Analog Devices Inc./Maxim Integrated MAX8836ZEREEE+

Overview

The MAX8836ZEREEE+ from Maxim Integrated is a 1.2A high-frequency PWM step-down converter with integrated 200mA low-noise LDO, optimized for PA power in WCDMA/CDMA handsets. It delivers fixed 3.1V or 3.4V output via HP pin selection, features 60mΩ bypass FET for ultra-low dropout, ±2% output voltage accuracy, and operates from 2.7V to 5.5V input.

For engineers reviewing the MAX8836ZEREEE+ datasheet, MAX8836ZEREEE+ pinout, MAX8836ZEREEE+ application, or MAX8836ZEREEE+ equivalent, this device supports fast transient response (25µs settling), high PSRR (65dB typ), low LDO noise (35µVRMS typ), and dual independent enable control (PA_EN/EN2) for power sequencing in RF front-end designs.

Technical Context

The MAX8836ZEREEE+ integrates two independent regulated outputs: a hysteretic PWM buck converter with voltage-positioning feedback for stable operation with small ceramic capacitors, and a separate low-noise LDO with bandgap reference and internal 1.25V reference. Its automatic bypass mode engages above 99% duty cycle using a dedicated 60mΩ p-channel FET, decoupled from switching noise by routing IN2 separately.

Control logic enables independent activation of the PA converter (PA_EN) and LDO2 (EN2), each with internal 800kΩ pulldown resistors. Thermal shutdown at +160°C with 20°C hysteresis protects against sustained overload, while soft-start limits inrush current during Li+-battery startup.

Key Specifications

Pinout & Package

MAX8836ZEREEE+ uses a 16-bump, 2mm × 2mm × 0.7mm UCSP package (R162A2+1) with bottom-side bumps. The package supports fine-pitch PCB assembly and thermal performance matching the WLP variant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output PA power management applications.

Compared with MAX8836ZEREEE+, MAX8835ZEREEE+ saves cost and complexity where LDO functionality is unnecessary, while TPS62231RGTR offers wider input range and higher max junction temperature but demands additional components and layout area for equivalent functionality.

Availability

MAX8836ZEREEE+ is available at Aetrix Electronics and suitable for WCDMA/CDMA handset production, smartphone RF front-end development, and wireless PDA power management requiring stable component supply across automotive-grade temperature ranges (-40°C to +85°C).

Supply support for MAX8836ZEREEE+ 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 applications in communications, computing, and industrial systems.

The MAX8836ZEREEE+ belongs to Maxim's high-efficiency RF power management product line, engineered specifically for low-noise, fast-transient PA supply in 3G/4G mobile handsets with strict size and thermal constraints.

FAQ

What output voltages does the MAX8836ZEREEE+ support, and how are they selected?

The MAX8836ZEREEE+ provides two fixed output voltages: 3.4V when HP = 0 (default, pulled down internally), and 3.1V when HP = 1. This selection is digital and non-volatile-no external resistors or programming are needed. Both outputs maintain ±2% accuracy over temperature and load, and the 25µs settling time between levels supports rapid PA gain switching in WCDMA/CDMA protocols.

How does the MAX8836ZEREEE+ achieve ultra-low dropout in bypass mode?

The MAX8836ZEREEE+ achieves ultra-low dropout using an integrated 60mΩ p-channel MOSFET that directly connects IN1A/IN1B to PAA/PAB during bypass mode. At 1A load, this yields <100mV dropout-critical for maintaining PA efficiency near end-of-battery life. The bypass threshold is referenced to IN2 (not IN1) to avoid false triggering from switching noise, ensuring reliable engagement only during true high-duty-cycle conditions.

Can the MAX8836ZEREEE+ LDO2 output be used independently of the PA converter?

Yes-the MAX8836ZEREEE+ LDO2 output (200mA, 2.85V) is fully independent: it has its own enable pin (EN2), input supply (IN2), and reference (REFBP). It operates even when PA_EN = 0 and the buck stage is disabled. This allows flexible power sequencing-for example, powering baseband logic before enabling the PA rail-and maintains low 35µVRMS noise regardless of buck-stage activity.

What is the purpose of the REFBP pin on the MAX8836ZEREEE+, and how should it be decoupled?

The REFBP pin on the MAX8836ZEREEE+ provides access to the internal 1.25V bandgap reference used by both the buck and LDO regulators. Bypassing REFBP to AGND with a 0.22µF ceramic capacitor reduces reference noise coupling into the LDO output, directly lowering LDO2 output noise to 35µVRMS. During shutdown, REFBP is internally pulled down through a 1kΩ resistor-no external pull-down is needed.

Does the MAX8836ZEREEE+ require external compensation components for stability?

No-the MAX8836ZEREEE+ uses a hysteretic PWM control architecture with voltage-positioning feedback, eliminating the need for external compensation. Its loop stability is inherent: the feedback path samples the LX node directly, removing phase lag from the output capacitor. This allows stable operation with as little as 4.7µF ceramic output capacitance and no external RC networks-reducing BOM count and PCB area.