AUSTIN, Texas -- July 20, 1998 -- Cirrus Logic Inc. (NASDAQ:CRUS) announced today the addition of three high-precision analog-to-digital converters (ADCs) to its 552x Crystal® family of industrial data acquisition ICs. The highly integrated 24-bit, Crystal ADCs (CS5522, CS5524 and CS5528) are capable of measuring ground referenced signals without external level-shifting components, improving the accuracy in industrial data acquisition while lowering system cost and complexity. As buffered, multi-channel single-supply devices, the new Crystal ADCs enable extremely precise measurements of temperature, pressure, voltage and current, and include all the capabilities needed to design complete signal acquisition solutions for industrial applications.

Capable of reliably performing over a wide range of extreme conditions, the new Crystal ADCs provide an ideal, low-cost solution for isolated and non-isolated industrial signal acquisition applications. The new entries combine two, four or eight channels, low power operation, the ability to handle negative input signals with a single power supply, stability over the full industrial temperature range, a simple interface, enhanced noise rejection and programmability.

"With the introduction of these devices, we continue to demonstrate our leadership in delivering cost-effective 24-bit conversion solutions," said Eric Broockman, vice president and general manager of the Crystal Semiconductor Products Division. "These Crystal products are excellent examples of how we’re providing 24-bit performance at 12-bit pricing, enabling critical industrial applications at a reasonable cost."

Each of the three new ADCs combine a low noise, low drift chopper stabilized instrumentation amplifier, a programmable gain stage and an on-chip charge pump drive to provide extremely precise voltage measurements, including full-scale bipolar and unipolar signals of 25mV, 55mV, 100mV, 1V, 2.5V and 5V. The new devices handle a reference input voltage of up to 5V directly from the supply, and include internal rough and fine charge buffers to ensure low input currents independent of input voltage. With superior voltage measurement features, these new industrial ADCs are ideal for thermocouple applications as well as bridge transducer digitizers, used in products such as panel meters, digital thermometers, weigh scales, electronic torque wrenches and other automatic manufacturing tools.

Electrical noise sources, common in industrial environments, are diminished with the implementation of the new ADCs into a system. The CS5522/24/28 trio rejects noise at 50 Hz and 60 Hz±3 Hz simultaneously. In addition, the new chips provide a 24-bit data word with up to 18 bits of noise-free resolution, providing a precise specification for data transfer.

Other features include:

A 3-wire SPI and Microwire compatible serial interface that is simple to use and reduces the number of parts required for optical isolation.

A 2- bit analog output latch to control switches, excitation sources and other peripheral components required for industrial application solutions.

A set of read/write registers for each channel providing an unprecedented level of system and self-calibration programmability. The ADCs can be instructed to down load calibration information from off-chip memory at power up for each individual channel.

A channel set-up register (CSR) provides the ability to program each channel with a unique output word rate (3.88 Hz to 303 Hz) and input range. In addition the CSR allows a sequence of channels to be sampled automatically in any order.

The CS5522/24/28 devices are register-compatible with the entire 552x family of Crystal ADCs aimed at a wide range of industrial applications. Included in this family are the 16- and 20-bit single channel ADCs (CS5525/26) and the industry’s lowest cost delta sigma 16-bit ADC (CS5529).

Support

An evaluation board is available for each product, along with analysis software. Application notes are also available on how to use the products in multiplexed applications and how to interface them to the 80C51, 68HC05/11 and PIC microcontrollers. Data sheets and application notes can be found at www.cirrus.com/crystal.html.

Price and Availability

The CS5522 is available in 20-pin Plastic-DIP (PDIP) and 20-pin Shrink Small Outline Packages (SSOP) and sells for $6.20 in quantities of 1,000. The CS5524/28 devices are available in 24-pin Plastic-DIP (PDIP) and 24-pin Shrink Small Outline Packages (SSOP) and sell for $7.40 and $7.80 in quantities of 1,000 respectively. Samples and production quantities are available now.

Crystal Brand Products

Cirrus Logic's Crystal brand products are recognized for providing high-performance mixed-signal and signal processing solutions for data acquisition, consumer/professional audio and video, and imaging applications. For the latest CS5522/24/28 product information contact a Cirrus Logic representative or visit http://www.cirrus.com/crystal.html

Cirrus Logic

Cirrus Logic is a premier supplier of system-level integrated circuits that demand high-performance mixed-signal processing and algorithmic expertise. The company’s products, sold under its own name and the Crystal product brand, enable high-volume applications in mass storage, communications, consumer electronics and industrial markets. Additional information about Cirrus Logic is available at www.cirrus.com

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Note to editors: Cirrus Logic and Crystal are registered trademarks of Cirrus Logic Inc. All other names noted herein could be trademarks of their respective holders.