Analog Devices Inc./Maxim Integrated MAX6138AEXR41+T

Overview

MAX6138AEXR41+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed reverse breakdown voltage of 4.096V, 0.1% initial accuracy, 25ppm/°C max temperature coefficient, and operation over –40°C to +85°C. It delivers stable regulation across 73µA to 15mA shunt current in space-constrained portable systems requiring high-accuracy analog-to-digital conversion.

For engineers reviewing the MAX6138AEXR41+T datasheet, MAX6138AEXR41+T pinout, MAX6138AEXR41+T application, or MAX6138AEXR41+T equivalent, this page provides verified specifications, SC70-3 package details, real-world use cases in battery-powered instrumentation, and validated alternative options for voltage reference selection.

Technical Context

The MAX6138AEXR41+T implements a laser-trimmed bandgap core to achieve 4.096V output with ±0.1% tolerance at +25°C and guaranteed stability over –40°C to +85°C. Its low dynamic impedance (0.5–1.0Ω) and wide 73µA–15mA operating current range enable robust regulation under varying load and supply conditions.

Unlike traditional zener references, it requires no external capacitor and remains stable with any capacitive load. Its 64µV_RMS wideband noise (10Hz–10kHz) and <120ppm long-term drift support high-resolution data acquisition where reference integrity directly impacts ADC effective resolution.

Key Specifications

Pinout & Package

MAX6138AEXR41+T is housed in a 3-pin SC70-3 surface-mount package (1.8mm × 1.8mm), 50% smaller than SOT23 equivalents. Pin 3 is No Connection (N.C.) and must be left floating or tied to Pin 2 per datasheet requirement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBVR and ADR3440ARJZ-R7, MAX6138AEXR41+T uniquely balances 0.1% accuracy, 25ppm/°C TC, SC70-3 size, and 73µA minimum current-making it optimal for space- and power-constrained 12–16-bit measurement systems where all three attributes are simultaneously required.

Availability

MAX6138AEXR41+T is available at Aetrix Electronics and suitable for portable data loggers, industrial sensor transmitters, medical wearable ECG front-ends, and automotive cabin air quality monitors requiring stable component supply across extended product lifecycles.

Supply support for MAX6138AEXR41+T 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

Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for demanding industrial, medical, and communications applications, with expertise in low-power, high-accuracy voltage regulation.

The MAX6138 series was developed specifically for space-constrained, battery-operated systems needing high-accuracy shunt references with minimal external components and guaranteed stability across temperature and load.

FAQ

What is the exact output voltage tolerance of MAX6138AEXR41+T at +25°C?

The MAX6138AEXR41+T has a guaranteed reverse breakdown voltage of 4.096V with a tolerance of ±0.1% at +25°C, corresponding to a range of 4.0919V to 4.1001V. This Grade A accuracy is laser-trimmed and fully production-tested, making MAX6138AEXR41+T suitable for applications requiring precise 4.096V reference such as 12-bit ADC full-scale alignment.

Can MAX6138AEXR41+T operate stably without an output capacitor?

Yes, MAX6138AEXR41+T is designed to be stable with any capacitive load and does not require an external output capacitor. Its internal architecture ensures phase margin and transient response remain within specification regardless of output capacitance, simplifying design in battery-backed real-time clock circuits and eliminating capacitor-related aging or ESR concerns in MAX6138AEXR41+T deployments.

What is the minimum shunt current required for MAX6138AEXR41+T to maintain regulation?

The minimum operating shunt current for MAX6138AEXR41+T is 73µA at –40°C to +85°C, as specified in the Electrical Characteristics table for the 4.096V variant. Maintaining at least this current ensures the device remains in reverse breakdown and delivers its rated accuracy and temperature coefficient; going below risks loss of regulation and increased output drift in MAX6138AEXR41+T applications.

How does the noise performance of MAX6138AEXR41+T affect high-resolution ADC systems?

MAX6138AEXR41+T delivers 64µV_RMS wideband noise (10Hz–10kHz), which translates to approximately 14.5 effective number of bits (ENOB) when used with a 16-bit SAR ADC. This low noise floor avoids degrading ADC performance, allowing MAX6138AEXR41+T to serve as a direct reference in precision data acquisition without added filtering stages that introduce offset or drift.

Is Pin 3 of MAX6138AEXR41+T functional or optional?

Pin 3 of MAX6138AEXR41+T is designated N.C. (No Connection) and is not electrically functional. The datasheet explicitly requires Pin 3 to be left floating or connected to Pin 2 (cathode); it must never be driven or loaded. This mechanical-only pin aids in SC70-3 package handling and thermal dissipation but plays no role in MAX6138AEXR41+T electrical operation.