参数资料
| 型号： | ADA4857-1YRZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC OPAMP VF ULDIST LP LN 8SOIC |
| 标准包装： | 98 |
| 放大器类型： | 电压反馈 |
| 电路数： | 1 |
| 转换速率： | 2800 V/µs |
| -3db带宽： | 850MHz |
| 电流 - 输入偏压： | 2µA |
| 电压 - 输入偏移： | 2000µV |
| 电流 - 电源： | 5mA |
| 电流 - 输出 / 通道： | 50mA |
| 电压 - 电源，单路/双路(±)： | 4.5 V ~ 10.5 V，±2.25 V ~ 5.25 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： | 768 (CN2011-ZH PDF) |
Data Sheet
ADA4857-1/ADA4857-2
Rev. C | Page 17 of 20
ACTIVE LOW-PASS FILTER (LPF)
Active filters are used in many applications such as antialiasing
filters and high frequency communication IF strips. With a
410 MHz gain bandwidth product and high slew rate, the
ADA4857-2 is an ideal candidate for active filters. Figure 48
shows the frequency response of 90 MHz and 45 MHz LPFs.
In addition to the bandwidth requirements, the slew rate must
be capable of supporting the full power bandwidth of the filter.
In this case, a 90 MHz bandwidth with a 2 V p-p output swing
requires at least 2800 V/s.
The circuit shown in Figure 49 is a 4-pole, Sallen-Key LPF. The
filter comprises two identical cascaded Sallen-Key LPF sections,
each with a fixed gain of G = 2. The net gain of the filter is equal
to G = 4 or 12 dB. The actual gain shown in Figure 48 is 12 dB.
This does not take into account the output voltage being divided in
half by the series matching termination resistor, RT, and the
load resistor.
Setting the resistors equal to each other greatly simplifies the
design equations for the Sallen-Key filter. To achieve 90 MHz,
the value of R should be set to 182 . However, if the value of R
is doubled, the corner frequency is cut in half to 45 MHz. This
would be an easy way to tune the filter by simply multiplying
the value of R (182 ) by the ratio of 90 MHz and the new
corner frequency in megahertz.
Figure 48 shows the output of each stage is of the filter and the
two different filters corresponding to R = 182 and R = 365 .
Resistor values are kept low for minimal noise contribution,
offset voltage, and optimal frequency response. Due to the low
capacitance values used in the filter circuit, the PCB layout and
minimization of parasitics is critical. A few picofarads can detune
the corner frequency, fc of the filter. The capacitor values shown
in Figure 49 actually incorporate some stray PCB capacitance.
Capacitor selection is critical for optimal filter performance.
Capacitors with low temperature coefficients, such as NPO
ceramic capacitors and silver mica, are good choices for filter
elements.
–42
–39
–36
–33
–30
–27
–24
–21
–18
–15
–12
–9
–6
–3
0
3
6
9
12
15
0.1
1
10
100
500
07040-
074
FREQUENCY (MHz)
M
AG
NI
T
UDE
(
d
B)
OUT1, f = 90MHz
OUT2, f = 90MHz
OUT1, f = 45MHz
OUT2, f = 45MHz
RL = 100
VS = ±5V
Figure 48. Low-Pass Filter Response
U1
C1
3.9pF
C2
5.6pF
R
RT
49.9
R
R1
348
R
R2
348
RT
49.9
+IN1
–5V
+5V
0.1F
10F
U2
C3
3.9pF
C4
5.6pF
R
R3
348
R4
348
–5V
+5V
0.1F
10F
OUT2
07040-
075
OUT1
Figure 49. 4-Pole, Sallen-Key Low-Pass Filter (ADA4857-2)
相关PDF资料 |
PDF描述 |
|---|---|
| LTC6244HDD#PBF | IC OPAMP CMOS R-R DUAL 8-DFN |
| 77311-122-05LF | CONN HEADER .100 SINGL STR 5POS |
| 77311-127-05LF | CONN HEADER .100 SINGL STR 5POS |
| AD8276BRZ | IC AMP DIFF R-R 550KHZ LP 8SOIC |
| 57102-F08-02LF | MINITEK |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADA4857-1YRZ-R7 | 功能描述:IC OPAMP VF ULDIST LP LN 8SOIC 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:通用 电路数:2 输出类型:满摆幅 转换速率:1.8 V/µs 增益带宽积:6.5MHz -3db带宽:4.5MHz 电流 - 输入偏压:5nA 电压 - 输入偏移:100µV 电流 - 电源:65µA 电流 - 输出 / 通道:35mA 电压 - 电源，单路/双路(±):1.8 V ~ 5.25 V，±0.9 V ~ 2.625 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-MSOP 包装:管件 |
| ADA4857-1YRZ-RL | 功能描述:IC OPAMP VF ULDIST LP LN 8SOIC 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) |
| ADA4857-2 | 制造商:AD 制造商全称:Analog Devices 功能描述:Ultralow Distortion, Low Power, Low Noise, High Speed Op Amp |
| ADA4857-2YCP-EBZ | 功能描述:BOARD EVAL FOR ADA4857-2YCP 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:- |
| ADA4857-2YCPZ-R2 | 制造商:Analog Devices 功能描述:OP Amp Dual Volt Fdbk 制造商:Analog Devices 功能描述:OP AMP DUAL VOLT FDBK 5.25V/10.5V 16LFCSP EP - Tape and Reel 制造商:Analog Devices 功能描述:OP Amp Dual Volt Fdbk }5.25V/10.5V 16-Pin LFCSP EP |
发布紧急采购，3分钟左右您将得到回复。