LT6600IS8-2.5 Linear Technology, LT6600IS8-2.5 Datasheet - Page 10

• Manufacturer Part Number: LT6600IS8-2.5
• Description: IC AMP DIFF LP FLTR 2.5MHZ 8SOIC
• Manufacturer: Linear Technology

Specifications of LT6600IS8-2.5

• Amplifier Type: Differential
• Number Of Circuits: 1
• Output Type: Differential
• Current - Input Bias: 15µA
• Voltage - Input Offset: 5000µV
• Current - Supply: 28mA
• 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: -

APPLICATIONS INFORMATION
LT6600-2.5
V
an AC ground with a 0.01μF capacitor or some instability
maybe observed. V
source, provided it remains at least 1.5V above V
least 1.5V below V
voltage of V
matched, their absolute value can vary by ±20%. This
should be taken into consideration when connecting an
external resistor network to alter the voltage of V
V
common mode output voltage is required, connect V
to a voltage source or resistor network. For 3V and 3.3V
supplies the voltage at V
to the mid-supply level. For example, voltage (V
1.65V on a single 3.3V supply. For power supply voltages
higher than 3.3V the voltage at V
mid-supply, as shown in Table 1. The voltage on V
should not exceed 1V below the voltage on V
is a high impedance input.
Table 1. Output Common Range for Various Supplies
NOTE: V
not exceed 1V below the voltage at V
common mode ranges shown in the table, the voltage at V
externally to a value below mid supply.
10
MID
OCM
VOLTAGE
SUPPLY
±5V
3V
5V
can be allowed to fl oat, but it must be bypassed to
can be shorted to V
OCM
is set by the voltage at this R
MID
DIFFERENTIAL OUT
VOLTAGE SWING
. While the internal 11k resistors are well
4V
2V
1V
8V
4V
2V
1V
9V
4V
2V
1V
MID
+
. An internal resistor divider sets the
P-P
P-P
P-P
P-P
P-P
P-P
P-P
P-P
P-P
P-P
P-P
can be driven from a low impedance
OCM
MID
MID
must be less than or equal
for simplicity. If a different
RANGE FOR LOW DISTORTION
. To achieve some of the output
IN
OUTPUT COMMON MODE
. The voltage at V
OCM
–3.75V ≤ V
–4.25V ≤ V
0.75V ≤ V
0.75V ≤ V
–3.5V ≤ V
1.4V ≤ V
2.4V ≤ V
1.5V ≤ V
1V ≤ V
1V ≤ V
–2V ≤ V
can be set above
OCM
OCM
OCM
OCM
OCM
OCM
OCM
OCM
OCM
OCM
OCM
MID
≤ 3.75V
≤ 1.6V
≤ 1.6V
≤ 2.6V
≤ 3.5V
≤ 3.75V
≤ 1.6V
≤ 2V
≤ 3.5V
≤ 3.75V
≤ 3.75V
MID
must be set
OCM
–
MID
OCM
. V
and at
should
.
OCM
OCM
OCM
) ≤
The LT6600-2.5 was designed to process a variety of input
signals including signals centered around the mid-sup-
ply voltage and signals that swing between ground and
a positive voltage in a single supply system (Figure 1).
The range of allowable input common mode voltage (the
average of V
the power supply level and gain setting (see Electrical
Characteristics).
Common Mode DC Currents
In applications like Figure 1 and Figure 3 where the
LT6600-2.5 not only provides lowpass fi ltering but also
level shifts the common mode voltage of the input signal,
DC 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 LT6600-2.5 (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 1580Ω feedback
resistor and the external 402Ω input resistor. The result-
ing 1.25mA common mode DC current in each input
path,must be absorbed by the sources V
V
differential amplifi er inside the LT6600-2.5, and therefore
sets the common mode output voltage of the fi lter. Since,
in the example of Figure 3, V
an additional 625μA (312μA 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 3.125mA 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
the common mode output voltage of both op amp stages
will be 2V and the resulting DC current will be 2mA. Of
course, by AC-coupling the inputs of Figure 3, the common
mode DC current can be reduced to 625μA.
OCM
sets the common mode output voltage of the 2nd
IN
+
and V
IN
–
in Figure 1) is determined by
OCM
differs from V
MID
MID
is shorted toV
sets the output
IN
+
MID
and V
by 0.5V,
660025fe
OCM
IN
–
.