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参数资料
| 型号： | AD7946BRM |
| 厂商： | ANALOG DEVICES INC |
| 元件分类： | ADC |
| 英文描述： | 14-Bit, 500 kSPS PulSAR⑩ ADC in MSOP/QFN |
| 中文描述： | 1-CH 14-BIT SUCCESSIVE APPROXIMATION ADC, SERIAL ACCESS, PDSO10 |
| 封装： | MO-187-BA, MSOP-10 |
| 文件页数： | 7/24页 |
| 文件大小： | 637K |
| 代理商： | AD7946BRM |
AD7946
Rev. A | Page 15 of 24
POWER SUPPLY
The AD7946 is specified at 4.5 V to 5.5 V. It uses two power
supply pins: a core supply VDD and a digital input/output
interface supply VIO. VIO allows direct interface with any
logic between 1.8 V and VDD. To reduce the supplies needed,
the VIO and VDD can be tied together. The AD7946 is
independent of power supply sequencing between VIO and
VDD. Additionally, it is very insensitive to power supply
variations over a wide frequency range, as shown in Figure 29,
which represents PSRR over frequency.
FREQUENCY (kHz)
P
S
RR
(dB)
04656-029
50
40
30
60
90
80
70
10
1
100
1k
10k
VDD = 5V
Figure 29. PSRR vs. Frequency
The AD7946 powers down automatically at the end of each
conversion phase and, therefore, the power scales linearly with
the sampling rate, as shown in Figure 30. This makes the part
ideal for low sampling rate (even a few Hz) and low battery-
powered applications.
04
65
6
-05
1
0.001
0.1
1
0.01
10
100
1000
10
100
1k
10k
100k
1M
SAMPLING RATE (SPS)
OP
E
R
A
T
ING
CUR
RE
NT
(
A
)
VIO
VDD = 5V
Figure 30. Operating Currents vs. Sampling Rate
SUPPLYING THE ADC FROM THE REFERENCE
For simplified applications, the AD7946, with its low operating
current, can be supplied directly using the reference circuit
shown in Figure 31. The reference line can be driven by one of
the following:
The system power supply directly.
A reference voltage with enough current output capability,
such as the ADR43x.
which can also filter the system power supply, as shown
in Figure 31.
AD8603
AD7946
VIO
REF
(NOTE 1)
VDD
10F
1F
10k
1k
47k
5V
1F
04
65
6
-03
1
NOTES
1. OPTIONAL REFERENCE BUFFER AND FILTER
Figure 31. Example of Application Circuit
SINGLE-SUPPLY APPLICATION
Figure 32 shows a typical 14-bit single-supply application. There
are different challenges to doing a single-supply, high resolution
design, and the ADA4841 addresses these nicely. The combina-
tion of low noise, low power, wide input range, rail-to-rail output,
and high speed make the ADA4841 a perfect driver solution for
low power, single-supply 14-bit ADCs, such as the AD7946. In a
single-supply system, one of the main challenges is to use the
amplifier in buffer mode to have the lowest output noise and
still preserve linearity compatible with the ADC. Rail-to-rail
input amplifiers usually have higher noise than the ADA4841
and cannot be used on their entire input range in buffer mode
because of the nonlinear region around the crossover point of
their input stage. The ADA4841, which has no crossover region
but has a wide linear input range from ground to 1 V below
positive rail, solves this issue, as shown in Figure 32, where it
can accept the 0 V to 4.096 V input range with a supply as low
as 5.2 V. This supply allows using a small, low dropout, low
temperature drift ADR364 reference voltage. Note that, like any
rail-to-rail output amplifier at the low end of its output range
close to ground, the ADA4841 can exhibit some nonlinearity on
a small region of approximately 25 mV from ground. The
ADA4841 drives a 1-pole, low-pass filter. This filter limits the
already very low noise contribution from the amplifier to the
AD7946.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD7946BRMRL7 | 制造商:AD 制造商全称:Analog Devices 功能描述:14-Bit, 500 kSPS PulSAR⑩ ADC in MSOP/QFN |
| AD7946BRM-RL7 | 制造商:Analog Devices 功能描述:ADC Single SAR 500ksps 14-bit Serial 10-Pin MSOP T/R |
| AD7946BRMZ | 功能描述:IC ADC 14BIT 500KSPS SAR 10-MSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:PulSAR® 其它有关文件:TSA1204 View All Specifications 标准包装:1 系列:- 位数:12 采样率（每秒）:20M 数据接口:并联 转换器数目:2 功率耗散（最大）:155mW 电压电源:模拟和数字 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-TQFP 供应商设备封装:48-TQFP（7x7） 包装:Digi-Reel® 输入数目和类型:4 个单端，单极；2 个差分，单极 产品目录页面:1156 (CN2011-ZH PDF) 其它名称:497-5435-6 |
| AD7946BRMZRL7 | 功能描述:IC ADC 14BIT 500KSPS 10-MSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:PulSAR® 标准包装:1,000 系列:- 位数:12 采样率（每秒）:300k 数据接口:并联 转换器数目:1 功率耗散（最大）:75mW 电压电源:单电源 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-SOIC（0.295"，7.50mm 宽） 供应商设备封装:24-SOIC 包装:带卷 (TR) 输入数目和类型:1 个单端，单极；1 个单端，双极 |
| AD7947 | 制造商:AD 制造商全称:Analog Devices 功能描述:3mW, 100kSPS, 14-Bit ADC in 6-Lead SOT-23 |
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