参数资料
型号: ADA4927-1YCPZ-R7
厂商: Analog Devices Inc
文件页数: 10/24页
文件大小: 0K
描述: IC OPAMP CF DIFF 65MA LN 16LFCSP
特色产品: ADA4927: Ultralow Distortion Current Feedback Differential ADC Driver
标准包装: 1
放大器类型: 电流反馈
电路数: 1
输出类型: 差分
转换速率: 5000 V/µs
-3db带宽: 2.3GHz
电流 - 输入偏压: 500nA
电压 - 输入偏移: 300µV
电流 - 电源: 20mA
电流 - 输出 / 通道: 65mA
电压 - 电源,单路/双路(±): 4.5 V ~ 11 V,±2.25 V ~ 5.5 V
工作温度: -40°C ~ 105°C
安装类型: 表面贴装
封装/外壳: 16-VFQFN 裸露焊盘,CSP
供应商设备封装: 16-LFCSP-VQ
包装: 标准包装
产品目录页面: 765 (CN2011-ZH PDF)
其它名称: ADA4927-1YCPZ-R7DKR
ADA4927-1/ADA4927-2
Rev. A | Page 18 of 24
Table 12. Differential Input, DC-Coupled
Nominal Gain (dB)
RF (Ω)
RG (Ω)
RIN, dm (Ω)
Differential Output Noise Density (nV/√Hz)
0
301
602
8.0
20
442
44.2
88.4
21.8
26
604
30.1
60.2
37.9
Table 13. Single-Ended Ground-Referenced Input, DC-Coupled, RS = 50 Ω
Nominal Gain (dB)
RF (Ω)
RG1 (Ω)
RT (Ω)
RIN, cm (Ω)
RG2 (Ω)1
Differential Output Noise Density (nV/√Hz)
0
309
301
56.2
401
328
8.1
20
511
39.2
158
73.2
77.2
18.6
26
806
28
649
54.2
74.4
29.1
1 RG2 = RG1 + (RS||RT).
Similar to the case of a conventional op amp, the output noise
voltage densities can be estimated by multiplying the input-
referred terms at +IN and IN by the appropriate output factor,
where:
(
)
2
1
N
β
G
+
=
2
is the circuit noise gain.
G1
F1
G1
1
R
β
+
=
R
and
G2
F2
G2
2
R
β
+
=
R
are the feedback factors.
When the feedback factors are matched, RF1/RG1 = RF2/RG2,
β1 = β2 = β, and the noise gain becomes
G
F
N
R
β
G
+
=
1
R
1
Note that the output noise from VOCM goes to zero in this case.
The total differential output noise density, vnOD, is the root-sum-
square of the individual output noise terms.
=
1
i
2
nOi
nOD
v
8
Table 12 and Table 13 list several common gain settings, associated
resistor values, input impedance, and output noise density for
both balanced and unbalanced input configurations.
IMPACT OF MISMATCHES IN THE FEEDBACK
NETWORKS
As previously mentioned, even if the external feedback networks
(RF/RG) are mismatched, the internal common-mode feedback
loop still forces the outputs to remain balanced. The amplitudes
of the signals at each output remain equal and 180° out of phase.
The input-to-output differential mode gain varies proportionately
to the feedback mismatch, but the output balance is unaffected.
The gain from the VOCM pin to VO, dm is equal to
2(β1 β2)/(β1 + β2)
When β1 = β2, this term goes to zero and there is no differential
output voltage due to the voltage on the VOCM input (including
noise). The extreme case occurs when one loop is open and the
other has 100% feedback; in this case, the gain from VOCM input
to VO,dm is either +2 or 2, depending on which loop is closed.
The feedback loops are nominally matched to within 1% in
most applications, and the output noise and offsets due to the
VOCM input are negligible. If the loops are intentionally mismatched
by a large amount, it is necessary to include the gain term from
VOCM to VO, dm and account for the extra noise. For example, if
β1 = 0.5 and β2 = 0.25, the gain from VOCM to VO, dm is 0.67. If the
VOCM pin is set to 2.5 V, a differential offset voltage is present at the
output of (2.5 V)(0.67) = 1.67 V. The differential output noise
contribution is (15 nV/√Hz)(0.67) = 10 nV/√Hz. Both of these
results are undesirable in most applications; therefore, it is best
to use nominally matched feedback factors.
