ba3835s ROHM Co. Ltd., ba3835s Datasheet - Page 8

• Manufacturer Part Number: ba3835s
• Description: Band-pass Filter For Spectrum Analyzer
• Manufacturer: ROHM Co. Ltd.

FOperation notes
(1)
The frequency characteristics of this IC are determined
by the resistor connected between the R
GND. For the specification conditions, the value of this
resistor is 100k . If it is necessary to set the frequency
characteristics accurately, use a variable resistor (note :
all bands will shift together).
(2)
To convert the bias sense output signal to the GND sense
signal, the IC performs a V / I conversion, and then an
I / V conversion using a 10k
put.
Therefore, if the load circuit connected to the A OUT pin
has a MOS structure there is no problem (eg. micropro-
cessor input port), but if the connected circuit has a low
input impedance, it may cause the output level to drop.
(3)
When using a common port for the output select control
and FL drive, you must add a diode and resistor as shown
in Fig. 4 to prevent the FL drive “L” voltage from destroy-
ing the IC.
608
Audio ICs
Frequency characteristics
Load characteristics
External resistor for the control pin
In this case, the “L” voltage applied to the internal
comparator input terminal V
To maintain a noise margin of at least 2.5V with re-
spect to the comparator threshold level V
resentative values for V
and 10k respectively. This gives :
V
20k )10k )R
1
=
20k )R
R
1
R
)R
1
)R
2
)R
ref
, R
resistor (typ.) for the out-
Vref
1
1.5V)0.25V<1.5V
1
and R
is given by :
2
REF
are 1.5V, 20k ,
terminal and
ref
, the rep-
(4)
Provided that the IC is operated within the recommended
operating conditions and the recommended temperature
range, the basic circuit functions are guaranteed. Within
these ranges, ratings for electrical characteristics for
conditions other than those stipulated cannot be guaran-
teed, but the inherent function of the bandpass filter will
be maintained.
(5)
Provided the recommended circuit constants are used,
the application circuit should function correctly. However,
we recommend that you confirm the characteristics of the
circuits in actual use and pay due attention to the caution-
ary notes given below.
If you change the circuit constants, check both the static
and transient characteristics of the circuit, and allow suffi-
cient margin to accommodate variations between both
ICs and external components. Note, also, that Rohm has
not been able to conduct a sufficient study into patent
rights.
And from this, the following condition is obtained :
In this case, the “L” level voltage V
be :
Recommended operating ranges
Application circuit
R < 30k
V
2
< 0.75V
BA3835S / BA3835F
2
for the IC will