Analog Devices Inc./Maxim Integrated MAX6138AEXR12+T

Overview

MAX6138AEXR12+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with 1.2205V reverse breakdown voltage, 0.1% initial accuracy, 25ppm/°C max temperature coefficient, and 60μA–15mA operating current range. It serves as a stable voltage reference in low-power analog signal chains and ADC/DAC biasing circuits for portable instrumentation.

For engineers reviewing the MAX6138AEXR12+T datasheet, MAX6138AEXR12+T pinout, MAX6138AEXR12+T application, or MAX6138AEXR12+T equivalent, key selection criteria include guaranteed ±4ppm/°C typical TC, no-output-capacitor stability, SC70-3 footprint compatibility, and 28μVRMS wideband noise performance over 10Hz–10kHz.

Technical Context

The MAX6138AEXR12+T implements a laser-trimmed bandgap core to deliver precise 1.2205V reverse breakdown voltage across –40°C to +85°C. Its two-terminal architecture eliminates need for external bias resistors or capacitors while maintaining regulation under capacitive loads up to 1µF.

Dynamic impedance remains ≤0.8Ω at 1mA/120Hz, enabling stable reference behavior during load transients. The device operates as a current-sink shunt element-its cathode (Pin 1) and anode (Pin 2) define the reference node, with Pin 3 unconnected or tied to Pin 2.

Key Specifications

Pinout & Package

MAX6138AEXR12+T uses the 3-pin SC70-3 surface-mount package (1.8mm × 1.8mm), 50% smaller than SOT23 equivalents. Pin 3 is NC and must be left floating or connected to Pin 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM4040C12IDCKR and ADR3412ARJZ-R7, MAX6138AEXR12+T uniquely combines 0.1% accuracy, SC70-3 size, and no-output-capacitor stability - making it optimal for space-constrained, battery-operated 12–16-bit measurement systems requiring minimal external components.

Availability

MAX6138AEXR12+T is available at Aetrix Electronics and suitable for portable medical sensors, industrial data acquisition modules, and handheld test equipment requiring stable component supply with tight initial tolerance and low thermal drift.

Supply support for MAX6138AEXR12+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 series delivers high-accuracy shunt voltage references in ultra-small SC70 packages, targeting space- and power-constrained systems needing stable, capacitor-free reference performance.

FAQ

What is the exact output voltage tolerance of MAX6138AEXR12+T at +25°C?

The MAX6138AEXR12+T has a reverse breakdown voltage of 1.2205V with ±0.0012V (±0.1%) tolerance at +25°C, corresponding to the Grade A accuracy bin. This is laser-trimmed and guaranteed across production lots, ensuring consistent performance in precision ADC reference applications without user calibration.

Can MAX6138AEXR12+T operate without an external output capacitor?

Yes, MAX6138AEXR12+T is designed to be stable with zero output capacitance and remains stable with any capacitive load up to 1µF. This eliminates the need for external capacitors in most applications, reducing BOM count and avoiding potential instability from ESR or layout parasitics that affect traditional shunt references.

What is the minimum shunt current required for regulation in MAX6138AEXR12+T?

The MAX6138AEXR12+T requires a minimum shunt current of 60μA to maintain regulation across its full –40°C to +85°C temperature range. At –40°C, the minimum is 45μA per datasheet, but 60μA is the guaranteed operational floor for all conditions - critical for ultra-low-power sleep-mode designs.

How does the temperature coefficient of MAX6138AEXR12+T compare to typical bandgap references?

MAX6138AEXR12+T guarantees ≤25ppm/°C over –40°C to +85°C, with typical performance within ±4ppm/°C. This exceeds standard bandgap references (often 50–100ppm/°C) and approaches buried-zener performance - achieved via laser trimming and BiCMOS process optimization for low thermal hysteresis.

Is Pin 3 of MAX6138AEXR12+T functional or optional?

Pin 3 of MAX6138AEXR12+T is designated N.C. (No Connection) and must be left floating or connected to Pin 2 (anode). It has no internal connection and serves only as a mechanical pad; connecting it to Pin 2 improves thermal symmetry and reduces package-induced voltage drift in high-precision layouts.