KH600
DATA SHEET
changing the common mode from 1V to 3V set V
s
= +7.5 and
-V
s
to -3.5V. This example calls for a supply voltage of greater
than 10V. This will not effect supply current because as Figure 11
indicates, changing ±V
s
has no effect on supply current.
-40
+V
s
= +7.5V
-V
s
= -3.5V
2V
pp
, 50MHz
Layout Considerations
General layout and supply bypassing play major roles in high
frequency performance. Cadeka has evaluation boards to use
as a guide for high frequency layout and as aid in device testing
and characterization. Follow the steps below as a basis for
high frequency layout:
• Include all recommended 6.8µF and 0.01µF
bypass capacitors
• Place the 6.8µF capacitors within 0.75 inches of
the power pin
• Place the 0.01µF capacitors within 0.1 inches of
the power pin
• Remove the ground plane under and around the part,
especially near the input and output pins to reduce
parasitic capacitance
• Minimize all trace lengths to reduce series inductances
• A 10pF to 50pF bypass capacitor can be used between
pins 5 and 6 and between pins 10 and 11 to reduce
crosstalk from the positive supply
Refer to the evaluation board layouts shown in Figure 22 for
more information.
Harmonic Distortion (dBc)
-45
-50
-55
-60
HD2
HD3
HD3
-65
-70
-75
-80
0
1
2
3
4
HD2
Common Mode Output Voltage (V)
Figure 19: 2V
pp
HD vs. Common Mode Voltage
-30
Harmonic Distortion (dBc)
-35
-40
-45
-50
-55
-60
-65
-70
-75
-80
0
+V
s
= +7.5V
-V
s
= -3.5V
5V
pp
, 50MHz
HD3
HD2
Evaluation Board Information
The following evaluation boards are available to aid in the
testing and layout of this device:
Evaluation
Board
KEB007
1
2
3
4
Description
Basic KH600 Eval Bd
KH600 Eval Bd with offset and
I
cc
Adjust Option
Products
KH600
KH600
Common Mode Output Voltage (V)
Figure 20: 5V
pp
HD vs. Common Mode Voltage
140
+V
s
= +7.5V
-V
s
= -3.5V
KEB009
Supply Current (mA)
120
100
I
s
, -I
s
Do not include capacitors C2, C3, C7, C11, and C12
that are shown on the KEB007 evaluation board. Evaluation
board schematics and layouts are shown in Figure 22. Refer
to the schematic shown in Figure 1 for the KEB007 board
and Figure 3 for the KEB009 board.
80
60
40
0
1
2
3
4
Common Mode Output Voltage (V)
Figure 21: Resulting I
s
and -I
s
REV. 2 January 2004
11
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
