Analog Devices Inc./Maxim Integrated DS2746G-C02+TR

Overview

DS2746G-C02+TR from Maxim Integrated is a low-cost, 2-wire battery monitor IC for system-side fuel gauging in portable electronics. It provides ratiometric 11-bit auxiliary A/D inputs, 14-bit bidirectional current measurement (±51.2mV range), and 11-bit battery voltage sensing (0–4.5V) with ±10mV accuracy at 3.6V. It operates in active mode (70µA typical) or sleep mode (1µA typical) and supports thermistor and pack ID resistor monitoring in smartphones and digital cameras.

For engineers reviewing the DS2746G-C02+TR datasheet, DS2746G-C02+TR pinout, DS2746G-C02+TR application, or DS2746G-C02+TR equivalent, key selection criteria include its 10-pin 3mm×3mm TDFN package, 2-wire interface compatibility up to 400kHz, ratiometric auxiliary input architecture, coulomb counting resolution (417µAhr LSB), and integrated offset bias/blanking features for high-accuracy charge accumulation.

Technical Context

The DS2746G-C02+TR implements dual independent A/D converters: one 14-bit signed current ADC measuring differential voltage across an external sense resistor (SNS–VSS), and one 11-bit voltage ADC multiplexing VIN, AIN0, and AIN1 sequentially every 660ms. Current integration occurs in hardware via the Accumulated Current Register (ACR), updated every 878ms with 6.25µVh LSB resolution.

VOUT drives external resistor dividers for AIN0/AIN1, enabling ratiometric measurement that eliminates supply-voltage error; VOUT is precharged for 13.3–14.2ms before each auxiliary conversion and disabled afterward to minimize power. Sleep mode activation requires both SCL and SDA held low for 1.5–2.2s when SMOD=1, and wake-up occurs on any VIH-level transition on either line.

Key Specifications

Pinout & Package

DS2746G-C02+TR uses a 10-pin 3mm × 3mm TDFN package with exposed thermal pad (connected to VSS). Pin functions are validated per Maxim's official datasheet (Rev. 19-4632).

Key Features

Applications

Equivalent & Alternatives

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

Compared with BQ27426YZFT and MAX17048G+T, DS2746G-C02+TR offers simpler integration via standard I²C, lower BOM cost due to external sense resistor flexibility, and deterministic coulomb counting without proprietary algorithms - making it optimal for cost-sensitive, firmware-light implementations.

Availability

DS2746G-C02+TR is available at Aetrix Electronics and suitable for smartphone battery management, digital camera fuel gauging, and handheld terminal runtime estimation requiring stable component supply and long-term industrial availability.

Supply support for DS2746G-C02+TR 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) designs precision analog, mixed-signal, and power management ICs for industrial, computing, and portable applications.

The DS2746G-C02+TR belongs to Maxim's battery fuel gauge product line, engineered specifically for cost-sensitive, system-side battery monitoring in 2.5G/3G handsets and PDAs where high-resolution coulomb counting and ratiometric auxiliary sensing are essential.

FAQ

What is the primary function of the DS2746G-C02+TR in a battery-powered system?

The DS2746G-C02+TR serves as a system-side battery monitor IC that performs real-time coulomb counting, battery voltage measurement, and ratiometric auxiliary voltage sensing (e.g., thermistor, pack ID). It delivers these measurements over a 2-wire I²C interface to a host processor, enabling accurate fuel gauging without requiring dedicated battery fuel gauge ICs inside the pack. Its design centers on minimizing system power while maintaining measurement fidelity - critical for DS2746G-C02+TR deployments in smartphones and digital cameras.

How does the DS2746G-C02+TR achieve ratiometric measurement on its auxiliary inputs?

The DS2746G-C02+TR achieves ratiometric measurement by driving the VOUT pin to supply the top of external resistor dividers connected to AIN0 and AIN1. The auxiliary A/D converter then measures each input as a fraction of VOUT rather than against a fixed internal reference. This architecture eliminates errors caused by VDD variation because both the reference (VOUT) and measured signal scale together. The DS2746G-C02+TR disables VOUT between conversions to reduce power - a feature confirmed in the device's timing diagrams and register control (VODIS bit).

What is the significance of the CTG pin on the DS2746G-C02+TR?

The CTG (Current Ground) pin on the DS2746G-C02+TR must be connected directly to the battery-side of the current-sense resistor - same net as VSS - to ensure accurate Kelvin sensing of the SNS–VSS differential voltage. This separate physical connection prevents PCB trace resistance from introducing gain or offset errors into current measurement. The DS2746G-C02+TR datasheet explicitly states CTG ties to the "battery side of the sense resistor," confirming its role in maintaining measurement integrity under high-current transients common in DS2746G-C02+TR applications like smartphone charging.

Can the DS2746G-C02+TR operate without external pull-up resistors on SCL and SDA?

No - the DS2746G-C02+TR requires external pull-up resistors on both SCL and SDA lines. Its SDA pin is open-drain and SCL is input-only; neither pin has internal pull-ups. The datasheet cautions that omitting pull-ups prevents wake-up from sleep mode when SMOD=1, as the device relies on VIH-level transitions to exit sleep. DS2746G-C02+TR's 0.2µA internal pulldowns on SCL/SDA are insufficient for bus signaling and serve only for disconnection detection - not bus termination.

What is the maximum sense resistor value supported by the DS2746G-C02+TR for ±3.4A current measurement?

The DS2746G-C02+TR supports ±3.4A full-scale current measurement with a 15mΩ sense resistor, as specified in its datasheet (416.7µA LSB, ±3.4A range). Using Ohm's Law (V = I × R), 3.4A × 15mΩ = 51mV - matching the device's ±51.2mV current-sense input range. Larger resistors (e.g., 20mΩ) extend resolution but reduce full-scale range to ±2.56A; smaller values (e.g., 10mΩ) increase range to ±5.12A but reduce resolution to 625µA/LSB. DS2746G-C02+TR's optimal balance for ±3.4A is therefore 15mΩ, validated in Table 2 of the official documentation.