Analog Devices Inc./Maxim Integrated MAX1797EUA+T

Overview

MAX1797EUA+T from Maxim Integrated is a high-efficiency, step-up DC-DC converter optimized for portable battery-powered devices. It delivers up to 1A output current with 95% peak efficiency, operates from 0.7V input down to startup at 0.85V, and supports pin-selectable 3.3V or 5.0V outputs - used in wireless handsets and portable terminals requiring ultra-low quiescent current and True Shutdown™.

For engineers reviewing the MAX1797EUA+T datasheet, MAX1797EUA+T pinout, MAX1797EUA+T application, or MAX1797EUA+T equivalent, key selection criteria include its 1A current limit, 25μA operating supply current, 2μA shutdown current, LX-damping for EMI reduction, and integrated LBI/LBO comparator active during shutdown.

Technical Context

The MAX1797EUA+T employs a minimum-off-time, current-limited control scheme combining PWM-like power delivery with pulse-skipping efficiency at light loads - enabling up to 500kHz switching frequency dependent on load and input voltage. Its internal synchronous rectifier eliminates external Schottky diodes, while proprietary LX-damping circuitry suppresses ringing using an integrated damping switch (RDAMP = 100–400Ω).

True Shutdown™ fully disconnects OUT from BATT via internal NFET/PFET isolation, placing OUT in high-impedance state with <2μA shutdown current. The LBI/LBO comparator remains functional in shutdown, supporting autonomous low-battery cutoff by connecting LBO to SHDN - with VLBI threshold of 0.85V (±25mV hysteresis) and ILBI ≤100nA.

Key Specifications

Pinout & Package

MAX1797EUA+T is housed in an 8-pin μMAX package (3.0mm × 3.0mm × 1.09mm), RoHS-compliant and thermally enhanced with exposed pad (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-up DC-DC converter applications.

Compared with TPS61040DRBT and LT1930ES5#TRMPBF, MAX1797EUA+T uniquely combines 1A current capability, True Shutdown™ output isolation, integrated LBI/LBO, and LX-damping - making it optimal for compact, battery-critical portable designs where autonomy and EMI compliance are mandatory.

Availability

MAX1797EUA+T is available at Aetrix Electronics and suitable for portable digital audio players, wireless handsets, and portable terminals requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MAX1797EUA+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 U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs for power, sensing, and communication applications.

The MAX1795/MAX1796/MAX1797 family was designed specifically for ultra-low-power, small-footprint step-up conversion in single-cell battery systems - emphasizing startup from sub-1V inputs, minimal quiescent current, and integrated system-level features like battery monitoring and EMI control.

FAQ

What is the minimum input voltage required for MAX1797EUA+T to start up?

The MAX1797EUA+T guarantees startup from +0.85V at TA = +25°C with RL = 3kΩ load. Once started, it continues operating down to +0.7V input. This enables reliable operation from nearly depleted alkaline or NiMH cells. Startup voltage varies slightly with temperature (−2.2mV/°C tempco) and load, but remains within 0.85V to 1.0V across −40°C to +85°C.

Can MAX1797EUA+T generate an adjustable output voltage, and how is it set?

Yes, MAX1797EUA+T supports adjustable output from +2.0V to +5.5V using a resistive voltage divider between OUT and GND, with FB connected to the divider midpoint. The internal feedback reference is 1.24V (±0.04V). To set VOUT, use R1 = R2 × [(VOUT / 1.24) − 1], selecting R2 ≤ 250kΩ to ensure accuracy and minimize bias current error.

How does the True Shutdown™ feature of MAX1797EUA+T improve system design?

True Shutdown™ fully disconnects the output from the input using internal NFET/PFET isolation, placing OUT in high-impedance state with <2μA shutdown current. This eliminates the need for external blocking MOSFETs or Schottky diodes, prevents battery drain through downstream loads, and simplifies power sequencing - especially critical in always-connected portable devices.

What is the purpose of the LX-damping circuit in MAX1797EUA+T, and does it affect output ripple?

The LX-damping circuit integrates a switch (RDAMP = 100–400Ω) that dissipates residual inductor energy after each switching cycle, suppressing high-frequency ringing at the LX node. This reduces radiated and conducted EMI without increasing output voltage ripple - which remains governed solely by inductor current ripple and output capacitor ESR.

Is the LBI/LBO comparator in MAX1797EUA+T functional during shutdown mode?

Yes, the LBI/LBO comparator remains fully operational during shutdown. LBI accepts input down to 0.7V, trips at 0.85V (±25mV hysteresis), and drives open-drain LBO high-impedance when below threshold. This allows autonomous low-battery cutoff - for example, by connecting LBO to SHDN - even when the main converter is disabled.