Analog Devices Inc./Maxim Integrated MAX6138AEXR30+T

Overview

MAX6138AEXR30+T from Maxim Integrated is a precision two-terminal shunt-mode bandgap voltage reference with a fixed 3.000V 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 space-constrained analog signal chains and portable power management circuits.

For engineers reviewing the MAX6138AEXR30+T datasheet, MAX6138AEXR30+T pinout, MAX6138AEXR30+T application, or MAX6138AEXR30+T equivalent, key selection criteria include guaranteed 0.1% accuracy at +25°C, SC70-3 package compatibility, low 45µVRMS wideband noise (10Hz–10kHz), and stability without external output capacitance.

Technical Context

The MAX6138AEXR30+T implements a laser-trimmed bandgap core to deliver precise 3.000V reverse breakdown voltage across –40°C to +85°C. Its two-terminal architecture requires only a series resistor for biasing, eliminating need for supply rails or enable logic.

It maintains regulation via dynamic current sinking (60μA–15mA), with low 0.3Ω typical reverse dynamic impedance at 1mA and guaranteed stability into capacitive loads up to 1µF - no external capacitor required for phase margin or transient response.

Key Specifications

Pinout & Package

MAX6138AEXR30+T is housed in a 3-pin SC70 surface-mount package (1.8mm × 1.8mm). Pin 3 is No Connect (N.C.) and must be left floating or tied to Pin 2 per datasheet guidance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLVH431AIDBZR and ADR3430ARJZ-R7, MAX6138AEXR30+T uniquely combines 0.1% accuracy, 25ppm/°C TC, and true two-terminal shunt operation in SC70-3 - enabling direct replacement of legacy LM4040 variants without layout or biasing changes.

Availability

MAX6138AEXR30+T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered data loggers, and industrial process transmitters requiring stable component supply and guaranteed long-term calibration integrity.

Supply support for MAX6138AEXR30+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 high-accuracy, low-drift shunt voltage references in ultra-compact packages for space- and power-constrained systems where traditional three-terminal references are impractical.

FAQ

What is the exact output voltage tolerance of MAX6138AEXR30+T at +25°C?

The MAX6138AEXR30+T guarantees a reverse breakdown voltage of 3.000V with ±0.003V (0.1%) tolerance at +25°C, as confirmed in the Electrical Characteristics table for the 'A' grade. This is laser-trimmed and 100% production tested, ensuring consistent performance without post-assembly calibration.

Can MAX6138AEXR30+T operate stably with a 100nF ceramic capacitor on its output?

Yes, MAX6138AEXR30+T is explicitly characterized as stable with any output capacitance, including 100nF ceramic capacitors. The device's internal design eliminates need for external stabilization, and its low dynamic impedance (0.3Ω typical) prevents ringing or oscillation even under capacitive loading - a key advantage over older shunt references like LM4040.

What is the minimum shunt current required for regulation in MAX6138AEXR30+T?

The MAX6138AEXR30+T requires a minimum shunt current of 60μA to maintain regulation across its full temperature range (–40°C to +85°C). At –40°C, the datasheet specifies IRMIN = 65μA for the 3.0V variant, but 60μA is the guaranteed maximum threshold for all grades - ensuring reliable startup and regulation in ultra-low-power battery systems.

How does the temperature coefficient of MAX6138AEXR30+T compare to LM4040C30?

MAX6138AEXR30+T guarantees ≤25ppm/°C over –40°C to +85°C, while LM4040C30 specifies 50ppm/°C. The MAX6138AEXR30+T achieves tighter drift control through advanced bandgap trimming and BiCMOS process optimization, delivering half the temperature-induced error - critical for high-accuracy measurement systems operating across wide ambient ranges.

Is Pin 3 of MAX6138AEXR30+T electrically connected internally?

No, Pin 3 of MAX6138AEXR30+T is designated N.C. (No Connection) and is not internally bonded. The datasheet explicitly states it must be left floating or connected to Pin 2 (cathode); doing so has no electrical effect but may improve mechanical robustness during reflow. This differs from some competing shunt references that repurpose Pin 3 as a trim or enable function.