Analog Devices Inc./Maxim Integrated DS2746G+

Overview

DS2746G+ from Maxim Integrated is a low-cost, 2-wire battery monitor IC for system-side fuel gauging in portable electronics. It performs ratiometric 11-bit auxiliary voltage measurements (AIN0/AIN1), 11-bit battery voltage sensing (VIN), and 14-bit bidirectional current measurement (±51.2mV full-scale) with integrated coulomb counting via an accumulated current register (ACR). It operates from 2.5V to 4.5V and targets cost-sensitive handheld devices requiring accurate state-of-charge estimation.

For engineers reviewing the DS2746G+ datasheet, DS2746G+ pinout, DS2746G+ application, or DS2746G+ equivalent, key selection considerations include its 10-pin 3mm×3mm TDFN package, 70µA typical active current, ±10mV voltage accuracy at 3.6V, ratiometric A/D architecture eliminating supply error, and sleep-mode current of 1µA - all critical for battery-powered system power budgeting and precision monitoring.

Technical Context

The DS2746G+ implements independent voltage and current A/D converters: a dedicated 11-bit SAR ADC measures VIN, AIN0, and AIN1 sequentially every 660ms (220ms per channel), while a separate 14-bit signed-current ADC samples SNS–VSS differentially every 878ms. VOUT enables only during auxiliary conversions to drive resistor dividers, reducing system power.

Its 2-wire interface uses fixed slave address 0x6C (0110110b), supports up to 400kHz clock frequency, and features automatic sleep entry after 1.5–2.2s of bus inactivity (SCL & SDA < VIL), with wake-up triggered by any VIH-level transition on either line - enabling host-controlled power management without external interrupts.

Key Specifications

Pinout & Package

DS2746G+ is housed in a 10-pin, 3mm × 3mm TDFN package with exposed thermal pad (connected to VSS). The compact 9mm² footprint supports high-density portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery monitor applications.

Compared with DS2746G+, MAX17043G+U offers superior SoC accuracy and algorithmic compensation but at higher complexity and cost, while BQ27426YZFT delivers production-ready gas gauge performance with less design effort but narrower feature flexibility in custom current-sense configurations.

Availability

DS2746G+ is available at Aetrix Electronics and suitable for smartphone battery management, digital camera power monitoring, PDA fuel gauging, industrial portable scanner power, and handheld terminal applications requiring stable component supply and RoHS-compliant packaging.

Supply support for DS2746G+ 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 precision analog, mixed-signal, and power management ICs for industrial, communications, and consumer markets.

The DS2746G+ belongs to Maxim's battery fuel-gauge product line, designed specifically for cost-sensitive, space-constrained portable electronics requiring accurate real-time coulomb counting and auxiliary sensor interfacing without host processor overhead.

FAQ

What is the primary function of the DS2746G+ in a battery management system?

The DS2746G+ serves as a system-side battery monitor IC that performs real-time voltage, bidirectional current, and auxiliary voltage measurements to enable accurate fuel gauging. It integrates a coulomb counter (ACR register), ratiometric A/D inputs for thermistors or ID resistors, and a low-power 2-wire interface - all within a 10-pin TDFN package. Its core role is to provide host processors with precise, low-overhead battery state data without requiring complex calibration or external computation.

Does the DS2746G+ support direct connection to a Li-ion battery pack without additional protection circuitry?

Yes, the DS2746G+ can interface directly with a Li-ion battery pack for voltage and current monitoring, but it is not a protection IC. It requires external components: a sense resistor (e.g., 15mΩ) between SNS and VSS, decoupling capacitors on VDD, and pull-up resistors on SCL/SDA. For overvoltage, overcurrent, or short-circuit protection, a separate protection IC (e.g., DW01A) must be used alongside DS2746G+ in the full BMS design.

How does the ratiometric measurement architecture of the DS2746G+ improve accuracy for thermistor readings?

The DS2746G+ measures AIN0 and AIN1 as a percentage of VOUT rather than against a fixed internal reference. Since both the thermistor divider output and VOUT share the same supply path, ratio-based conversion cancels out errors caused by VDD drift or noise. This eliminates the need for tight regulation of VDD and improves thermistor reading stability across varying battery voltages - a key advantage in single-cell Li-ion systems where VDD sags during load.

What is the significance of the VOUT pin timing and how is it controlled in the DS2746G+?

The VOUT pin in the DS2746G+ supplies the reference voltage for auxiliary resistor dividers and is activated only during AIN0/AIN1 conversions to minimize power draw. It precharges for 13.3–14.2ms before AIN0 sampling and remains active through both AIN0 and AIN1 measurements. Its operation is software-controllable via the VODIS bit in the Status/Config register (address 01h); clearing VODIS = 0 enables automatic gating, while setting VODIS = 1 disables VOUT entirely.

Can the DS2746G+ maintain accurate accumulated current (ACR) during extended sleep periods?

Yes, the DS2746G+ retains the Accumulated Current Register (ACR) value in volatile memory during sleep mode, consuming only 1µA typical current. While the ACR is not stored in nonvolatile memory, its contents remain intact as long as VDD is maintained above 2.5V. No recalibration is needed upon wake-up, and current accumulation resumes immediately upon exiting sleep - making DS2746G+ suitable for intermittent-monitoring applications like smart battery packs in standby devices.