Analog Devices Inc./Maxim Integrated DS2438Z+T&R

Overview

DS2438Z+T&R from Maxim Integrated is a 1-Wire® smart battery monitor IC with on-chip temperature sensing (−55°C to +125°C, 0.03125°C resolution), 10-bit battery voltage ADC (0–10 V, 10 mV LSB), integrated current accumulator for fuel gauging, elapsed time meter (1-second resolution, 136-year range), and 40-byte nonvolatile EEPROM - deployed in portable computing and cellular phone battery packs.

For engineers reviewing the DS2438Z+T&R datasheet, DS2438Z+T&R pinout, DS2438Z+T&R application, or DS2438Z+T&R equivalent, key selection criteria include 1-Wire interface compatibility, parasitic power operation, battery current monitoring via external sense resistor, temperature accuracy without thermistors, and EEPROM-based battery parameter storage.

Technical Context

The DS2438Z+T&R implements a parasitically powered 1-Wire interface requiring only DQ and GND connections, enabling multi-drop topology with unique 64-bit ROM addressing. Its internal architecture integrates a two's-complement temperature sensor, dual-path ADC (VDD or VAD input selectable), and background current measurement at 36.41 Hz using VSENS± inputs.

It features three accumulators: volatile ICA (net charge, 0.4882 mV·hr LSB), nonvolatile CCA/DCA (charging/discharging lifetime totals, 15.625 mV·hr LSB), and configurable threshold filtering (±2/4/8 LSB) to suppress low-current integration errors. All registers are accessed via 1-Wire memory/control commands after ROM function initialization.

Key Specifications

Pinout & Package

DS2438Z+T&R is housed in an 8-pin SOIC (150-mil) package with exposed pad not electrically connected. Pin 6 and Pin 7 are no-connect (NC) terminals; all other pins are functional and validated per Maxim's official DS2438 datasheet Rev. 070605.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX17043G+T and BQ27426YZFT, the DS2438Z+T&R uniquely delivers 1-Wire multi-drop capability, on-die temperature sensing, and 40-byte user EEPROM in a single SOIC-8 package-making it optimal for legacy or resource-constrained hosts needing minimal interconnect and chemistry-agnostic firmware.

Availability

DS2438Z+T&R is available at Aetrix Electronics and suitable for portable computing, cellular phone battery packs, and handheld instrumentation requiring stable component supply, long-lifecycle support, and lead-free compliance.

Supply support for DS2438Z+T&R 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 digital ICs for industrial, communications, computing, and consumer applications.

The DS2438Z+T&R belongs to Maxim's 1-Wire smart battery monitor product line, engineered to simplify battery pack telemetry by integrating temperature, voltage, current, time, and memory functions into a single parasitically powered device.

FAQ

What is the operating voltage range of the DS2438Z+T&R?

The DS2438Z+T&R operates from 2.4 V to 10.0 V on the VDD pin. It also supports parasitic power mode, where VDD is unconnected and power is drawn solely from the DQ line during high pulses - enabling functionality even when the battery is fully discharged. In parasitic mode, timing and pull-up requirements per the 1-Wire specification must be strictly observed to ensure reliable operation of the DS2438Z+T&R.

Does the DS2438Z+T&R require an external thermistor for temperature measurement?

No, the DS2438Z+T&R includes an on-die temperature sensor with −55°C to +125°C range and 0.03125°C resolution, eliminating the need for external thermistors in battery packs. The sensor is factory-calibrated and outputs data in 13-bit two's complement format via the 1-Wire interface. This integrated capability reduces BOM cost and PCB area while improving thermal response time compared to surface-mounted thermistors - a core design advantage of the DS2438Z+T&R.

How does the DS2438Z+T&R perform battery current measurement?

The DS2438Z+T&R measures battery current by digitizing the voltage across an external sense resistor (RSENS) connected between VSENS+ and VSENS−. It performs background A/D conversions at 36.41 Hz, storing results in two's complement format (0.2441 mV LSB) and updating accumulators accordingly. The DS2438Z+T&R supports offset calibration via a dedicated nonvolatile register and configurable current-threshold filtering to minimize integration drift - essential for accurate fuel gauging over extended use.

Can the DS2438Z+T&R store battery-specific configuration data?

Yes, the DS2438Z+T&R includes 40 bytes of nonvolatile EEPROM (pages 3–7) specifically allocated for user-defined battery data such as chemistry type, nominal capacity, charge methodology, manufacturing date, and calibration coefficients. These bytes are written via 1-Wire memory commands and retained across power cycles and battery disconnects - enabling firmware-agnostic battery customization and field-upgradable pack parameters without modifying the DS2438Z+T&R hardware.

What is the difference between DS2438Z+T&R and DS2438AZ+T&R?

The DS2438AZ+T&R is identical to the DS2438Z+T&R in electrical specifications and pinout but differs in disconnect behavior: the DS2438AZ+T&R does not enter low-power sleep mode when the DQ line goes low for ≥2 seconds (i.e., on battery pack removal), whereas the DS2438Z+T&R does. This makes the DS2438AZ+T&R suitable for applications requiring continuous current/time tracking during temporary disconnection - a functional distinction explicitly documented in Maxim's ordering information and DS2438 datasheet Rev. 070605 for the DS2438Z+T&R.