Analog Devices Inc./Maxim Integrated MAX8805ZEWECC+T

Overview

MAX8805ZEWECC+T from Maxim Integrated is a 4MHz, 2V/V gain, 600mA high-frequency step-down converter with dual 200mA low-noise LDOs and integrated 60mΩ bypass FET, designed specifically to dynamically power the power amplifier (PA) in WCDMA/NCDMA handsets. It supports analog DAC-controlled output voltage (0.4V–VBATT), delivers 7.5µs settling time for 0.8V→3.4V transitions, and operates from 2.7V–5.5V input.

For engineers reviewing the MAX8805ZEWECC+T datasheet, MAX8805ZEWECC+T pinout, MAX8805ZEWECC+T application, or MAX8805ZEWECC+T equivalent, key selection considerations include its 4MHz switching frequency, 2V/V REFIN-to-PA gain, 600mA PA output drive, dual independent LDO enable control, and 2mm × 2mm UCSP package with 16-bump layout.

Technical Context

The MAX8805ZEWECC+T implements a hysteretic PWM control scheme enabling fast transient response and stable operation with minimal external components-only 2.2µF ceramic capacitors required on input/output. Its voltage-positioning feedback architecture removes phase lag by sampling LX directly, eliminating need for large output capacitance while achieving tight load regulation.

Bypass mode is activated either automatically when VREFIN exceeds 0.465×VIN2 (enabling seamless transition during high-power PA transmission) or forcibly via HP logic input. The internal 60mΩ p-channel bypass FET ensures low dropout (<100mV at 90mA) and supports up to 2.9A total bypass current (1.1A step-down + 1.8A bypass path).

Key Specifications

Pinout & Package

The MAX8805ZEWECC+T is housed in a 16-bump, 2mm × 2mm × 0.7mm UCSP (Ultra-Compact Silicon Package) with 4×4 bump grid, optimized for high-density mobile PCB layouts and thermal performance in thin-profile handsets.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX8805YEREEC+T and MAX8805XEREEC+T, the MAX8805ZEWECC+T uniquely balances 4MHz speed, 2V/V linearity, and 600mA drive for mainstream WCDMA PA applications-offering optimal trade-off between size, noise, and dynamic response without requiring gain recalibration or layout changes.

Availability

MAX8805ZEWECC+T is available at Aetrix Electronics and suitable for WCDMA 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 MAX8805ZEWECC+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 portable, automotive, and industrial applications.

The MAX8805 family was engineered specifically for dynamic PA power control in 3G cellular handsets, integrating step-down conversion, bypass FET, and dual LDOs to replace 6+ discrete components in space-constrained RF power chains.

FAQ

What is the switching frequency of the MAX8805ZEWECC+T?

The MAX8805ZEWECC+T operates at a fixed 4MHz switching frequency. This high frequency allows the use of small 2.2µF ceramic input and output capacitors, significantly reducing solution size compared to lower-frequency alternatives. It also shifts switching noise above sensitive RF bands, easing EMI filtering requirements in handset designs.

What output voltage range does the MAX8805ZEWECC+T support for the PA rail?

The MAX8805ZEWECC+T supports a dynamically adjustable PA output voltage from 0.4V to VBATT (up to 5.5V), set linearly by the analog REFIN input using a 2V/V gain. For example, a 0.9V REFIN produces ~1.8V at PAA/PAB. The device maintains regulation down to 0.4V while delivering up to 600mA, making it suitable for modern low-voltage PAs.

How does the bypass mode function in the MAX8805ZEWECC+T?

The MAX8805ZEWECC+T features both automatic and forced bypass modes. Automatic bypass engages when VREFIN exceeds 0.465×VIN2, connecting IN1A/IN1B directly to PAA/PAB via the internal 60mΩ p-channel FET. Forced bypass is triggered by driving the HP pin high. In either mode, the step-down converter enters 100% duty cycle, minimizing dropout and maximizing efficiency during high-power transmission bursts.

What are the key differences between the MAX8805ZEWECC+T and MAX8805YEREEC+T?

The MAX8805ZEWECC+T and MAX8805YEREEC+T share the same 2V/V gain, 600mA PA drive, and UCSP package, but differ in switching frequency (4MHz vs. 2MHz) and settling time (7.5µs vs. 10.2µs). The MAX8805ZEWECC+T achieves faster transient response and smaller external components, while the MAX8805YEREEC+T offers slightly better light-load efficiency and lower EMI fundamental frequency.

Can the dual LDOs in the MAX8805ZEWECC+T be used independently?

Yes, the MAX8805ZEWECC+T provides fully independent control of its two 200mA LDOs via separate EN1 and EN2 logic inputs. Each LDO can be enabled or disabled without affecting the other or the PA step-down converter. This enables flexible power sequencing-for example, powering LDO1 for PA bias while keeping LDO2 off until auxiliary circuitry is ready-reducing system standby current.