Palo Alto, Calif. Designed for a variety of consumer, computing, communications and industrial applications, Agilent Technologies Inc. bolsters its isolation products portfolio with the introduction of the industry's first line of 3.3-volt (V), 15 Mbaud, multi-channel and bi-directional digital optocouplers. By leveraging the company's patented manufacturing technology for stacking LEDs, Agilent was able to design the highly integrated parts necessary to develop multi-channel optocouplers. Available in dual, triple and quad channels, the company says this new product family can reduce part count, board space and system costs.
The integration of two, three and four optocouplers in a single package is achieved through stacking LED die and an insulating layer on a silicon substrate. With the insulating material between the LED and active circuitry, the optocoupler can provide safe, high-voltage insulation performance, which is key when providing electrical isolation of signal lines to protect low-voltage circuitry from high-voltage surges. For more information about the LED stacking technology, please read Agilent's white paper
Gary Tay, business development manager for Agilent's Isolation Products Division says use of the stacking LED technology allows the company to integrate multi-channels in a single package for higher integration, and enables the use of a very thin package compared with traditional optocoupler packaging. Another key feature is the bi-directional functionality for two-way data transfer, which simplifies signal routing on printed-circuit boards. This saves the designer in the routing of the printed-circuit board by replacing two optocouplers with one bi-directional optocoupler with single routing, Tay said.
The ACSL-6xx0 series optocouplers provide minimum 10 MBaud operating speeds, with 15 MBaud typical performance. The devices are supplied in compact 8-pin (4.9 mm x 5.9 mm x 1.7 mm for dual-channel) and 16-pin (9.9 mm x 5.9 mm x 1.7 mm for triple- and quad-channel) thin small outline integrated circuit (SOIC) packages to further reduce board-space requirements.
In addition to the higher integration, the new optocouplers boast a wide voltage supply range and wide operating temperature range. These devices feature high common-mode rejection of 10 kV/microsecond minimum and operate from 3.0 V to 5.5 V supply voltages. The operating temperature range is -40°C to 100°C. These devices are pending safety regulatory approval. They are designed to meet the most widely accepted international safety regulations including UL1577 (2500 Vrms), CSA Component Acceptance Notice No. 5, and the newly established standard to replace VDE 0884, IEC/EN/DIN EN 60747-5-2.
A significant feature of the new optocouplers is the wide supply voltage range of 3.0 to 5.5 V, which enable customers to use one part for both 3- and 5-volt applications, said Tay. And coupled with the wide operating temperature range of -40°C to 100°C, the optocouplers can be used in a variety of consumer to industrial applications, he said.
Key operating temperature ranges for current optocouplers in the market include 0°C to 70°C for less stringent consumer and computing applications, or -40°C to 85°C, which typically covers consumer and industrial applications. By moving to -40°C to 100°C, it covers nearly all of the industrial applications, superceding the other two ranges, Tay said. He also notes that the temperature range may extend up to 125°C in the future for automotive applications.
In computer systems, the Agilent ACSL series optocouplers provide the benefits of reduced part count and board space for parallel interfaces and serial interfaces such as RS232/485/422, SPI (serial peripheral interface), and the Inter-Integrated Circuit (I2C) bus. They offer the same benefits in industrial, test and measurement, and medical systems for programmable logic controllers (PLC), fieldbus interfaces and data acquisition, as well as in communications applications such as POE power-over-Ethernet (PoE) and networking boards, and for plasma display panels and other consumer appliances.
Digital isolation for A/D conversion block diagram
(Click on Image to Enlarge)
In this case, the ADC, a 24-bit sigma delta or fast conversion type, converts the analog voltage to a digital number. The quad-channel and bi-directional ACSL-6410 provides a high CMR of 10 kV/microsecond and electrical isolation of 2500 Vrms between the host system and the data acquisition circuitry and sensors. The power supply is isolated, typically via a transformer to isolate the AC line voltage from the DC voltages generated to power the data acquisition system.
Agilent is currently offering the dual and quad versions. Four other devices will be available in third quarter 2005. These include the ACSL-6300 (triple unidirectional channels), ACSL-6310 (triple bi-directional (2/1) channels), ACSL-6410 (quad bi-directional (3/1) channels), and ACSL-6420 (quad bi-directional (2/2) channels). Because of this new technology, there are additional possibilities for higher integration and higher value-added products in the future, Tay said.
The Agilent ACSL-6400 with quad unidirectional channels is priced at $4.14 each, and the ACSL-6210 with dual bi-directional channels is priced at $2.53 each, both in quantities of 10,000.
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