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參數資料
| 型號： | AD7854L |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | 12-Bit Sampling ADC(單電源,200kSPS 12位采樣A/D轉換器) |
| 中文描述： | 12位采樣ADC（單電源，速度高達200ksps的12位采樣的A / D轉換器） |
| 文件頁數： | 16/28頁 |
| 文件大小： | 268K |
| 代理商： | AD7854L |
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AD7854/AD7854L
–16–
REV. 0
RE FE RE NCE SE CT ION
For specified performance, it is recommended that when using
an external reference, this reference should be between 2.3 V
and the analog supply AV
DD
. T he connections for the reference
pins are shown below. If the internal reference is being used,
the REF
IN
/REF
OUT
pin should be decoupled with a 100 nF
capacitor to AGND very close to the REF
IN
/REF
OUT
pin. T hese
connections are shown in Figure 16.
If the internal reference is required for use external to the ADC,
it should be buffered at the REF
IN
/REF
OUT
pin and a 100 nF
capacitor should be connected from this pin to AGND. T he typical
noise performance for the internal reference, with 5V supplies is
150 nV/
√
Hz
@ 1 kHz and dc noise is 100
μ
V p-p.
AV
DD
DV
DD
C
REF1
C
REF2
REF
IN
/REF
OUT
AD7854/
AD7854L
ANALOG
SUPPLY
+3V TO +5V
0.1μF
0.1μF
10μF
0.1μF
0.01μF
0.1μF
Figure 16. Relevant Connections Using Internal Reference
T he REF
IN
/REF
OUT
pin may be overdriven by connecting it to
an external reference. T his is possible due to the series resis-
tance from the REF
IN
/REF
OUT
pin to the internal reference.
T his external reference can be in the range 2.3 V to AV
DD
.
When using AV
DD
as the reference source, the 10 nF capacitor
from the REF
IN
/REF
OUT
pin to AGND should be as close as
possible to the REF
IN
/REF
OUT
pin, and also the C
REF1
pin
should be connected to AV
DD
to keep this pin at the same volt-
age as the reference. T he connections for this arrangement are
shown in Figure 17. When using AV
DD
it may be necessary to
add a resistor in series with the AV
DD
supply. T his has the effect
of filtering the noise associated with the AV
DD
supply.
Note that when using an external reference, the voltage present
at the REF
IN
/REF
OUT
pin is determined by the external refer-
ence source resistance and the series resistance of 150 k
from
the REF
IN
/REF
OUT
pin to the internal 2.5 V reference. T hus, a
low source impedance external reference is recommended.
AV
DD
DV
DD
C
REF1
C
REF2
REF
IN
/REF
OUT
AD7854/
AD7854L
ANALOG
SUPPLY
+3V TO +5V
0.1μF
0.1μF
10μF
0.1μF
0.01μF
0.01μF
Figure 17. Relevant Connections, AV
DD
as the Reference
AD7854/AD7854L PE RFORMANCE CURVE S
Figure 18 shows a typical FFT plot for the AD7854 at 200 kHz
sample rate and 10 kHz input frequency.
FREQUENCY – kHz
0
–20
–1200
100
20
S
40
60
–40
–60
–80
80
–100
AV
DD
= DV
= 3.3V
F
SAMPLE
= 200kHz
F
IN
SNR = 72.04dB
THD = –88.43dB
Figure 18. FFT Plot
Figure 19 shows the SNR versus frequency for different supplies
and different external references.
INPUT FREQUENCY – kHz
74
73
690
100
20
S
40
80
72
71
70
60
AV
DD
= DV
WITH 2.5V REFERENCE
UNLESS STATED OTHERWISE
5.0V SUPPLIES, WITH 5V REFERENCE
5.0V SUPPLIES
5.0V SUPPLIES, L VERSION
3.3V SUPPLIES
Figure 19. SNR vs. Frequency
Figure 20 shows the power supply rejection ratio versus fre-
quency for the part. T he power supply rejection ratio is defined
as the ratio of the power in ADC output at frequency f to the
power of a full-scale sine wave:
PSRR (dB) =
10
log (Pf/Pfs)
Pf
= Power at frequency f in ADC output,
Pfs
= power of a full-
scale sine wave. Here a 100 mV peak-to-peak sine wave is
coupled onto the AV
DD
supply while the digital supply is left
unaltered. Both the 3.3 V and 5.0 V supply performances are
shown.
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| AD7854LAQ | 制造商:Rochester Electronics LLC 功能描述:12 BIT SINGLE CHANNEL PARALLEL ADC I.C. - Bulk |
| AD7854LAR | 制造商:Analog Devices 功能描述:ADC Single SAR 100ksps 12-bit Parallel 28-Pin SOIC W 制造商:Rochester Electronics LLC 功能描述:12-BIT SINGLE CHANNEL PARALLEL ADC I.C. - Bulk |
| AD7854LAR-REEL | 制造商:Analog Devices 功能描述:ADC Single SAR 100ksps 12-bit Parallel 28-Pin SOIC W T/R 制造商:Analog Devices 功能描述:ADC SGL SAR 100KSPS 12-BIT PARALLEL 28SOIC W - Tape and Reel |
| AD7854LARS | 功能描述:IC ADC 12BIT PARALLEL LP 28-SSOP RoHS:否 類別:集成電路 (IC) >> 數據采集 - 模數轉換器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:- 位數:12 采樣率（每秒）:3M 數據接口:- 轉換器數目:- 功率耗散（最大）:- 電壓電源:- 工作溫度:- 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應商設備封裝:SOT-23-6 包裝:帶卷 (TR) 輸入數目和類型:- |
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