Analog Devices Inc./Maxim Integrated MAX1806EUA33

Overview

MAX1806EUA33 from Maxim Integrated is a preset 3.3V, 500mA low-dropout linear regulator with ±1% output voltage accuracy, 175mV dropout at full load, and 210µA ground current - designed for power-sensitive portable systems including cellular phones, PDAs, and USB hubs.

For engineers reviewing the MAX1806EUA33 datasheet, MAX1806EUA33 pinout, MAX1806EUA33 application, or MAX1806EUA33 equivalent, key selection criteria include guaranteed 500mA output under 175mV dropout, active-low POK monitoring, 0.02µA shutdown current, thermal overload protection, and compatibility with 1µF/10µF ceramic input/output capacitors.

Technical Context

The MAX1806EUA33 employs an internal PMOS pass transistor with 0.4Ω R_DS(ON), enabling low quiescent current and eliminating base-drive losses typical of PNP regulators. Its dual-mode feedback architecture selects between factory-trimmed preset regulation (3.3V) and adjustable mode via the SET pin.

Regulation relies on a precision 0.8V internal reference and error amplifier comparing feedback against that reference. The POK output asserts low when V_OUT falls below 93% of nominal (3.069V), using open-drain N-channel logic compatible with pullup to V_OUT.

Key Specifications

Pinout & Package

The MAX1806EUA33 uses an 8-pin Power-µMAX package with exposed thermal pad on the underside for enhanced heat dissipation. The package measures 3mm × 3mm × 0.8mm and requires soldering of both GND pin and exposed pad to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS76333DBVR and MCP1700T-3302E/TT, the MAX1806EUA33 uniquely delivers 500mA output with 175mV dropout and integrated POK/thermal protection in a thermally enhanced µMAX package - making it the only option among the three qualified for sustained high-current portable applications requiring system-level fault monitoring.

Availability

MAX1806EUA33 is available at Aetrix Electronics and suitable for cellular telephones, USB hubs, and portable computing equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

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 portable applications.

The MAX1806 series was developed specifically for battery-powered portable electronics requiring high-output-current LDOs with ultra-low quiescent current and robust fault protection - targeting PDA, cellular phone, and docking station power architectures.

FAQ

What is the guaranteed output voltage tolerance for MAX1806EUA33 over temperature?

The MAX1806EUA33 guarantees ±1% output voltage accuracy over the full operating temperature range of -40°C to +85°C at load currents from 1mA to 500mA. At +85°C, the specification tightens to ±1.5% for 100mA load and ±3% across the full 1–500mA range, ensuring reliable performance in thermally stressed portable environments where the MAX1806EUA33 is commonly deployed.

Can MAX1806EUA33 be used with ceramic output capacitors, and what ESR requirement applies?

Yes, the MAX1806EUA33 is fully compatible with ceramic output capacitors. It requires a maximum ESR of 0.1Ω on the 10µF output capacitor (C_OUT) to ensure stability and optimal transient response. Surface-mount X5R or X7R ceramics meeting this ESR spec are recommended and widely available - enabling compact, low-profile designs without tantalum or aluminum electrolytic components.

Does MAX1806EUA33 support adjustable output voltage, or is it fixed at 3.3V?

The MAX1806EUA33 is factory-trimmed for fixed 3.3V output and operates in preset mode when the SET pin is connected to GND. While the underlying MAX1806 architecture supports adjustable operation (0.8V–4.5V) via external resistors, the MAX1806EUA33 variant is not characterized or guaranteed for adjustable use - its electrical specifications, including accuracy and stability, apply only to the 3.3V preset configuration.

What thermal management is required for MAX1806EUA33 at 500mA continuous load?

At 500mA continuous load with 5.5V input and 3.3V output, the MAX1806EUA33 dissipates 1.1W (P = I_OUT × (V_IN − V_OUT)). To remain within its 1.3W absolute maximum rating and avoid thermal shutdown, the exposed thermal pad must be soldered to a minimum 100mm² copper area connected to the PCB ground plane using ≥4 thermal vias - otherwise junction temperature exceeds 170°C under worst-case ambient conditions.

How does the POK output of MAX1806EUA33 interface with a microcontroller GPIO?

The POK output of MAX1806EUA33 is an open-drain N-channel MOSFET requiring an external pullup resistor (typically 100kΩ to V_OUT). When V_OUT ≥ 3.069V (93% of 3.3V), POK floats high-impedance; when V_OUT drops below that threshold, POK pulls low. This allows direct connection to a µC GPIO configured as an interrupt-capable input with internal or external pullup - enabling precise brownout detection without additional level-shifting circuitry in the MAX1806EUA33 design.