Product roundup:
<_align3d_center>A/D and D/A converter ICs

BY DAVID MORRISON
Associate Editor

A survey of newly announced data converter chips does more than indicate the obvious trends in device performance, integration, and cost. It denotes the current state of the art with actual specifications signaling the latest achievements in key areas such as sampling speed, power consumption, integration, and cost.

Given the diversity of applications–from communications and imaging to instrumentation and professional audio–it's not surprising to find that A/D and D/A converters offer many levels of performance. At lower resolutions, monolithic devices provide high-speed, low-power operation, and tiny SMT packaging at a low cost. At higher levels of precision, monolithics compete with the more expensive functionally complete modular components (MCMs or hybrids) that deliver high performance–often over extended temperature ranges.

A/D CONVERTERS

6 to 14 bits. Offering 6-bit resolution, the MAX1011 A/D converter from Maxim Integrated Products (Sunnyvale, CA) produces binary-coded output at up to 90 Msamples/s. The device, which integrates a voltage reference and a clock oscillator, consumes 210 mW from 5-V analog and 3.3-V digital supplies.

The device interfaces directly with baseband signals, making it suitable for use in IF sampling receivers. The converter's input amplifier provides a true differential input with a –0.5-dB analog bandwidth of 55 MHz and user-selectable full-scale ranges of 125, 250, or 500 mVp-p. Packaged in a 24-pin QSOP, the MAX1011 is priced at $2.95 each in lots of 1,000.

At the 8-bit level, several A/D converters have recently been introduced for communications and imaging. From Signal Processing Technologies (Colorado Springs, CO), the SPT7734 is a 40-Msample/s converter with an on-chip track-and-hold function. The chip offers high dynamic range–SINAD is 48 dB at an input of 10 MHz–and low-power operation–175 mW at 5 V.

The SPT7734 8-bit 40-Msample/s A/D converter
from Signal Processing Technologies

The device features TTL- and CMOS-compatible inputs and outputs, with outputs at user-selectable 3- or 5-V levels. Available in 28-pin SOPs and 32-pin TQFPs, the SPT7734 costs $3.95 each in lots of 1,000.

Analog Devices (Norwood, MA) has introduced an 8-bit converter with on-chip sample-and-hold amplifier and programmable reference. The AD9280 uses a multistage differential pipeline architecture to provide 32-Msample/s operation with no missing codes over temperature. The chip operates from 2.7 to 5.5-V supplies, consuming 95 mW at 3 V.

Differential nonlinearity is specified at 0.5 LSB. The converter may be configured for a user-selectable input range, offset, single-ended or differential input, and internal or external reference. The AD9280 is housed in a 28-pin SSOP and is priced at $3.37 each in lots of 1,000.

From Harris Semiconductor (Melbourne, FL), the HI2303 is a three-channel 8-bit device that integrates video functions such as dc clamping, a voltage reference, and selectable subsampling data modes of 4:4:4, 4:2:2, and 4:1:1.

Harris Semiconductor's HI2303 3-channel 8-bit video A/D converter

The converter produces 24-bit RGB or YUV video at up to 50 Msamples/s while operating from 3- or 5-V digital supplies. The HI2303 is offered in an 80-pin PQFP for $19.74 each in lots of 100.

Exar (Fremont, CA) has introduced a family of three A/D converters for CCD, CIS, and other imaging applications. Offering 8-bit resolution, the MP8832 is a simultaneous-sampling 4-Msample/s triple A/D converter with an internal voltage reference.

The gains and offsets of individual channels can be adjusted independently and a gamma-correction circuit provides independent adjustment of each converter's transfer function. The XRD4433 is offered in a 44-pin PQFP at a cost of $6.85 each in lots of 1,000.

A 10-bit device, Exar's XRD4433 is a 3-Msample/s triple A/D converter that provides pixel-to-pixel correction of CCD or other inputs by updating gain and offset parameters supplied from an external correction memory. Both gain and offset can be adjusted independently for each channel.

The IC consumes 350 mW while operating from a 5-V supply and an external 1-V reference. Packaged in a 64-pin PQFP, the XRD4433 costs $6.25 each in lots of 1,000.

