Linear Technology LT6551 User manual

LT6551
1
DESCRIPTION
Demonstration circuit 866 is a Quad Video Amplifier fea-
turing the LT6551. The Demo Circuit is designed to oper-
ate from a single po er supply from 4.5V to 12V. The
inputs and outputs are ac-coupled and include 75 Ω ter-
minations for video cables. The LT6551 has a fixed volt-
age-gain of t o, thus ith a terminated output cable, the
net gain is nominally unity.
Design files for this circuit board are available. Call
the LTC factory.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT and
Po erPath are trademarks of Linear Technology Corporation.
PERFORMANCE SUMMARY
Specification s are at T
A
= 25°C
SYM BOL PA AM ETE CON DITIONS M IN TYP M AX UN ITS
V+ Input Supply Range 4.5 5 12.0 V
Z
IN
Input Impedance ac-coupled 75 Ω
Z
OUT
Output Impedance ac-coupled 75 Ω
A Gain Output terminated into 75 Ω
Output terminated into hi-Z
0
+6
dB
dB
BW Band idth -3dB, small-signal 60 M Hz
Crosstalk 10M Hz 65 dB
V
IN
Input signal s ing V+= 5V, no output clipping
V+= 9V, no output clipping
±0.8
±1.5
V
V
I
S
Po er Supply Current V+= 5V, no signal 40 m Α
OPERATING PRINCIPLES
DC866 provides four identical channels of ideband sig-
nal amplification suitable for driving HDTV or high-
resolution RGB video display cables. Each amplifier sec-
tion of the LT6551 provides a fixed gain of 2, and ith
series “back-termination” at the outputs (included on the
board), results in unity gain transmission of a video sig-
nal to a destination load, ith frequency response sho n
in Figure 2.
Each input is terminated to analog ground to properly
load the input signal cable. AC-coupling is provided for
both inputs and outputs, along ith biasing circuitry, to
provide single-supply operation. Figure 3 sho s the typi-
cal crosstalk bet een adjacent channels.
Figure 4 sho s the material list of the components used
by DC866, and Figure 5 sho s the electrical interconnec-
tion.
DEMO CIRCUIT
866
QUICK START GUIDE
LT6551
Quad Video Amplifier
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LT6551
2
QUICK START PROCEDURE
Demonstration circuit 866 is easy to set up to evaluate
the performance of the LT6551. R efer to Figure 1 for
proper measurement equipment setup and follo the
procedure belo :
1. Prior to connecting the po er supply, preset the out-
put voltage to 5V, or to the desired level, if different.
2. W ith po er off, connect the po er supplies to V+ and
GN D using banana to clip-lead cables.
3. If using a Net ork Analyzer, perform the THR U trans-
mission cal ith all cabling, adapters, impedance con-
verters, etc. in place as the reference 0dB path.
4. Energize the po er supply.
5. Connect the N et ork Analyzer (if used) to the appro-
priate channels to measure frequency response and
crosstalk as desired.
6. For video-signal evaluation, connect a component-
video signal source to the inputs and a monitor and/or
video analyzer to the outputs.
COM +
Power Supply
+5.00
+5.00+5.00
+5.00
Inputs
Outputs
Figure 1. Proper M easurem ent Equipm ent Setup
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LT6551
3
10dB/DIV
100kHz – 100M Hz 100kHz – 100M Hz
Figure 2. Typical Sm all-Signal Frequency esponse Figure 3. Typical Adjacent-Channel Crosstalk
Figure 4. DC866 Bill of M aterial
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LT6551
4
Figure 5. DC866 Electrical Schem atic Diagram
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