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參數資料
| 型號： | ADV7120KP50 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | DAC |
| 英文描述： | CMOS 80 MHz, Triple 8-Bit Video DAC |
| 中文描述： | TRIPLE, PARALLEL, 8 BITS INPUT LOADING, 8-BIT DAC, PQCC44 |
| 封裝： | PLASTIC, LCC-44 |
| 文件頁數： | 6/12頁 |
| 文件大?。?/td> | 188K |
| 代理商： | ADV7120KP50 |
ADV7120
REV. B
–6–
T E RMINOLOGY
Blanking Level
T he level separating the
SYNC
portion from the video portion
of the waveform. Usually referred to as the front porch or back
porch. At 0 IRE units, it is the level which will shut off the pic-
ture tube, resulting in the blackest possible picture.
Color Video (RGB)
T his usually refers to the technique of combining the three pri-
mary colors of red, green and blue to produce color pictures
within the usual spectrum. In RGB monitors, three DACs are
required, one for each color.
Sync Signal (
SYNC
)
T he position of the composite video signal which synchronizes
the scanning process.
Gray Scale
T he discrete levels of video signal between reference black and
reference white levels. An 8-bit DAC contains 256 different lev-
els while a 6-bit DAC contains 64.
Raster Scan
T he most basic method of sweeping a CRT one line at a time to
generate and display images.
Reference Black Level
T he maximum negative polarity amplitude of the video signal.
Reference White Level
T he maximum positive polarity amplitude of the video signal.
Sync Level
T he peak level of the
SYNC
signal.
Video Signal
T hat portion of the composite video signal which varies in gray
scale levels between reference white and reference black. Also
referred to as the picture signal, this is the portion which may be
visually observed.
CIRCUIT DE SCRIPT ION AND OPE RAT ION
T he ADV7120 contains three 8-bit D/A converters, with three
input channels each containing an 8-bit register. Also inte-
grated on board the part is a reference amplifier and CRT con-
trol functions
BLANK
,
SYNC
and REF WHIT E.
Digital Inputs
24-bits of pixel data (color information) R0–R7, G0–G7 and
B0–B7 are latched into the device on the rising edge of each
clock cycle. T his data is presented to the three 8-bit DACs and
is then converted to three analog (RGB) output waveforms.
(See Figure 2.)
T hree other digital control signals are latched to the analog
video outputs in a similar fashion.
BLANK
,
SYNC
and REF
WHIT E are each latched on the rising edge of CLOCK to
maintain synchronization with the pixel data stream.
T he
BLANK
and
SYNC
functions allow for the encoding of
these video synchronization signals onto the RGB video output.
T his is done by adding appropriately weighted current sources
to the analog outputs, as determined by the logic levels on the
BLANK
and
SYNC
digital inputs. Figure 3 shows the analog
output, RGB video waveform of the ADV7120. T he influence
of
SYNC
and
BLANK
on the analog video waveform is
illustrated.
T he REF WHIT E control input drives the RGB video outputs
to the white level. T his function could be used to overlay a cur-
sor or crosshair onto the RGB video output.
T able I details the resultant effect on the analog outputs of
BLANK
,
SYNC
and REF WHIT E.
All these digital inputs are specified to accept T T L logic levels.
Clock Input
T he CLOCK input of the ADV7120 is typically the pixel clock
rate of the system. It is also known as the dot rate. T he dot rate,
and hence the required CLOCK frequency, will be determined
by the on-screen resolution, according to the following
equation:
Dot Rate = (Horiz: Res)
×
(Vert Res)
×
(Refresh Rate)/
(Retrace Factor)
Horiz Res
=
Number of pixels/line
Vert Res
=
Number of lines/frame
Refresh Rate
=
Horizontal scan rate. T his is the rate at
which the screen must be refreshed, typi-
cally 60 Hz for a noninterlaced system or
30 Hz for an interlaced system.
Retrace Factor
=
T otal blank time factor. T his takes into ac-
count that the display is blanked for a cer-
tain fraction of the total duration of each
frame (e.g., 0.8).
CLOCK
ANALOG OUTPUTS
(IOR, IOG, IOB, I
SYNC
)
DIGITAL INPUTS
(R0-R7, G0-G7, B0-B7;
SYNC, BLANK,
REF WHITE)
DATA
Figure 2. Video Data Input/Output
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相關代理商/技術參數 |
參數描述 |
|---|---|
| ADV7120KP50-REEL | 制造商:Analog Devices 功能描述:DAC 3-CH Segment 8-bit 44-Pin PLCC T/R 制造商:Rochester Electronics LLC 功能描述:TRIPLE 8 BIT VIDEO DAC IC - Tape and Reel |
| ADV7120KP80 | 制造商:Analog Devices 功能描述:DAC 3-CH Segment 8-bit 44-Pin PLCC 制造商:Rochester Electronics LLC 功能描述:TRIPLE 8 BIT VIDEO DAC IC - Bulk |
| ADV7120KP80-REEL | 制造商:Analog Devices 功能描述:DAC 3-CH Segment 8-bit 44-Pin PLCC T/R |
| ADV7120KPZ30 | 功能描述:IC DAC VIDEO 3CH 30MHZ 44PLCC RoHS:是 類別:集成電路 (IC) >> 數據采集 - 數模轉換器 系列:- 產品培訓模塊:Data Converter Fundamentals DAC Architectures 標準包裝:750 系列:- 設置時間:7µs 位數:16 數據接口:并聯 轉換器數目:1 電壓電源:雙 ± 功率耗散（最大）:100mW 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:28-LCC（J 形引線） 供應商設備封裝:28-PLCC（11.51x11.51） 包裝:帶卷 (TR) 輸出數目和類型:1 電壓，單極；1 電壓，雙極 采樣率（每秒）:143k |
| ADV7120KPZ50 | 功能描述:IC DAC VIDEO 3CH 50MHZ 44PLCC RoHS:是 類別:集成電路 (IC) >> 數據采集 - 數模轉換器 系列:- 標準包裝:2,400 系列:- 設置時間:- 位數:18 數據接口:串行 轉換器數目:3 電壓電源:模擬和數字 功率耗散（最大）:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:36-TFBGA 供應商設備封裝:36-TFBGA 包裝:帶卷 (TR) 輸出數目和類型:* 采樣率（每秒）:* |
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