参数资料
型号: AD9878BST
厂商: ANALOG DEVICES INC
元件分类: 通信及网络
英文描述: Mixed-Signal Front End for Broadband Applications
中文描述: SPECIALTY TELECOM CIRCUIT, PQFP100
封装: MS-026BED, LQFP-100
文件页数: 29/36页
文件大小: 749K
代理商: AD9878BST
AD9878
ADC VOLTAGE REFERENCES
The AD9878 has three independent internal references for its
10-bit and 12-bit ADCs. Both 12-bit and 10-bit ADCs are
designed for 2 V p-p input voltages and have their own internal
reference. Figure 29 shows the proper connections of the REFT
and REFB reference pins. External references might be necessary
for systems that require high accuracy gain matching between
ADCs, or for improvements in temperature drift and noise
characteristics. External references REFT and REFB must be
centered at AVDD/2, with offset voltages as specified by the
following equations:
Rev. A | Page 29 of 36
V
5
2
:
12
,
10
+
AVDD
REFT
V
5
2
:
12
,
10
AVDD
REFT
A differential level of 1 V between the reference pins results in a
2 V p-p ADC input level AIN. Internal reference sources can be
powered down when external references are used (Address 0x02).
VIDEO INPUT
For sampling video-type waveforms, such as NTSC and PAL
signals, the video input channel provides black-level clamping.
Figure 37 shows the circuit configuration for using the video
channel input (Pin 98). An external blocking capacitor is used
with the on-chip video clamp circuit to level-shift the input signal
to a desired reference point. The clamp circuit automatically
senses the most negative portion of the input signal and adjusts
the voltage across the input capacitor. This forces the black level
of the input signal to be equal to the value programmed in the
clamp level register (Register Address 0x07).
By default, the video input is disabled and disconnected from
both ADCs. By setting Register 0x07, Bit 7 = 1, the video input
is enabled and connected to the ADC input as determined by
the state of Reg 0x03, Bit 6 ( 0= ADC12A connected, 1 =
ADC12B connected.)
2mA
VIDEO INPUT
0.1
μ
F
CLAMP LEVEL + FS/2
CLAMP LEVEL
AD9878
OFFSET
BUFFER
12
+
DAC
ADC
LPF
CLAMP
LEVEL
0
Figure 37. Video Clamp Circuit Input
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相关代理商/技术参数
参数描述
AD9878BSTRL 制造商:Analog Devices 功能描述:Mixed Signal Front End 100-Pin LQFP T/R 制造商:Analog Devices 功能描述:MIXED SGNL FRONT END 100LQFP - Tape and Reel
AD9878BSTZ 功能描述:IC FRONT-END MIXED-SGNL 100-LQFP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模拟前端 (AFE) 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 位数:- 通道数:2 功率(瓦特):- 电压 - 电源,模拟:3 V ~ 3.6 V 电压 - 电源,数字:3 V ~ 3.6 V 封装/外壳:32-VFQFN 裸露焊盘 供应商设备封装:32-QFN(5x5) 包装:带卷 (TR)
AD9878-EB 制造商:Analog Devices 功能描述:EVAL KIT FOR MIXED-SGNL FRONT END FOR BROADBAND APPLICATIONS - Bulk
AD9879 制造商:AD 制造商全称:Analog Devices 功能描述:Mixed-Signal Front End Set-Top Box, Cable Modem
AD9879_05 制造商:AD 制造商全称:Analog Devices 功能描述:Mixed-Signal Front End Set-Top Box, Cable Modem