Texas Instruments LM4132CMFX-3.3

Overview

LM4132CMFX-3.3 from Texas Instruments is a precision low-dropout (LDO) voltage reference IC delivering a stable 3.3 V output with 0.05% initial accuracy (A-grade), 10 ppm/°C temperature coefficient (0°C to 85°C), and 60 µA quiescent current. It operates from VIN = VREF + 400 mV to 5.5 V, supports up to 20 mA load current, and features an enable pin for 3 µA shutdown mode-ideal for battery-powered instrumentation and data acquisition systems.

For engineers reviewing the LM4132CMFX-3.3 datasheet, LM4132CMFX-3.3 pinout, LM4132CMFX-3.3 application, or LM4132CMFX-3.3 equivalent, key selection criteria include dropout voltage (175 mV at 10 mA), 0.1–10 Hz noise (310 µV_PP), line regulation (85 ppm/V), thermal hysteresis (75 ppm), and SOT-23-5 package compatibility in space-constrained designs.

Technical Context

The LM4132CMFX-3.3 uses EEPROM-trimmed CMOS band-gap architecture to achieve laser-trimmed bipolar-level precision without laser trimming, correcting curvature, tempco, and accuracy at package level to overcome assembly-induced shifts. Its internal LDO regulator eliminates need for output buffer or mandatory C_OUT, unlike traditional shunt references.

It implements a dedicated enable input (pin 3) with VIH = 65% VIN and VIL = 35% VIN, supporting seamless power sequencing in multi-rail systems. The no-connect (N/C) pin (pin 1) is electrically isolated and must remain floating per TI's pin function specification.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, gull-wing leads. RoHS-compliant, moisture sensitivity level 1 (MSL-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with REF3333AIDBVR and ADR3433ARJZ-R7, LM4132CMFX-3.3 uniquely combines A-grade 0.05% accuracy, 10 ppm/°C tempco, enable-controlled 3 µA shutdown, and 20 mA drive-all in SOT-23-5-making it optimal for high-precision, power-gated industrial and automotive systems where both accuracy and dynamic power management are mandatory.

Availability

LM4132CMFX-3.3 is available at Aetrix Electronics and suitable for portable instrumentation, automotive engine control units, and industrial data loggers requiring stable component supply with guaranteed long-term availability and traceable lot-level documentation.

Supply support for LM4132CMFX-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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in precision analog ICs and automotive-grade components.

The LM4132 family was designed to deliver laser-trimmed reference performance using cost-effective, EEPROM-programmable CMOS processes-targeting high-accuracy, low-power, and automotive-qualified applications where stability and manufacturability are critical.

FAQ

What is the maximum load current supported by the LM4132CMFX-3.3?

The LM4132CMFX-3.3 delivers up to 20 mA of output current while maintaining regulation and specified accuracy. This capability eliminates the need for external buffer amplifiers in most 12-bit to 16-bit ADC reference applications. At 10 mA load, dropout remains 175 mV, and output voltage deviation stays within ±0.5% across temperature and line variations. The LM4132CMFX-3.3 is not rated for continuous 25 mA operation-only the automotive-grade LM4132-3.3-Q1 variant supports that level.

Does the LM4132CMFX-3.3 require an output capacitor (COUT) for stability?

No, the LM4132CMFX-3.3 is internally compensated and stable without an output capacitor. TI's datasheet explicitly states C_OUT is optional, and the device performs reliably with only the required input capacitor (C_IN ≥ 1 µF ceramic). Adding C_OUT may improve transient response in high-dynamic-load scenarios but is never mandatory-unlike many older voltage references that demand specific ESR or capacitance values.

What is the purpose of the N/C pin (Pin 1) on the LM4132CMFX-3.3?

Pin 1 of the LM4132CMFX-3.3 is a true no-connect (N/C) terminal-electrically isolated from all internal circuitry and not bonded to the die. TI's Pin Functions table mandates it be left floating with no PCB trace or solder connection. Connecting or grounding Pin 1 may cause unpredictable behavior or violate absolute maximum ratings, as it serves no functional role and exists solely for mechanical symmetry in the SOT-23-5 package layout.

How does the enable pin (EN) of the LM4132CMFX-3.3 behave during power-up?

The LM4132CMFX-3.3 enable pin (Pin 3) is active-high with hysteresis: VIH = 65% VIN and VIL = 35% VIN. During power ramp, the device remains in shutdown until VIN reaches ~1.2 V (assuming 3.3 V target) and EN exceeds 65% of that rising VIN. This prevents erratic turn-on during brown-out conditions. Once enabled, the reference settles to final value in <100 µs-verified in TI's Figure 8 (Turnon Transient Response).

Is the LM4132CMFX-3.3 suitable for automotive applications?

The LM4132CMFX-3.3 is not AEC-Q100 qualified. Only the LM4132-3.3-Q1 variants (e.g., LM4132CQMF3.3/NOPB) carry AEC-Q100 Grade 1 certification for –40°C to +125°C operation. While the LM4132CMFX-3.3 shares identical electrical specs and SOT-23-5 packaging, its qualification status is limited to commercial/industrial use. For automotive ECUs, ADAS modules, or infotainment systems, the Q1 version must be selected to meet functional safety and reliability requirements.