Analog Devices Inc./Maxim Integrated MAX14921ECS+T

Overview

MAX14921ECS+T from Maxim Integrated is a high-accuracy 16-cell battery measurement analog front-end (AFE) IC designed for voltage monitoring and level-shifting in lithium-ion, lithium-metal phosphate, and other flat-curve battery packs up to +65V. It simultaneously samples all 16 cell voltages with ±0.5mV max error, integrates 16-channel passive balancing FET drivers, and features self-calibrating unity-gain differential amplifiers referenced to ground - enabling precise state-of-charge and impedance estimation in energy storage systems.

For engineers reviewing the MAX14921ECS+T datasheet, MAX14921ECS+T pinout, MAX14921ECS+T application, or MAX14921ECS+T equivalent, this device is selected for high-voltage multicell BMS designs requiring sub-millivolt accuracy, daisy-chain SPI control, integrated diagnostics (open-wire/UV/OV detection), and operation across –40°C to +85°C industrial temperature range.

Technical Context

The MAX14921ECS+T implements a simultaneous-sampling architecture with charge-injection error calibration, supporting 16 differential cell inputs (CV0–CV16) and internal level-shifting to AGND. Its buffered AOUT output delivers unity-gain, ground-referenced cell voltage differences (0.5V–4.5V range) with <±0.5mV total error after self-calibration.

It integrates diagnostics including open-wire detection on all CV inputs, programmable undervoltage/overvoltage thresholds per cell, thermal shutdown at +140°C, and a daisy-chainable SPI interface with guaranteed timing (tCP = 208 ns). The device includes an internal 5V LDO (±2.5% accuracy, 10mA load), 16 BA_ gate drivers (6.5–12mA sink), and supports external 1µF sampling capacitors.

Key Specifications

Pinout & Package

MAX14921ECS+T is housed in an 80-pin TQFP package (12mm × 12mm) with exposed pad (not electrically connected per datasheet). Pin functions are validated per Maxim's official pin description table and functional diagram (Rev 3, March 2015).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX14921ECS+T, MAX14920ECS+T reduces channel count and package size for smaller stacks, while BQ7695200PAPR trades precision and analog flexibility for embedded processing and protection - making MAX14921ECS+T optimal for high-accuracy, externally controlled BMS architectures.

Availability

MAX14921ECS+T is available at Aetrix Electronics and suitable for energy storage packs, electric vehicle battery management systems, and industrial telecom backup systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX14921ECS+T 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 high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications applications.

The MAX14921ECS+T belongs to Maxim's battery management AFE product line, engineered specifically for high-accuracy, high-voltage multicell monitoring in mission-critical energy systems where measurement integrity directly impacts safety and longevity.

FAQ

What is the maximum battery stack voltage supported by MAX14921ECS+T?

MAX14921ECS+T supports battery stacks up to +65V, with CV2–CV16 rated for input voltages from +1.5V to +65V relative to AGND. This allows direct monitoring of 16-series lithium-ion or lithium-metal phosphate cells without external voltage dividers or isolation, provided proper PCB layout and creepage/clearance rules are followed.

Does MAX14921ECS+T require external calibration components?

No, MAX14921ECS+T performs on-chip self-calibration of amplifier offset at power-up and on command. It uses internal circuitry and the external 1µF sampling capacitors (CTn/CBn) to correct charge-injection errors - eliminating need for factory-trimmed resistors, external DACs, or manual calibration routines in production.

How does MAX14921ECS+T handle open-wire detection?

MAX14921ECS+T executes hardware-based open-wire detection on all CV inputs during normal operation. It compares expected vs. measured voltage relationships across adjacent cells and asserts diagnostic flags via SPI register bits - enabling detection within one conversion cycle without host CPU overhead or additional external comparators.

Can MAX14921ECS+T operate without its internal LDO enabled?

Yes. MAX14921ECS+T can disable its internal 5V LDO by connecting LDOIN to VA instead of VP. In this mode, VA must be supplied externally with a stable +5V ±2.5% source. The LDO remains active in shutdown (EN = low), but disabling it reduces power dissipation in high-VP applications where external regulation is already available.

What is the purpose of the SAMPL pin on MAX14921ECS+T?

The SAMPL pin controls the sampling/hold phase of MAX14921ECS+T's switched-capacitor front-end. When SAMPL is high, CV inputs are tracked; on the falling edge, all 16 cell differentials are simultaneously held and level-shifted to AOUT. This synchronous capture ensures coherent, skew-free measurements essential for impedance and SOC calculations.