Also from Exar, the MP8831 is a single 10-bit A/D converter that operates at 1.67 Msamples/s. The chip includes digitally controlled references, which allow imaging systems to calibrate for individual pixel offset and gain errors. At 6-bit resolution, offset can be adjusted from 0.175 to 0.345 V, while at 10-bit resolution (full-scale) the range is adjustable from 0 to 2.82 V. The MP8831 is available in 28-pin SOPs and DIPs and is priced at $5.75 each in lots of 1,000.

The SPT7870/7871 from Signal Processing Technologies (Colorado Springs, CO) are 10-bit A/D converters aimed at high-speed applications such as professional video, HDTV and RF communications. The converters employ a two-stage subranging flash/folder architecture to deliver 100 Msamples/s.

The devices feature an on-chip track-and-hold function, a –1 to +1-V analog input range, ECL and PECL ('7870) or TTL outputs ('7871), and ±5-V operation. The SPT7870/71 are available in 44-pin cerquad packages and are priced at $50 each in lots of 1,000.

From Burr-Brown (Tucson, AZ) comes a family of 10-bit sampling A/Ds that offer a high effective number of bits (ENOB). The ADS822/ 823/824 are pin-compatible 5-V devices that operate at speeds up to 40, 60, and 70 MHz, respectively, with power consumptions of 190, 265, and 315 mW.

The ADS822/823/824 10-bit 40 to
70-MHz sampling A/Ds from Burr-Brown

The converters offer a 9.3 or 9.5 ENOB and an SNR of 59 or 60 dB. Options include an internal or external voltage reference, a 1- or 2-Vp-p input range, and single-ended or differential operation. Packaging is in 28-pin SSOPs with prices starting at $6.80 each in lots of 1,000.

The AK5482 from AKM Semiconductor (San Jose, CA) is a 10-bit, 20-MHz A/D converter based on a pipeline architecture. Operating from 3 V, the chip consumes 50 mW at full sampling speed. Features include an integrated sample-and-hold circuit, a 1-Vp-p input range, and binary-coded output. Offered in a 24-pin VSOP, the AK5482 is priced at $5.63 each in lots of 5,000.

Texas Instruments (Dallas, TX) has introduced a 10-bit A/D that provides a glueless serial interface for both the company's TMS320 digital signal processors and SPI/QSPI-compatible microcontrollers. The TLV1572 operates at up to 1.25 Msamples/s from 2.7 to 5.5-V supplies with a power dissipation of 8 mW at 3 V.

An automatic power-down mode reduces current consumption to 10 µA when conversions are not being performed. The TLV1572 comes in an 8-pin SOP and costs $4.20 each in lots of 1,000.

Analog Devices has introduced two families of 10-bit A/D converters with on-chip temperature sensors. Offered in µSOP, TSSOP, and SOP packages, the AD741x and AD781x provide an I² C ('741x) or SPI interface ('781x) and come in single- or four-channel-input versions, or as temperature-monitoring-only devices.

Maximum conversion times are 20 µs when converting a temperature reading and 10 µs when converting an analog input signal. Operating from a 2.7 to 5.5-V supply, the chips consume approximately 3.5 µW at 10 samples/s. Prices start at $1.25 each in lots of 1,000.

Sipex (Billerica, MA) is offering two 10-bit sampling A/Ds–the SP8527 and SP8537–that feature low-power 3- or 5-V operation. The SP8527 samples at up to 38.3 kHz, while consuming 0.26 mW at 3.3 V. The SP8537 performs 29.5-kHz sampling with a 0.33-mW power consumption at the same voltage. Power drops linearly as sampling speed is reduced, and the chip automatically switches to a 2.5-µW max power-down mode when not performing conversions.

Features include a three- or four-wire serial interface, a fully differential input, and 8-pin NSOP packaging. In addition, the SP8537 features a two-channel multiplexer, which allows either one-channel-differential or two-channel-single-ended input. The converters are priced at $1.50 each in 1,000-piece quantities.

Among the recently introduced 12-bit A/D converters are three from Burr-Brown , including a family of pin-compatible converters intended for use in wireless access and wireless local-loop applications. The ADS803/804/805 offer 5-, 10-, and 20-MHz sampling, respectively, and feature a track-and-hold amplifier, an internal reference, and a 2 to 5-Vp-p input range.

