Analog Devices Inc./Maxim Integrated MAX6138CEXR50+T

Overview

MAX6138CEXR50+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed 5.000V reverse breakdown voltage, ±0.5% initial accuracy, 25ppm/°C max temperature coefficient over –40°C to +85°C, 54µA–80µA minimum operating current, and 80µV_RMS wideband noise (10Hz–10kHz). It serves as a stable voltage reference in low-power, space-constrained analog signal chains and ADC/DAC biasing circuits.

For engineers reviewing the MAX6138CEXR50+T datasheet, MAX6138CEXR50+T pinout, MAX6138CEXR50+T application, or MAX6138CEXR50+T equivalent, key selection considerations include its SC70-3 package footprint, shunt-current regulation range (60µA–15mA), no-output-capacitor stability, and guaranteed long-term drift of ≤120ppm over 1000 hours.

Technical Context

The MAX6138CEXR50+T implements a laser-trimmed bandgap core in BiCMOS process to deliver precise 5.000V reverse breakdown voltage with minimal thermal hysteresis. Its two-terminal architecture eliminates need for external feedback networks, simplifying integration into high-impedance bias and reference divider topologies.

It operates as a programmable current sink: reverse current (cathode-to-anode) between 60µA and 15mA maintains stable 5.000V across terminals, with dynamic impedance as low as 0.5Ω at 1mA and guaranteed stability under capacitive loads up to 1µF without external compensation.

Key Specifications

Pinout & Package

MAX6138CEXR50+T is housed in a 3-pin SC70 surface-mount package (1.8mm × 1.8mm, 0.95mm height) with RoHS-compliant lead finish. Pin 3 is NC (no connection) 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 LM4040C50IDCKR, MAX6138CEXR50+T delivers identical 0.5% accuracy in a 50% smaller package with one-quarter the temperature coefficient - directly reducing board area and system-level calibration overhead in portable and industrial measurement systems.

Availability

MAX6138CEXR50+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition systems, automotive cabin sensors, and smart energy meters requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6138CEXR50+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6138 series was designed as a family of precision shunt references targeting space-constrained, battery-operated, and high-accuracy measurement systems - delivering improved accuracy, lower tempco, and smaller packaging than legacy solutions like LM4040.

FAQ

What is the guaranteed initial accuracy of MAX6138CEXR50+T?

The MAX6138CEXR50+T is specified with ±0.5% initial accuracy at +25°C, meaning its reverse breakdown voltage falls within 4.975V to 5.025V under standard test conditions. This grade ('C') is confirmed in the Electrical Characteristics table for MAX6138_50, and applies across the full –40°C to +85°C operating range with guaranteed tempco limits.

Can MAX6138CEXR50+T operate without an external output capacitor?

Yes, MAX6138CEXR50+T does not require an external output capacitor for stability and remains stable with any capacitive load from 0 to 1µF. This is verified in the Applications Information section and Typical Operating Characteristics (output impedance vs. frequency plots), eliminating design risk and BOM cost associated with capacitor selection and placement.

What is the minimum shunt current required for regulation in MAX6138CEXR50+T?

The MAX6138CEXR50+T requires a minimum shunt current of 54µA (typical) to 80µA (max) to maintain regulation, as specified in the Electrical Characteristics-MAX6138_50 table. Designers must ensure the source resistor and supply voltage combination guarantees ≥80µA shunt current under worst-case conditions (min VS, max ILOAD).

How does the SC70-3 package of MAX6138CEXR50+T compare to SOT23 alternatives?

The SC70-3 package of MAX6138CEXR50+T measures 1.8mm × 1.8mm - 50% smaller in area than standard SOT23-3 packages. This enables higher component density in portable and wearable designs. The pinout is compatible with SC70 land pattern #90-0208, and the device uses the same reflow profile as other SC70 components.

Is Pin 3 of MAX6138CEXR50+T functional or optional?

Pin 3 of MAX6138CEXR50+T is designated N.C. (No Connection) and is not functional. Per the Pin Description and Typical Operating Circuit diagrams, it must be left floating or connected to Pin 2 (cathode); connecting it elsewhere may compromise performance or reliability. This is a mechanical pad for package symmetry, not an electrical terminal.