Data Sheet
For a given load capacitance, adjust R to optimize the
tradeoff between settling time and bandwidth. In general,
2.5
2
S
reducing R will increase bandwidth at the expense of ad-
S
SOIC-8
ditional overshoot and ringing.
1.5
1
SOT23-6
Overdrive Recovery
An overdrive condition is defined as the point when ei-
ther one of the inputs or the output exceed their specified
voltage range. Overdrive recovery is the time needed for
the amplifier to return to its normal or linear operating
point. The recovery time varies, based on whether the
input or output is overdriven and by how much the range
is exceeded. The CLCx003 will typically recover in less
than 20ns from an overdrive condition. Figure 5 shows the
CLC1003 in an overdriven condition.
0.5
0
-40
-20
0
20
40
60
80
Ambient Temperature (°C)
Figure 3. Maximum Power Derating
3
2
Driving Capacitive Loads
VIN = .8Vpp
G = 5
2
2
Increased phase delay at the output due to capacitive load-
ing can cause ringing, peaking in the frequency response,
and possible unstable behavior. Use a series resistance,
1
1
Input
1
0
0
R , between the amplifier and the load to help improve
S
Output
stability and settling performance. Refer to Figure 4.
-1
-1
-2
-2
-1
-2
-3
Input
+
-
Rs
Output
CL
RL
Rf
0
0.25
0.5
0.75
1
1.25
1.5
1.75
2
T im e ( u s )
Rg
Figure 5. Overdrive Recovery
Figure 4. Addition of R for Driving
S
Capacitive Loads
Considerations for Offset and Noise Performance
Offset Analysis
The CLC1003 family of amplifiers is capable of driving up to
300pF directly, with no series resistance. Directly driving
500pF causes over 4dB of frequency peaking, as shown in
the plot on page 6. Table 1 provides the recommended R
for various capacitive loads. The recommended R values
There are three sources of offset contribution to consider;
input bias current, input bias current mismatch, and input
offset voltage. The input bias currents are assumed to
be equal with and additional offset current in one of the
inputs to account for mismatch. The bias currents will not
S
S
result in <=1dB peaking in the frequency response. The
affect the offset as long as the parallel combination of R
f
Frequency Response vs. C plots, on page 6, illustrates
L
and R matches R . Refer to Figure 6.
g
t
the response of the CLCx003.
+V
s
R
g
R
f
C (pF)
L
R (Ω)
S
-3dB BW (MHz)
500
1000
3000
10
7.5
4
27
20
15
–
R
CLC1003
+
t
IN
R
L
-V
s
Table 1: Recommended R vs. C
S
L
Figure 6: Circuit for Evaluating Offset
©2004-2008 CADEKA Microcircuits LLC
www.cadeka.com
13
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
