Analog Devices Inc./Maxim Integrated MAX1806EUA33+

Overview

MAX1806EUA33+ from Maxim Integrated is a 3.3V fixed-output, 500mA low-dropout linear regulator with ±1% output voltage accuracy, 175mV dropout at full load, and 210μA ground current. It uses an internal PMOS pass transistor and features active-low power-OK (POK) monitoring, 0.02μA shutdown current, and thermal/short-circuit protection-designed for space-constrained portable power rails in USB hubs and docking stations.

For engineers reviewing the MAX1806EUA33+ datasheet, MAX1806EUA33+ pinout, MAX1806EUA33+ application, or MAX1806EUA33+ equivalent, key selection criteria include guaranteed 500mA output under 175mV dropout, preset 3.3V operation without external resistors, POK threshold at 93% of nominal output, and compatibility with 1.3W power-μMAX thermal pad layout.

Technical Context

The MAX1806EUA33+ implements a dual-mode feedback architecture: SET pin grounded selects factory-trimmed 3.3V regulation via internal resistor divider, while the 800mV reference enables adjustable mode. Its P-channel MOSFET pass device eliminates base-drive current, enabling stable 210μA quiescent operation across load and temperature.

Power-OK logic monitors VOUT against a precision 93% threshold with open-drain N-channel output; thermal shutdown activates at +170°C with 20°C hysteresis. Input undervoltage lockout engages below 1.85V (40mV hysteresis), and short-circuit current limit is specified at 700–2500mA.

Key Specifications

Pinout & Package

The MAX1806EUA33+ is housed in an 8-pin power-μMAX package (1.3W rating) with an exposed metal thermal pad on the underside requiring solder connection to PCB ground plane for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76333DBVR and MCP1826-3302E/DB, the MAX1806EUA33+ delivers higher current with lower dropout and integrated POK-making it optimal for thermally constrained, feature-rich portable systems requiring deterministic power sequencing.

Availability

MAX1806EUA33+ is available at Aetrix Electronics and suitable for USB hubs, docking stations, and cellular telephones requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MAX1806EUA33+ 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, communications, and consumer applications.

The MAX1806 belongs to Maxim's μMAX low-dropout regulator family, engineered for portable equipment requiring high current density, ultra-low quiescent current, and integrated power-monitoring features in miniature packages.

FAQ

What is the maximum input voltage for the MAX1806EUA33+?

The MAX1806EUA33+ supports an input voltage range of +2.25V to +5.5V. Absolute maximum rating is +6V on IN and SHDN pins, but continuous operation above +5.5V is not specified. Operation below +2.25V triggers undervoltage lockout at ~1.85V (40mV hysteresis), disabling regulation until VIN rises above the threshold.

Does the MAX1806EUA33+ require external resistors to set its 3.3V output?

No-the MAX1806EUA33+ has a factory-trimmed internal resistor divider that fixes the output at 3.3V ±1%. The SET pin must be connected to GND to activate preset mode. External resistors are only needed if adjusting the output voltage outside the 3.3V default, which is not required for MAX1806EUA33+ operation.

How does the POK (power-OK) output function on the MAX1806EUA33+?

The POK pin on the MAX1806EUA33+ is an open-drain N-channel output that pulls low when VOUT drops below 93% of nominal (3.069V). It goes high-impedance once VOUT exceeds this threshold. A 100kΩ pullup resistor to OUT is required to generate a logic-high signal. During shutdown, POK is forcibly held low regardless of output voltage.

What thermal design considerations apply to the MAX1806EUA33+ package?

The MAX1806EUA33+ uses an 8-pin power-μMAX package with an exposed metal thermal pad on the underside. This pad must be soldered to a large PCB copper area or ground plane using multiple thermal vias to dissipate heat. Failure to connect the pad limits power handling to <1W and risks thermal shutdown at currents near 500mA under ambient >70°C.

Can the MAX1806EUA33+ be used in adjustable-output configurations?

Yes-the MAX1806EUA33+ supports adjustable mode by disconnecting SET from GND and connecting an external resistor divider between OUT and SET. However, doing so disables the factory-trimmed 3.3V preset and introduces accuracy dependency on resistor tolerance and temperature drift. For 3.3V operation, SET must remain grounded per datasheet configuration.