參數(shù)資料
型號: ADS930E
英文描述: 8-Bit, 30MHz Sampling ANALOG-TO-DIGITAL CONVERTER
中文描述: 8位,30MHz的采樣模擬數(shù)字轉(zhuǎn)換器
文件頁數(shù): 9/11頁
文件大?。?/td> 191K
代理商: ADS930E
9
ADS930
R
1
1k
OPA680
V
IN
R
F
402
R
S
50
R
G
402
C
0.1μF
V
CM
C
0.1μF
0.1μF
IN
IN
CM
+5V
+3V
22pF
ADS930
R
P
402
The pipelined quantizer architecture has 7 stages with each
stage containing a two-bit quantizer and a two bit digital-
to-analog converter, as shown in Figure 2. Each two-bit
quantizer stage converts on the edge of the sub-clock, which
is the same frequency of the externally applied clock. The
output of each quantizer is fed into its own delay line to
time-align it with the data created from the subsequent
quantizer stages. This aligned data is fed into a digital error
correction circuit which can adjust the output data based on
the information found on the redundant bits. This technique
provides the ADS930 with excellent differential linearity
and guarantees no missing codes at the 8-bit level.
The ADS930 includes an internal reference circuit that
provides the bias voltages for the internal stages (for details
see “Internal Reference”). A midpoint voltage is established
by the built-in resistor ladder which is made available at pin
26 “CM”. This voltage can be used to bias the inputs up to
the recommended common-mode voltage or to level shift
the input driving circuitry. The ADS930 can be used in both
a single-ended or differential input configuration. When
operated in single-ended mode, the reference midpoint (pin
26) should be tied to the inverting input, pin 24.
To accommodate a bipolar signal swing, the ADS930 oper-
ates with a common-mode voltage (V
CM
) which is derived
from the internal references. Due to the symmetric resistor
ladder inside the ADS930, V
CM
is situated between the top
and bottom reference voltage. Equation (1) can be used for
calculating the common-mode voltage level.
V
CM
= (REFT +REFB)/2
(1)
APPLICATIONS
DRIVING THE ANALOG INPUTS
Figure 3 shows an example of an ac-coupled, single-ended
interface circuit using high-speed op amps which operate on
dual supplies (OPA650, OPA658). The mid-point reference
voltage, (V
CM
), biases the bipolar, ground-referenced input
signal. The capacitor C
1
and resistor R
1
form a high-pass
filter with the –3dB frequency set at
f
–3dB
= 1/(2
π
R
1
C
1
)
(2)
The values for C
1
and R
1
are not critical in most applications
and can be set freely. The values shown in Figure 3 corre-
spond to a corner frequency of 1.6kHz.
Figure 4 depicts a circuit that can be used in single-supply
applications. The mid-reference biases the op amp up to the
appropriate common-mode voltage, for example V
CM
=
+1.5V. With the use of capacitor C
G
, the DC gain for the
non-inverting op amp input is set to +1V/V. As a result, the
transfer function is modified to
V
OUT
= V
IN
{(1 + R
F
/R
G
) + V
CM
}
(3)
Again, the input coupling capacitor C
1
and resistor R
1
form
a high-pass filter. At the same time, the input impedance is
defined by R
1
. Resistor R
S
isolates the op amp’s output from
the capacitive load to avoid gain peaking or even oscillation.
It can also be used to establish a defined bandwidth to reduce
the wideband noise. Its value is usually between 10
and
100
.
FIGURE 4. Interface Circuit Example Using the Voltage Feedback Amplifier OPA680.
FIGURE 3. AC-Coupled Driver.
402
OPA650
OPA658
V
IN
402
R
1
1k
V
CM
C
0.1μF
0.1μF
IN
IN
CM
+5V
10
–5V
+3V
ADS930
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADS930E 制造商:Texas Instruments 功能描述:IC's
ADS930E/1K 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 8-Bit 30 MSPS SE/ Diff Input RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
ADS930E/1KG4 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 8-Bit 30 MSPS SE/ Diff Input RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
ADS930EG4 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 8-Bit 30 MSPS SE/ Diff Input RoHS:否 制造商:Texas Instruments 通道數(shù)量:2 結(jié)構(gòu):Sigma-Delta 轉(zhuǎn)換速率:125 SPs to 8 KSPs 分辨率:24 bit 輸入類型:Differential 信噪比:107 dB 接口類型:SPI 工作電源電壓:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-32
ADS-930MC 制造商:Murata Power Solutions 功能描述:Single ADC Pipelined 500ksps 16-bit Parallel 40-Pin TDIP