Analog Devices Inc./Maxim Integrated MAX6349THUT+

Overview

The MAX6349THUT+ from Maxim Integrated is a 150mA, low-dropout linear voltage regulator with integrated microprocessor reset circuit, featuring +3.3V fixed output, -5% reset threshold, push-pull active-high RESET output, and manual reset (MR) input - designed for battery-powered portable electronics requiring stable supply and reliable power-on reset sequencing.

For engineers reviewing the MAX6349THUT+ datasheet, MAX6349THUT+ pinout, MAX6349THUT+ application, or MAX6349THUT+ equivalent, this page delivers verified electrical parameters, SOT23-6 package mapping, functional pin roles, real-world use cases in USB devices and handheld instruments, and two validated alternative parts with documented technical and application differences.

Technical Context

The MAX6349THUT+ employs an internal P-channel MOSFET pass transistor to achieve 180mV dropout at 100mA while maintaining 25µA quiescent current. Its reset circuit uses the same 1.23V reference as the regulator core, enabling precise tracking of output voltage tolerance (–5% V_OUT) without external components.

It operates across +2.5V to +5.5V input range and supports adjustable output via SET pin resistor divider (1.23V to 5.0V), though the TH suffix denotes fixed +3.3V operation with preset –5% reset threshold and active-high push-pull RESET output. MR input provides TTL/CMOS-compatible manual reset assertion with 1µs minimum pulse width and 120ns glitch rejection.

Key Specifications

Pinout & Package

MAX6349THUT+ 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 connection to large PCB copper area for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6329THUT+, the MAX6349THUT+ trades shutdown capability for manual reset - essential for field-serviceable devices. Versus TPS76333DBVR, it integrates reset logic and timing, reducing component count and eliminating timing mismatch risks between regulator and supervisor.

Availability

MAX6349THUT+ is available at Aetrix Electronics and suitable for USB devices, handheld instruments, palm top computers, and PCMCIA cards requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX6349THUT+ 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 and mixed-signal ICs for power management, sensing, and connectivity in industrial, medical, and portable applications.

The MAX6329/MAX6349 product line targets battery-powered microprocessor systems needing integrated power regulation and deterministic reset behavior - optimized for minimal external components and ultra-low quiescent current.

FAQ

What output voltage does the MAX6349THUT+ provide, and how is it set?

The MAX6349THUT+ provides a fixed +3.3V output with ±3.0% accuracy over temperature and load. This is achieved by connecting the SET pin to GND, which selects the internal feedback network. The TH suffix explicitly denotes the +3.3V/-5% reset variant - no external resistors are required or recommended for this configuration. The MAX6349THUT+ does not support adjustable output in this version.

Does the MAX6349THUT+ include thermal protection, and how does it behave under overload?

Yes, the MAX6349THUT+ includes thermal shutdown protection that activates at +160°C junction temperature, turning off the pass transistor until the die cools by 20°C hysteresis. During continuous overload, this results in pulsed output rather than latch-up, allowing safe intermittent operation. The GND pin doubles as a thermal pad - effective PCB copper area is required to maintain TJ < +150°C at full 150mA load.

How does the manual reset (MR) input function on the MAX6349THUT+?

The MR input on the MAX6349THUT+ is an active-low signal with internal 20kΩ pullup to V_OUT. A logic low (≤0.2×V_OUT) asserts the RESET output for the full 100ms timeout period, even if V_OUT remains within specification. It accepts TTL/CMOS levels and requires no external debounce - a simple momentary switch from MR to GND suffices. The MAX6349THUT+ datasheet specifies 1µs minimum pulse width and 120ns glitch rejection.

What capacitor value is required for stable operation of the MAX6349THUT+?

The MAX6349THUT+ requires a minimum 1µF ceramic output capacitor (X7R or X5R dielectric) placed close to the OUT and GND pins for stability across –40°C to +85°C. Larger values (e.g., 10µF) improve load transient response and PSRR. A 1µF capacitor between IN and GND is also recommended to suppress input ripple. Using Z5U/Y5V dielectrics may require ≥2.2µF for low-temperature stability.

Is the MAX6349THUT+ pin-compatible with other MAX6329/MAX6349 variants?

Yes, all MAX6329/MAX6349 devices share identical SOT23-6 pinout and footprint, including the MAX6349THUT+. Pin functions are consistent across variants: IN (1), GND (2), MR/SHDN (3), RESET/RESET (4), SET (5), OUT (6). However, MR (MAX6349) and SHDN (MAX6329) are mutually exclusive functions on pin 3 - swapping parts requires verifying external circuit compatibility with the active function.