Burr-Brown's ADS803 12-bit A/D converter

The converters have an SFDR of 80 dB and an SNR of 69 dB. Packaging is in 28-pin SSOPs and SOPs with pricing at $9.95 each in lots of 1,000.

The ADS7841 is a four-channel sampling A/D converter with a synchronous serial interface. Designed for 2.7 to 5-V operation, the device consumes less than 2 mW at 2.7 V while operating at up to 200 kHz. In power-down mode, the supply current drops to less than 3 µA.

Features include an input multiplexer that can be configured for either four single ended or two differential inputs. An alternate source for the MAX1247, the ADS7841 comes in 16-pin DIPs and SSOPs and is priced at $4.59 each in lots of 1,000.

Another 12-bit converter, the ADS7843 serves as a complete touch-screen controller. Features include low-power operation (less than 0.6 mW at 75 kHz), an SPI/SSI serial interface, and a touch interrupt function to alert the processor that operation has begun.

The device also operates in a sense mode that eliminates variations in the screen. Packaged in a 16-pin SSOP, the ADS7843 is priced starting at $4.95 each in lots of 1,000.

At 14 bits of resolution, the MAX125/126 from Maxim Integrated Products (Sunnyvale, CA) are 2 x 4-channel 14-bit simultaneous-sampling A/D converters developed for motor control and power monitoring. The chips feature four track-and-hold amplifiers with a two-channel multiplexer on each analog input–which allows monitoring of one motor and up to six auxiliary inputs–or two three-phase motors and four additional inputs.

Inputs are fault protected to ±17 V and sampling speeds range from 76 ksamples/s for four-channel operation up to 250 ksamples/s for one channel. Conversion results are stored sequentially in on-chip memory. The MAX125/126 are offered in 36-pin SSOPs and are priced at $13.42 each in lots of 1,000.

The LTC1418 from Linear Technology (Milpitas, CA) is a 200-ksample/s A/D converter that consumes 15 mW while operating from 5- or ±5-V supplies. The device, which guarantees no missing codes over temperature, can be configured for either serial or parallel output.

Other features include a 20-MHz sample-and-hold amplifier, an internal or external voltage reference, and two selectable power-down modes. The LTC1418 is available in 28-pin DIPs and SSOPs with prices starting at $12.75 each in lots of 1,000.

16 bits and above. At the higher levels of precision, the newer A/D converters are a mix of monolithic and modular components. Among the monolithic devices is a 16-bit 20-Msample/s A/D converter that breaks the 1-MHz Nyquist input barrier.Analog Devices' AD9260 uses a modified sigma-delta architecture to achieve a dynamic range of 90 to 100 dB, a THD of –98 dB, and an SFDR of 101 dB–all over a 1.25-MHz Nyquist signal bandwidth. Operating from 5 V, the converter consumes less than 600 mW, which can be reduced to as low as 150 mW for applications at less than full bandwidth.

A key feature is the converter's three-stage digital decimation filter, which reduces front-end anti-aliasing filter requirements. The filter may be bypassed to produce undecimated data or programmed for 2, 4, or 8 times decimation. The AD9260 is packaged in a 44-pin MQFP, and is priced at $39.90 each in lots of 1,000.

From Linear Technology , the LTC1604 is a complete 16-bit sampling A/D converter that operates at 333 ksamples/s with no pipeline delay and no missing codes over temperature. The chip provides a 90-dB SINAD and a –100-dB THD. Power consumption is 220 mW at ±5 V, which reduces to 7.5 mW in nap mode and 10 µW in sleep mode.

The converter accepts single-ended or differential inputs, operates with an internal or external reference, and has a three-state parallel interface. The LTC1604 is housed in a 36-pin SSOP with a price starting at $23.50 each in lots of 1,000.

The CS5529 from Cirrus Logic (Austin, TX) offers 16-bit precision at a low cost of $3.80 each in 1,000-piece quantities. The sigma-delta converter features a rough- and fine-charged buffered front end, a digital filter, self/system calibration circuitry, and the ability to operate from a 5-V reference. Operation is from ±2.5- or 5-V supplies, and programming is via an SPI-compatible three-wire interface.

Cirrus Logic's CS5529 16-bit A/D converter

Aimed at industrial applications, the converter provides a 6-bit output latch that allows control of two analog and four digital devices without added isolation costs. The CS5529 offers fully specified accuracy at all output rates, settles in one conversion cycle, and comes in 20-pin DIPs and SSOPs.

