Analog Devices Inc./Maxim Integrated DS2781E+

Overview

DS2781E+ 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 error, 0.125°C resolution), and current (±51.2 mV full-scale, ±1% gain error), and estimates remaining capacity in mAh and % using on-chip FuelPack™ algorithms with EEPROM-stored cell characterization. It operates directly from the battery pack (2.5–10 V) and supports embedded battery management in portable GPS and two-way radios.

For engineers reviewing the DS2781E+ datasheet, DS2781E+ pinout, DS2781E+ application, or DS2781E+ equivalent, key selection considerations include its 1-Wire® interface (standard/overdrive modes), dual power modes (ACTIVE/SLEEP), integrated 24-byte parameter + 16-byte user EEPROM, and TSSOP-8 package with verified pin mapping for direct integration into thin prismatic battery packs.

Technical Context

The DS2781E+ implements a dedicated fuel-gauging architecture with separate 15-bit+sign current ADC (18.6 kHz sampling), voltage ADC (9.76 mV LSB), and on-die temperature sensor, all synchronized to an internal timebase (±2% error). Its capacity estimation engine uses real-time inputs-voltage, temperature, accumulated current-and programmable piecewise-linear cell models (Full, Active Empty, Standby Empty) stored in EEPROM.

It features dual SLEEP entry triggers: bus-low detection (tSLEEP = 2 s nominal) and VIN under-voltage (selectable 2.45 V or 4.9 V threshold), both preserving ACR and register state. Communication occurs via Maxim's 1-Wire interface with factory-programmed 64-bit ID, supporting multidrop buses without additional addressing logic.

Key Specifications

Pinout & Package

TSSOP-8 package (3 mm × 4.4 mm, 0.65 mm pitch) with exposed pad not present; pin 1 marked by dot; requires 0.1 µF VB bypass capacitor and direct VSS connection to battery negative terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2781E+, BQ27426YZFT shifts interface complexity to the host and removes programmable cell modeling flexibility, while MAX17048G+T trades dual-cell support and SLEEP versatility for lower power and smaller footprint - making DS2781E+ optimal for rugged, multi-cell industrial battery packs needing deterministic 1-Wire integration.

Availability

DS2781E+ is available at Aetrix Electronics and suitable for commercial two-way radios, portable GPS navigation systems, and industrial PDA designs requiring stable component supply, long-lifecycle support, and RoHS-compliant lead-free packaging.

Supply support for DS2781E+ 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, automotive, and computing applications - with emphasis on reliability, integration, and embedded intelligence.

The DS2781E+ belongs to Maxim's battery fuel gauge product line, engineered specifically for standalone, EEPROM-configurable capacity estimation in 1–2 cell Li-ion/Li-polymer battery packs used in portable professional electronics.

FAQ

What is the primary function of the DS2781E+ in a battery pack?

The DS2781E+ serves as a standalone fuel gauge IC that measures voltage, temperature, and current to estimate remaining capacity in milliamp-hours and percentage of full charge. It executes the FuelPack™ algorithm using on-chip EEPROM-stored cell parameters, eliminating the need for host-side gauging software. The DS2781E+ delivers this information via its 1-Wire interface and supports both 1-cell and 2-cell Li-ion/Li-polymer configurations.

Does the DS2781E+ require an external microcontroller to operate?

No, the DS2781E+ is a stand-alone fuel gauge IC and does not require an external microcontroller to perform voltage, temperature, and current measurements or execute its capacity estimation algorithm. It autonomously updates registers and preserves accumulated current (ACR) in EEPROM. However, a host system (e.g., radio MCU or GPS processor) is needed to read those registers via the 1-Wire interface - the DS2781E+ itself contains no embedded firmware execution unit.

How does the DS2781E+ handle battery pack disconnection detection?

The DS2781E+ detects pack disconnection via its DQ pin: if DQ remains low for tSLEEP (1.5–2.5 s, nominal 2 s), and the PMOD bit is enabled, it enters PMOD SLEEP mode - preserving ACR and register contents while reducing current draw to 3–5 µA. This behavior relies on the absence of the host pull-up voltage on DQ. The DS2781E+ exits SLEEP when DQ transitions high, such as upon reinsertion into a powered system.

Can the DS2781E+ be used with a 2-cell Li-ion battery pack?

Yes, the DS2781E+ explicitly supports both 1-cell and 2-cell Li-ion/Li-polymer battery stacks. Its VIN input accepts up to 9.99 V, covering the full range of a 2-cell pack (0–8.4 V). The device's FuelPack™ algorithm uses programmable cell model curves (Full, Active Empty, Standby Empty) stored in EEPROM to adapt capacity estimation to the specific number of cells and their characteristics - confirmed in the DS2781E+ datasheet Section "Operates in One-Cell or Two-Cell Applications".

What is the role of the OVD pin on the DS2781E+?

The OVD pin on the DS2781E+ selects the 1-Wire communication speed: logic-high enables overdrive mode (140 kbps), while logic-low selects standard timing (16 kbps). All devices on a multidrop 1-Wire bus must use the same speed, so OVD must be tied consistently across slaves. This pin does not affect internal measurement functions - it solely configures the physical layer timing of the 1-Wire interface used to access DS2781E+ registers and EEPROM.