参数资料
| 型号： | AD7891YPZ-1 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 20/20页 |
| 文件大小： | 0K |
| 描述： | IC DAS 12BIT 8CH 44-PLCC |
| 标准包装： | 1 |
| 类型： | 数据采集系统（DAS） |
| 分辨率（位）： | 12 b |
| 采样率（每秒）： | 500k |
| 数据接口： | 串行，并联 |
| 电压电源： | 单电源 |
| 电源电压： | 5V |
| 工作温度： | -55°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 44-LCC（J 形引线） |
| 供应商设备封装： | 44-PLCC（16.59x16.59） |
| 包装： | 管件 |
AD7891
–9–
REV. D
TERMINOLOGY
Signal-to-(Noise + Distortion) Ratio
This is the measured ratio of signal to (noise + distortion) at the
output of the ADC. The signal is the rms amplitude of the
fundamental. Noise is the rms sum of all nonfundamental
signals up to half the sampling frequency (fS/2), excluding dc.
The ratio is dependent upon the number of quantization levels
in the digitization process; the more levels, the smaller the quan-
tization noise. The theoretical signal-to-(noise +distortion) ratio
for an ideal N-bit converter with a sine wave input is given by
Signal-to-(Noise + Distortion) = (6.02N + 1.76) dB
Therefore, for a 12-bit converter, this is 74 dB.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of harmonics to the
fundamental. For the AD7891, it is defined as
THD dB
log
() =
++++
20
2222
2
V
VVVV
V
2345
6
1
where V1 is the rms amplitude of the fundamental and V2, V3,
V4, V5 and V6 are the rms amplitudes of the second through the
sixth harmonics.
Peak Harmonic or Spurious Noise
Peak harmonic or spurious noise is defined as the ratio of the rms
value of the next largest component in the ADC output spectrum
(up to fS/2 and excluding dc) to the rms value of the fundamental.
Normally, the value of this specification is determined by the larg-
est harmonic in the spectrum, but for parts where the harmonics
are buried in the noise floor, it is a noise peak.
Intermodulation Distortion
With inputs consisting of sine waves at two frequencies, fa and
fb, any active device with nonlinearities creates distortion
products at sum and difference frequencies of mfa
± nfb, where
m, n = 0, 1, 2, 3, and so on. Intermodulation terms are those for
which neither m nor n are equal to zero. For example, the
second-order terms include (fa + fb) and (fa – fb), while the
third-order terms include (2fa + fb), (2fa – fb), (fa + 2fb), and
(fa – 2fb).
The AD7891 is tested using the CCIF standard where two
input frequencies near the top end of the input bandwidth are
used. In this case, the second- and third-order terms are of
different significance. The second-order terms are usually dis-
tanced in frequency from the original sine waves while the third-
order terms are usually at a frequency close to the input
frequencies. As a result, the second- and-third order terms are
specified separately. The calculation of the intermodulation
distortion is as per the THD specification where it is the ratio of
the rms sum of the individual distortion products to the rms
amplitude of the fundamental expressed in dBs.
Channel-to-Channel Isolation
Channel-to-channel isolation is a measure of the level of
crosstalk between channels. It is measured by applying a full-
scale 20 kHz (AD7891-1) or 100 kHz (AD7891-2) sine wave
signal to one input channel and determining how much that
signal is attenuated in each of the other channels. The figure
given is the worst case across all eight channels.
Relative Accuracy
Relative accuracy or endpoint nonlinearity is the maximum
deviation from a straight line passing through the endpoints of
the ADC transfer function.
Differential Nonlinearity
This is the difference between the measured and the ideal 1 LSB
change between any two adjacent codes in the ADC.
Positive Full-Scale Error (AD7891-1,
10 V and
5 V;
AD7891-2,
2.5 V)
This is the deviation of the last code transition (01. . .110 to
01. . .111) from the ideal 4
REF IN – 3/2 LSB (AD7891-1
±10 V range), 2 REF IN – 3/2 LSB (AD7891-1 ± 5V range),
or REF IN – 3/2 LSB (AD7891-2,
±2.5 V range), after the
bipolar zero error has been adjusted out.
Positive Full-Scale Error (AD7891-2, 0 V to 5 V and 0 V to 2.5 V)
This is the deviation of the last code transition (11. . .110 to
11. . .111) from the ideal 2
REF IN – 3/2 LSB (0 V to 5 V
range), or REF IN – 3/2 LSB (0 V to 2.5 V range), after the
unipolar offset error has been adjusted out.
Bipolar Zero Error (AD7891-1,
10 V and
5 V; AD7891-2,
2.5 V)
This is the deviation of the midscale transition (all 0s to all 1s)
from the ideal AGND – 1/2 LSB.
Unipolar Offset Error (AD7891-2, 0 V to 5 V and 0 V to 2.5 V)
This is the deviation of the first code transition (00. . .000 to
00. . .001) from the ideal AGND + 1/2 LSB.
Negative Full-Scale Error (AD7891-1,
10 V and
5 V;
AD7891-2,
2.5 V)
This is the deviation of the first code transition (10. . .000 to
10. . .001) from the ideal –4
REF IN + 1/2 LSB (AD7891-1
±10 V range), –2 REF IN + 1/2 LSB (AD7891-1 ± 5V range),
or –REF IN + 1/2 LSB (AD7891-2,
±2.5 V range), after bipolar
zero error has been adjusted out.
Track/Hold Acquisition Time
Track/hold acquisition time is the time required for the output of
the track/hold amplifier to reach its final value, within
±1/2 LSB,
after the end of conversion (the point at which the track/hold
returns to track mode). It also applies to situations where a
change in the selected input channel takes place or where there
is a step input change on the input voltage applied to the selected
VIN input of the AD7891. It means the user must wait for the
duration of the track/hold acquisition time after the end of
conversion or after a channel change/step input change to VIN
before starting another conversion, to ensure the part operates
to specification.
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| LTC6906IS6#TRMPBF | IC OSC SILICON 1MHZ TSOT23-6 |
| AD7891YSZ-2 | IC DAS 12BIT 8CH 44-MQFP |
| LTC6907IS6#TRPBF | IC OSC SILICON 4MHZ TSOT23-6 |
| LTC6906IS6#TRPBF | IC OSC SILICON 1MHZ TSOT23-6 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7891YPZ-1REEL | 功能描述:IC DAS 12BIT 8CH 44-PLCC RoHS:是 类别:集成电路 (IC) >> 数据采集 - ADCs/DAC - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 类型:数据采集系统（DAS） 分辨率（位）:16 b 采样率（每秒）:21.94k 数据接口:MICROWIRE?，QSPI?，串行，SPI? 电压电源:模拟和数字 电源电压:1.8 V ~ 3.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（6x6） 包装:托盘 |
| AD7891YS1 | 制造商:AD 功能描述:New |
| AD7891YS-1 | 制造商:Analog Devices 功能描述:ADC Single 454.5ksps 12-bit Parallel/Serial 44-Pin MQFP |
| AD7891YS-1REEL | 制造商:Analog Devices 功能描述:ADC Single 454.5ksps 12-bit Parallel/Serial 44-Pin MQFP T/R 制造商:Analog Devices 功能描述:ADC SGL 454.5KSPS 12-BIT PARALLEL/SERL 44MQFP - Tape and Reel |
| AD7891YS-2 | 制造商:Analog Devices 功能描述:ADC Single 500ksps 12-bit Parallel/Serial 44-Pin MQFP 制造商:Rochester Electronics LLC 功能描述:8 CHANNEL, 12-BIT ADC I.C. - Bulk |
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