Analog Devices Inc./Maxim Integrated MAX6349TLUT-T

Overview

The MAX6349TLUT-T from Maxim Integrated is a 150mA, low-dropout linear voltage regulator with integrated microprocessor reset circuit in SOT23-6 package. It delivers a fixed +3.3V output, features ±3.0% regulation accuracy over 0°C to +85°C, consumes only 25µA quiescent current, and provides 180mV dropout at 100mA load-ideal for battery-powered USB devices and handheld instruments requiring stable, low-power supply and reliable power-on reset.

For engineers reviewing the MAX6349TLUT-T datasheet, MAX6349TLUT-T pinout, MAX6349TLUT-T application, or MAX6349TLUT-T equivalent, key selection criteria include its -5% reset threshold (T-suffix), push-pull active-high RESET output (L-suffix), manual reset input (MR), 1µF minimum ceramic output capacitor requirement, and thermal/short-circuit protection-critical for portable embedded systems with tight power and board space constraints.

Technical Context

The MAX6349TLUT-T integrates a P-channel MOSFET LDO regulator core with a precision 1.23V internal reference shared by both regulation and reset functions. Its reset supervisor monitors VOUT against a -5% threshold (2.92V to 3.185V at 3.3V output) and asserts RESET for ≥100ms after recovery, ensuring processor clock and supply stability before boot.

It implements manual reset via MR pin with 20kΩ internal pullup to OUT, 120ns glitch rejection, and 500ns MR-to-reset delay. The SET pin is grounded for fixed 3.3V operation, enabling automatic feedback path selection without external resistors.

Key Specifications

Pinout & Package

Package: SOT23-6 - compact 2.9mm × 1.6mm surface-mount footprint with GND pin acting as thermal pad; requires soldering to PCB ground plane for optimal thermal dissipation (θJA = 140°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6349TLUT-T, MAX6329TLUT-T trades MR for SHDN to achieve sub-1µA shutdown, while TPS3808G33DBVR sacrifices integration and MR support for Texas Instruments' qualification pedigree in industrial applications-neither offers pin-compatible replacement without layout changes.

Availability

MAX6349TLUT-T 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 MAX6349TLUT-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 portable applications.

The MAX6329/MAX6349 product line targets battery-powered embedded systems needing highly integrated, ultra-low-quiescent power regulation with deterministic reset behavior-optimized for minimal external components and robust operation under voltage transients.

FAQ

What is the reset threshold voltage for MAX6349TLUT-T?

The MAX6349TLUT-T has a -5% reset threshold relative to its 3.3V output, specified as 2.92V (min) to 3.185V (max) over temperature. This threshold is factory-trimmed and shares the same 1.23V internal reference as the regulator, ensuring tracking between output voltage and reset point. The T-suffix explicitly denotes the -5% variant, confirmed in Maxim's Selector Guide and Electrical Characteristics table.

Does MAX6349TLUT-T require an external resistor network to set the output voltage?

No, MAX6349TLUT-T does not require external resistors. Its "T" suffix indicates fixed +3.3V output, and the "L" suffix specifies push-pull active-high RESET. In this configuration, the SET pin is internally connected to ground via precision resistors-no external divider is needed. The datasheet confirms that connecting SET to GND enables preset mode, and the top-mark "AAJQ" corresponds to the TLUT-T variant in the Selector Guide.

What is the function of the MR pin on MAX6349TLUT-T?

The MR (Manual Reset) pin on MAX6349TLUT-T is an active-low input that forces the RESET output high for ≥100ms when pulled low, even if VOUT remains within regulation. It features a 20kΩ internal pullup to OUT, 120ns glitch rejection, and 500ns propagation delay. This allows direct connection to a momentary switch (MR to GND) or logic signal-no external debounce or biasing is required, simplifying system-level reset implementation.

Can MAX6349TLUT-T operate with a 1µF ceramic output capacitor?

Yes, MAX6349TLUT-T is fully stable with a 1µF X7R or X5R ceramic capacitor at the OUT pin, as specified in the datasheet's Applications Information and Typical Operating Characteristics. This value meets the minimum requirement across the full -40°C to +85°C range and 0–150mA load. Using 1µF ceramic reduces cost and board area versus tantalum, and avoids ESR-related instability seen with Z5U/Y5V dielectrics below -10°C.

What protection features are built into MAX6349TLUT-T?

MAX6349TLUT-T integrates thermal shutdown (trip at +160°C, 20°C hysteresis), output short-circuit protection (350mA current limit), and reverse leakage protection (zero IN-to-OUT current when VOUT > VIN). These functions operate autonomously without external components: thermal protection cycles the pass transistor during overload, short-circuit limit prevents damage during sustained fault, and reverse protection eliminates need for external blocking diodes in dual-supply or backup-battery configurations.