Among non-monolithic devices, the ADS-937 from Datel (Mansfield, MA) is a functionally complete 16-bit, 1-MHz A/D converter that samples up to Nyquist with no missing codes. A temperature-compensating auto-calibration circuit enables the edge-triggered ADS-937 to guarantee performance over both the commercial and military temperature ranges.

The ADS-937 16-bit 1-MHz A/D
converter from Datel

The device, which is packaged in a 32-pin side-brazed metal TDIP, consumes 1.25 W from ±15- and ±5-V supplies. Specifications include an SNR of 88 dB, peak harmonics of –90 dB, and user-selectable input ranges of 0 to –10 V or ±5 V. In quantities of 100, pricing is $341 for the commercial version (ADS-937MC) and $434 for the military version (ADS-937MM).

Edge Technology (Lynnfield, MA) has introduced two 16-bit sampling A/D converters for applications such as radar, communications, and imaging. Housed in shielded metal cases, the converters are self contained and require no external components or heat sinks.

The ET2673 is a 20-MHz sampling A/D converter that specifies an SFDR of 93 dB, an SNR of 80 dB, and a differential nonlinearity (DNL) of ±0.5 LSB. The TTL-compatible part guarantees no missing codes over temperature and can operate beyond Nyquist frequencies. Power consumption is 6 W. In 100-piece quantities, the ET2673 is priced at $2,900 each.

The ET2668 is an 8-MHz converter that offers an SFDR of 90 dB, an SNR of 83 dB, and a DNL of ±0.5 LSB. The device consumes 1.8 W and comes in a case that measures 2.4 x 1.4 x 0.375 in. The ET2668 costs $384 each in lots of 1,000.

Another functionally complete device, the ADS-951 from Datel is an 18-bit,
1-MHz sampling A/D converter. The edge-triggered device samples full-scale inputs up to Nyquist with no missing codes over the full military temperature range. Specifications include an SFDR of 90 dB, a THD of 89 dB, and an SNR of 89 dB.

Datel's ADS-951 18-bit 1-MHz
sampling A/D converter.

Operating from ±5- and ±15-V supplies, the TTL-compatible converter consumes 1.25 W. Packaged in a 32-pin ceramic TDIP, the ADS-951 costs $415 each in lots of 100.

At the 20-bit level, Edge Technology's ET4800 offers a 1-MHz sampling A/D converter that guarantees no missing codes. The self-contained TTL-compatible converter provides an SFDR of 120 dB, an SNR of 120 dB, a THD of –120 dB, and a DNL of ±0.5 LSB.

Power consumption is 4 W, which eliminates the need for a heat sink, and packaging is in a 3 x 4 x 0.375-in. shielded metal case. The ET4800 is priced at $960 in 100-piece quantities.

Two manufacturers have introduced monolithic converters with the 24-bit resolution required in professional audio applications. The AK5392 from AKM Semiconductor is a two-channel converter that uses an enhanced dual-bit sigma-delta architecture. It achieves a dynamic range and SNR of 116 dB at sampling rates of 1 to approximately 54 kHz.

AKM Semiconductor's AK5392
24-bit stereo A/D converter

Operating from 5-V analog and 3 to 5.25-V digital supplies, the converter consumes 470 mW. Available in a 28-pin SOP, the AK5392 is priced at $19.95 each in lots of 5,000.

Cirrus Logic has introduced two 24-bit stereo A/D converters. The CS5396 delivers 120 dB of dynamic range along with 96-kHz sampling. In addition, THD + N is specified at greater than 105 dB. The device performs sampling, A/D conversion, and anti-alias filtering to generate two channels of serial output at sample rates of up to 100 kHz.

The CS5360 24-bit stereo A/D
converter from Cirrus Logic

For compatibility with existing designs, a psychoacoustic noise-shaping filter truncates the output to 16, 18, or 20 bits while preserving 24-bit sound quality. The CS5396 is available in a 28-pin SOP and priced at less than $26 each in 1,000-piece quantities.

Another 24-bit stereo converter, the CS5360 offers a high dynamic range of 105 dB at a low cost–$7.50 each in lots of 1,000. The 5-V device, which performs sampling and anti-alias filtering, provides a –95 dB THD + N, a 0.0025-dB passband ripple, and an 85-dB stopband attenuation.

