参数资料
型号: TLV990-28PFBG4
厂商: TEXAS INSTRUMENTS INC
元件分类: 消费家电
英文描述: SPECIALTY CONSUMER CIRCUIT, PQFP48
封装: GREEN, PLASTIC, TQFP-48
文件页数: 11/23页
文件大小: 408K
代理商: TLV990-28PFBG4
TLV99028
3V, 10BIT, 28MSPS AREA CCD ANALOG FRONT END
SLAS300A AUGUST 2000 REVISED MARCH 2004
19
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
automatic optical black and offset correction (continued)
A weighted rolling average of the optical black pixels is taken during averaging. The weighting factor can be
programmed in control register2. The weighting factor determines the speed of convergence of the digital
filtering implemented within the CCD signal processor. Weighting factors closer to 1 result in faster
convergence. As the weighting factor decreases towards its minimum value of 1/256, the speed of convergence
of the digital filtering decreases.
The algorithm also takes hot pixels and cold pixels into consideration. A hot optical black pixel is a defective
pixel that generates too much charge, while a cold pixel is the one that generates very little or no charge. A digital
comparator compares the digitized optical black pixels with user-selected hot and cold pixel limits. If the optical
black pixel value is out of range, then that hot or cold pixel is replaced with the value of the previous pixel.
Due to different exposure times, there might be a sudden optical black level shift at the start of each frame. Thus,
a quick optical black level correction is desirable. The user can set an internal control bit (the SOF bit in control
register2) to automatically disable the hot/cold pixel limits and to set the digital filtering weighting factor to 1
(equivalent to one-line averaging). In this way the optical black correction could be performed very quickly for
the first line of each frame.
The number of black pixels in each line is programmable. The number of black pixels per line that can be
averaged is 2N, where N can be any integer from 0 to 6.
The autocalibration feature can be bypassed if the user prefers to directly program the offset DAC registers.
Switching the autocalibration mode to the direct-programming mode requires two register writes. First, the
control bits for the offset DACs in the control register must be changed; then the desired offset value for the
register is loaded to the offset DAC registers for proper error correction. If the total offset, including optical black
level, is less than
±255 ADC LSBs, only the FDAC needs to be programmed. When switching from direct-
programming mode to autocalibration mode, the previous DAC register values, rather than default DAC register
values, are used as starting offsets.
相关PDF资料
PDF描述
TLV990-40PFB SPECIALTY CONSUMER CIRCUIT, PQFP48
TLV990-40PFBG4 SPECIALTY CONSUMER CIRCUIT, PQFP48
TLV990APFB SPECIALTY CONSUMER CIRCUIT, PQFP48
TLV990BPFB SPECIALTY CONSUMER CIRCUIT, PQFP48
TM21R-5A-3232-LP(50) 32 CONTACT(S), FEMALE, RIGHT ANGLE TELECOM AND DATACOM CONNECTOR, SOLDER, JACK
相关代理商/技术参数
参数描述
TLV990-40 制造商:Texas Instruments 功能描述:CCD Analogue Front End 40MSPS TLV990-40
TLV99040PFB 制造商:Texas Instruments 功能描述:
TLV990-40PFB 功能描述:视频模拟/数字化转换器集成电路 3-V 10-Bit 40 MSPS Area CCD RoHS:否 制造商:Texas Instruments 输入信号类型:Differential 转换器数量:1 ADC 输入端数量:4 转换速率:3 Gbps 分辨率:8 bit 结构: 输入电压:3.3 V 接口类型:SPI 信噪比: 电压参考: 电源电压-最大:3.45 V 电源电压-最小:3.15 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:TCSP-48 封装:Reel
TLV990-40PFBG4 功能描述:视频模拟/数字化转换器集成电路 3-V 10-Bit 40 MSPS Area CCD RoHS:否 制造商:Texas Instruments 输入信号类型:Differential 转换器数量:1 ADC 输入端数量:4 转换速率:3 Gbps 分辨率:8 bit 结构: 输入电压:3.3 V 接口类型:SPI 信噪比: 电压参考: 电源电压-最大:3.45 V 电源电压-最小:3.15 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:TCSP-48 封装:Reel
TLV990B 制造商:TI 制造商全称:Texas Instruments 功能描述:3-V, 10-BIT, 28-MSPS AREA CCD AND VIDEO SIGNAL PROCESSOR