Analog Devices Inc./Maxim Integrated MAX77178EWC+

Overview

MAX77178EWC+ from Maxim Integrated is a high-bandwidth step-down DC-DC converter IC optimized for dynamic power management of LTE/WCDMA power amplifiers in multiband smartphones and data cards. It delivers 1A peak output current, supports 2.5V–5.5V input, provides four logic-selectable output voltages (1.0V/1.7V/2.325V/2.9V), and achieves ±3% output voltage accuracy with 20µs typical settling time - enabling fast PA envelope tracking in polar transmitter architectures.

For engineers reviewing the MAX77178EWC+ datasheet, MAX77178EWC+ pinout, MAX77178EWC+ application, or MAX77178EWC+ equivalent, key selection criteria include its 8MHz switching frequency, 0.47µH inductor compatibility, WLP-12 package (1.75mm × 1.4mm, 0.4mm pitch), analog-compatible control interface via SEL0/SEL1, and integrated overcurrent/overtemperature protection for robust RF PA supply operation.

Technical Context

The MAX77178EWC+ implements a synchronous buck topology with adaptive smart FET scaling to optimize efficiency across varying PA load conditions. Its 8MHz fixed-frequency PWM operation enables use of miniature 0.47µH inductors and low-ESR ceramic capacitors while maintaining sub-25mV load transient response at 500mA step changes.

Control is implemented via two logic inputs (SEL0, SEL1) that select one of four precise output voltages without external DAC or feedback resistor networks. The device enters skip mode under light loads to reduce no-load supply current to 0.1µA (typ), and features 100% duty-cycle capability for ultra-low dropout operation during battery voltage sag.

Key Specifications

Pinout & Package

MAX77178EWC+ uses a 12-bump Wafer-Level Package (WLP) measuring 1.75mm × 1.4mm with 0.4mm pitch. Bumps are on the bottom side; top-side marking includes "77178" and date code.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX77179EWC+, the MAX77178EWC+ trades analog flexibility for deterministic, software-simple voltage selection - ideal for baseband SoCs with limited GPIO resources. Against TPS628641YKAR, it delivers proven 3GPP-compliant transient performance in a smaller 1.75mm × 1.4mm WLP, but with lower peak current (1A vs. 2A).

Availability

MAX77178EWC+ is available at Aetrix Electronics and suitable for LTE/WCDMA smartphones, mobile data cards, and multimode tablets requiring stable component supply, tight RF timing compliance, and ultra-compact power management integration.

Supply support for MAX77178EWC+ 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 MAX77178 product line delivers high-bandwidth, low-footprint DC-DC converters specifically engineered for dynamic PA power control in 3G/4G mobile devices - prioritizing RF spectral purity, fast transient response, and minimal PCB area.

FAQ

What is the primary function of the MAX77178EWC+ in a mobile RF system?

The MAX77178EWC+ serves as a high-speed, logic-controlled step-down DC-DC converter dedicated to powering LTE and WCDMA power amplifiers. It dynamically adjusts its output voltage (1.0V/1.7V/2.325V/2.9V) via SEL0/SEL1 inputs to match PA efficiency requirements per band or protocol, achieving 20µs settling time to meet 3GPP spectral mask specifications. Its 8MHz switching frequency and WLP-12 package enable compact, thermally efficient integration in space-constrained handsets.

Does the MAX77178EWC+ require external feedback resistors to set output voltage?

No, the MAX77178EWC+ does not require external feedback resistors. Its output voltage is determined solely by the logic states of SEL0 and SEL1 pins, which select one of four factory-trimmed values: 1.0V, 1.7V, 2.325V, or 2.9V. This eliminates resistor networks, saves PCB area, and removes drift-related inaccuracies - all output voltages maintain ±3% accuracy over -40°C to +85°C without calibration.

Can the MAX77178EWC+ operate with a 0.47µH inductor, and why is this value specified?

Yes, the MAX77178EWC+ is explicitly designed for use with a 0.47µH inductor, as confirmed in the datasheet's Electrical Characteristics and Applications Information sections. This value enables optimal performance at 8MHz switching frequency - balancing core loss, DC resistance, and saturation current (≥2.1A) while minimizing physical size (e.g., TDK VLS201610ET-R47N). Using 0.47µH allows full 1A output capability with <25mV load transient ripple and supports the IC's adaptive FET scaling algorithm.

What protection features are integrated into the MAX77178EWC+?

The MAX77178EWC+ integrates overcurrent protection (high-side limit: 1.2–2.0A), overtemperature shutdown (160°C junction, 20°C hysteresis), and input undervoltage lockout (2.2V threshold with 100mV hysteresis). It also features a 0.1µA (typ) shutdown mode and automatic bypass mode entry when VIN–VOUT < 125mV. These protections ensure robust operation during PA fault events, battery sag, or thermal overload without external circuitry.

Is the MAX77178EWC+ pin-compatible with the MAX77179EWC+?

No, the MAX77178EWC+ and MAX77179EWC+ are not pin-compatible. While both use the same 12-bump WLP-12 package (1.75mm × 1.4mm), their pin functions differ: MAX77178EWC+ uses B1/B1/C1 for SEL0/SEL1, whereas MAX77179EWC+ uses those bumps for MODE_SEL/BYP/REF. The AGND, EN, INx, LX, FB, GSNS, and PGND pins align, but logic-control and analog-control pins are mutually exclusive - requiring PCB redesign for substitution.