Beijing Sifang Automation: Leading the Way in Smart-Grid Equipment with Signal-Chain ICs

Founded in 1994, Beijing Sifang Automation is a top smart-grid equipment supplier in China. The company’s product portfolio includes solutions for power system automation, relay protection, power system security and stability control, HVDC transmission control, dispatching automation, distribution automation, power simulation, and rail transportation for electric power system and related industries, including petrochemical, coal, and metallurgy.

• Need high-quality, high-performance, cost-competitive signal-chain ICs with long lifecycles

Sifang’s power-grid protection products have circuits with low, medium, and high voltages. They require high-quality semiconductors that have long lifecycles, as the equipment is expected to operate continuously, with some technology upgrades, for up to 15 years. Also important considerations are performance and cost of the semiconductors.

• Met quality, performance, cost, and lifecycle requirements
• Highly integrated ICs helped save board space and costs

Sifang has been working with Maxim Integrated for more than 15 years, in particular using Maxim Integrated’s signal-chain products in its power-grid protection solutions. According to Mr. Chen Qiurong, sr. manager of Hardware R&D at Sifang, the company has found that Maxim Integrated’s ICs meet its top requirements: high quality, long lifecycle, high performance, and cost-competitiveness.

The company is currently using these Maxim Integrated signal-chain ICs:

• MAX125 high-speed, multichannel, 14-bit data acquisition system with simultaneous track/holds. The system features a simultaneous-sampling analog-to-digital converter (ADC) and a high-speed parallel digital signal processing (DSP) interface.
• MAX16006 low-voltage, quad-/hex-/octal-voltage microprocessor supervisor for complex multivoltage systems. This device has a reset output that asserts when any of the voltages that are monitored fall below their respective thresholds or when the manual reset input is asserted.
• MAX6725 dual/triple ultra-low-voltage SOT23 microprocessor supervisory circuit for monitoring two- or three-system power-supply voltages. Compared to using separate ICs or discrete components, this device improves system reliability while reducing size.
• MAX13487E +5V, half-duplex RS-485/RS-422-compatible transceiver. This transceiver features reduced slew-rate drivers that minimize electromagnetic interference (EMI) and reduce reflections caused by improperly terminated cables, allowing error-free transmission up to 500kbps.
• MAX14841E low-voltage, high-speed, half-duplex RS-485 transceiver. This transceiver is optimized to deliver high speeds over extended cable runs while maximizing noise tolerance. Its high electrostatic discharge (ESD) protection helps increase equipment uptime.
• DS1338Z I2C real-time clock with 56-Byte NV SRAM. Low-power operation extends battery backup runtime, and a surface-mount package with integrated crystal saves board space while simplifying the design.

The level of integration available in many of these ICs is saving Sifang the expense and board space that would otherwise be required to support extra components to provide the same functionality. For example, the MAX13487E has a proprietary AutoDirection control that eliminates the need for an isolated control channel. As another example, the MAX16001 features open-drain outputs with internal pullups, which reduce the number of external components needed.

“Maxim ICs are good for the power grid, and we hope Maxim can develop more products for this application area,” said Mr. Chen. “We benefit from the quality of the signal-chain products as well as Maxim’s reliability as a supplier.”