LT6600IS8-10#TRPBF Linear Technology, LT6600IS8-10#TRPBF Datasheet - Page 11

• Manufacturer Part Number: LT6600IS8-10#TRPBF
• Description: IC AMP DIFF LP FLTR 10MHZ 8-SOIC
• Manufacturer: Linear Technology

Specifications of LT6600IS8-10#TRPBF

• Amplifier Type: Differential
• Number Of Circuits: 1
• Output Type: Differential
• Current - Input Bias: 40µA
• Voltage - Input Offset: 8000µV
• Current - Supply: 36mA
• Voltage - Supply, Single/dual (±): 3 V ~ 11 V, ±1.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -
• -3db Bandwidth: -
• Slew Rate: -
• Gain Bandwidth Product: -

APPLICATIONS INFORMATION
currents will be generated through the DC path between
input and output terminals. Minimize these currents to
decrease power dissipation and distortion.
Consider the application in Figure 3. V
common mode voltage of the 1st differential amplifi er
inside the LT6600-10 (see the Block Diagram section) at
2.5V. Since the input common mode voltage is near 0V, there
will be approximately a total of 2.5V drop across the series
combination of the internal 402Ω feedback resistor and the
external 100Ω input resistor. The resulting 5mA common
mode DC current in each input path, must be absorbed by
the sources V
output voltage of the 2nd differential amplifi er inside the
LT6600-10, and therefore sets the common mode output
voltage of the fi lter. Since in the example, Figure 3, V
differs from V
per side) of DC current will fl ow in the resistors coupling
the 1st differential amplifi er output stage to fi lter output.
Thus, a total of 12.5mA is used to translate the common
mode voltages.
A simple modifi cation to Figure 3 will reduce the DC
common mode currents by 36%. If V
V
stages will be 2V and the resulting DC current will be
8mA. Of course, by AC coupling the inputs of Figure 3, the
common mode DC current can be reduced to 2.5mA.
Noise
The noise performance of the LT6600-10 can be evaluated
with the circuit of Figure 7.
OCM
the common mode output voltage of both op amp
V
IN
IN
R
R
MID
IN
IN
+
Figure 7. (S8 Pin Numbers)
and V
by 0.5V, an additional 2.5mA (1.25mA
1
7
2
8
LT6600-10
+
–
–2.5V
2.5V
6
3
IN
+
–
–
0.1μF
0.1μF
. V
4
5
OCM
25Ω
sets the common mode
25Ω
TTWB-1010
COILCRAFT
MID
MID
1:1
sets the output
is shorted to
SPECTRUM
ANALYZER
INPUT
50Ω
6600 F07
OCM
Given the low noise output of the LT6600-10 and the 6dB
attenuation of the transformer coupling network, it will
be necessary to measure the noise fl oor of the spectrum
analyzer and subtract the instrument noise from the fi lter
noise measurement.
Example: With the IC removed and the 25Ω resistors
grounded, measure the total integrated noise (e
spectrum analyzer from 10kHz to 10MHz. With the IC
inserted, the signal source (V
input resistors grounded, measure the total integrated
noise out of the fi lter (e
connected, set the frequency to 1MHz and adjust the
amplitude until V
output amplitude, V
A = V
noise (e
Table 1 lists the typical input referred integrated noise for
various values of R
Figure 8 is plot of the noise spectral density as a function
of frequency for an LT6600-10 with R
the fi xture of Figure 7 (the instrument noise has been
subtracted from the results).
Table 1. Noise Performance
The noise at each output is comprised of a differential
component and a common mode component. Using a
transformer or combiner to convert the differential outputs
to single-ended signal rejects the common mode noise and
gives a true measure of the S/N achievable in the system.
Conversely, if each output is measured individually and the
noise power added together, the resulting calculated noise
level will be higher than the true differential noise.
PASSBAND
GAIN (V/V)
e
IN
4
2
1
OUT
=
IN
/V
) as:
(e
IN
. Now compute the input referred integrated
O
100Ω
200Ω
402Ω
R
)
IN
2
A
– (e
IN
IN
OUT
measures 100mV
S
.
INTEGRATED NOISE
INPUT REFERRED
)
10kHz TO 10MHz
, and compute the passband gain
2
24μV
34μV
56μV
O
). With the signal source
RMS
RMS
RMS
IN
) disconnected, and the
LT6600-10
P-P
IN
INPUT REFERRED
NOISE dBm/Hz
. Measure the
= 402Ω using
–149
–146
–142
S
11
) of the
66001fd