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September, 1996
Confused about which D-A converter to use for
what application?
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The following table, put together with inputs from major digital-to-analog-converter
manufacturers, should help.
Application engineers at these companies are continuously bemused by
engineers who want to use (say) a 16- or 18-bit audio converter for machine-tool
applications.
Novice users don't realize that the 16 bits promoted with regard
to audio D-A converters is an ac specification describing the dynamic
range of the device, and
not its dc accuracy. (It
will never repeatedly resolve one part in 65,535 - nor does it have to
for consumer audio.)
The mechanical play in a robotic arm or machine tool, moreover, typically
makes it impossible to maintain 16-bit accuracy. A dc-accurate 12-bit converter
is preferred for these applications.
The table here maps out the key specifications and sources of
components for different applications. |
Process control
(transmitters) |
12 bits, DNL=1 LSB, INL=±1/2
LSB, 4-20-mA current-loop output, -40¡C to +85¡C temperature
range |
$4-7 |
Maxim
MAX535, MAX538;
Analog
Devices AD421;
Linear Technology
LTC1451, LTC1446 (dual);
Micro Linear
ML 2375 |
Process control
(high accuracy) |
14-16-bit resolution,
10-ms settling time,
DNL=1 LSB, monotonicity |
$8-16 |
Maxim
MAX542, MAX545;
Burr-Brown
DAC712, DAC714, DAC715;
Crystal Semiconductor |
ATE pin electronics,
arbitrary waveform generators |
12-14-bit resolution,
100-125-MHz conversion rate,
DNL=1 LSB, multiple channels
(or multiple DACs in one package) |
$8.75-30 |
Maxim
MAX547;
Analog
Devices AD8600;
Harris
HI5741;
Linear Technology
LTC1446 (dual), LTC1458 (quad);
Signal Processing Technology
SPT9712 |
Cell phones, VCO control |
8 bits, DNL=1 LSB,
2.7-3.6-V supply voltage,
< 1-mA current |
$2.25-4.75 |
Maxim
MAX512, MAX522;
Linear Technology
LTC1451;
Micro Linear
ML2330 |
Portable instruments |
2.7-V supply, small size,
current £ 1 mA |
$2.80-4.75
(for singles) |
Maxim
MAX 533;
Linear Technology
LTC1451, LTC1446 (dual);
Micro Linear
ML 2330 |
Digital audio |
16-20-bit resolution, THD and noise
= -88 to -92 dB, dynamic range = 96 dB to -98 dB |
$3.15-8 |
Burr-Brown
PCM1710, PCM1717/1718;
Analog
Devices AD1857;
Crystal Semiconductor
CS4327,
CS4329, CS 4330 |
RF frequency synthesizers |
Direct Digital Synthesis 10-12
bits, 100-125-MHz conversion rate, INL = 1.5 LSB, DNL = 1.0 LSB |
$8.75-$30 |
Analog
Devices AD9850;
Harris
HI5721, HI5731;
Signal Processing Technology
SPT9712 |
Radar processing |
Direct Digital Synthesis 6-12
bits, 100-1,000-MHz conversion rate, INL = 1.5 LSB, DNL = 1.0 LSB |
$125-$295 |
Signal
Processing Technology SPT7610;
Datel
DAC-HF12 |
Video (professional) |
10-12-bit resolution, 80-MHz conversion
rate, INL = 1.25 LSB, DNL = 0,25 LSB |
$7-19.95 for 10 bits,
$145 for 12 bits |
Harris
HI5780,
Signal Processing Technology
SPT7861; SPT7930 (12-bit);
Datel
DAC-330, DAC-338 |
Video (consumer) |
8 bits, 40-MHz conversion rate,
INL = 1.3 LSB, DNL = 0,25 LSB |
$3.20-3.85
(for singles) |
Harris
HI1171, HI1177 (dual);
Signal Processing Technology
SPT5100 (dual and triple) |
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