The MAX17040, MAX17041, and MAX17042 are a series of fuel gauge chips produced by Maxim Integrated, primarily used for measuring the capacity of lithium-ion (Li+) batteries in handheld and portable devices. Here are the main parameters and characteristics of these chips:

MAX17040
Application: Fuel gauge for single-cell Li-ion batteries.
Voltage Measurement Accuracy: Provides ±12.5mV accuracy for 5.00V.
Algorithm: Utilizes the ModelGauge™ algorithm for precise Relative State-of-Charge (RSOC) calculations, eliminating the need for a full charge-discharge learning cycle or a sense resistor.
Interface & Package: Supports a 2-wire interface (e.g., I²C), low power consumption, and small form factor (8-pin, 2mm x 3mm TDFN leadless package) or 9-ball UCSP™ package with 0.4mm pitch.
Features: Offers temperature compensation, reduces microcontroller (µC) interaction, and a fast-start mode for accurate initial SOC estimation, allowing the IC to be placed on the system side, reducing costs and constraints on battery power supply links.

MAX17041
Application: Fuel gauge for two-cell (2S) battery packs.
Voltage Measurement Accuracy: Provides ±30mV accuracy for 10.00V (slightly lower precision compared to MAX17040 but suitable for higher voltage ranges).
Algorithm & Interface: Also employs the ModelGauge™ algorithm, supports a 2-wire interface (e.g., I²C), and offers similar characteristics and advantages as the MAX17040.
Package: Available in the same small form factor packages as the MAX17040.

MAX17042
Presumed Application: Although specific parameters are not readily available, based on naming conventions and the series' typical offerings, the MAX17042 is likely designed for fuel gauging of specific battery configurations (such as higher cell counts or specialized applications).
Features: Potentially inherits the high-precision voltage measurement, ModelGauge™ algorithm, low power consumption, and small form factor packaging of the MAX17040/MAX17041, with optimizations for specific requirements.

Common Characteristics
High Precision: All chips offer high-precision voltage measurement and capacity estimation.
Intelligent Management: Enables intelligent battery management through the ModelGauge™ algorithm, eliminating complex calibration processes.
Low Power Consumption: Suitable for portable devices with stringent power consumption requirements.
Versatile Applications: Used in a wide range of applications, including digital cameras, video and action cameras, handheld computers and terminals, health monitoring devices, medical equipment, wireless speakers, and more.