Datasheet

LT6600-2.5
7
660025fe
PIN FUNCTIONS
IN
–
and IN
+
(Pins 1, 12/Pins 1, 8): Input Pins. Signals can
be applied to either or both input pins through identical
external resistors, R
IN
. The DC gain from differential inputs
to the differential outputs is 1580/R
IN
.
NC (Pins 2, 5, 11/NA): No Connection
V
OCM
(Pin 3/Pin 2): DC Common Mode Reference Voltage-
for the 2nd Filter Stage. Its value programs the common
mode voltage of the differential output of the fi lter. This
is a high impedance input, which can be driven from an
external voltage reference, or it can be tied to V
MID
on the
PC board. V
OCM
should be bypassed with a 0.01F ceramic
capacitor unless it is connected to a ground plane.
V
+
and V
–
(Pins 4, 8, 9/Pins 3, 6): Power Supply Pins. For
a single 3.3V or 5V supply (V
–
grounded) a quality 0.1F
ceramic bypass capacitor is required from the positive
supply pin (V
+
) to the negative supply pin (V
–
). The bypass
should be as close as possible to the IC. For dual supply
applications, bypass V
+
to ground and V
–
to ground with
a quality 0.1F ceramic capacitor.
OUT
+
and OUT
–
(Pins 6, 7/Pins 4, 5): Output Pins. These
are the fi lter differential outputs. Each pin can drive a 100
and/or 50pF load to AC ground.
V
MID
(Pin 10/Pin 7): The V
MID
pin is internally biased at
mid-supply, see Block Diagram. For single supply op-
eration, the V
MID
pin should be bypassed with a quality
0.01F ceramic capacitor to V
–
. For dual supply operation,
V
MID
can be bypassed or connected to a high quality DC
ground. A ground plane should be used. A poor ground
will increase noise and distortion. V
MID
sets the output
common mode voltage of the 1st stage of the fi lter. It has
a 5.5k impedance, and it can be overridden with an
external low impedance voltage source.
(DFN/SO)
BLOCK DIAGRAM
–
+
–
+
V
OCM
–
–
+
+
V
OCM
1580Ω
1580Ω
800Ω
800Ω
800Ω
800Ω
V
+
V
–
11k
11k
OP AMP
PROPRIETARY
LOWPASS
FILTER STAGE
V
IN
–
V
IN
+
R
IN
R
IN
660025 BD
IN
+
V
OCM V
+
OUT
+
OUT
–
V
–
V
MID
IN
–