Electronic Design


SPST And SPDT Switches Are Added To Low-Voltage CMOS Switch Family
A line of CMOS switches has been extended to include a pair of single-pole/single-throw (SPST) switches and a single-pole/double-throw (SPDT) switch. The ADG741 and ADG742 SPST switches and the ADG749 SPDT are now included in the low-voltage, low-resistance switch family.

The ADG741 switch is closed with a logic input of "1." Conversely, the switch of the ADG742 is opened with the same input. All three devices are designed to operate at supply voltages as low as 1.8 V and consume less than 10 µW. The switches offer a typical on-resistance of 2 Ω and typical tON of 12 to 14 ns.

All three switches have less than 3-dB bandwidths up to 240 MHz. According to the company, they are suited for data-acquisition systems, communication systems, audio and video switching, and automatic test equipment applications.

These CMOS switches come in six-lead SC-70 packages. In 1000-unit quantities, the ADG741 and ADG742 cost $0.65 each. In similar quantities, the ADG749 costs $0.70 each.

Analog Devices Inc., Ray Stata Technology Center, 804 Woburn St., Wilmington, MA 01887; (800) ANALOGD; fax (781) 937-1021; www.analog.com.

Small 24-Bit ADC Offers Both 50- and 60-Hz Rejection
The LTC2413 24-bit analog-to-digital converter (ADC) enables direct digitization of inputs in applications such as weigh scales, temperature measurements, gas analyzers, and strain gauge transducers with four linearity and no microprocessor calibration. The device provides simultaneous 50- and 60-Hz rejection.

An on-chip oscillator is included. The ADC performs transparent offset and full-scale calibration on every conversion to provide 4-ppm total unadjusted error. Its high-accuracy DNL guarantees true 24-bit output with no missing codes. Also, its integral nonlinearity (INL) is only 2 ppm. An output noise of 800 nVRMS and a common-mode rejection-ratio (CMRR) of 140 dB are provided. A no-latency architecture simplifies system design in multiplexed applications by reducing software overhead. This ADC operates with a supply range of 2.7 to 5 V. It consumes 200 µA during conversion and 20 µA during shutdown.

The LTC2413 is available in the 16-pin SOP package over both the commercial and industrial temperature ranges. In 1000-unit quantities, it costs $8.30 each.

Linear Technology Corp., 1630 McCarthy Blvd., Milpitas, CA 95035-7417; (408) 432-1900; fax (408) 434-6441; www.linear-tech.com.

Rail-To-Rail Op Amp Fits Desktop And Notebook TFT-LCD Displays
The LM8272 dual rail-to-rail op amp offers high output current to drive demanding applications. The device suits desktop and notebook TFT-LCD displays. Also, the LM8272's stable capacitive load drive eliminates flickering displays, thereby providing a stable screen image.

The device's VIP3 process enables a supply voltage range of 2.5 to 24 V. This gives the end user a greater degree of design freedom. The 130 mA of short-circuit output current required by larger TFT panels is included. Rail-to-rail input and output enables a maximum dynamic range at any supply voltage. Also, this op amp provides a slew rate of 12 V/µs and a gain bandwidth of 15 MHz.

The LM8272 is currently available in an MSOP-8 package. In quantities of 1000 units, the device is priced at $1.30 each.

National Semiconductor, 2900 Semiconductor Dr., P.O. Box 58090, Santa Clara, CA 95052-8090; (800) 272-9959; Internet: www.national.com.

Dual And Triple Op Amps Suit Power- Sensitive High-Speed Applications
The MIC915 dual and MIC916 triple op amps consume only 2.4 mA each. These devices are designed to meet the needs of power-sensitive high-speed applications.

Both devices are unity-gain stable. Also, they can drive any capacitance load. Supply voltages of 2.5 and 9 V are specified. A typical input offset voltage of 1 mV and a large signal voltage gain of 73 dB are provided. The PSRR is 81 dB while the common-mode rejection ratio (CMRR) is 98 dB. These op amps have slew rates of 270 V/µs and gain bandwidths of 135 MHz. Also, IttyBitty, SOT23-5 packaging is offered.

The MIC915BMM is packaged in an MSOP-10 and costs $1.95 each in 1000-unit quantities. Packaged in a QSOP-16, the MIC916BQS costs $2.98 in similar quantities.

Micrel Semiconductor, 1849 Fortune Dr., San Jose, CA 95131; (408) 944-0800; www.micrel.com.

ADC Provides High-Speed Signal Acquisition For Motor Control
The ADS7864 12-bit analog-to-digital converter (ADC) features simultaneous six-channel signal acquisition at a 500-kHz sampling rate. This device suits motor-control and power-monitoring applications.

With six input channels grouped into three pairs, it measures all three phases of motor-control or power-monitoring systems. It converts these analog signals to a digital signal used by a DSP or microprocessor. The six on-board sample-and-hold amplifiers feature fully differential inputs. This provides common-mode rejection of 80 dB at 50 kHz. Input noise rejection in high-noise environments is minimized.

A parallel interface with six FIFO registers enables fast availability of data. The output data for each channel is available as a 16-bit word. And, the ADC interfaces seamlessly with the TMS20C5000 DSP platform.

The ADS7864 is packaged on a 48-pin TQFP. It costs $6.75 in 1000-unit quantities.

Texas Instruments Inc., 12500 TI Blvd., Dallas, TX 75243-4136; (800) 336-5236; www.ti.com.

ADC And Audio Switcher Achieves 115-dB Signal-To-Noise Ratio
According to its manufacturer, the Audio Director & Digitizer is a fully upgradable analog-to-digital converter (ADC) and automatic audio switcher that significantly improves any audio system's sound quality. Basically, it produces improved sonics from any digital receiver by bypassing the internal ADC. Analog sources, then, automatically are switched and converted to a very high-quality digital signal. Designers simply need a single digital audio input of any format on the receiver or processor.

This device features automatically switched eight-line level and manually switched phono-stage analog audio inputs. The 24-bit digital signal that results from the conversion of analog sources has 256 times the resolution of the 16-bit audio found on many CDs. The converter uses the Crystal CS5396 analog-to-digital chip to achieve a 115-dB signal-to-noise ratio. A transport sets the jitter performance for the entire playback system, while an analog-to-digital clock jitter during sampling defines the recording's ultimate performance.

Contact the company for pricing and availability information.

MSB Technology Corporation, 14251 Pescadero Rd., 3/30, La Honda, CA 94020; (650) 747-0400; fax (650) 747-0405; www.msbtech.com.

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