Application of an 8-Channel Simultaneous Sampling ADC (CM2248) in Battery Formation and Grading Test Equipment

01 Introduction

Simu Microelectronics has introduced the CM2248, a 16-bit, 8-channel simultaneous sampling SAR ADC. Each channel integrates analog input clamp protection and a second-order anti-aliasing filter. All channels can perform simultaneous sampling at a rate of 200 kSPS. The CM2248 is pin-compatible with ADI’s AD7606 and TI’s ADS8588. Its key features are outlined below.

02 CM2248 Features

• Bipolar analog input ranges: ±10 V, ±5 V

• 8 simultaneous sampling input channels

• Fully integrated data acquisition solution

  • Analog input clamp protection

  • Input buffer with 1 MΩ analog input impedance

  • Second-order anti-aliasing analog filter

  • On-chip precision reference and buffer

  • 16-bit, 200 kSPS ADC (all channels)

  • Oversampling capability via digital filtering

• Performance

  • 92 dB SNR, –105 dB THD

  • ±1 LSB INL, ±0.8 LSB DNL

  • Low power consumption: 150 mW in operating mode, 30 mW in standby mode

  • Analog input ESD up to 8 kV

  • All products undergo rigorous reliability testing

03 Solution Overview

In recent years, against the global backdrop of carbon neutrality, the new energy vehicle market has experienced explosive growth, driving a continuous increase in the installation of power batteries. Battery formation and capacity grading are critical stages in the battery manufacturing process, and battery manufacturers have placed higher demands on formation and grading test (BFT) equipment for large-capacity power batteries:

1. Multi-channel parallel operation is required to achieve higher current capability.

2. Lower-cost series charging must be supported (requiring high common-mode current and voltage measurement).

3. Battery formation and grading require higher-precision voltage and current measurement (typically around 0.05% accuracy).

4. Low cost and high reliability.

More flexible digital closed-loop topology architectures are better suited to the requirements of modern BFT equipment. They enable easier implementation of multi-channel phase-shifted parallel operation to achieve higher current test capability. Such solutions typically require a high-precision, multi-channel synchronous SAR ADC to sample battery voltage and current. The ADC’s sampling accuracy across the full temperature range becomes a key factor affecting overall BFT system accuracy. A representative circuit topology is shown in the figure.

04 Product Advantages

In summary, even without oversampling, the CM2248 achieves an SNR of up to 92 dB, enabling BFT equipment to realize higher-precision voltage and current regulation. Its low THD and excellent INL performance help achieve a more stable digital closed-loop control system. The CM2248 is highly suitable for high-precision sampling in battery formation and grading applications, and its performance is directly comparable to ADI’s AD7606 and TI’s ADS8588.