Analog Devices Inc./Maxim Integrated MAX8805ZEWEDD+T

Overview

MAX8805ZEWEDD+T from Maxim Integrated is a 4MHz, 600mA high-frequency step-down converter with integrated 60mΩ bypass FET and dual 200mA low-noise LDOs, designed specifically for dynamic power control of WCDMA/NCDMA power amplifiers in mobile handsets. It supports analog voltage positioning via REFIN input (2V/V gain), delivers 7.5µs settling time for 0.8V–3.4V output transitions, and operates from 2.7V–5.5V input.

For engineers reviewing the MAX8805ZEWEDD+T datasheet, MAX8805ZEWEDD+T pinout, MAX8805ZEWEDD+T application, or MAX8805ZEWEDD+T equivalent, key selection criteria include its 4MHz switching frequency for minimal external component count, automatic/forced bypass mode for PA efficiency optimization, dual independent LDO enable control, and 2mm × 2mm UCSP package compatibility with space-constrained RF front-end layouts.

Technical Context

The MAX8805ZEWEDD+T implements a hysteretic PWM control scheme enabling fast transient response and stable operation with only 2.2µF ceramic input/output capacitors. Its voltage-positioning feedback architecture removes phase lag by sampling LX directly, allowing precise load regulation (ΔVOUT ≈ 0.5 × LESR × ILOAD) without large output capacitance.

Bypass mode is triggered either automatically when VREFIN exceeds 0.465 × VIN2 or forcibly via HP logic input, engaging the 60mΩ p-channel MOSFET to connect IN1A/IN1B directly to PAA/PAB-enabling >1.2A total current delivery with sub-100mV dropout at 90mA while disabling the PWM stage.

Key Specifications

Pinout & Package

MAX8805ZEWEDD+T is housed in a 16-bump, 2mm × 2mm × 0.7mm UCSP (Ultra Compact Silicon Package) with 4×4 bump grid and lead-free/RoHS-compliant finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8805YERExy+T, MAX8805ZEWEDD+T offers smaller passive components and tighter layout tolerance due to 4MHz operation; compared with MAX8805XERExy+T, it provides lower REFIN voltage range for same PA output, easing DAC design but limiting maximum V_{PA_} at fixed V_BATT.

Availability

MAX8805ZEWEDD+T is available at Aetrix Electronics and suitable for WCDMA/NCDMA handset design, smartphone RF front-end development, and wireless PDA power management requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX8805ZEWEDD+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX8805 family is engineered for dynamic PA power control in 3G cellular handsets, integrating step-down conversion, bypass FET, and dual LDOs into a single ultra-compact UCSP to replace discrete solutions and reduce RF subsystem complexity.

FAQ

What is the switching frequency of the MAX8805ZEWEDD+T and why does it matter?

The MAX8805ZEWEDD+T operates at 4MHz. This high frequency allows the use of small 2.2µF ceramic input and output capacitors and minimizes inductor size-reducing total solution footprint by up to 40% versus 2MHz alternatives like the MAX8805Y. It also improves transient response and shifts switching noise above sensitive RF bands.

How does the MAX8805ZEWEDD+T handle high-power PA transmission bursts?

The MAX8805ZEWEDD+T handles high-power bursts using its integrated 60mΩ bypass FET. When triggered-either automatically (via REFIN threshold) or forcibly (via HP pin)-it connects the battery directly to the PA outputs (PAA/PAB), delivering >1.2A with <100mV dropout while disabling the PWM stage to eliminate switching losses.

What is the REFIN-to-PA_{_} gain for the MAX8805ZEWEDD+T and how is it used?

The MAX8805ZEWEDD+T has a 2V/V REFIN-to-PA_{_} gain. A DAC-driven analog voltage applied to REFIN (0.4V–2.0V) sets the PA output as V_{PA_} = 2 × V_REFIN, enabling continuous, noise-immune power adjustment across the full WCDMA transmit range without digital interface overhead.

Can the dual LDOs on the MAX8805ZEWEDD+T be used independently?

Yes-the MAX8805ZEWEDD+T provides independent enable inputs (EN1 and EN2) for each 200mA LDO. This allows staggered power-up, selective powering of PA bias circuits, and dynamic shutdown of unused LDOs to reduce quiescent current-critical for battery-operated handset sleep modes.

What package type and dimensions does the MAX8805ZEWEDD+T use?

The MAX8805ZEWEDD+T uses a 16-bump, 2mm × 2mm × 0.7mm UCSP (Ultra Compact Silicon Package) with lead-free/RoHS-compliant finish. Its 4×4 bump grid and low profile make it ideal for thin, space-constrained mobile handset PCBs where thermal and EMI performance are tightly coupled to package geometry.