參數(shù)資料
型號(hào)： ADA4938-2ACPZ-RL
廠商： Analog Devices Inc
文件頁(yè)數(shù)： 17/28頁(yè)
文件大小： 0K
描述： IC ADC DRIVER DUAL DIFF 24LFCSP
標(biāo)準(zhǔn)包裝： 5,000
類型： ADC 驅(qū)動(dòng)器
應(yīng)用： 數(shù)據(jù)采集
安裝類型： 表面貼裝
封裝/外殼： 24-VFQFN 裸露焊盤(pán)，CSP
供應(yīng)商設(shè)備封裝： 24-LFCSP-VQ（4x4）
包裝： 帶卷 (TR)
ADA4938-1/ADA4938-2
Rev. A | Page 24 of 28
HIGH PERFORMANCE ADC DRIVING
The ADA4938-x is ideally suited for dc-coupled baseband
applications. The circuit in Figure 69 shows a front-end connection
for an ADA4938-x driving an AD9446, 16-bit, 80 MSPS ADC.
The AD9446 achieves its optimum performance when it is
driven differentially. The ADA4938-x eliminates the need for a
transformer to drive the ADC, performs a single-ended-to-
differential conversion, buffers the driving signal, and provides
appropriate level shifting for dc coupling.
The ADA4938-x is configured with a single 10 V supply and
unity gain for a single-ended input to differential output. The
61.9 Ω termination resistor, in parallel with the single-ended
input impedance of 267 Ω, provides a 50 Ω termination for the
source. The additional 26 Ω (226 Ω total) at the inverting input
balances the parallel impedance of the 50 Ω source and the
termination resistor driving the noninverting input.
The signal generator has a symmetric, ground-referenced bipolar
output. The VOCM pin of the ADA4938-x is biased with an external
resistor divider to obtain the desired 3.5 V output common-mode.
One-half of the common-mode voltage is fed back to the summing
nodes, biasing IN and +IN at 1.75 V. For a common-mode vol-
tage of 3.5 V, each ADA4938-x output swings between 2.7 V
and 4.3 V, providing a 3.2 V p-p differential output.
The output of the amplifier is dc-coupled to the ADC through a
second-order, low-pass filter with a 3 dB frequency of 50 MHz.
The filter reduces the noise bandwidth of the amplifier and
isolates the driver outputs from the ADC inputs.
The AD9446 is configured for a 4.0 V p-p full-scale input by
setting R1 = R2 = 1 kΩ between the VREF pin and SENSE pin
The circuit in Figure 70 shows a simplified front-end connection
for an ADA4938-x driving an AD9246, 14-bit, 125 MSPS ADC.
The AD9246 achieves its optimum performance when it is
driven differentially. The ADA4938-x eliminates the need for a
transformer to drive the ADC, performs a single-ended-to-
differential conversion, buffers the driving signal, and provides
appropriate level shifting for dc coupling.
The ADA4938-x is configured with dual ±5 V supplies and a
gain of ~2 V/V for a single-ended input to differential output.
The 76.8 Ω termination resistor, in parallel with the single-
ended input impedance of 137 Ω, provides a 50 Ω dc termination
for the source. The additional 30.1 Ω (120 Ω total) at the inverting
input balances the parallel dc impedance of the 50 Ω source and
the termination resistor driving the noninverting input.
The signal generator has a symmetric, ground-referenced
bipolar output. The VOCM pin of the ADA4938-x is connected to
the CML pin of the AD9246 to set the output common-mode
level at the appropriate point. A portion of this is fed back to the
summing nodes, biasing IN and +IN at 0.55 V. For a common-
mode voltage of 0.9 V, each ADA4938 output swings between
0.4 V and 1.4 V, providing a 2 V p-p differential output.
The output is dc-coupled to a single-pole, low-pass filter. The filter
reduces the noise bandwidth of the amplifier and provides some
level of isolation from the switched capacitor inputs of the ADC.
The AD9246 is set for a 2 V p-p full-scale input by connecting the
SENSE pin to AGND. The inputs of the AD9246 are biased at
1 V by connecting the CML output, as shown in Figure 70.
VIN+
VIN–
47pF
30nH
24.3
24.3
50
SIGNAL
GENERATOR
226
200
VOCM
10V
ADA4938
+
61.9
200
200
16
BUFFER T/H
ADC
CLOCK/
TIMING
REF
SENSE
AGND
VREF
AD9446
3.3V (A)
AVDD1
5V (A)
AVDD2
3.3V (D)
DRVDD
06
59
2-
05
4
10V
R1
R2
Figure 69. ADA4938 Driving an AD9446, 16-Bit, 80 MSPS ADC
1.8V
DRVDD
AVDD
VIN–
VIN+
AD9246
AGND
CML
SENSE
D13 TO
D0
10pF
33
VOCM
33
50
VIN
90
90
76.8
+5V
–5V
ADA4938
+
200
200
30.1
0.1F
06
59
2-
0
5
6
Figure 70. ADA4938 Driving an AD9246, a 14-Bit, 125 MSPS ADC
相關(guān)PDF資料
PDF描述
ADA4941-1YRZ-R7 IC DIFF ADC DRIVER 18BIT 8SOIC
ADA4960-1ACPZ-R2 IC ADC DRIVER DIFF 16LFCSP
ADATE205BSVZ IC DCL DUAL 250MHZ ATE 100TQFP
ADATE206BSVZ IC DCL DUAL 500MHZ ATE 100TQFP
ADAU1401AWBSTZ-RL IC AUDIO PROC 28/56BIT 48LQFP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADA4938-2YCP-EBZ 功能描述:BOARD EVAL FOR ADA4938-2YCP RoHS:是 類別:編程器，開(kāi)發(fā)系統(tǒng) >> 評(píng)估板 - 運(yùn)算放大器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:-
ADA4939-1 制造商:AD 制造商全稱:Analog Devices 功能描述:Ultralow Distortion Differential ADC Driver
ADA4939-1YCP-EBZ 功能描述:BOARD EVAL FOR ADA4939-1YCP RoHS:是 類別:編程器，開(kāi)發(fā)系統(tǒng) >> 評(píng)估板 - 運(yùn)算放大器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:-
ADA4939-1YCPZ-R2 制造商:Analog Devices 功能描述:SP Amp Differential ADC Driver Single 5.25V 16-Pin LFCSP EP T/R 制造商:Analog Devices 功能描述:SP AMP DIFFERENTIAL ADC DRVR SGL 5.25V 16LFCSP EP - Tape and Reel 制造商:Analog Devices 功能描述:SP Amp Differential ADC Driver Single 5.25V 16-Pin LFCSP EP Tape & Reel
ADA4939-1YCPZ-R7 功能描述:IC AMP DIFF ULDIST LN 16LFCSP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標(biāo)準(zhǔn)包裝:50 系列:- 放大器類型:J-FET 電路數(shù):2 輸出類型:- 轉(zhuǎn)換速率:13 V/µs 增益帶寬積:3MHz -3db帶寬:- 電流 - 輸入偏壓:65pA 電壓 - 輸入偏移:3000µV 電流 - 電源:1.4mA 電流 - 輸出 / 通道:- 電壓 - 電源，單路/雙路(±):7 V ~ 36 V，±3.5 V ~ 18 V 工作溫度:-40°C ~ 85°C 安裝類型:通孔 封裝/外殼:8-DIP（0.300"，7.62mm） 供應(yīng)商設(shè)備封裝:8-PDIP 包裝:管件
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*