参数资料
| 型号： | AD8028ARZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 11/25页 |
| 文件大小： | 0K |
| 描述： | IC OPAMP R-R DUAL LDIST 8SOIC |
| 标准包装： | 98 |
| 放大器类型： | 电压反馈 |
| 电路数： | 2 |
| 输出类型： | 满摆幅 |
| 转换速率： | 100 V/µs |
| -3db带宽： | 190MHz |
| 电流 - 输入偏压： | 4µA |
| 电压 - 输入偏移： | 200µV |
| 电流 - 电源： | 6.5mA |
| 电流 - 输出 / 通道： | 120mA |
| 电压 - 电源，单路/双路(±)： | 2.7 V ~ 12 V，±1.35 V ~ 6 V |
| 工作温度： | -40°C ~ 125°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-SO |
| 包装： | 管件 |
| 产品目录页面： | 769 (CN2011-ZH PDF) |
AD8027/AD8028
Rev. C | Page 18 of 24
In the event that the crossover region cannot be avoided,
specific attention has been given to the input stage to ensure
constant transconductance and minimal offset in all regions of
operation. The regions are PNP input pair running, NPN input
pair running, and both running at the same time (in the
200 mV crossover region). Maintaining constant transconduc-
tance in all regions ensures the best wideband distortion
performance when going between these regions. With this
technique, the AD8027/AD8028 can achieve greater than 80 dB
SFDR for a 2 V p-p, 1 MHz, and G = 1 signal on ±1.5 V
supplies. Another requirement needed to achieve this level of
distortion is that the offset of each pair must be laser trimmed
to achieve greater than 80 dB SFDR, even for low frequency
signals.
OUTPUT STAGE
The AD8027/AD8028 use a common-emitter output structure
to achieve rail-to-rail output capability. The output stage is
designed to drive 50 mA of linear output current, 40 mA within
200 mV of the rail, and 2.5 mA within 35 mV of the rail.
Loading of the output stage, including any possible feedback
network, lowers the open-loop gain of the amplifier. Refer to
Figure 49 for the loading behavior. Capacitive load can degrade
the phase margin of the amplifier. The AD8027/AD8028 can
drive up to 20 pF, G = 1, as shown in Figure 10. A small (25 Ω
to 50 Ω) series resistor, RSNUB, should be included, if the
capacitive load is to exceed 20 pF for a gain of 1. Increasing the
closed-loop gain increases the amount of capacitive load that
can be driven before a series resistor needs to be included.
B
DC ERRORS
The AD8027/AD8028 use two complementary input stages to
achieve rail-to-rail input performance, as mentioned in the
Input Stage section. To use the dc performance over the entire
common-mode range, the input bias current and input offset
voltage of each pair must be considered.
Referring to Figure 56, the output offset voltage of each pair is
calculated by
+
=
G
F
G
PNP
OS
OUT
PNP
OS
R
V
,
+
=
G
F
G
NPN
OS
OUT
NPN
OS
R
V
,
where the difference of the two is the discontinuity experienced
when going through the crossover region.
The size of the discontinuity is defined as
(
)
+
×
=
G
F
G
NPN
OS,
PNP
OS,
DIS
R
V
Using the crossover select feature of the AD8027/AD8028 helps
to avoid this region. In the event that the region cannot be
avoided, the quantity (VOS, PNP – VOS, NPN) is trimmed to minimize
this effect.
Because the input pairs are complementary, the input bias cur-
rent reverses polarity when going through the crossover region
shown in Figure 37. The offset between pairs is described by
()
+
×
=
F
G
F
G
S
NPN
B,
PNP
B,
NPN
OS,
PNP
OS,
R
I
V
IB, PNP is the input bias current of either input when the PNP
input pair is active, and IB, NPN is the input bias current of either
input pair when the NPN pair is active. If RS is sized so that
when multiplied by the gain factor it equals RF, this effect is
eliminated. It is strongly recommended to balance the imped-
ances in this manner when traveling through the crossover
region to minimize the dc error and distortion. As an example,
assuming that the PNP input pair has an input bias current of
6 μA and the NPN input pair has an input bias current of
2 μA, a 200 μV shift in offset occurs when traveling through
the crossover region with RF equal to 0 Ω and RS equal to 25 Ω.
In addition to the input bias current shift between pairs, each
input pair has an input bias current offset that contributes to the
total offset in the following manner:
F
B
G
F
G
S
B
OS
R
I
R
I
V
+
+
=
Δ
VOUT
IB+
RF
RG
IB–
VOS
RS
+–
VI
+
–
SELECT
–V
+V
–
+
AD8027/
AD8028
03327-A-055
Figure 56. Op Amp DC Error Sources
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| AD8028ARZ | 制造商:Analog Devices 功能描述:AMP LOW DISTORTION RRI/O SMD 8028 |
| AD8028ARZ-REEL | 功能描述:IC OPAMP R-R DUAL LDIST 8SOIC RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:50 系列:LinCMOS™ 放大器类型:通用 电路数:4 输出类型:- 转换速率:0.05 V/µs 增益带宽积:110kHz -3db带宽:- 电流 - 输入偏压:0.7pA 电压 - 输入偏移:210µV 电流 - 电源:57µA 电流 - 输出 / 通道:30mA 电压 - 电源，单路/双路(±):3 V ~ 16 V，±1.5 V ~ 8 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:管件 产品目录页面:865 (CN2011-ZH PDF) 其它名称:296-1834296-1834-5 |
| AD8028ARZ-REEL7 | 功能描述:IC OPAMP R-R DUAL LDIST 8SOIC RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:50 系列:LinCMOS™ 放大器类型:通用 电路数:4 输出类型:- 转换速率:0.05 V/µs 增益带宽积:110kHz -3db带宽:- 电流 - 输入偏压:0.7pA 电压 - 输入偏移:210µV 电流 - 电源:57µA 电流 - 输出 / 通道:30mA 电压 - 电源，单路/双路(±):3 V ~ 16 V，±1.5 V ~ 8 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:管件 产品目录页面:865 (CN2011-ZH PDF) 其它名称:296-1834296-1834-5 |
| AD8028WARMZ-R7 | 功能描述:Voltage Feedback Amplifier 2 Circuit Rail-to-Rail 10-MSOP 制造商:analog devices inc. 系列:- 包装:剪切带（CT） 零件状态:有效 放大器类型:电压反馈 电路数:2 输出类型:满摆幅 压摆率:100 V/μs 增益带宽积:- -3db 带宽:190MHz 电流 - 输入偏置:4μA 电压 - 输入失调:200μV 电流 - 电源:6.5mA 电流 - 输出/通道:120mA 电压 - 电源，单/双（±）:2.7 V ~ 12 V，±1.35 V ~ 6 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商器件封装:10-MSOP 标准包装:1 |
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