Features include a high-pass filter that removes dc offset at the converter's input and a peak-signal-level register that can be used to drive bar graph displays. The CS5360 is available in a 20-pin SSOP.

D/A CONVERTERS

8 to 14 bits. The TLC5617 from Texas Instruments is a dual 10-bit D/A converter that interfaces easily with the company's TMS320 digital signal processors. The device converts serial digital input into one or both of two analog outputs and communicates with the DSP chip over a three-wire serial interface.

The device features a buffered reference input and three modes of operation–fast, slow, and power-down–for optimizing speed and power. The TLC5617 comes in 8-pin SOPs and DIPs with a price starting at $4.57 each in lots of 1,000.

From Analog Devices , the AD5300/5310/5320 are 8-, 10-, and 12-bit voltage-output D/A converters, respectively, that come in 6-pin SOT-23 packages or in 8-pin µSOPs. The pin-compatible devices operate from 2.7 to 5.5-V supplies with a power consumption of 0.4 mW at 3 V.

In power-down mode, current consumption drops to 20 nA at 3 V, and the output switches to a resistor network of known values. Other features include an internal reference, a power-on reset, and rail-to-rail output. The ICs are priced at $1.25 ('5300), $1.70 ('5310), and $2.50 ('5320) each in lots of 1,000.

Maxim Integrated Products has introduced a family of dual D/A converters in 16-pin QSOPs. The MAX5154 to MAX5157 are 12-bit devices that consume 250 µA per converter while operating from either 5 V ('5154/5156) or 2.7 to 3.6 V ('5155/5157).

The converters can be powered down independently and accept two inputs for reference voltages, allowing different full-scale ranges for each converter. Outputs swing rail to rail, and output amplifiers offer a choice of fixed or variable gain. Other features include a three-wire serial interface, double-buffered inputs, a “clear” function that zeros the outputs, and a power-on reset.

The MAX5158/5159 are pin-compatible 10-bit versions of the MAX-5154/5155. In lots of 1,000, pricing starts at $6.15 each for the 12-bit converters and at $4.55 for the 10-bit converters.

The DAC7624/7625 from Burr-Brown are 12-bit quad voltage-output D/A converters packaged in 28-bit DIPs and SOPs. The converters guarantee monotonic operation over a –40° to 85°C temperature range and settle in 10 µs to 0.12%. The chips consume 10 mW while operating from 5- or ±5-V supplies.

Both parts accept parallel input data, allow simultaneous update of all converters, and provide a data-readback mode for input registers. An asynchronous reset clears all registers to midscale ('7624) or zero scale ('7625). Pricing is $9.15 each in lots of 1,000.

Linear Technology has introduced two 12-bit devices that feature 2.7 to 5.5-V low-power operation, rail-to-rail outputs, and a DNL of ±0.5 dB. The LTC1659 is a single converter packaged in an 8-pin MSOP, while the LTC1448 is a dual converter housed in an 8-pin SOP. The chips, which consume 250 ('1659) or 350 µA ('1448), drive capacitive loads up to 1,000 pF.

Features include rail-to-rail outputs, a power-on reset, and a three-wire serial interface. In addition, the LTC1659 has a Schmitt trigger on the clock input to allow direct interface with an optocoupler. In 1,000-piece quantities, pricing starts at $4.45 ('1659) and at $6.40 each ('1448).

From Texas Instruments , the TLC5618 is a 12-bit dual D/A converter that offers two modes of operation for trading off power dissipation and speed. In the fast mode, the converter settles in 2.5 µs while consuming 8 mW.

In the slow mode, settling time increases to 12.5 µs while power drops to 3 mW. In addition, a power-down mode reduces current consumption to 1 µA. The chip's data input can be updated at rates up to 1.2 MHz with the option of simultaneous or independent updates of each converter.

Other features include a three-wire serial interface, buffered reference inputs, and 5-V operation. The TLC5618 is packaged in 8-pin DIPs and SOPs with prices starting at $4.20 each in lots of 1,000.

From Maxim Integrated Products , the 5-V MAX5150/5152 and the 3-V MAX5151/5153 are 13-bit dual D/A converters that offer small size and low power. Offered in 16-pin QSOPs, the devices draw just 250 µA per converter, which can be shut down independently to 1 µA.

