Analog Devices Inc./Maxim Integrated MAX1972EEE+T

Overview

The MAX1972EEE+T from Maxim Integrated is a dual-output, current-mode PWM buck regulator IC operating at a fixed 1.4MHz switching frequency, delivering up to 750mA per output across an input range of 2.6V–5.5V. It features 180° out-of-phase operation, ±1% output voltage accuracy over load/line/temperature, and integrated power-on reset (POR) with 175ms delay and open-drain power-fail output (PFO) triggered at 3.94V input threshold - optimized for USB-powered xDSL modems and compact dual-rail power systems.

For engineers reviewing the MAX1972EEE+T datasheet, MAX1972EEE+T pinout, MAX1972EEE+T application, or MAX1972EEE+T equivalent, this page provides verified functional identity, confirmed pin roles, exact package mapping (16-pin QSOP), real-world efficiency curves, and two validated alternative parts with documented technical and application-level differences.

Technical Context

The MAX1972EEE+T implements a current-mode PWM control architecture with internal slope compensation, using MOSFET on-resistance for current sensing - eliminating external sense resistors. Its dual regulators switch 180° out of phase to reduce input ripple current and enable smaller input capacitors.

It integrates synchronous rectification, soft-start via REF pin (25µA ramp current), undervoltage lockout (2.35V falling threshold), thermal shutdown at 170°C, and a precision 1.200V reference (±1.0% over temperature). The PFO monitors VCC and asserts high when input drops below 3.94V, while POR holds low for 175ms after both outputs reach 92% regulation.

Key Specifications

Pinout & Package

MAX1972EEE+T is housed in a 16-pin QSOP (Quad Small Outline Package) with 0.65mm pitch, thermally enhanced PGND pad, and standard JEDEC MS-013AC footprint. Pin 16 is PGND (power ground), distinct from signal GND (Pin 8), enabling separate analog/digital ground routing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output buck regulator applications.

Compared with MAX1970EEE+T, the MAX1972EEE+T offers longer POR hold time for robust boot sequencing, while TPS65270RGET adds programmability at the cost of missing PFO - making MAX1972EEE+T the optimal choice for USB-powered xDSL and fixed dual-rail applications requiring fail-safe monitoring.

Availability

MAX1972EEE+T is available at Aetrix Electronics and suitable for xDSL modems, USB-powered portable instruments, copper Gigabit SFP modules, and dual-LDO replacement designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for MAX1972EEE+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 computing markets.

The MAX1972EEE+T belongs to Maxim's high-frequency dual buck regulator product line, designed specifically for space-constrained, USB-powered broadband communication equipment requiring precise dual-rail generation and power-fail monitoring.

FAQ

What is the switching frequency of the MAX1972EEE+T and why is it significant?

The MAX1972EEE+T operates at a fixed 1.4MHz switching frequency. This high frequency allows use of small 3.3µH–6.8µH ceramic inductors and low-ESR ceramic capacitors, reducing board area and cost. Critically, it places switching noise outside the xDSL upstream band (25–138kHz), preventing interference in DSL modem applications - a key design requirement confirmed in Maxim's application notes.

Does the MAX1972EEE+T support sub-1V output voltages, and how is this achieved?

Yes, the MAX1972EEE+T supports sub-1V outputs (down to 0.8V) on one channel when the other output is set above 1.2V. This is implemented using cross-coupled feedback resistors between FB1 and FB2, as detailed in the Output Voltage Selection section of the datasheet. The configuration requires no additional ICs and maintains ±1% accuracy, enabling direct powering of low-voltage I/O domains like DDR3L or LPDDR interfaces.

How does the PFO (power-fail output) function in the MAX1972EEE+T?

The PFO in the MAX1972EEE+T is an open-drain output that goes high when the input voltage (VCC) falls below 3.94V (typical falling threshold). It is specifically intended for USB power failure detection in xDSL modems. The output requires an external pullup resistor (10–100kΩ) to VCC or an output rail and can sink ≥1mA at 0.05V low level - enabling direct interfacing with microcontroller interrupt pins or supervisor ICs.

What is the purpose of the 175ms POR delay in the MAX1972EEE+T?

The 175ms POR delay in the MAX1972EEE+T ensures the device holds its active-low reset signal until both output rails have stabilized and remain within regulation for a defined period. This provides sufficient time for downstream microcontrollers, FPGAs, or memory devices to complete power-up sequencing and internal initialization before release - a critical timing margin verified across -40°C to +85°C operation.

Can the MAX1972EEE+T replace discrete LDOs, and what efficiency advantage does it offer?

Yes, the MAX1972EEE+T is explicitly positioned as a dual LDO replacement. At 500mA load with VIN=5V, VOUT1=3.3V/VOUT2=2.5V, it achieves >88% efficiency - versus typical LDO efficiency of ~65% under same conditions. This 23% improvement reduces thermal load, eliminates heat sinks, and extends battery life in portable USB-powered devices, as confirmed by Maxim's efficiency curves (Fig. MAX1970TOC01).