Analog Devices Inc./Maxim Integrated DS2781G+

Overview

DS2781G+ from Maxim Integrated is a standalone 1-cell or 2-cell Li-ion/Li-polymer fuel gauge IC that measures voltage (0–9.99 V, ±100 mV error), temperature (±3°C, 0.125°C resolution), and current (±51.2 mV sense range, ±1% full-scale gain error), and estimates remaining capacity in mAh and % using on-chip FuelPack™ algorithms and 24-byte parameter EEPROM. It operates directly from the battery pack (2.5–10 V) and supports embedded battery management in portable GPS and industrial handheld terminals.

For engineers reviewing the DS2781G+ datasheet, DS2781G+ pinout, DS2781G+ application, or DS2781G+ equivalent, key selection considerations include its 10-pin TDFN-EP package with exposed pad, 1-Wire® multidrop interface (standard/overdrive), SLEEP mode entry via VIN undervoltage or DQ bus-low timeout, and factory-calibrated current gain with user-programmable RSGAIN and RSTC registers for sense-resistor compensation.

Technical Context

The DS2781G+ integrates a 15-bit+sign current ADC sampling at 18.6 kHz, a temperature-compensated voltage ADC with 9.76 mV LSB, and an internal timebase with ±2% error. Its on-chip FuelPack™ algorithm uses three programmable piecewise-linear cell models (Full, Active Empty, Standby Empty) - each with five segments and user-defined breakpoints - to estimate capacity across temperature and load conditions without host-side computation.

It features dual power modes: ACTIVE mode enables continuous measurement and coulomb counting, while SLEEP mode (entered via UVEN or PMOD logic) disables accumulation but preserves register contents and supports wake-up via DQ state change or pull-up. All nonvolatile storage - including ACR backup, COB, AB, and cell parameters - resides in on-chip EEPROM with 50,000 write cycles and 15 ms copy time.

Key Specifications

Pinout & Package

DS2781G+ uses a 3 mm × 4 mm, 10-pin TDFN-EP package with exposed pad (EP) for thermal dissipation. Pin 1 is VB; pins 2 and 3 are tied to VSS; EP must be connected to VSS for optimal thermal performance and noise immunity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar fuel gauge applications.

Compared with DS2781G+, BQ27426YZFT demands host-level algorithm management and lacks direct pack-level autonomy, while MAX17048G+T sacrifices 2S compatibility and programmable SLEEP entry conditions - making DS2781G+ uniquely suited for ruggedized, multi-cell, standalone battery packs requiring minimal host interaction.

Availability

DS2781G+ is available at Aetrix Electronics and suitable for digital video cameras, commercial two-way radios, industrial PDAs and handheld PC data terminals, portable GPS navigation systems, and other portable electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for DS2781G+ 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 precision analog, mixed-signal, and power management ICs for industrial, automotive, and computing applications.

The DS2781G+ belongs to Maxim's fuel gauge IC product line, designed specifically for autonomous, high-accuracy battery capacity estimation in Li-ion/Li-polymer packs without host processor dependency.

FAQ

What is the primary function of the DS2781G+?

The DS2781G+ is a standalone fuel gauge IC that autonomously measures battery voltage, temperature, and current; performs coulomb counting; and estimates remaining capacity in mAh and % using on-chip FuelPack™ algorithms. It requires no host MCU for core fuel-gauging functions and communicates via 1-Wire interface. The DS2781G+ supports both 1-cell and 2-cell Li-ion/Li-polymer configurations and stores calibration data and cell parameters in on-chip EEPROM.

Does the DS2781G+ support multidrop 1-Wire configurations?

Yes, the DS2781G+ supports multidrop 1-Wire buses using its factory-programmed 64-bit unique ID (8-bit family code + 48-bit serial number + 8-bit CRC). All devices on the same bus must operate at the same speed - selected globally via the OVD pin - and the master must use ROM search commands to address individual devices. This enables multiple DS2781G+ units or mixed 1-Wire peripherals (e.g., temperature sensors) on a single data line.

How does the DS2781G+ handle current measurement accuracy across temperature?

The DS2781G+ compensates for sense resistor drift using its programmable RSTC register, which applies temperature-dependent gain correction in steps of 30.5 ppm/°C up to +7782 ppm/°C. Combined with factory-calibrated RSGAIN and periodic ADC offset correction (once per hour), this ensures current measurement remains within ±1% full-scale error across –20°C to +70°C. The DS2781G+ also supports user-defined COB (current offset bias) for fine-tuning static errors.

What power-saving modes does the DS2781G+ offer, and how are they triggered?

The DS2781G+ offers two SLEEP modes: UVEN SLEEP (triggered when VIN falls below 2.45 V or 4.9 V) and PMOD SLEEP (triggered when DQ remains low for ≥2 s). In SLEEP mode, measurement and accumulation halt, reducing current to 3–5 μA while preserving register contents. UVEN SLEEP wakes on DQ state change; PMOD SLEEP wakes when DQ is pulled high. Both modes prevent battery over-discharge and extend shelf life without host intervention.

Can the DS2781G+ be used in 2-cell battery packs?

Yes, the DS2781G+ explicitly supports both 1-cell and 2-cell Li-ion/Li-polymer configurations. Its VIN input accepts 0–9.99 V, covering the full 2S range (0–8.4 V nominal, up to 8.7 V fully charged) with margin. The device performs voltage, temperature, and current measurements independently of cell count, and its FuelPack™ algorithm uses user-programmable cell model parameters to adapt capacity estimation to the specific stack configuration.