LT6600IS8-10#TR Linear Technology, LT6600IS8-10#TR Datasheet - Page 8

• Manufacturer Part Number: LT6600IS8-10#TR
• Description: IC AMP DIFF FILTER 2.5MHZ 8SOIC
• Manufacturer: Linear Technology

Specifications of LT6600IS8-10#TR

• 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: Contains lead / RoHS non-compliant
• Current - Output / Channel: -
• -3db Bandwidth: -
• Slew Rate: -
• Gain Bandwidth Product: -

LT6600-10
APPLICATIONS INFORMATION
Interfacing to the LT6600-10
Note: The referenced pin numbers correspond to the S8
package. See the Pin Functions section for the equivalent
DFN-12 package pin numbers.
The LT6600-10 requires 2 equal external resistors, R
set the differential gain to 402Ω/R
are the voltages V
components, Figure 1. The difference between V
V
and V
the voltages V
of the LT6600-10 are the fi lter outputs. The difference
between V
The average of V
output voltage.
Figure 1 illustrates the LT6600-10 operating with a single
3.3V supply and unity passband gain; the input signal is
DC coupled. The common mode input voltage is 0.5V and
the differential input voltage is 2V
output voltage is 1.65V and the differential output voltage
is 2V
output voltage is determined by the voltage at V
V
mid-supply voltage. In addition, the common mode input
voltage can be equal to the mid-supply voltage of V
to the Distortion vs Input Common Mode Level graphs in
the Typical Performance Characteristics section).
Figure 2 shows how to AC couple signals into the
LT6600-10. In this instance, the input is a single-ended
signal. AC coupling allows the processing of single-ended or
differential signals with arbitrary common mode levels. The
0.1μF coupling capacitor and the 402Ω gain setting resistor
form a high pass fi lter, attenuating signals below 4kHz.
Larger values of coupling capacitors will proportionally
reduce this highpass 3dB frequency.
In Figure 3 the LT6600-10 is providing 12dB of gain. The
gain resistor has an optional 62pF in parallel to improve
the passband fl atness near 10MHz. The common mode
output voltage is set to 2V.
8
IN
OCM
–
P-P
is the differential input voltage. The average of V
IN
is shorted to V
–
for frequencies below 10MHz. The common mode
is the common mode input voltage. Similarly,
OUT
+
OUT
and V
IN
+
OUT
+
and V
OUT
MID
and V
+
and V
–
the output common mode is the
OUT
is the differential output voltage.
IN
–
–
OUT
presented to these external
appearing at Pins 4 and 5
–
IN
P-P
is the common mode
. The inputs to the fi lter
. The common mode
OCM
MID
IN
. Since
+
(refer
IN
and
, to
IN
+
Use Figure 4 to determine the interface between the
LT6600-10 and a current output DAC. The gain, or
“transimpedance”, is defi ned as A = V
the transimpedance, use the following equation:
By setting R1 + R2 = 402Ω, the gain equation reduces
to A = R1Ω.
The voltage at the pins of the DAC is determined by R1,
R2, the voltage on V
or I
348Ω. The voltage at V
DAC pins is given by:
I
50.4Ω.
Evaluating the LT6600-10
The low impedance levels and high frequency operation
of the LT6600-10 require some attention to the matching
networks between the LT6600-10 and other devices. The
previous examples assume an ideal (0Ω) source impedance
and a large (1kΩ) load resistance. Among practical examples
where impedance must be considered is the evaluation
of the LT6600-10 with a network analyzer. Figure 5
is a laboratory setup that can be used to characterize the
LT6600-10 using single-ended instruments with 50Ω
source impedance and 50Ω input impedance. For a unity
gain confi guration the LT6600-10 requires a 402Ω source
resistance yet the network analyzer output is calibrated
for a 50Ω load resistance. The 1:1 transformer, 53.6Ω
and 388Ω resistors satisfy the two constraints above.
The transformer converts the single-ended source into a
differential stimulus. Similarly, the output the LT6600-10
will have lower distortion with larger load resistance yet
the analyzer input is typically 50Ω. The 4:1 turns (16:1
impedance) transformer and the two 402Ω resistors of
IN
A =
V
is I
IN
DAC
–
IN
). Consider Figure 4 with R1 = 49.9Ω and R2 =
402 • R1
R1+ R2
–
= V
= 103mV +I
or I
PIN7
IN
+
Ω
•
.The transimpedance in this example is
R1+ R2 + 402
MID
IN
43.6Ω
R1
and the DAC output current (I
MID
is 1.65V. The voltage at the
+I
IN
OUT
R1+ R2
R1• R2
/I
IN
Ω. To compute
66001fd
IN
+