LTC1562CG-2#PBF Linear Technology, LTC1562CG-2#PBF Datasheet - Page 9

• Manufacturer Part Number: LTC1562CG-2#PBF
• Description: IC FILTER UNIV RC QUAD LN 20SSOP
• Manufacturer: Linear Technology

Specifications of LTC1562CG-2#PBF

• Filter Type: Universal, Continuous-Time
• Frequency - Cutoff Or Center: 300kHz
• Number Of Filters: 4
• Max-order: 8th
• Voltage - Supply: 4.75 V ~ 10.5 V, ±4.75 V ~ 5.25 V
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS
order lowpass response the gain magnitude becomes QH
at frequency f
a frequency below f
Basic Bandpass
There are two different ways to obtain a bandpass function
in Figure 3, both of which give the following transfer
function form:
The value of the gain parameter H
configuration as follows. When Z
R
6a) with a gain parameter H
capacitor of value C
output (Figure 6b), with the same H
the gain parameter now H
transfer function has a gain magnitude of H
when the frequency equals f
at that frequency. Q measures the sharpness of the peak
(the ratio of f
function, as illustrated in Figure 4.
by R2 and R
Basic Highpass
When Z
response appears at the V1 output (Figure 7).
V
IN
IN
O
H
(= 2 f
, a bandpass response results at the V1 output (Figure
V s
V s
BP
IN
1
R
( )
IN
( )
( )
IN
(a) Resistive Input
s
INV
O
of Figure 3 is a capacitor of value C
1/4 LTC1562-2
) and Q are set by R2 and R
Figure 6. Basic Bandpass Configurations
2nd ORDER
Q
H
O
s
O
to – 3dB bandwidth) in a 2nd order bandpass
HP
2
as described previously in Setting f
V1
, and for Q > 0.707, a gain peak occurs at
–
R
( )
Q
s
H
V2
B
IN
U
O
O
, as shown in Figure 4.
R2
gives a bandpass response at the V2
s
/
2
O
Q s
V
B
OUT
INFORMATION
/
U
= (R
Q s
O
and has a phase shift of 180
B
–
Q
O
V
IN
H s
= R
/7958 )(C
2
O
/
H
B
Q s
IN
depends on the circuit
Q
C
2
BP
W
O
IN
/R
is a resistor of value
Q
(b) Capacitive Input
= 2 f
(s) expression, and
as above. For a 2nd
IN
INV
1/4 LTC1562-2
. Alternatively, a
B
2nd ORDER
2
O
IN
(its peak value)
O
IN
V1
/100pF). This
and Q are set
, a highpass
R
Q
U
V2
O
and Q.
R2
1562-2 F06
V
OUT
L
H
eters
a 2nd order highpass response the gain magnitude at
frequency f
cies (f >> f
frequency above f
function includes a sign inversion.
Signal Swings
The V1 and V2 outputs are capable of swinging to within
roughly 100mV of each power supply rail. As with any
analog filter, the signal swings in each 2nd order section
must be scaled so that no output overloads (saturates),
even if it is not used as a signal output. (Filter literature
often calls this the “dynamics” issue.) When an unused
output has a larger swing than the output of interest, the
section’s gain or input amplitude must be scaled down to
avoid overdriving the unused output. The LTC1562-2 can
still be used with high performance in such situations as
long as this constraint is followed.
For an LTC1562-2 section as in Figure 3, the magnitudes
of the two outputs V2 and V1, at a frequency = 2 f, have
the ratio,
regardless of the details of Z
quency above or below 200kHz produces larger output
amplitude at V1 or V2, respectively. This relationship can
guide the choice of filter design for maximum dynamic
range in situations (such as bandpass responses) where
there is more than one way to achieve the desired fre-
quency response with an LTC1562-2 section.
H
|
| ( ) |
= C
V j
V j
2
1
IN
( ) |
O
/100pF is the highpass gain parameter. Param-
= 2 f
O
Figure 7. Basic Highpass Configuration
O
is QH
). For Q > 0.707, a gain peak occurs at a
V
O
IN
(
and Q are set by R2 and R
200
H
O
C
, and approaches H
f
IN
kHz
as shown in Figure 4. The transfer
INV
1/4 LTC1562-2
)
2nd ORDER
V1
IN
R
Q
. Therefore, an input fre-
V2
R2
1562-2 F07
LTC1562-2
H
V
OUT
at high frequen-
Q
as above. For
15622fa
9