TSH70, 71, 72, 73, 74, 75
19/25
TESTING CONDITIONS:
Layout precautions:
To use the TSH7X circuits in the best manner at
high frequencies, some precautions have to be
taken for power supplies:
- First of all, the implementation of a proper ground
plane in both sides of the PCB is mandatory for
high speed circuit applications to provide low inductance and low resistance common return.
- Power supply bypas s capacitors (4.7uF and c eramic 100pF) should be placed as close as poss ible to the IC pins in order to improve high frequency bypassing and reduce harmonic distortion. The
power supply capa citors must be incorporated for
both the negative and the positive pins.
- Proper termination of all inputs and outputs must
be in accordance with output termination resistors;
then the amplifier load wi ll be only resistive and
the stab ilit y of the a m p li fier will be impro v ed.
All leads must be wide and as s hort as possible
especially for op amp inputs and outputs in order
to decrease parasitic capacitance and inductance.
- For lower gain application, a ttention should be
paid not to use large feedback resist ance (>1kΩ)
to reduce time constant with parasitic capacitances.
- Choose component sizes as small as possible
(SMD).
- Finally, on output, the load capacitance must be
negligible to maintain good stability. You can put a
serial resistance the closest to the output pin to
minimize its influence.
CCIR330 video line
Maximum input level:
The input level m us t not exce ed the f oll owing values:
❑ negative peak: must be greater than
-Vcc+400mV.
❑ positive peak value: must be lower than
+Vcc-400mV.
The electrical characteristics show the influence of
the load on this parameter.
Video capabilities:
To characterize the differential phase and differential gain a CCIR330 video line is used.
The video line contains 5 (flat) levels of luma on
which is superimposed chroma signal. (the first
level contains no luma). T he luma gives va rious
amplitudes which def ine the sat uration of the signal. The chrominance gives various phases which
define the colour of the signal.
Differential phase (respectively differential gain)
distortion is present if a signal chrominance phase
(gain) is affected by luminance level. They represent the ability to uniformly process the high frequency information at all luminance levels.
When differential gain is present, colour saturation
is not correctly reproduced.
The input generator is the Rohde & Schwarz
CCVS. The output measurement is done by the
Rohde and Schwarz VSA.
Measurement on Rohde and Schwarz VSA.