参数资料
型号: LTC2222IUK-11#TRPBF
厂商: Linear Technology
文件页数: 7/24页
文件大小: 0K
描述: IC ADC 11BIT 105MSPS SAMPL 48QFN
标准包装: 2,000
位数: 11
采样率(每秒): 105M
数据接口: 并联
转换器数目: 1
功率耗散(最大): 535mW
电压电源: 单电源
工作温度: -40°C ~ 85°C
安装类型: 表面贴装
封装/外壳: 48-WFQFN 裸露焊盘
供应商设备封装: 48-QFN-EP(7x7)
包装: 带卷 (TR)
输入数目和类型: 1 个单端,双极; 1 个差分,双极
LTC2222-11
15
222211f
signal at its optimum DC level. Figure 3 shows a 1:1 turns
ratio transformer. Other turns ratios can be used if the
source impedance seen by the ADC does not exceed 100
for each ADC input. A disadvantage of using a transformer
is the loss of low frequency response. Most small RF
transformers have poor performance at frequencies be-
low 1MHz.
Figure 4 demonstrates the use of a differential amplifier to
convert a single ended input signal into a differential input
signal. The advantage of this method is that it provides low
frequency input response; however, the limited gain band-
width of most op amps will limit the SFDR at high input
frequencies.
Figure 5 shows a single-ended input circuit. The imped-
ance seen by the analog inputs should be matched. This
circuit is not recommended if low distortion is required.
The 25
resistorsand12pFcapacitorontheanaloginputs
serve two purposes: isolating the drive circuitry from the
sample-and-hold charging glitches and limiting the
wideband noise at the converter input. For input frequen-
cies higher than 100MHz, the capacitor may need to be
decreased to prevent excessive signal loss.
For input frequencies above 100MHz the input circuits of
Figure 6, 7 and 8 are recommended. The balun trans-
former gives better high frequency response than a flux
coupled center tapped transformer. The coupling capaci-
tors allow the analog inputs to be DC biased at 1.6V. In
Figure 8 the series inductors are impedance matching
elements that maximize the ADC bandwidth.
Reference Operation
Figure 9 shows the LTC2222-11 reference circuitry con-
sisting of a 1.6V bandgap reference, a difference amplifier
and switching and control circuit. The internal voltage
reference can be configured for two pin selectable input
ranges of 2V (
±1V differential) or 1V (±0.5V differential).
Tying the SENSE pin to VDD selects the 2V range; tying the
SENSE pin to VCM selects the 1V range.
The 1.6V bandgap reference serves two functions: its
output provides a DC bias point for setting the common
mode voltage of any external input circuitry; additionally,
the reference is used with a difference amplifier to gener-
ate the differential reference levels needed by the internal
ADC circuitry. An external bypass capacitor is required for
the 1.6V reference output, VCM. This provides a high
frequency low impedance path to ground for internal and
external circuitry.
APPLICATIO S I FOR ATIO
WU
UU
25
25
AIN
+
AIN
12pF
2.2
F
VCM
LTC2222-11
222211 F04
+
CM
ANALOG
INPUT
HIGH SPEED
DIFFERENTIAL
AMPLIFIER
LTC6600-20,
LT1993
Figure 4. Differential Drive with an Amplifier
Figure 5. Single-Ended Drive
25
0.1
F
ANALOG
INPUT
VCM
AIN
+
AIN
1k
12pF
222211 F05
2.2
F
1k
25
0.1
F
LTC2222-11
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LTC2222UK 制造商:LINER 制造商全称:Linear Technology 功能描述:12-Bit,105Msps/80Msps ADCs
LTC2222UK-11 制造商:LINER 制造商全称:Linear Technology 功能描述:11-Bit, 105Msps ADC
LTC2223 制造商:LINER 制造商全称:Linear Technology 功能描述:12-Bit,105Msps/80Msps ADCs
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LTC2223CUK#PBF 功能描述:IC ADC 12BIT 80MSPS SAMPLE 48QFN RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 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