QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1016
5V TRIPLE HIGH SPEED VIDEO AMPLIFIER
1
LT6557 / LT6558
DESCRIPTION
Demonstration Circuit 1016 (DC1016) is a 5V Triple High
Speed Video Amplifier featuring the LT6557 or LT6558 in
DFN packaging. The DC1016A–A version demonstrates
the gain-of-two LT6557, while the DC1016A–B features
the unity-gain LT6558. The board is designed to demon-
strate AC-coupled performance in 5V single-supply op-
eration. The LT6557 and LT6558 include automatic in-
ternal biasing that is programmable with one resistor.
Table 1 indicates the performance that is achieved with
this evaluation board.
Design files for this circuit board are available. Call
the LTC factory.
Table 1.
Performance Summary (T
A
= 25°C)
PARAMETER
CONDITION
VALUE
Supply Voltage
Recommended Min/Max
+5V/+10V
Supply Current
V
+
= 5V
65mA
Input Impedance, INR, ING, INB
75
Ω
to ground, ac-coupled internal
signals
Output Impedance, OUTR, OUTG, OUTB
75
Ω
, ac-coupled
CAL trace Impedance
75
Ω
nominal
Outputs terminated into 75
Ω
0dB nominal
Gain (–A version)
Outputs terminated into High impedance
+6dB nominal
Outputs terminated into 75
Ω
–6dB nominal
Gain (–B version)
Outputs terminated into High impedance
0dB nominal
V
IN
= 125mV
PP
(-16dBm), –3dB, R
L
=75
Ω
7Hz to 380MHz typical
Frequency Response
V
IN
= 125mV
PP
(-16dBm), ±0.1dB, R
L
=75
Ω
7Hz to 130MHz typical
Worst-case All Hostile, 10MHz
–75dB typical
Crosstalk
Worst-case All Hostile, 100MHz
–55dB typical
Input Signal Voltage Range
+5.0V Supply, No Output Clipping
±0.6V about average dc (–A)
±1.2V about average dc (–B)
Logic Low Voltage (Amplifiers ON)
≤ (
V
+
– 2)V
On/Off Control Input
Logic High Voltage (Amplifiers OFF)
≥ (
V
+
– 0.5)V or open circuit
OPERATING PRINCIPLES
DC1016 provides three identical channels of wideband
signal amplification suitable for driving HDTV or high-
resolution RGB video display cables. The LT6557 pro-
vides a gain of two for driving terminated video cables
and the LT6558 has unity gain for use with high-
impedance loads. Each amplifier section is provided with
series “back-termination” at the outputs (included on the
board), which results in unity gain transmission of a
video signal to a destination load (75
Ω
for –A; 1k
Ω
or
more for –B). Each input is dc terminated to analog
ground to properly load the input signal cable. The in-
puts are ac-coupled after termination to eliminate input
