LT6604-2.5 Linear Technology, LT6604-2.5 Datasheet - Page 7

• Manufacturer Part Number: LT6604-2.5
• Description: Dual Very Low Noise Differential Amplifier and 2.5MHz Lowpass Filter
• Manufacturer: Linear Technology

TYPICAL PERFORMANCE CHARACTERISTICS
+INA, –INA (Pins 2, 4): Channel A Input Pins. Signals can
be applied to either or both input pins through identical
external resistors, R
inputs to the differential outputs is 1580Ω/R
V
for the 2nd Filter Stage in channel A. Its value programs
the common mode voltage of the differential output of
the fi lter. Pin 6 is a high impedance input, which can be
driven from an external voltage reference, or Pin 6 can be
tied to Pin 34 on the PC board. Pin 6 should be bypassed
with a 0.01μF ceramic capacitor unless it is connected to
a ground plane.
V
(can be ground).
V
supply, see Block Diagram. For single supply operation
the V
ceramic capacitor to V
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. Pin 8 sets the output common mode
voltage of the 1st stage of the fi lter in channel B. It has a
5.5kΩ impedance, and it can be overridden with an external
low impedance voltage source.
PIN FUNCTIONS
OCMA
–
MIDB
(Pins 7, 24, 31, 32, 35): Negative Power Supply Pin
MIDB
(Pin 8): The V
(Pin 6): DC Common Mode Reference Voltage
pin should be bypassed with a quality 0.01μF
DIFFERENTIAL
200mV/DIV
50mV/DIV
INPUT
V
OUT
+
IN
MIDB
Transient Response Gain = 1
. The DC gain from the differential
–
. For dual supply operation, Pin 8
pin is internally biased at mid-
500ns/DIV
IN
.
660425 G17
+INB, –INB (Pins 10, 12): Channel B Input Pins. Signals
can be applied to either or both input pins through identi-
cal external resistors, R
inputs to the differential outputs is 1580Ω/R
V
for the 2nd Filter Stage in Channel B. Its value programs
the common mode voltage of the differential output of
the fi lter. Pin 14 is a high impedance input, which can be
driven from an external voltage reference, or Pin 14 can be
tied to Pin 8 on the PC board. Pin 14 should be bypassed
with a 0.01μF ceramic capacitor unless it is connected to
a ground plane.
V
for Channels A and B. For a single 3.3V or 5V supply
(V
is required from each positive supply pin (V
the negative supply pin (V
close as possible to the IC. For dual supply applications,
bypass the negative supply pins to ground and each of the
positive supply pins (V
0.1μF ceramic capacitor.
+OUTB, –OUTB (Pins 19, 21): Output Pins. Pins 19 and
21 are the fi lter differential outputs for channel B. With a
typical short-circuit current limit greater than ±40mA, each
pin can drive a 100Ω and/or 50pF load to AC ground.
OCMB
+
–
A, V
grounded) a quality 0.1μF ceramic bypass capacitor
–110
–130
–10
–30
–50
–70
–90
+
(Pin 14): DC Common Mode Reference Voltage
B (Pins 25, 17): Positive Power Supply Pins
100k
Channel Separation vs Frequency
(Note 9)
1M
FREQUENCY (Hz)
+
IN
A, V
. The DC gain from differential
–
). The bypass should be as
+
10M
B) to ground with a quality
V
V
R
EACH OUTPUT
GAIN = 1
IN
S
L
= 5V
= 800Ω AT
= 2V
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LT6604-2.5
660425 G18
P-P
100M
IN
+
A, V
.
+
B) to
660425f
7