Analog Devices Inc./Maxim Integrated MAX6138BEXR50+T

Overview

MAX6138BEXR50+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed 5.000V reverse breakdown voltage, 0.2% initial accuracy, 25ppm/°C max temperature coefficient, and 60μA–15mA operating current range. It delivers stable reference voltage in space-constrained battery-powered systems such as portable instrumentation and industrial sensor front-ends.

For engineers reviewing the MAX6138BEXR50+T datasheet, MAX6138BEXR50+T pinout, MAX6138BEXR50+T application, or MAX6138BEXR50+T equivalent, key selection criteria include shunt-current compliance, low-noise performance (80µVRMS), SC70-3 package footprint, and guaranteed stability without output capacitors across capacitive loads.

Technical Context

The MAX6138BEXR50+T implements a laser-trimmed bandgap core in BiCMOS process to achieve precise 5.000V reverse breakdown with ±0.2% tolerance at +25°C and monotonic drift over –40°C to +85°C. Its dynamic impedance remains ≤1.1Ω at 1mA/120Hz, enabling tight regulation under varying load currents.

Unlike series references, it operates as a two-terminal shunt device requiring external source resistance (RS) to set bias current-enabling flexible integration into high-side or floating reference topologies. It exhibits no minimum output capacitance requirement and remains stable with any capacitive load up to 1µF.

Key Specifications

Pinout & Package

MAX6138BEXR50+T is housed in a 3-pin SC70-3 surface-mount package (1.8mm × 1.8mm × 0.9mm), 50% smaller than comparable SOT23 devices. Pin 3 is No Connect (N.C.) 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 LM4040C50IDBZR, MAX6138BEXR50+T provides tighter initial accuracy (0.2% vs. ≥0.5%), lower temperature coefficient (25ppm/°C vs. ≥100ppm/°C), and superior noise performance (80µVRMS vs. ≥120µVRMS), making it optimal for high-fidelity analog signal chains where reference stability directly impacts measurement fidelity.

Availability

MAX6138BEXR50+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition systems, and handheld test equipment requiring stable component supply, consistent parametric performance, and long-term availability assurance.

Supply support for MAX6138BEXR50+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 product line delivers ultra-compact, high-accuracy shunt voltage references optimized for space- and power-constrained systems where stability, low noise, and guaranteed temperature performance are critical.

FAQ

What is the exact output voltage tolerance of MAX6138BEXR50+T at +25°C?

The MAX6138BEXR50+T has a guaranteed reverse breakdown voltage of 5.000V with ±0.2% initial accuracy at +25°C, corresponding to a range of 4.990V to 5.010V. This specification is confirmed in the Electrical Characteristics table for MAX6138_50 (5.0V version) under the MAX6138B grade, and applies strictly to the MAX6138BEXR50+T variant.

Does MAX6138BEXR50+T require an external output capacitor for stability?

No, MAX6138BEXR50+T does not require an external output capacitor. The device is designed to remain stable with any capacitive load from 0 to at least 1µF, as verified in the Typical Operating Characteristics section and explicitly stated in the Applications Information. This eliminates layout constraints and reduces BOM count.

What is the minimum shunt current needed for proper regulation of MAX6138BEXR50+T?

The minimum operating shunt current for MAX6138BEXR50+T is 60μA across the full temperature range (–40°C to +85°C), with typical values as low as 54μA at +25°C. Maintaining ≥60μA ensures stable 5.000V regulation; falling below this risks loss of reference accuracy and increased noise.

Can MAX6138BEXR50+T be used in automotive under-hood applications?

MAX6138BEXR50+T is rated for –40°C to +85°C operation and meets industrial temperature requirements, but it is not AEC-Q200 qualified or specified for under-hood automotive use (which typically requires –40°C to +125°C). For cabin or infotainment modules within its temperature envelope, MAX6138BEXR50+T is suitable - confirmed by its inclusion in automotive cabin sensor application examples.

How does the pin configuration of MAX6138BEXR50+T differ from standard three-terminal shunt references?

MAX6138BEXR50+T uses a true two-terminal shunt architecture with a third N.C. pin: Pin 1 is the anode (+), Pin 2 is the cathode (–), and Pin 3 is unconnected (or tied to Pin 2). Unlike three-terminal references with separate reference, cathode, and anode pins, MAX6138BEXR50+T's N.C. pin serves no electrical function - simplifying routing while retaining SC70-3 mechanical compatibility.