- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄98229 > THS7319IZSVT (TEXAS INSTRUMENTS INC) 3 CHANNEL, VIDEO AMPLIFIER, PBGA9 PDF資料下載
參數(shù)資料
| 型號： | THS7319IZSVT |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | 音頻／視頻放大 |
| 英文描述： | 3 CHANNEL, VIDEO AMPLIFIER, PBGA9 |
| 封裝： | 1.50 X 1.50 MM, 0.35 MM HEIGHT, GREEN, UCSP-9 |
| 文件頁數(shù)： | 15/33頁 |
| 文件大?。?/td> | 733K |
| 代理商： | THS7319IZSVT |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁當(dāng)前第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁
SBOS468A – JUNE 2009 – REVISED JULY 2009.............................................................................................................................................................. www.ti.com
Another benefit of the THS7319 over a passive RLC
One final benefit of the THS7319 over a passive filter
filter is the input and output impedance. With a
is power dissipation. A DAC driving a video line must
passive filter, the input impedance presented to the
be able to drive a 37.5-
load: the receiver 75-
DAC varies significantly, from 35
to over 1.5 k,
resistor and the 75-
impedance matching resistor
and may cause voltage variations over frequency.
next to the DAC to maintain the source impedance
The THS7319 input impedance is 2.4 M
, and only
requirement. This requirement forces the DAC to
the 2-pF input capacitance plus the PCB trace
drive at least 1.25 VP (100% saturation CVBS)/37.5
capacitance impact the input impedance. As such,
= 33.3 mA. A DAC is a current-steering element, and
the voltage variation appearing at the DAC output is
this amount of current flows internally to the DAC
better controlled with a fixed termination resistor and
even if the output is 0 V. Thus, power dissipation in
the high input impedance buffer of the THS7319.
the DAC may be very high, especially when three
channels are being driven.
On the output side of the filter, a passive filter again
has a large impedance variation over frequency. The
Using the THS7319 with a high input impedance can
EIA770 specifications require the return loss to be at
reduce DAC power dissipation significantly. This
least 25 dB over the video frequency range of use.
outcome is possible because the resistance that the
For a video system, this requirement implies that the
DAC drives can be substantially increased. It is
source impedance (which includes the source, series
common to set this resistance in a DAC by a
resistor, and the filter) must be better than 75
,
current-setting resistor on the DAC itself. Thus, the
+9/–8
. The THS7319 is an operational amplifier
resistance can be 300
or more, substantially
that approximates an ideal voltage source, which is
reducing the current drive demands from the DAC
desirable because the output impedance is very low
and
saving
significant
amounts
of
power.
For
and can source and sink current. To properly match
example, a 3.3-V, three-channel DAC dissipates
the transmission line characteristic impedance of a
330 mW alone for the steering current capability
video line, a 75-
series resistor is placed on the
(three channels × 33.3 mA × 3.3 V) if it must drive a
output. To minimize reflections and to maintain a
37.5-
load. With a 300- load, the DAC power
good return loss meeting EIA specifications, this
dissipation as a result of current steering current
output impedance must maintain a 75-
impedance.
would only be 41 mW (three channels × 4.16 mA ×
A wide impedance variation of a passive filter cannot
3.3 V), or over eight times lower power. For overall
ensure this level of performance. On the other hand,
system power, this scenario must also account for the
the THS7319 has approximately 1
of output
THS7319 power. The THS7319 only consumes
impedance, or a return loss of 40 dB, at 11 MHz.
3.4 mA total quiescent current. The quiescent power
Thus, the system is matched significantly better with
added is then 3.3 V × 3.4 mA = 11.2 mW. The total
a THS7319 compared to a passive filter.
system power is then 41 mW + 11 mW = 52 mW, or
a factor of six times lower power compared to the
DAC driving the line directly. Saving power by adding
the THS7319 in a system is easy to see and
accomplish, not to mention the added benefit of a
three-pole filter on each channel.
22
Copyright 2009, Texas Instruments Incorporated
Product Folder Link(s): THS7319
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| THS7360IPWR | VIDEO AMPLIFIER, PDSO20 |
| THS7360IPW | VIDEO AMPLIFIER, PDSO20 |
| THS7364IPWR | 6 CHANNEL, VIDEO AMPLIFIER, PDSO20 |
| THS7364IPW | 6 CHANNEL, VIDEO AMPLIFIER, PDSO20 |
| THS7365IPWR | 6 CHANNEL, VIDEO AMPLIFIER, PDSO20 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| THS7320 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:3-Channel ED Filter Video Amplifier with 4-V/V Gain |
| THS7320IYHCR | 制造商:Texas Instruments 功能描述:3-CHANL ED FILTER VIDEO AMP, 4V/V GAIN - Tape and Reel 制造商:Texas Instruments 功能描述:IC 3-CH INTEG VIDEO AMP 9DSBGA 制造商:Texas Instruments 功能描述:Video Amplifiers 3-Ch ED Fltr Video Amp w/ 4V/V Gain 制造商:Texas Instruments 功能描述:3-Chanl ED Filter Video Amp, 4V/V Gain |
| THS7320IYHCT | 制造商:Texas Instruments 功能描述:IC 3-CH INTEG VIDEO AMP 9DSBGA |
| THS7320YHCEVM | 制造商:Texas Instruments 功能描述:THS7320YHCEVM - Boxed Product (Development Kits) 制造商:Texas Instruments 功能描述:Texas Instruments THS7320YHCEVM Development Kits 制造商:Texas Instruments 功能描述:MODULE EVAL FOR THS7320 ZSV 制造商:Texas Instruments 功能描述:EVAL BOARD, THS7320 VIDEO AMPLIFIER, Silicon Manufacturer:Texas Instruments, Silicon Core Number:THS7320, Kit Application Type:Amplifier, Application Sub Type:Video Buffer and Filter, Kit Contents:Eval Board THS7320 |
| THS7327 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:3-Channel RGBHV Video Buffer with I2C Control, Selectable Filters, Monitor Pass-Thru,2:1 Input MUX, and Selectable Input Bias Modes |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。