H1155I View Datasheet(PDF) - Intersil
Part Name
Description
Manufacturer
H1155I Datasheet PDF : 13 Pages
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HFA1155
50
AV = +2
40
30
20
10
0
0 50 100 150 200 250 300 350 400
LOAD CAPACITANCE (pF)
FIGURE 1. RECOMMENDED SERIES OUTPUT RESISTOR vs
LOAD CAPACITANCE
To order evaluation boards (part number HFA11XXEVAL or
OPAMPSOT23EVAL), please contact your local sales office.
The schematic and layout of the HFA11XXEVAL and
OPAMPSOT23EVAL boards are shown below.
511Ω
511Ω
NC
IN
10µF
1
50Ω
2
3
8
0.1µF
10µF
7
50Ω
6
+5V
OUT
4
0.1µF
-5V
5
GND
NC
GND
FIGURE 2. HFA11XXEVAL SCHEMATIC
HFA11XXEVAL TOP LAYOUT
PC Board Layout
The frequency response of this amplifier depends greatly on
the amount of care taken in designing the PC board. The
use of low inductance components such as chip
resistors and chip capacitors is strongly recommended,
while a solid ground plane is a must!
Attention should be given to decoupling the power supplies.
A large value (10µF) tantalum in parallel with a small value
chip (0.1µF) capacitor works well in most cases.
Terminated microstrip signal lines are recommended at the
input and output of the device. Output capacitance, such as
that resulting from an improperly terminated transmission
line, will degrade the frequency response of the amplifier
and may cause oscillations. In most cases, the oscillation
can be avoided by placing a resistor in series with the output.
Care must also be taken to minimize the capacitance to ground
seen by the amplifier’s inverting input. The larger this
capacitance, the worse the gain peaking, resulting in pulse
overshoot and eventual instability. To reduce this capacitance,
remove the ground plane under traces connected to -IN and
keep these traces as short as possible.
Examples of good high frequency layouts are the evaluation
boards shown below.
Evaluation Boards
The performance of the HFA1155IB (SOIC) may be
evaluated using the HFA11XX Evaluation Board and a SOIC
to DIP adaptor like the Aries Electronics Part Number
08-350000-10. The SOT-23 version can be evaluated using
the OPAMPSOT23EVAL board.
Note that the feedback and gain setting resistors on both
boards must be changed to the appropriate values listed in
the “Optimum Feedback Resistor” table.
VH
1
+IN
V+
VL V-
GND
HFA11XXEVAL BOTTOM LAYOUT
5
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