Reinforced isolation meets highest industrial performance

November 13, 2014 // By Graham Prophet
Texas Instruments has introduced data converter and digital isolation device families that enable high levels of reinforced isolation ratings along with precision performance for high-voltage applications. TI has used on-chip, oxide-based isolations structures, in series stacks to achieve high voltage ratings, while maintaining noise and dynamic range performance.

Digital isolation and delta-sigma modulator families offer reinforced isolation to help protect electronic equipment from high line voltages. The ISO7842 family provides the highest immunity reinforced isolators and are claimed as first to offer an isolation barrier with a withstand-working breakdown voltage of 1,500 Vrms for a minimum lifetime of 40 years. The AMC1304 delta-sigma modulator family offers precision performance and the lowest power consumption with reinforced isolation for current shunt monitoring. The performance of the Δ-Σ modulator permits the use of smaller-value current measurement shunts in data-acquisition and motor-control boards, reducing losses and resistive heating.

These new devices offer robust, high-speed, high-performance reinforced isolation to meet critical functional and safety isolation requirements for applications exposed to potential high voltage breakdowns, while providing decades of reliability with precision analogue performance and high immunity for noisy industrial environments.

The ISO7842 family provides superior overall reinforced isolation breakdown ratings: 8,000 V maximum transient overvoltage, according to standard DIN V VDE 0884-10; or an isolation rating of 5,700 Vrms, according to standard UL 1577, surpassing typical ratings of 5,000 Vrms. (UL Recognized Component and DIN V VDE 0844-10 certifications are planned). The highest working voltage at 1,500 Vrms, for long-term rating, is up to 50% higher than competitive solutions, TI says. High common mode transient immunity (CMTI) performance of 100 kV/µsec provides reliable communication in noisy environments.

With the highest surge voltage protection rating of 12,800 VPEAK, the ISO7842 can withstand high instantaneous voltage pulses. The ISO7842 provides accurate timing with more than 100 Mbps data rate and low jitter.

The AMC1304 family provides precision with offset error maximum of 150 µV and gain error of ±0.3%, claimed as the industry's best DC performance. With the lowest thermal drift specification, the devices ensure high accuracy over the entire operating temperature range of -40 to 125 C. AC performance allows motor control designers to minimise distortion and noise. They have CMOS and LVDS data