Automotive Electronics

Silicon Labs Introduces New Family Of Low Power Digital Isolators

Silicon Laboratories Inc. introduced the Si84xx ISOpro digital isolator family, which the company says is the industry’s first to support as many as six unidirectional isolation channels capable of data rates up to 150 Mbps.

Offering space-efficient packaging options, a choice of isolation ratings up to 2.5 kVRMS and what is described as the industry’s most highly integrated I²C isolators, the ISOpro family delivers system design flexibility for use in applications such as power supplies, motor control systems, hybrid electric vehicles, industrial networking, medical and consumer products.

Building on Silicon Labs’ patented CMOS-based isolation technology, the ISOpro family offers flexible solutions to simplify isolation design challenges, with the following key features: support for what is described as the highest data rate in the industry at 150 Mbps across the widest temperature range: -40 to +125°C, making the devices suitable in a wide variety of industrial applications; jitter performance of less than 250 ps (peak) is more than two times lower than competitive offerings. Low jitter is critical to enabling robust and reliable performance essential for minimizing data transmission errors and bit-error-rates (BERs); what is said to be industry-leading electro-static discharge (ESD) performance of 4kV human body model (HBM), 2kV charged device model (CDM) and 400V machine model (MM) to enable the highest reliability in harsh application environments; and over 25 kV/us of common mode transient immunity (CMTI) and up to 50 V/m of electric field immunity to provide robust performance and safe operation in applications such as switch mode power supplies, motor control and industrial networking.

For systems with bidirectional communications ports, such as Power over Ethernet (PoE) power sourcing equipment (PSE), switch mode power supplies (SMPS) and isolated SMBus or PMBus interfaces, the ISOpro family includes single-chip, I²C-compatible isolators. The Si8400 provides bidirectional isolated channels on both the serial data (SDA) and serial clock (SCL) lines, combining the I²C transmit and receive lines to reduce BOM cost and complexity. The Si8405 offers two additional independent unidirectional channels for system signals such as a reset or interrupt, eliminating ten or more discrete components and the need for additional isolators on the PCB. In addition, the Si8400 and Si8405 support bus speeds of up to 1.7 Mbps, nearly twice as fast the competition, and I2C clock stretching to simplify the design task of matching bus speeds.

Efficiency continues to be a critical consideration for designers when estimating their power budgets. With typical power consumption of less than 1.7mA at 10 Mbps and less than 4mA at 100 Mbps, the ISOpro family offers up to four times lower power consumption than competitive solutions. In addition, the devices feature an optional 200A energy-efficient "sleep mode" to reduce quiescent power by more than 3 times over the closest competitor. The Si84xx also features typical propagation delays of less than 10 ns that are said to be 65% lower than optocoupler-based solutions. Low propagation delays enable higher bandwidths in closed loop systems and higher data rates in communication links.

"Isolators are a critical safety component in many switch mode power supplies, hybrid electric vehicles, lighting, motor control, communications and other power subsystems. Silicon Labs is proud to offer best-in-class isolator technology to meet all the isolation design challenges of these systems," said Dave Bresemann, Vice President of Silicon Labs. "With 70 new ISOpro digital isolator products, Silicon Labs gives system designers maximum flexibility in their design without sacrificing performance."

Samples of the ISOpro Si84xx one- and two-channel devices are available in narrow body (NB) SOIC-8 packages; the 3, 4, 5 and 6-channel devices are available in NB SOIC-16 and wide body (WB) SOIC-16 packages. Pricing for the Si84xx devices starts at $0.59 in high volume, and full production is scheduled for Q2 2009.

Silicon Laboratories Inc.
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