Electronic Design

Analog

Network Time Server Accurately Synchronizes Enterprise Servers
TrueTime Inc.
(800) 328-1230; fax (707) 527-6640; www.truetime.com

The NTS-150 Network Time Server derives reliable and secure time directly from the atomic clocks aboard the GPS satellite system and distributes it over the network using the Network Time Protocol (NTP). This high-performance Stratum 1 network time server offers users the ability to accurately synchronize enterprise servers, workstations, routers, and other networked devices to within 1 to 10 ms.

According to the company, the high-bandwidth capability of the NTS-150 is essential as modern broadband networks grow larger and the need for reliable time becomes critical. The high availability and throughput of this time server allow it to support thousands of network clients with no degradation in timing accuracy. An HTTP Web interface enables remote access via a common browser. A display and keypad enable the unit to be easily configured from the front panel without having to communicate via the RS-232 port or telnet. Available now, the NTS-150 starts at $2395.

DAC Family Supports SACD Direct Stream Digital
AKM Semiconductor Inc.
(888) 256-7364; www.akm.com

Members of a line of Direct Stream Digital (DSD) digital-to-analog converters (DACs) are capable of supporting both Super Audio CD (SACD) DSD and 24-bit, 192-kHz DVD-audio formats. The AK4383 is a two-channel DAC targeted to high-end audiophile and professional applications. According to the company, the AK4357 is the world's first six-channel DSD integrated circuit. It is suited for multichannel audio applications, including home theater and surround recording. Both devices use the company's advanced 32-level multibit S-? modulator.

The devices feature the jitter-tolerant performance of the company's switched-capacitor (SC) technology. Both feature direct-balanced (differential) outputs to reduce implementation costs while increasing the performance for systems with excessive clock jitter. The AK4383 and AK4357 suit audio DVD and SACD players, car audio, and electronic musical instruments. The products incorporate a digital volume control, enabling control of replay levels irrespective of the data format. A "soft Mute" function is also included. Both devices have a simple three-wire interface for connection to decoders, DSPs, or microcontrollers. They operate from a single 5-V supply. While the six-channel AK4357 is packaged in a 48-pin LQFP, the two-channel AK4383 is available in a 20-pin TSSOP. In 1000-unit quantities, the AK4357 and AK4383 cost $4.84 and $2.59, respectively.

ADC Features I2C Serial Interface In A Small Package
Texas Instruments Inc.
(800) 336-5236; www.ti.com

The ADS7823 12-bit analog-to-digital converter (ADC) features an I2C serial interface. According to the company, this device features high resolution in a small MSOP-8 package. Additionally, the device draws only 350 µA in high-speed mode. This ADC is specifically designed for voltage-supply monitoring, remote data acquisition, supervisory circuitry, and transducer-interface applications in personal computers, network servers, and industrial process control.

This device supports all three I2C serial bus and data transmission protocols, including standard (up to 100 kbits/s), fast (up to 400 kbits/s), and high speed (up to 3.4 Mbits/s). The ADC offers a sample-and-hold amplifier and an internal asynchronous clock. Additional features include a 50-kHz sampling rate and guaranteed no missing codes to 12 bits. Operating from 2.7 to 5 V, the device features an internal four-word FILO. Available now, the ADS7823 costs $2.98 in 1000-unit quantities.

3-V ADCs Boast Low Power And High Speed
Analog Devices Inc.
(800) ANALOG-D; fax (781) 937-1021; www.analog.com

The AD9218 is a 3-V, 10-bit analog-to-digital converter (ADC). It is more than 160% faster than other 10-bit dual ADCs with similar power consumption. The AD9218 features a sample rate of 105 Msamples/s. It is optimized for applications requiring low power and pc-board savings. The device operates at conversion rates of 40, 65, 80, or 105 Msamples/s. Its signal-to-noise ratio (SNR) at 105 Msamples/s is 56 dBc with an input frequency of 41 MHz. The AD9218 is packaged in a 48-lead 7- by 7-mm LQFP.

According to the company, the AD9235 is the industry's first 3-V, 12-bit ADC. This device is 30% faster than other 12-bit converters in its class. It offers a sample rate of 65 Msamples/s. The AD9235 enables IF sampling up to 100 MHz in small or portable applications, such as pico-cell cellular base stations. This device achieves an SNR of 70.4 dBc and a spurious-free dynamic range (SFDR) of 84 dBc. The AD9235 is packaged in a 28-lead TSSOP. Both of the devices are suited for portable instrumentation, communications, and broadband applications.

In 1000-unit quantities, the AD9218 costs $9.25 (40 Msamples/s), $11.76 (65 Msamples/s), $13.36 (80 Msamples/s), and $17.12 (105 Msamples/s). In similar quantities, the AD9235 costs $12.38 (20 Msamples/s), $15.08 (40 Msamples/s), and $17.02 (65 Msamples/s).

Analog Input/AC Output Module Controls 120-V AC Loads
Huron Net Works Inc.
(313) 995-2637; fax (313) 995-2876; www.huronnet.com

The DN-A101 is an analog input/ac output module suited for using DeviceNet to control any 120-V ac load. It can also be used to measure any analog signal from 4 to 20 mA or for control-loop applications. The device was originally designed for controlling lights and fan motors in energy-management and HVAC systems. It additionally features a general application for automation and process control.

The 8-bit input can be used for monitoring any analog value from any 4- to 20-mA transmitter, including current, voltage, temperature, pressure, and flow. The power for this transmitter is supplied directly by the DeviceNet bus. The DN-A101 output allows users to automate switching of any ac load over DeviceNet. The triac output directly switches 120-V ac loads up to 0.6 A. Additional contactors or relays can be utilized to control larger loads. The design of this module features three LEDs for monitoring module status, network status, and output. The node address and baud rate can be set by either a DIP switch or over the network.

The module is housed in a compact, rugged aluminum enclosure. The DN-A101 costs $185.

Audio Devices Handle Consumer Recording Applications
Wolfson Microelectronics Ltd.
+44 (0)131 667 9386; fax +44 (0)131 667 5176; www.wolfsonmicro.com

The WM8734 is a codec designed to meet the performance requirements of consumer recording applications. The WM8739 is an analog-to-digital converter (ADC) designed for Internet appliances. These devices feature low power consumption, suiting them for use in portable appliances.

The devices are built using the company's proprietary low-order, multibit, S-? architecture. According to the company, the devices are not affected by jitter. They offer class-leading linearity and sound quality. The WM8734 codec integrates a programmable gain amp (PGA), an ADC, and a digital-to-analog converter (DAC). The WM8739 ADC features an integrated input PGA. The inclusion of the PGA allows users to employ the full dynamic range of the ADC. Both chips support 24-bit resolution and up to 32-bit I/O. Sampling rates of up to 96 kHz are offered. While the integrated ADC in the WM8734 offers a signal-to-noise ratio (SNR) of 90 dB, the integrated DAC provides an SNR of 100 dB. The devices operate on a power-supply range from 2.7 to 3.6 V. Both devices are available in a 20-pin SSOP package.

In 1000-unit quantities, the WM8739 and WM8734 cost $4.33 and $4.79, respectively.

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