Analog Devices Inc./Maxim Integrated MAX6349SLUT-T

Overview

MAX6349SLUT-T from Maxim Integrated is a 150mA, low-dropout linear voltage regulator with integrated microprocessor reset circuit, preset +3.3V output, -5% reset threshold, and open-drain active-low RESET output in SOT23-6 package. It delivers 25µA quiescent current, 180mV dropout at 100mA, and operates from 2.5V to 5.5V input - ideal for battery-powered USB devices and handheld instruments requiring reliable power sequencing and brownout protection.

For engineers reviewing the MAX6349SLUT-T datasheet, MAX6349SLUT-T pinout, MAX6349SLUT-T application, or MAX6349SLUT-T equivalent, key selection criteria include its fixed +3.3V output, -5% reset tolerance, manual reset (MR) input, thermal/short-circuit protection, and compatibility with 1µF ceramic output capacitors - all critical for portable embedded systems with tight power budgets.

Technical Context

The MAX6349SLUT-T integrates a P-channel MOSFET LDO regulator core and a precision reset supervisor sharing the same 1.23V reference. Its reset circuit monitors VOUT continuously and asserts open-drain RESET for ≥100ms after VOUT rises above the -5% threshold (2.92V min at 3.3V output), ensuring stable clock and supply conditions before processor release.

It features a dedicated MR input with 20kΩ internal pullup to OUT, TTL/CMOS-compatible logic thresholds (VIL = 0.2×VOUT, VIH = 0.8×VOUT), and 500ns MR-to-RESET delay. The SET pin is grounded for fixed +3.3V operation, eliminating external feedback components while maintaining ±3.0% output accuracy over 0°C to +85°C.

Key Specifications

Pinout & Package

MAX6349SLUT-T is housed in a 6-pin SOT23-6 package with exposed pad for thermal dissipation; GND pin serves dual role as electrical ground and heatsink - requires soldering to large copper area for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO-with-reset applications.

Compared with TPS3808G33DBVR and ADM6315-33ARTZ-RL7, MAX6349SLUT-T uniquely combines manual reset, thermal protection, and 25µA IQ in a 6-pin SOT23 - enabling robust, self-contained power supervision in space-constrained portable designs without external components.

Availability

MAX6349SLUT-T is available at Aetrix Electronics and suitable for USB devices, handheld test equipment, PCMCIA cards, and low-power cellular modems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX6349SLUT-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 MAX6349SLUT-T belongs to Maxim's micropower LDO regulator family designed specifically for battery-powered portable electronics requiring integrated reset supervision, minimal quiescent current, and compact packaging.

FAQ

What is the function of the MR pin on the MAX6349SLUT-T?

The MR (Manual Reset) pin on the MAX6349SLUT-T is an active-low input that forces the RESET output to assert regardless of VOUT status - allowing external logic, a switch, or test equipment to initiate a system reset while the regulator remains within specification. It features a 20kΩ internal pullup to OUT, accepts TTL/CMOS levels, and responds to pulses as short as 1µs. This capability is exclusive to the MAX6349 series and not present in the MAX6329 variants.

Does the MAX6349SLUT-T require external resistors to set its output voltage?

No, the MAX6349SLUT-T does not require external resistors to set its output voltage. It is factory-configured for +3.3V fixed output, achieved by internally connecting the SET pin reference to ground. The SET pin is left unconnected in this variant - no external resistor divider is needed, simplifying layout and reducing BOM count compared to adjustable-output regulators.

What is the minimum output capacitor required for stable operation of the MAX6349SLUT-T?

The MAX6349SLUT-T requires a minimum 1µF ceramic or tantalum output capacitor for stable operation across the full temperature range and up to 150mA load. X7R or X5R dielectric ceramics are recommended for consistent ESR performance; Z5U/Y5V types may require ≥2.2µF below -10°C. A 1µF capacitor on the IN pin is also advised to improve line transient response and PSRR.

How does the MAX6349SLUT-T handle reverse current flow from OUT to IN?

The MAX6349SLUT-T incorporates reverse leakage protection that actively disables the internal pass transistor and parasitic paths when VOUT exceeds VIN - resulting in zero reverse leakage current. This allows safe operation with auxiliary supplies (e.g., backup batteries) connected to OUT without requiring external blocking diodes, preserving efficiency and simplifying power architecture in dual-supply systems.

What thermal protection features does the MAX6349SLUT-T include?

The MAX6349SLUT-T includes thermal shutdown protection that disables the pass transistor when junction temperature exceeds +160°C, with 20°C hysteresis for automatic recovery. During continuous overload, it enters pulsed operation to limit average power dissipation. The GND pin doubles as a thermal pad - effective heat dissipation requires soldering to a large PCB copper area or ground plane per the SOT23-6 thermal guidelines.