Texas Instruments LM4120IM5-3.3

Overview

LM4120IM5-3.3 from Texas Instruments is a precision micropower low-dropout bandgap voltage reference delivering 3.3 V output with ±0.5% initial accuracy, 50 ppm/°C temperature coefficient, and 120 mV typical dropout at 1 mA load. It features enable control, ±5 mA source/sink capability, and 160 μA typical supply current - designed for high-accuracy analog signal chains in space-constrained portable systems.

For engineers reviewing the LM4120IM5-3.3 datasheet, LM4120IM5-3.3 pinout, LM4120IM5-3.3 application, or LM4120IM5-3.3 equivalent, key selection criteria include dropout performance at low input margins, power-down current (<2 μA), thermal hysteresis (0.5 mV/V), noise (36 µV_PP, 10 Hz–10 kHz), and SOT-23-5 package compatibility with high-density PCB layouts.

Technical Context

The LM4120IM5-3.3 implements a trimmed bandgap core with internal error amplifier and pass transistor, enabling stable 3.3 V reference operation down to VIN = VOUT + 120 mV. Its enable pin controls analog startup via ~6 µA threshold current and logic-level thresholds (V_H = 2.4 V, V_L = 0.4 V), supporting remote on/off without external circuitry.

Designed for industrial temperature range (−40°C to +85°C), it guarantees 50 ppm/°C tempco and ±0.5% initial accuracy across that range. The REF pin is unconnected and must be isolated from noise and capacitance; GND pin current varies with load and temperature, requiring careful layout per TI's mechanical stress mitigation guidelines.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package, 1.60 mm × 2.90 mm body size, RoHS-compliant, tape-and-reel packaging (1000 pcs/reel).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM4120IM5-3.3, LM4040C33IDBZR trades enable functionality and low dropout for simpler biasing, while REF3033AIDBZR offers superior accuracy at the cost of power-down capability - making LM4120IM5-3.3 optimal for portable systems needing both precision and dynamic power control.

Availability

LM4120IM5-3.3 is available at Aetrix Electronics and suitable for portable medical sensors, industrial data loggers, and automotive cabin controllers requiring stable component supply with guaranteed long-term sourcing.

Supply support for LM4120IM5-3.3 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 specializing in analog and embedded processing technologies, with decades of leadership in precision reference design and high-reliability manufacturing.

The LM4120 product line delivers micropower, low-dropout voltage references for battery-operated and space-constrained systems where accuracy, thermal stability, and dynamic power control are critical.

FAQ

What is the maximum input voltage rating for LM4120IM5-3.3?

The absolute maximum input voltage for LM4120IM5-3.3 is 14 V. Operating above this risks permanent damage. For reliable long-term operation, TI specifies a recommended maximum of 12 V under normal conditions - well within the device's 2 V to 12 V operating range. This headroom supports transient suppression in noisy industrial environments without derating concerns.

Does LM4120IM5-3.3 require an external output capacitor, and what value is recommended?

Yes, LM4120IM5-3.3 requires an external output capacitor for stability and transient response. TI specifies a minimum of 0.022 µF ceramic, with optimal range 0.022 µF to 0.047 µF. Capacitors larger than 0.047 µF must be tantalum, and values up to 1 µF are permitted with appropriate layout precautions. The LM4120IM5-3.3 remains stable across this range when layout guidelines for REF pin isolation and grounding are followed.

How does the enable pin function on LM4120IM5-3.3, and what are its voltage thresholds?

The enable pin on LM4120IM5-3.3 is an analog input controlling device startup and shutdown. It requires ≥2.4 V (V_H) for normal operation and ≤0.4 V (V_L) to enter power-down mode. During activation, ~6 µA current flows into the pin. Floating the pin is not recommended - tie to VIN for always-on operation or to MCU GPIO for controlled sequencing. The LM4120IM5-3.3 draws <2 μA in shutdown, enabling aggressive power gating.

What is the thermal hysteresis specification for LM4120IM5-3.3, and why does it matter?

LM4120IM5-3.3 has a thermal hysteresis of 0.5 mV/V over −40°C to +125°C - meaning output voltage may shift up to 1.65 mV (0.5 mV/V × 3.3 V) after repeated thermal cycling. This matters in applications requiring repeatable measurements after temperature excursions, such as field-deployed environmental monitors. Unlike long-term drift, hysteresis is non-cumulative and resets with each thermal cycle.

Can LM4120IM5-3.3 drive a 10 kΩ load directly, and what is the resulting load regulation error?

Yes, LM4120IM5-3.3 can drive a 10 kΩ load (330 µA at 3.3 V) within its ±5 mA capability. Load regulation is specified at 0.03–0.08 %/mA over 0–1 mA, translating to ≤0.033% error (≈1.1 mV) for this load. At full 5 mA, error remains ≤0.04 %/mA, confirming robust performance across its rated output range - critical for driving multiple op-amp inputs or ADC references simultaneously.