Analog Devices Inc./Maxim Integrated MAX8668ETEP+

Overview

MAX8668ETEP+ from Maxim Integrated is a dual step-down DC-DC converter with dual low-noise LDO regulators, designed to power microprocessors and DSPs in portable electronics. It delivers 600mA on OUT1 and 1200mA on OUT2 with adjustable output voltages from 0.6V to 3.3V, operates at 1.5MHz hysteretic-PWM, and achieves 100µA no-load supply current with all outputs enabled - enabling compact, high-efficiency power delivery in smartphones and digital cameras.

For engineers reviewing the MAX8668ETEP+ datasheet, MAX8668ETEP+ pinout, MAX8668ETEP+ application, or MAX8668ETEP+ equivalent, key selection criteria include guaranteed output current per rail, input voltage ranges (IN12: 2.6–5.5V; IN34: 1.7–5.5V), individual enable control per regulator, LDO dropout voltage (≤250mV @ 300mA), and thermal shutdown threshold (+160°C).

Technical Context

The MAX8668ETEP+ integrates two synchronous step-down converters using a proprietary hysteretic-PWM architecture operating at 1.5MHz, enabling ultra-small external components (e.g., 2.2µH inductors) and fast transient response. Each buck stage features p-channel high-side switches (R_DS(ON) ≤ 0.6Ω for OUT1, ≤ 0.27Ω for OUT2) and valley-current limiting (1200mA min for OUT2, 600mA min for OUT1).

It also includes two independent LDOs (OUT3/OUT4), each delivering up to 300mA with 20µA quiescent current, 75µV_RMS output noise (100Hz–100kHz), and operation down to 1.7V input. All four regulators feature individual enables (EN1–EN4), soft-start (100µs for LDOs, variable for bucks), and separate power-ground pins (PGND1/PGND2) for optimal noise isolation.

Key Specifications

Pinout & Package

MAX8668ETEP+ is housed in a 3mm × 3mm, 16-pin thin QFN package with exposed paddle (EP) that must be connected to GND, PGND1, and PGND2 for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-buck + dual-LDO power management applications.

Compared with TPS65023RGZR and ADP5022ACPZ-2-R7, the MAX8668ETEP+ uniquely combines adjustable buck outputs (0.6V–3.3V), voltage positioning capability, and industry-leading 100µA no-load current - making it optimal for next-generation portable devices requiring both flexibility and battery longevity.

Availability

MAX8668ETEP+ is available at Aetrix Electronics and suitable for smartphone, digital camera, portable media player, and handheld instrument applications requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MAX8668ETEP+ 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, automotive, communications, and consumer markets.

The MAX8667/MAX8668 product line was engineered specifically for space-constrained portable electronics, integrating dual high-efficiency buck converters and dual low-noise LDOs with independent enable control to simplify multi-rail power design.

FAQ

What is the maximum input voltage rating for the MAX8668ETEP+ step-down regulators?

The MAX8668ETEP+ step-down regulators (OUT1 and OUT2) have an absolute maximum input voltage rating of +6.0V on IN12, but the recommended operating range is 2.6V to 5.5V. Exceeding 5.5V may trigger overvoltage protection or cause permanent damage. The IN34 supply for LDOs is rated up to +6.0V relative to GND but must remain ≤ VIN12 and within 1.7V–5.5V for normal operation. Always observe the 0.3V negative tolerance limit on all pins.

Can the MAX8668ETEP+ support voltage positioning on both buck outputs simultaneously?

Yes, the MAX8668ETEP+ supports voltage positioning on both OUT1 and OUT2 via separate FB1 and FB2 pins. Each feedback node can be configured with a three-resistor network (R1/R2/R6) to sense voltage at the LX node, enabling programmable droop proportional to load current and inductor DCR. This reduces output voltage deviation during load transients and lowers total output capacitance requirements for both rails independently.

What is the thermal resistance (θ_JA) of the MAX8668ETEP+ in its 3mm × 3mm QFN package?

The MAX8668ETEP+ has a typical junction-to-ambient thermal resistance (θ_JA) of 48°C/W when mounted on a standard 4-layer PCB with the exposed paddle fully soldered to a 1-inch² copper pour. This value assumes 2 oz. copper, internal ground/power planes, and no additional heatsinking. For continuous 1.2A operation on OUT2, die temperature rise is ~58°C above ambient - well below the +150°C max junction limit under typical conditions.

Does the MAX8668ETEP+ require external compensation components for stability?

No, the MAX8668ETEP+ uses a hysteretic-PWM control architecture that is inherently stable and does not require external compensation components. Its 1.5MHz fixed-frequency operation and internal error amplifier eliminate the need for loop compensation networks (e.g., type-II/III compensators), simplifying design and reducing BOM count. Stability is maintained across all load and input conditions specified in the datasheet.

How does the MAX8668ETEP+ handle power sequencing between its four regulated outputs?

The MAX8668ETEP+ provides full power sequencing control through four independent enable inputs (EN1–EN4). Each regulator starts soft-start only when its respective EN pin is driven high; the first enable after shutdown incurs a longer t_PWRON (25µs for bucks, 45µs for LDOs), while subsequent enables use shorter t_EN (15µs/35µs). This allows designers to implement arbitrary sequencing - e.g., enabling LDOs before bucks, or powering core before I/O - without external timers or supervisors.