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参数资料
| 型号： | LTC2221CUP#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/32页 |
| 文件大小： | 0K |
| 描述： | IC ADC 12-BIT 135MSPS 64-QFN |
| 标准包装： | 2,000 |
| 位数： | 12 |
| 采样率（每秒）： | 135M |
| 数据接口： | 并联 |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 931mW |
| 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： | 64-WFQFN 裸露焊盘 |
| 供应商设备封装： | 64-QFN（9x9） |
| 包装： | 带卷 (TR) |
| 输入数目和类型： | 1 个单端，双极; 1 个差分，双极 |
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LTC2220/LTC2221
19
22201fa
Each pipelined stage shown in Figure 1 contains an ADC,
a reconstruction DAC and an interstage residue amplifier.
In operation, the ADC quantizes the input to the stage and
the quantized value is subtracted from the input by the
DAC to produce a residue. The residue is amplified and
output by the residue amplifier. Successive stages operate
out of phase so that when the odd stages are outputting
their residue, the even stages are acquiring that residue
and vice versa.
When ENC is low, the analog input is sampled differentially
directly onto the input sample-and-hold capacitors, inside
the “Input S/H” shown in the block diagram. At the instant
that ENC transitions from low to high, the sampled input
is held. While ENC is high, the held input voltage is
buffered by the S/H amplifier which drives the first pipelined
ADC stage. The first stage acquires the output of the S/H
during this high phase of ENC. When ENC goes back low,
the first stage produces its residue which is acquired by
the second stage. At the same time, the input S/H goes
back to acquiring the analog input. When ENC goes back
high, the second stage produces its residue which is
acquired by the third stage. An identical process is re-
peated for the third and fourth stages, resulting in a fourth
stage residue that is sent to the fifth stage ADC for final
evaluation.
Each ADC stage following the first has additional range to
accommodate flash and amplifier offset errors. Results
from all of the ADC stages are digitally synchronized such
that the results can be properly combined in the correction
logic before being sent to the output buffer.
SAMPLE/HOLD OPERATION AND INPUT DRIVE
Sample/Hold Operation
Figure 2 shows an equivalent circuit for the LTC2220/
LTC2221 CMOS differential sample-and-hold. The analog
inputs are connected to the sampling capacitors (CSAMPLE)
through NMOS transistors. The capacitors shown at-
tached to each input (CPARASITIC) are the summation of all
other capacitance associated with each input.
During the sample phase when ENC is low, the transistors
connect the analog inputs to the sampling capacitors and
they charge to, and track the differential input voltage.
When ENC transitions from low to high, the sampled input
voltage is held on the sampling capacitors. During the hold
phase when ENC is high, the sampling capacitors are
disconnected from the input and the held voltage is passed
to the ADC core for processing. As ENC transitions from
high to low, the inputs are reconnected to the sampling
capacitors to acquire a new sample. Since the sampling
capacitors still hold the previous sample, a charging glitch
proportional to the change in voltage between samples will
be seen at this time. If the change between the last sample
and the new sample is small, the charging glitch seen at
the input will be small. If the input change is large, such as
the change seen with input frequencies near Nyquist, then
a larger charging glitch will be seen.
CSAMPLE
1.6pF
VDD
LTC2220/LTC2221
AIN
+
22201 F02
CSAMPLE
1.6pF
VDD
AIN
–
ENC–
ENC+
1.6V
6k
1.6V
6k
CPARASITIC
1pF
CPARASITIC
1pF
15
15
Figure 2. Equivalent Input Circuit
Single-Ended Input
For cost sensitive applications, the analog inputs can be
driven single-ended. With a single-ended input the har-
monic distortion and INL will degrade, but the SNR and
DNL will remain unchanged. For a single-ended input, AIN+
should be driven with the input signal and AIN– should be
connected to 1.6V or VCM.
Common Mode Bias
For optimal performance the analog inputs should be
driven differentially. Each input should swing
±0.5V for
APPLICATIO S I FOR ATIO
WU
UU
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相关代理商/技术参数 |
参数描述 |
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| LTC2221IUP | 制造商:Linear Technology 功能描述:ADC Single Pipelined 135Msps 12-bit Parallel 64-Pin QFN EP |
| LTC2221IUP#PBF | 功能描述:IC ADC 12-BIT 135MSPS 64-QFN RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| LTC2221IUP#TRPBF | 功能描述:IC ADC 12-BIT 135MSPS 64-QFN RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 位数:12 采样率（每秒）:3M 数据接口:- 转换器数目:- 功率耗散（最大）:- 电压电源:- 工作温度:- 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-23-6 包装:带卷 (TR) 输入数目和类型:- |
| LTC2222 | 制造商:LINER 制造商全称:Linear Technology 功能描述:12-Bit,105Msps/80Msps ADCs |
| LTC2222-11 | 制造商:LINER 制造商全称:Linear Technology 功能描述:11-Bit, 105Msps ADC |
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