighter temperature stability; compared with REF3020AIDBZR, it enables lower operating current at the cost of reduced initial accuracy - making it optimal for cost-sensitive, space-constrained industrial analog modules requiring robust 0.5% performance.

Availability

LM4040C20IDBZT is available at Aetrix Electronics and suitable for data-acquisition systems, analog input modules, and field transmitters requiring stable component supply with guaranteed long-term sourcing and consistent parametric performance.

Supply support for LM4040C20IDBZT 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 leadership in precision reference design.

The LM4040 series was engineered for high-accuracy, low-power shunt reference applications in industrial, automotive, and portable instrumentation - prioritizing simplicity, stability, and minimal external component count.

FAQ

What is the operating temperature range for LM4040C20IDBZT?

The LM4040C20IDBZT is specified for industrial temperature operation from –40°C to +85°C. Its C-grade accuracy (±0.5% initial tolerance) and 100 ppm/°C temperature coefficient are fully characterized across this range, with overtemperature tolerance of ±1.15% per datasheet Section 6.6.

Does LM4040C20IDBZT require an output capacitor?

No, LM4040C20IDBZT is stable with all capacitive loads and does not require an output capacitor. This simplifies layout and reduces BOM count - a key advantage over series references that mandate minimum output capacitance for stability.

What is the minimum cathode current needed for LM4040C20IDBZT regulation?

The LM4040C20IDBZT requires a minimum cathode current of 45 μA (typical) at 25°C to maintain regulation. At full temperature range (–40°C to 85°C), the maximum specified minimum is 80 μA, ensuring reliable start-up and stability in low-power sensor nodes.

How does the pinout of LM4040C20IDBZT differ from other LM4040 variants?

LM4040C20IDBZT uses the SOT-23-3 (DBZ) package with Pin 1 = Cathode, Pin 2 = Anode, and Pin 3 = NC (no internal connection). Unlike SC-70 or TO-92 variants, the DBZ package omits unused pins - Pin 3 must remain unconnected and floating.

Can LM4040C20IDBZT replace LM4040A20IDBZT in an existing design?

Yes, LM4040C20IDBZT is pin-compatible and functionally interchangeable with LM4040A20IDBZT, but with relaxed initial accuracy (±0.5% vs. ±0.1%) and identical temperature coefficient. Designers should verify that system-level total error budget accommodates the wider tolerance before substitution.