In addition to their supply voltages, the parts are differentiated by their output amplifier. In the MAX5150/5151, the amplifier has a fixed gain of two, while in the MAX5152/5153 the amplifier offers access to its inverting input for controlling gain and other parameters. Other features include rail-to-rail outputs, a power-on reset, and a serial-data output for daisy chaining.

In addition, two reference-voltage inputs allow different full-scale ranges for each converter. Also available in DIPs, the converters are priced starting at $7.95 each in lots of 1,000.

The MAX535 is a 13-bit D/A with a precision output amplifier in an 8-pin µMAX (or DIP) package. The chip consumes 280 µA, which reduces to 10 µA in the shutdown mode. As with the MAX5152/5153, the output amplifier of the MAX535 provides access to its inverting input.

In addition, the device features rail-to-rail output, settles in 16 µs, and resets to 0 V at power on. The MAX535 also include a serial interface and Schmitt-trigger inputs. Pricing starts at $4.95 each in lots of 1,000.

Offering 14-bit precision, the Analog Devices AD9774 is a 4-times oversampling D/A converter that integrates an interpolation filter, a voltage reference, and a PLL clock multiplier. Optimized for use in the transmit path of wideband applications, the converter achieves an SFDR of greater than 76 dB for output signals up to 13 MHz.

The AD9774 14-bit 4x oversampling D/A converter from Analog Devices

The device, which is specified over the industrial temperature range, supports input data rates up to 32 Msamples/s, suppresses inband images by 69 dB, and operates from 2.7 to 5.5 V. Packaged in a 44-pin MQFP, the AD9774 costs $24.95 each in lots of 1,000.

16-bits and above. The LTC1595/1596 from Linear Technology are serial-input 16-bit multiplying D/A converters that offer ±1 LSB max integral nonlinearity error and DNL over the industrial temperature range without autocalibration. The chips include an internal deglitching circuit that provides a 1-nVs glitch impulse.

Packaged in 8-pin DIPs and SOPs, the LTC1595 is pin compatible with the 12-bit DAC8043. The LTC1596 is offered in 16-pin DIPs and SOPs and is pin compatible with the DAC8143 and the AD7543. Features include a three-wire serial interface, the ability to daisy-chain multiple converters on the same bus, and an asynchronous reset function. Pricing begins at $12.25 for the LTC1595 and $12.75 for the LTC1596 each in lots of 1,000.

The AK4324 from AKM Semiconductor is a 24-bit sigma-delta stereo D/A converter that offers a 96-kHz sampling rate and a 105-dB dynamic range. The 5-V converter includes a 24-bit digital filter that provides ±0.005 dB of passband ripple and 75 dB of stopband attenuation.

Analog outputs are filtered by a second-order switched-capacitor filter with high tolerance to clock jitter. Other features include digital de-emphasis for 32-, 44.1-, 48-, and 96-kHz sampling and soft mute. The AK4324 is packaged in a 24-pin VSOP and costs $4.50 each in lots of 5,000.

Cirrus Logic's CS4390 is a 24-bit stereo sigma-delta D/A converter that offers 106 dB of dynamic range, 115 dB of SNR, and –97 dB of THD + N. Features include independent muting of left and right channels, low clock-jitter sensitivity, and digital de-emphasis for 32, 44.1, and 48 kHz.

Cirrus Logic's CS4390 24-bit
stereo delta-sigma D/A converter

In addition, the converter offers filtered line-level outputs, linear-phase filtering, and an internal voltage reference. Pin compatible with the company's 20-bit CS4329, the chip is offered in 20-pin DIPs and SSOPs with pricing at $5.30 each in lots of 1,000.

The ET4801 from Edge Technology is a functionally complete 25-bit, 1-MHz D/A converter that provides 120 dB of SFDR. Other key specifications include a THD of –120 dB and a 20-ppm settling time of 1 µs.

The ET4801 25-bit 1-MHz D/A
converter from Edge Technology

The TTL-compatible device consumes 3.5 W from ±15- and ±5-V supplies and is packaged in a 2.5 x 2.5 x 0.375-in. shielded metal case. Pricing for the ET4801 is $750 each in lots of 100.