LTC1562-2 Linear Technology, LTC1562-2 Datasheet - Page 6

• Manufacturer Part Number: LTC1562-2
• Description: Very Low Noise/ Low Distortion Active RC Quad Universal Filter
• Manufacturer: Linear Technology

PIN
LTC1562-2
INV A, INV B, INV C, INV D: Each of the INV pins is a virtual-
ground summing point for the corresponding 2nd order
section. For each section, all three external components
Z
described further in the Applications Information. Note
that the INV pins are sensitive internal nodes of the filter
and will readily receive any unintended signals that are
capacitively coupled into them. Capacitance to the INV
nodes will also affect the frequency response of the filter
sections. For these reasons, printed circuit connections to
the INV pins must be kept as short as possible, less than
one inch (2.5cm) total and surrounded by a ground plane.
V1 A, V1 B, V1 C, V1 D: Output Pins. Provide a bandpass,
highpass or other response depending on external cir-
cuitry (see Applications Information section). Each V1 pin
BLOCK DIAGRA
6
IN
U
SHDN
, R2, R
V
V
+
–
FUNCTIONS
Q
U
connect to the INV pin as shown in Figure 3 and
V
V
+
–
SHUTDOWN
SWITCH
SHUTDOWN
SWITCH
R
R
U
W
AGND
Overall Block Diagram Showing Four 3-Terminal 2nd Order Sections
D
A
INV
INV
–
–
+
+
C
C
V1
V1
also connects to the R
order filter section (see Figure 3 and Applications Informa-
tion). Each output is designed to drive a nominal net load
of 4k and 30pF, which includes the loading due to the
external R
outputs are loaded as lightly as possible.
V2 A, V2 B, V2 C, V2 D: Output Pins. Provide a lowpass,
bandpass or other response depending on external cir-
cuitry (see Applications Information section). Each V2 pin
also connects to the R2 resistor of the corresponding 2nd
order filter section (see Figure 3 and Applications Informa-
tion). Each output is designed to drive a nominal net load
of 4k and 30pF, which includes the loading due to the
external R2. Distortion performance improves when the
outputs are loaded as lightly as possible.
2ND ORDER SECTIONS
Q
V2
V2
. Distortion performance improves when the
B
C
INV
INV
Q
–
–
+
+
resistor of the corresponding 2nd
C
C
V1
V1
V2
V2
1562-2 BD