Mismatched feedback networks also result in a degradation of
the ability of the circuit to reject input common-mode signals,
much the same as for a four-resistor difference amplifier made
from a conventional op amp.
As a practical summarization of the previous issues, resistors of
1% tolerance produce a worst-case input CMRR of approximately
40 dB, a worst-case differential-mode output offset of 25 mV
due to a 2.5 V VOCM input, negligible VOCM noise contribution,
and no significant degradation in output balance error.
CALCULATING THE INPUT IMPEDANCE FOR AN
APPLICATION CIRCUIT
The effective input impedance of a circuit depends on whether
the amplifier is being driven by a single-ended or differential
signal source. For balanced differential input signals, as shown
in Figure 48, the input impedance (RIN, dm) between the inputs
(+DIN and DIN) is simply RIN, dm = RG + RG = 2 × RG.
+VS
–VS
ADA4927
+IN
–IN
RF
+DIN
–DIN
VOCM
RG
VOUT, dm
07
57
4-
04
8
Figure 48. The ADA4927 Configured for Balanced (Differential) Inputs
相关PDF资料
PDF描述
4-103327-0-22 CONN HEADR BRKWAY .100 22POS STR
929834-07-04 CONN HEADER .100 SNGL STR 4POS
LT1999IMS8-20#PBF IC OP AMP CURRENT SENSE 8-MSOP
957212-5002-AR CONN HDR 12POS 2MM R/A T/H 10AU
LT1999IS8-20#PBF IC OP AMP CURRENT SENSE 8-SOIC
相关代理商/技术参数
参数描述
ADA4927-1YCPZ-RL 功能描述:IC OPAMP CF DIFF 65MA LN 16LFCSP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:50 系列:- 放大器类型:J-FET 电路数:2 输出类型:- 转换速率:13 V/µs 增益带宽积:3MHz -3db带宽:- 电流 - 输入偏压:65pA 电压 - 输入偏移:3000µV 电流 - 电源:1.4mA 电流 - 输出 / 通道:- 电压 - 电源,单路/双路(±):7 V ~ 36 V,±3.5 V ~ 18 V 工作温度:-40°C ~ 85°C 安装类型:通孔 封装/外壳:8-DIP(0.300",7.62mm) 供应商设备封装:8-PDIP 包装:管件
ADA4927-2 制造商:AD 制造商全称:Analog Devices 功能描述:Ultralow Distortion Current Feedback Differential ADC Driver
ADA4927-2YCP-EBZ 功能描述:BOARD EVAL FOR ADA4927-2YCP RoHS:是 类别:编程器,开发系统 >> 评估板 - 运算放大器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:-
ADA4927-2YCPZ-R2 功能描述:IC OPAMP CF DIFF DUAL LN 24LFCSP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:1,000 系列:- 放大器类型:电压反馈 电路数:4 输出类型:满摆幅 转换速率:33 V/µs 增益带宽积:20MHz -3db带宽:30MHz 电流 - 输入偏压:2nA 电压 - 输入偏移:3000µV 电流 - 电源:2.5mA 电流 - 输出 / 通道:30mA 电压 - 电源,单路/双路(±):4.5 V ~ 16.5 V,±2.25 V ~ 8.25 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-SOIC(0.154",3.90mm 宽) 供应商设备封装:14-SOIC 包装:带卷 (TR)
ADA4927-2YCPZ-R7 功能描述:IC OPAMP CF DIFF DUAL LN 24LFCSP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:2,500 系列:Excalibur™ 放大器类型:J-FET 电路数:1 输出类型:- 转换速率:45 V/µs 增益带宽积:10MHz -3db带宽:- 电流 - 输入偏压:20pA 电压 - 输入偏移:490µV 电流 - 电源:1.7mA 电流 - 输出 / 通道:48mA 电压 - 电源,单路/双路(±):4.5 V ~ 38 V,±2.25 V ~ 19 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SOIC 包装:带卷 (TR)