ISL55001 Intersil Corporation, ISL55001 Datasheet - Page 9

• Manufacturer Part Number: ISL55001
• Description: High Supply Voltage 220MHz Unity-Gain Stable Operational Amplifier
• Manufacturer: Intersil Corporation

For sourcing:
For sinking:
Where:
• V
• I
• V
• R
• I
• N = 1 number of amplifiers
By setting the two PD
can solve the output current and R
overheat.
Power Supply Bypassing Printed Circuit Board
Layout
As with any high frequency device, a good printed circuit
board layout is necessary for optimum performance. Lead
lengths should be as short as possible. The power supply
pin must be well bypassed to reduce the risk of oscillation.
For normal single supply operation, where the V
connected to the ground plane, a single 4.7µF tantalum
PD
PD
SMAX
LOAD
MAX
MAX
S
OUT
LOAD
V
= Supply voltage
1
=
=
= Maximum output voltage of the application
= Load current
= Maximum quiescent supply current
= Load resistance tied to ground
V
V
1kΩ
S
S
R
1
×
×
I
I
SMAX
SMAX
1kΩ C
R
MAX
+
+
2
i
i
∑
1nF
∑
=
=
n
n
1
1
2
equations equal to each other, we
(
1nF
(
C
V
V
1kΩ
1
OUTi
R
S
9
A
–
V
OUTi
–
LOAD
1kΩ
V
R
S
B
+
-
)
)
×
×
to avoid the device
V+
V-
I
V
---------------- -
LOADi
V
5V
V
5V
1nF
1nF
C
C
OUTi
R
FIGURE 26. SALLEN-KEY LOW PASS FILTER
2
3
5
5
Li
S
- pin is
V
OUT
R
1kΩ
7
ISL55001
capacitor in parallel with a 0.1µF ceramic capacitor from V
to GND will suffice. This same capacitor combination should
be placed at each supply pin to ground if split supplies are to
be used. In this case, the V
supply rail.
Printed Circuit Board Layout
For good AC performance, parasitic capacitance should be
kept to minimum. Use of wire wound resistors should be
avoided because of their additional series inductance. Use
of sockets should also be avoided if possible. Sockets add
parasitic inductance and capacitance that can result in
compromised performance. Minimizing parasitic capacitance
at the amplifier's inverting input pin is very important. The
feedback resistor should be placed very close to the
inverting input pin. Strip line design techniques are
recommended for the signal traces.
Application Circuits
Sallen-Key Low Pass Filter
A common and easy to implement filter taking advantage of
the wide bandwidth, low offset and low power demands of
the ISL55001. A derivation of the transfer function is
provided for convenience (See Figure 26).
Sallen-Key High Pass Filter
Again this useful filter benefits from the characteristics of the
ISL55001. The transfer function is very similar to the low
pass so only the results are presented (See Figure 27).
K
( H
( H
Holp
Q
Holp
Q
Vo
wo
wo
V
1
=
) s
R
jw
=
=
−
=
=
=
1
1
1 (
3
=
)
Vi
+
K
=
=
RC
=
−
−
1
R
1
K
K
R
R
1
R
R
K
1
K
1
+
1
B
A
2
C
−
C
)
C
1
K
1
1
w
R
1
2
R
R
R
R
Vo
s
−
2
2
2
2
2
C
1
R
+
V
C
C
C
2
1
1
1
2
1
C
2
Equations simplify if we let all
components be equal R=C
s
V
+
1
2
+
R
1
+
Vo
1
2
C
C
((
R
R
1
1
2
−
1
1
2
s
−
C
+
C
Vi
S
K
2
1
- pin becomes the negative
jw
R )
=
+
((
K
0
1
1
C
1
R
−
R
1
K
2
+
1
C
C
R
R )
2
1
1
1
C
C
2
1
+
+
R
R
1
21
C
C
2
2
+
s )
R
March 9, 2006
+
2
C
1
FN6200.1
2
)
S
+