Analog Devices Inc./Maxim Integrated MAX6138CEXR41-T

Overview

MAX6138CEXR41-T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed reverse breakdown voltage of 4.096V, ±0.5% initial accuracy, 25ppm/°C max temperature coefficient, and operation over –40°C to +85°C - designed for high-accuracy analog signal conditioning in space-constrained portable systems.

For engineers reviewing the MAX6138CEXR41-T datasheet, MAX6138CEXR41-T pinout, MAX6138CEXR41-T application, or MAX6138CEXR41-T equivalent, key selection criteria include its 4.096V output stability across 73µA–15mA shunt current, low 64µVRMS wideband noise (10Hz–10kHz), SC70-3 package compatibility, and absence of required output capacitance.

Technical Context

The MAX6138CEXR41-T implements a laser-trimmed BiCMOS bandgap core to deliver stable 4.096V reference voltage without series pass elements. Its two-terminal architecture requires only external source resistance (RS) to regulate shunt current between 73µA (min) and 15mA (max), enabling simple integration into high-side or floating reference configurations.

It achieves thermal stability via curvature-compensated bandgap design, with guaranteed 25ppm/°C TC over –40°C to +85°C and long-term drift of ≤120ppm after 1000 hours. Dynamic impedance remains ≤1.0Ω at 1mA/120Hz, ensuring minimal load-induced voltage perturbation.

Key Specifications

Pinout & Package

MAX6138CEXR41-T is housed in a 3-pin SC70-3 surface-mount package (1.8mm × 1.8mm × 0.9mm), occupying 50% less board area than comparable SOT23 references. Pin 3 is NC and must be left floating or tied to Pin 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431ACDBVR and LM4040C41IDBZR, the MAX6138CEXR41-T delivers superior thermal stability (25ppm/°C vs. 100ppm/°C), smaller SC70-3 footprint, and lower wideband noise - making it optimal for high-accuracy, space-constrained, battery-operated instrumentation where long-term drift and layout density are critical.

Availability

MAX6138CEXR41-T is available at Aetrix Electronics and suitable for portable data loggers, industrial 4–20mA transmitters, and medical patient monitors requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6138CEXR41-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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX6138 family was developed to replace larger, less accurate shunt references in space-critical portable and battery-powered systems - delivering high initial accuracy, low temperature drift, and SC70 packaging without sacrificing stability or noise performance.

FAQ

What is the minimum operating current for MAX6138CEXR41-T?

The MAX6138CEXR41-T requires a minimum shunt current of 73µA to maintain regulation at 4.096V across its full temperature range (–40°C to +85°C). This value is specified in the Electrical Characteristics table for the _41 variant under IRMIN (max = 73µA). Operating below this threshold risks loss of reference accuracy and increased sensitivity to load variations.

Does MAX6138CEXR41-T require an external output capacitor?

No, the MAX6138CEXR41-T does not require an external output capacitor for stability. It is explicitly characterized and guaranteed stable with capacitive loads from 0 to 1µF, eliminating the need for compensation components and reducing layout complexity - a key advantage over many competing shunt references.

What is the temperature coefficient specification for MAX6138CEXR41-T?

The MAX6138CEXR41-T has a maximum temperature coefficient of 25ppm/°C over the –40°C to +85°C operating range. This is measured using the "box" method per datasheet Note 2 and applies to all accuracy grades (A/B/C). Typical performance is tighter, often ≤4ppm/°C, but design must accommodate the 25ppm/°C worst-case bound.

Can MAX6138CEXR41-T be used in place of LM4040C41IDBZR?

The MAX6138CEXR41-T shares the same 4.096V output and ±0.5% initial accuracy as LM4040C41IDBZR, but offers significantly better thermal stability (25ppm/°C vs. 100ppm/°C) and a smaller SC70-3 package (1.8mm × 1.8mm vs. SOT23's 2.9mm × 1.6mm). It is a functional upgrade where space and temperature performance are critical - though not pin-compatible due to different pinout and package geometry.

What is the wideband noise performance of MAX6138CEXR41-T?

The MAX6138CEXR41-T exhibits 64µVRMS wideband noise over the 10Hz to 10kHz bandwidth, as measured at 100µA shunt current. This low noise level helps preserve effective number of bits (ENOB) in high-resolution ADC applications and minimizes error in precision analog front-ends where reference noise directly contributes to total system uncertainty.