Analog Devices Inc./Maxim Integrated MAX6349YLUT+T

Overview

The MAX6349YLUT+T from Maxim Integrated is a 150mA, low-dropout linear voltage regulator with integrated microprocessor reset circuit, preset +1.8V output, -10% reset threshold (VTH = 1.50V to 1.65V), open-drain active-low RESET output, and manual reset (MR) input - designed for battery-powered portable electronics requiring stable supply and reliable power-on reset.

For engineers reviewing the MAX6349YLUT+T datasheet, MAX6349YLUT+T pinout, MAX6349YLUT+T application, or MAX6349YLUT+T equivalent, key selection factors include its 180mV dropout at 100mA, 25µA quiescent current, 1µF minimum output capacitor requirement, thermal/short-circuit protection, and MR-driven reset assertion while VOUT remains in specification.

Technical Context

The MAX6349YLUT+T integrates a P-channel MOSFET LDO regulator core with an independent reset supervisor using a shared 1.23V reference. Its fixed +1.8V output is set by internal feedback; SET must be connected to GND. The reset circuit monitors VOUT against a -10% threshold (1.50V–1.65V) and asserts open-drain RESET for ≥100ms after recovery.

Unlike the MAX6329, this variant includes a dedicated MR input with 20kΩ internal pullup to OUT, TTL/CMOS-compatible logic levels, 1µs minimum pulse width, and 500ns MR-to-RESET delay. It lacks shutdown functionality but provides reverse leakage protection and operates across 2.5V–5.5V input range.

Key Specifications

Pinout & Package

Package: 6-pin SOT23-6 (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm body, exposed pad not present; requires standard SMT reflow profile and GND pad soldering for thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator with manual reset applications.

Compared with MAX6349YLUT+T, MAX6329YLUT+T replaces MR with SHDN and changes RESET to push-pull, making it unsuitable for manual reset use cases; TPS76318QDBVRQ1 offers higher temperature rating but adds BOM complexity and quiescent current penalty, with no functional integration of reset or MR.

Availability

MAX6349YLUT+T is available at Aetrix Electronics and suitable for handheld instruments, USB devices, cellular telephones, and palm top computers requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MAX6349YLUT+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 industrial, communications, and consumer applications.

The MAX6329/MAX6349 product line delivers micropower LDO regulators with integrated reset for space-constrained, battery-operated systems where supply stability and deterministic power-on sequencing are critical.

FAQ

What output voltage does the MAX6349YLUT+T deliver, and how is it configured?

The MAX6349YLUT+T delivers a fixed +1.8V output with ±3.0% accuracy over 0°C to +85°C. This is achieved by connecting the SET pin directly to GND - no external resistors are required. The 'Y' suffix in MAX6349YLUT+T explicitly denotes the +1.8V version with -10% reset threshold and open-drain RESET output. Attempting to use an external resistor divider on SET will disable regulation.

Does the MAX6349YLUT+T support manual reset, and what are the electrical requirements for the MR pin?

Yes, the MAX6349YLUT+T includes a dedicated MR (manual reset) input. MR is active-low with an internal 20kΩ pullup to OUT. To assert reset, drive MR ≤0.2×VOUT (e.g., ≤0.36V at VOUT = 1.8V) for ≥1µs. The MR-to-RESET delay is 500ns (max), and reset remains asserted for ≥100ms after MR returns high. No external pullup or debounce circuitry is needed.

What is the minimum output capacitor required for stable operation of the MAX6349YLUT+T?

The MAX6349YLUT+T requires a minimum 1µF ceramic or tantalum capacitor from OUT to GND for stable operation across temperature and load (0–150mA). X7R or X5R dielectrics are recommended for full -40°C to +85°C coverage; Z5U/Y5V types may require ≥2.2µF below -10°C. A 1µF capacitor between IN and GND further improves PSRR and transient response.

How does the MAX6349YLUT+T handle reverse current flow when the output is powered externally?

The MAX6349YLUT+T includes reverse leakage protection: when VOUT > VIN, internal circuitry disables the pass transistor and parasitic paths, resulting in zero reverse current from OUT to IN. This allows safe operation with auxiliary supplies (e.g., backup coin cell) without external blocking diodes - a key advantage in battery-swappable or energy-harvesting systems.

What protection features are built into the MAX6349YLUT+T, and how do they behave under fault conditions?

The MAX6349YLUT+T integrates thermal shutdown (trips at TJ ≥ +160°C, resets at +140°C), output short-circuit protection (350mA current limit), and reverse leakage protection. During sustained overload, it enters thermal cycling - turning off until cooled by 20°C, then resuming operation. Short-circuit current limiting prevents damage during indefinite GND faults, and all protections operate independently of external components.