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REV. L

(5) Thermal design

Perform thermal design in which there are adequate margins by taking into account the allowable power dissipation in

actual states of use.

(6) Shorts between pins and misinstallation

When mounting the LSI on a board, pay adequate attention to orientation and placement discrepancies of the LSI. If it

is misinstalled and the power is turned on, the LSI may be damaged. It also may be damaged if it is shorted by a

foreign substance coming between pins of the LSI or between a pin and a power supply or a pin and a GND.

(7) Operation in strong magnetic fields

Adequately evaluate use in a strong magnetic field, since there is a possibility of malfunction.

(8) Frequency characteristics

The frequency characteristics of this IC are determined

by the resistor connected between the R

and GND. For the specification conditions, the value of

this resistor is 100kΩ If it is necessary to set the

frequency characteristics accurately, use a variable

resistor

(note: all bands will shift together).

(9) Load characteristics

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 10kΩresistor (Typ.) for

the output. Therefore, if the load circuit connected to

the AOUT pin has a MOS structure there is no problem

(eg. Microprocessor input port), but if the connected

circuit has a low input impedance, it may cause the

output level to drop.

(10) External resistor for the control pin

When using a common port for the output select

control and FL drive, you must add a diode and resistor

as shown in the right figure to prevent the FL drive

“L”

voltage from destroying the IC.

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

respect to the comparator threshold level VREF, the

representative values for VREF, R1 and R2 are 1.5V,

20kΩ, and 10kΩrespectively. This gives:

And from this, the following condition is obtained:

R＜30kΩ

In this case, the

“L” level voltage V2 for the IC will be:

V

(11) Recommended operating ranges

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 guaranteed, but the inherent

function of the band pass filter will be maintained.

(12) Output offset voltage

The relationship between the output offset voltage and

the output selection cycle (cycle time) for this IC is

shown in Fig.5. The maximum output offset voltage of

150mV that is given in the electrical characteristics

table is under the condition that Ts = 200ms.

When Ts is greater than 50ms, the graph of the output

offset voltage is a straight line at 150mV. When Ts is

below 50ms, due to transient

characteristics of the peak hold circuit, the graph is a

line sloping downwards to the right. In other words, the

shorter

the cycle, the larger the output offset voltage.

Furthermore, the output offset voltage may shift due to

soldering or other temperature stresses from the

surroundings. Therefore, when setting the spectral

analyzer light level, take into consideration the points

given above

and make sure that it does not light by mistake during

quiescent periods. Use the chart below as a guide for

this, and, if necessary, leave even a larger margin.

× 1.5V+0.25V ＜ 1.5V

20kΩ+20kΩ+R

20kΩ+R

BA3834F