Defining VIN as the voltage applied to the input pin, " />
參數(shù)資料
型號(hào): ADA4922-1ARDZ-RL
廠商: Analog Devices Inc
文件頁數(shù): 9/20頁
文件大?。?/td> 0K
描述: IC ADC DRIVER 18BIT DIFF 8-SOIC
標(biāo)準(zhǔn)包裝: 2,500
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: 8-SOIC(0.154",3.90mm Width)裸露焊盤
供應(yīng)商設(shè)備封裝: 8-SOIC-EP
包裝: 帶卷 (TR)
ADA4922-1
Rev. 0 | Page 17 of 20
Defining VIN as the voltage applied to the input pin, the
equations that govern the two signal paths are given in
Equation 12 and Equation 13.
VOUT+ = +VIN
(12)
VOUT = VIN + 2(REF)
(13)
When the REF voltage is set to the midswing level of the input
signal, the two output signals fall directly on top of each other
with minimal offset. Setting the REF voltage elsewhere results
in an offset between the two outputs. This effect is illustrated in
The best use of the REF pin can be further illustrated by
considering a single-supply example that uses a 10 V dc power
supply and has an input signal that varies between 2 V and 7 V.
This is a case where the midswing level of the input signal is not
at midsupply but is at 4.5 V. By setting the REF input to 4.5 V
and neglecting offsets, Equation 12 and Equation 13 are used to
calculate the results. When the input signal is at its midpoint of
4.5 V, VOUT+ is at 4.5 V, as is VOUT. This can be considered as a
type of baseline state where the differential output voltage is
zero. When the input increases to 7 V, VOUT+ tracks the input to
7 V and VOUT decreases to 2 V. This can be viewed as a positive
peak signal where the differential output voltage equals 5 V.
When the input signal decreases to 2 V, VOUT+ again tracks to
2 V, and VOUT increases to 7 V. This can be viewed as a negative
peak signal where the differential output voltage equals 5 V.
The resulting differential output voltage is 10 V p-p.
The previous discussion exposes how the single-ended-to-
differential gain of 2 is achieved.
INTERNAL FEEDBACK NETWORK POWER
DISSIPATION
While traditional op amps do not have on-chip feedback
elements, the ADA4922-1 contains two on-chip 600 Ω resistors
that comprise an internal feedback loop. The power dissipated
in these resistors must be included in the overall power dissipation
calculations for the device. Under certain circumstances, the
power dissipated in these resistors could be considerably more
than the device’s quiescent current. For example, on ±12 V
supplies with the REF pin tied to ground and OUT at 9 V dc,
each 600 Ω resistor carries 15 mA and dissipates 135 mW. This
is a significant amount of power and must therefore be included
in the overall device power dissipation calculations. For ac
signals, rms analysis is required.
DISABLE FEATURE
The ADA4922-1 includes a disable feature that can be asserted
to minimize power consumption in a device that is not needed
at a particular time. When asserted, the disable feature does not
place the device output in a high impedance or three-state
condition. The disable feature is asserted by applying a control
voltage to the DIS pin and is active low. See the Specifications
section for the high and low level voltage specifications.
DRIVING A DIFFERENTIAL INPUT ADC
The ADA4922-1 provides the single-ended-to-differential
conversion that is required to drive most high resolution ADCs.
Figure 50 shows how the ADA4922-1 simplifies ADC driving.
VIN
±10V
0.1
μF
–12V
HIGH VOLTAGE
HIGH RESOLUTION
ADC
VS–
VS+
DIS
056
81
-0
49
R
IN
8
OUT+
ADA4922-1
OUT–
4
5
6
73
REF
2
0.1
μF
–12V
0.1
μF
+12V
0.1
μF
+12V
R
C
Figure 50. Driving a Differential Input ADC
For example, consider the case where the input signal
bandwidth is 100 KHz and R = 41.2 Ω and C = 3.9 nF, as is
shown in Figure 50, to form a single-pole filter with 3 dB
bandwidth of approximately 1 MHz. The ADA4922-1 output
noise (with zero source resistance) integrated over this
bandwidth appears at the ADC input and is calculated as
()
rms
μV
15
MHz
1
2
π
Hz
nV/
12
)
(
,
=
=
rms
V
dm
ADC
n,
(14)
The rms value of a 20 V p-p signal at the ADC input is 7 V rms,
yielding a SNR of 113 dB at the ADC input.
相關(guān)PDF資料
PDF描述
ADA4922-1ACPZ-RL IC ADC DRIVER 18BIT DIFF 8-LFCSP
VE-24J-IV-F3 CONVERTER MOD DC/DC 36V 150W
LTC6400CUD-26#PBF IC ADC DRIVER DIFF 16-QFN
VI-JND-MW-S CONVERTER MOD DC/DC 85V 100W
LTC6360CMS8E#TRPBF IC ADC DRIVER TRUE ZERO 8MSOP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ADA4927-1 制造商:AD 制造商全稱:Analog Devices 功能描述:Ultralow Distortion Current Feedback Differential ADC Driver
ADA4927-1YCP-EBZ 功能描述:BOARD EVAL FOR ADA4927-1YCP RoHS:是 類別:編程器,開發(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:-
ADA4927-1YCPZ-R2 制造商:Analog Devices 功能描述:SP Amp Differential ADC Driver Single 11V 16-Pin LFCSP EP T/R 制造商:Analog Devices 功能描述:SP AMP DIFFERENTIAL ADC DRVR SGL 11V 16LFCSP EP - Tape and Reel 制造商:Analog Devices 功能描述:ANAADA4927-1YCPZ-R2 ULTRALW DISTORTION C 制造商:Analog Devices 功能描述:OP AMP CF DIFF 65MA LN 16LFCSP 制造商:Analog Devices 功能描述:OP AMP, CF, DIFF, 65MA, LN, 16LFCSP 制造商:Analog Devices 功能描述:OP AMP, CF, DIFF, 65MA, LN, 16LFCSP; No. of Amplifiers:1; Input Offset Voltage:1.3mV; Bandwidth:2.3GHz; Amplifier Case Style:LFCSP; No. of Pins:16; Supply Voltage Range:4.5V to 11V; Slew Rate:5000V/s; Supply Current:20mA; Operating ;RoHS Compliant: Yes
ADA4927-1YCPZ-R2 制造商:Analog Devices 功能描述:IC DIFF AMP 2.3GHZ 5000V/ LFCSP-16
ADA4927-1YCPZ-R7 功能描述:IC OPAMP CF DIFF 65MA LN 16LFCSP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 放大器類型:通用 電路數(shù):4 輸出類型:- 轉(zhuǎn)換速率:0.6 V/µs 增益帶寬積:1MHz -3db帶寬:- 電流 - 輸入偏壓:45nA 電壓 - 輸入偏移:2000µV 電流 - 電源:1.4mA 電流 - 輸出 / 通道:40mA 電壓 - 電源,單路/雙路(±):3 V ~ 32 V,±1.5 V ~ 16 V 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:14-TSSOP(0.173",4.40mm 寬) 供應(yīng)商設(shè)備封裝:14-TSSOP 包裝:帶卷 (TR) 其它名稱:LM324ADTBR2G-NDLM324ADTBR2GOSTR