There is a growing demand for metal-cased batteries with high energy density, particularly for smartwatches and smartphones.

The S-821A/1B Series is an IC that can provide Nch high-side protection, which is necessary for short-circuit protection in metal-cased batteries.
By placing the Nch MOSFETs, which control charging and discharging, on the positive side (high-side) of the lithium battery, the ground levels of the battery pack and system can reach the same voltage, contributing to a simplified system design.

The S-821A/1B Series has an internal triple boost charge pump, which can increase the drive voltage of the Nch MOSFET.
This reduces the on-resistance, suppressing the heat generated by the MOSFET and improving safety during charging.

The S-821A/1B Series has three levels of discharge overcurrent protection, and the accuracy of each level is considered top-class in the industry^{*1, *2}. Furthermore, the overcharge detection voltage accuracy of ±15mV is also recognized as top-class within the industry^*1.
This allows the battery performance to be maximized, such as charging capacity and usage time, without compromising the safety of the battery pack.

Furthermore, the package is available in the compact WLP-8V (1.52 × 1.08 × t0.35 (max.) mm) and the SNT-8A (2.46 × 1.97 × t0.5 (max.) mm) with outer leads, which are easily mountable, allowing you to choose the one that best suits your application.

*1 As a 1-cell battery protection IC.
Based on our research as of October 2024.
*2 S-821B Series

The S-821A/1B Series is equipped with a power-saving input pin (PS pin), which can activate a power-saving function with an external signal, enabling it to stop the discharge of the battery.
At the same time, the power-saving function can suppress the current consumption of the protection IC to 50nA max.

When the product is not used during the period of stock, it prolongs the period until the battery runs out of power, protecting it from deep discharge and strengthening the safety of the product.

Overheating protection can be achieved by connecting an NTC thermistor to the S-821A/1B Series. By using an NTC thermistor with a resistance of 100kΩ or 470kΩ, temperatures from +65°C to +85°C can be detected. This improves battery safety and prevents malfunctions and problems caused by overheating.