Analog Devices Inc./Maxim Integrated MAX15028ATB/V+T

Overview

MAX15028ATB/V+T from Maxim Integrated is an AEC-Q100 qualified 1A low-dropout linear regulator with dual-supply architecture: main input (IN) operates from 1.425V to 3.6V, while BIAS input accepts 3V to 5.5V to maintain internal circuitry operation during IN rail collapse-enabling automotive "dead-man" LDO functionality. It delivers ±2% output accuracy over –40°C to +125°C, achieves 75mV typical dropout at 1A, and supports adjustable output from 0.5V to VIN using external resistors.

For engineers reviewing the MAX15028ATB/V+T datasheet, MAX15028ATB/V+T pinout, MAX15028ATB/V+T application, or MAX15028ATB/V+T equivalent, key selection criteria include BIAS-supplied shutdown current (<2µA), thermally enhanced 3mm × 3mm TDFN-EP package with exposed pad, guaranteed 225mV max dropout at 1A, ceramic capacitor compatibility (1µF IN / 4.7µF OUT), and automotive-grade thermal/ESD robustness.

Technical Context

The MAX15028ATB/V+T integrates a p-channel MOSFET pass transistor (75mΩ typ) enabling stable regulation down to 1.425V input without base-drive current penalty. Its dual-rail architecture decouples control logic power (BIAS) from power path (IN), allowing continuous bias supply during key-off conditions in automotive systems.

Internal soft-start uses a 5µA current source charging an external SS-to-GND capacitor to limit inrush; feedback is referenced to a 0.499V (±2mV) bandgap voltage with 0.1–0.2µA input bias current. Thermal shutdown activates at +165°C (15°C hysteresis), and short-circuit protection limits output current to 1.4–2.0A depending on temperature.

Key Specifications

Pinout & Package

MAX15028ATB/V+T is housed in a 10-pin thermally enhanced TDFN package (3mm × 3mm) with exposed pad (EP) for optimal thermal dissipation. The EP must be soldered to a large copper ground plane via multiple vias to achieve θJA = 41°C/W and θJC = 9°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPS7A8300RGRT and NCP114AMX330TCG, MAX15028ATB/V+T uniquely combines AEC-Q100 qualification, 1A output, ultra-low BIAS shutdown current (<2µA), and true dual-rail operation-making it the only viable option for automotive dead-man LDO requirements where IN collapse must not interrupt internal logic.

Availability

MAX15028ATB/V+T is available at Aetrix Electronics and suitable for automotive infotainment, server memory regulation, optical transceiver biasing, and 5G base station RF front-end power requiring stable component supply across extended temperature and long product lifecycles.

Supply support for MAX15028ATB/V+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, automotive, and communications applications.

The MAX15028ATB/V+T belongs to Maxim's automotive-qualified LDO family engineered specifically for fail-safe power supervision in vehicles-supporting dead-man operation, low dark current, and extended temperature reliability.

FAQ

What is the purpose of the BIAS pin on the MAX15028ATB/V+T?

The BIAS pin on the MAX15028ATB/V+T supplies power exclusively to the internal control circuitry-including error amplifier, reference, and enable logic-allowing the device to remain functional even when the main IN rail collapses to 0V. This enables "dead-man" operation critical in automotive systems, where the BIAS rail (typically 3.3V or 5V from an always-on LDO) sustains regulation and monitoring functions during key-off. In shutdown, BIAS current drops below 2µA.

Can the MAX15028ATB/V+T operate without the BIAS supply connected?

No-the MAX15028ATB/V+T requires a valid BIAS supply between 3V and 5.5V to function. Unlike the MAX15027 variant, the MAX15028ATB/V+T does not derive internal power from IN; its control circuitry is powered solely by BIAS. If BIAS is unconnected or out-of-range, the device will not regulate, regardless of IN voltage or EN state. This architecture ensures deterministic behavior during IN rail failure.

What is the minimum output capacitor required for stable operation of the MAX15028ATB/V+T at 1A load?

The MAX15028ATB/V+T requires a minimum 4.7µF ceramic output capacitor with low ESR for stable 1A operation across –40°C to +125°C. This value is validated in the datasheet for transient response (15mV deviation at 500mA step) and phase margin. Smaller capacitors may be used at reduced loads: COUT(min) = 1µF × (IOUT / 0.25A). For improved transient suppression, values up to 100µF ceramic are supported.

How does the soft-start function work on the MAX15028ATB/V+T, and what capacitor value is recommended?

The MAX15028ATB/V+T implements soft-start by charging an external capacitor (CSS) from the SS pin to GND using a 5µA internal current source. As CSS charges, the SS voltage ramps linearly; the output voltage follows until SS reaches the internal 0.499V reference, then locks to regulation. A 0.1µF capacitor yields ~20ms soft-start time (tSS = CSS × 10⁵). Larger values extend ramp time to limit inrush into heavy downstream capacitance.

Is the MAX15028ATB/V+T pin-compatible with the MAX15027 series?

No-the MAX15028ATB/V+T and MAX15027 share the same 10-pin TDFN package but differ in pin function: Pin 3 is BIAS on MAX15028ATB/V+T (not used on MAX15027), and IN occupies pins 1–3 on MAX15027 versus pins 1–2 on MAX15028ATB/V+T. Direct replacement requires PCB layout revision. The MAX15028ATB/V+T is not a drop-in substitute for MAX15027-based designs due to this pin mapping change.