Recently, China EEWorld forum initiated a discussion, inviting engineers to share the key indicators or factors they consider when selecting battery management chips. The forum also encouraged netizens to recommend chips they have used. SCT's 100V buck converter chip series was listed among the recommended options.

The "Most Powerful Domestic Chips" list is selected based on a comprehensive evaluation of engineers' real-world usage experiences, industry experts' insights, and editorial perspectives. It aims to provide engineers with a quick reference guide to assess the quality and performance of domestic chips.

Here's why:

The SCT2A25 uses a Constant On-Time (COT) mode control with integrated loop compensation, greatly simplifying the external configuration of the converter. The SCT2A25 features a typical low static current of 140µA and operates in Pulse Frequency Modulation (PFM) mode, allowing the converter to achieve high conversion efficiency under light load or no-load conditions.

Figure 2   100 v Buck converter

SCT’s 100V buck converter chip series offers a wide range of 48V system solutions, with over ten mature part numbers available for you to choose from.

Compact Size, Big Impact — The Ultimate Choice for Cost-Performance Ratio

-- SCT2A00 | 01

The SOT23-6 package, with a working frequency of 300kHz, continuous output current of 0.6A, and peak current limit of 1.3A, perfectly supports high-voltage, low-current applications (such as BMS and electric control systems for two-wheeled vehicles).

With an extremely low static current of 49µA and a no-load current of only 60µA, the chip achieves over 85% efficiency at a 10mA load, effectively reducing standby power consumption. The chip integrates a ripple injection circuit internally and adopts a COT control mode. With simplified external components and a compact package, the board area is further optimized.

The pin layout is compatible with mainstream products on the market, featuring overcurrent protection, output overvoltage protection, over-temperature protection, and programmable under-voltage lockout, ensuring comprehensive safety for the chip.

Figure 3  SCT2A00 application example

For applications requiring higher output current, SCT 's SCT2A12 from the 100V series, in an ESOP-8L package, enhances heat dissipation and supports a continuous output current of 1A. It uses a safer overcurrent protection method, with peak current limiting to 1.8A when the output voltage is below 60V, and 1.5A when the output voltage exceeds 60V, ensuring the chip's reliability under high voltage conditions.

Figure 4  SCT2A12 application example

Fearless of the circuit startup moment, the 4A peak current is truly powerful!

-- SCT2A25/6 | 02

In certain scenarios, such as GPS trackers, the subsequent circuitry may draw a large current during startup, requiring the chip to have a strong current output capability without causing damage. The SCT2A25/6 can effectively handle this scenario with its 4A peak output current, providing the necessary high current for the downstream circuitry during startup without causing any output voltage abnormalities due to the surge. The continuous output current of 2A also meets the needs for higher output currents.

The chip is set to operate at a frequency of 300kHz, using the COT control mode to simplify the loop. The ESOP-8 package meets the heat dissipation requirements for high current, with the chip temperature only reaching 80°C under a 2A load (Vin = 48V, Vout = 12V).

The SCT2A25 features pin compatibility with mainstream products on the market, while the SCT2A26 optimizes the pin layout without changing the functionality, making board design more convenient.

Figure 5  SCT2A26 application example

Tight on board space? The integrated LDO provides more power without increasing any cost!

-- SCT2A27 | 03

In most applications, after converting a higher voltage to a lower voltage through a primary buck converter, a secondary buck or LDO is often required to achieve a more stable low-voltage power supply system. Although the LDO occupies very little space, it inevitably increases the board area and procurement costs.

The SCT2A27 builds on the high-performance buck converter with continuous output of 2A, peak current of 4A, and an ESOP-8 package. It integrates an LDO with configurable output voltages of 5V or 3.3V and a 200mA output current capability. The VBIAS pin serves as the input for the integrated LDO while also effectively reducing the static current of the buck and improving its efficiency under light load conditions. In certain configurations, the LDO can also operate independently of the buck.

Figure 6  SCT2A27 application example

Multiple Operating Modes/Frequencies, Supporting Isolation Buck

-- SCT2A22/3 | 04

Synchronous buck converters typically operate in three modes under light load conditions:

1. **FPWM (Forced Pulse Width Modulation)** – The switching frequency remains constant, and in this mode, the inductor current may become negative.

2. **PFM (Pulse Frequency Modulation)** – The switching frequency is reduced to improve efficiency under light load conditions.

3. **USM (Universal Switching Mode)** – The frequency does not drop below 20kHz to avoid entering the audible range and producing noise.

These modes provide a balance between efficiency, stability, and noise reduction, optimizing performance for different operating conditions.

Each mode has its advantages and drawbacks:

PFM Mode: High efficiency but relatively larger output voltage ripple.

USM Mode: No noise but lower efficiency under very light load compared to PFM.

FPWM Mode: Low efficiency at light load but minimal output voltage ripple and can support isolation buck applications.

Each mode is optimized for different trade-offs in terms of efficiency, ripple, and noise, allowing the converter to adapt to various application requirements.

The SCT2A22 is a 100V chip that supports Isolation buck, operating in FPWM mode with an output current of 1A. It offers a maximum operating frequency of 600kHz, which can be set independently. By using a transformer, it allows for one buck output and one isolation buck output, effectively saving component costs.

Figure 7 SCT2A22 with 5V Isolation Output

The SCT2A23 has an output current of 1.2A and a fixed operating frequency of 300kHz. It integrates a ripple injection circuit internally, simplifying external components. By setting the MODE pin, you can select from three light-load operating modes: FPWM, PFM, and USM, allowing for flexible configuration to meet the needs of different applications.

When set to PFM/USM mode, the output can be connected to the VCC pin through a diode to reduce internal power consumption, further improving efficiency under light load. In practical tests, the efficiency at 1mA can be increased by over 10%.

Figure 8  SCT2A23 Low IQ Application

When the VCC pin is connected to the MODE pin, the chip can be set to FPWM mode. In this mode, it supports Isolation buck applications.

Figure 9 SCT2A23 IsoBuck with 5V isolation Output

SCT has a well-established product lineup for high-voltage buck converters, with two synchronous topology families and two asynchronous topology families, covering the main current ranges from 0.6A to 2A. Throughout the product iteration process, we continuously optimize performance, achieving lower static current, higher reliability, and better cost-effectiveness.

We have incorporated many pin-compatible designs across different products to facilitate future product iterations and replacements, enabling us to launch more excellent products to meet customer needs. We believe that whether for existing applications, 48V systems, or upcoming new scenarios, you will always find suitable power management chips at SCT!