Highly integrated power management chip meets the application requirements of portable devices-EEWORLD

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At present, mobile phones, multimedia digital music and audio-visual products, professional video and photography electronic products are all developing towards miniaturization, high integration and higher performance. The multimedia functions of handheld products are becoming more and more abundant, and the above evolution is attributed to the rapid development of the semiconductor industry. From separate power chips to highly integrated PMUs, from separate RF, baseband, and storage devices to single-chip SoCs. Highly integrated semiconductor devices have achieved product performance upgrades and rapid expansion of functions. As a key component, LDO is closely related to its development. For complex handheld devices, the requirements for LDO are also multifaceted, involving noise suppression ratio, quiescent current, heat dissipation, operating temperature range, etc.

In order to meet market demand, Shengbang Microelectronics has successively launched several highly integrated multi-channel power products, such as 5/7-channel DC/DC SGM2100, SGM2101, 4-channel high-performance RF LDO SGM2024 SGM2026, etc., which meet the domestic handheld device demand for high integration and small chip size, creating a new market hotspot.

Among them, SGM2026 is a 4-channel 200mA rated output circuit launched by Shengbang Microelectronics for system multi-power requirements (especially special needs for interference, noise suppression, and high output stability). The channel output PSRR is as high as 68dB (1kHz) or more linear voltage regulated power supply, which can meet the needs of digital cameras, GPS, mobile phones, mobile digital TVs and other handheld electronic products for highly integrated power management chips. The chip pin function is shown in Figure 1.

Figure 1, SGM2026 chip pin function distribution.

The basic performance parameters of SGM2026 are as follows:

1. Very low output noise: typically 30?Vrms (10Hz~100kHz), which can meet most analog signal processing requirements;

2. Under the condition of 200mA load, the voltage difference of each channel is as low as 220mV, which can greatly extend the life of the handheld product system power supply;

3. The system quiescent current is as low as 340?A when unloaded, which can fully save the limited power of the system and extend the standby time;

4. The PSRR parameter is as high as 68dB at 1kHz, which can suppress most of the noise that the system does not need;

5. Overtemperature protection and current limiting protection functions can ensure the reliability and safety of the system;

6. Single-channel shutdown function and system shutdown current as low as 10nA can ensure zero leakage in the shutdown state;

7. The normal operating temperature range of -40℃～+85℃ can meet the application of most industries;

8. TQFN (3mmx3mm) The package ensures effective heat dissipation and extremely small size, which is the same size as the single-channel SOT23-5 package (the most popular package in portable products). In terms of application areas, mobile phones, as the epitome of handheld electronic products, represent the development characteristics of the semiconductor industry. With a weight of dozens of grams and a size less than the size of a business card, they complete the system's calls, information transmission, processing of multimedia files such as audio and video, network links, and transmission and analysis of satellite and ground content. These complex functions are usually composed of different functional units such as baseband, RF, and storage, and different functional blocks have different requirements for power supply. For example, the clock part requires extremely low noise and stable output, and has high requirements for power chips. Similarly, the signal transmission and reception of the RF part require stable and clean power supply, and have high requirements for transient response characteristics. The system's I/O port also requires a stable voltage reference to complete the signal throughput transmission, and the baseband core power supply needs to be efficient and stable to ensure a long enough working time. Shengbang Microelectronics' SGM2026 has been widely used on the TD-SCDMA platform and CDMA mobile phone platform, and plays a key role in the solutions of many design companies. It provides great convenience for the timely and effective implementation of various solutions in terms of performance and volume. It can ensure that customers can use a simple method to complete the power-on and power-off timing control of a complex PMU, effectively saving the cost and performance of the entire system. The application circuit is shown in Figure 2. Figure 2: Application circuit diagram of SGM2026 on TD-SCDMA platform and CDMA mobile phone platform. The figure describes the functional implementation case of SGM2026. In some mobile phone platforms on the market, SGM2026 is used to generate 4 independent 2.8V voltages. Each of them can control the output according to the system power-on timing requirements, such as: the phase-locked loop voltage Vpll required by the system baseband, the voltage reference for RF transceiver, Vtx / Vrx, and Vi/o for peripheral auxiliary systems such as FM, WiFi and other functional modules... When the system is powered on, it is necessary to initialize the system first, then turn on the peripheral RF and other auxiliary units, and then start FM or WiFi and other functional modules according to user needs. The design of SGM2026's 4 groups of outputs are controlled separately, which can meet the user's power-on timing requirements according to the system. In addition, SGM2026 has high isolation between different channels, low noise of each output voltage (<30?VRMS), and high suppression ratio of power supply noise (>70dB, 1kHz). These characteristics can just meet the high reliability, stability and high noise suppression requirements of the mobile phone system baseband and RF for power supply. In addition, the cost reduction brought by high integration also caters to the product demand in the era of economic recession. What the mobile phone system needs is highly reliable stability and noise suppression capability. In the process of realizing the product, the solution design company fully considered factors such as chip heat dissipation control and system noise suppression. Heat dissipation is achieved by optimizing wiring, and the system routing is as close as possible to make the output close to the load end. In addition, according to the parameter characteristics of different units (analog, digital), the common ground design of the system power supply is fully considered to reduce the unknown risks caused by high integration, such as load capacitance parameters exceeding the specification, interference between different channels causing system instability, etc. The individual control of different channels, combined with the timing control required by the system, the customer's design process considers possible risks such as power backflow. Use methods such as ground pull to avoid chip control failure. By selecting products with fast shutdown characteristics, the timing specification control of power on and power off can be achieved. Using 2~3 products can realize multi-channel system power supply and achieve system design goals.

　　

　　

　　

Keywords：SGM2026 Reference address：Highly integrated power management chip meets the application requirements of portable devices

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