NTE1509
Integrated Circuit
10–Step Dot/Bar Display Driver
for Logarithmic Scale
Description:
The NTE1509 is a monolithic integrated circuit in an 18–Lead DIP type package that senses analog
voltage levels and drives 10 LEDs, LCDs, or vacuum fluorescent displays, providing a logarithmic 3dB
analog display. A single pin changes the display from a bar graph to a moving dot display. LED current
is regulated and programmable, eliminating the need for current limiting resistors. The whole display
system can operate from a single supply as low as 3V or as high as 25V
The circuit contains its own adjustable reference and accurate 10–step voltage divider. The high im-
pedance input buffer accepts signals down to GND and up to within 1.5V of the positive supply. Fur-
ther, it needs no protection against inputs of
±35V.
The input buffer drives 10 individual comparators
referenced to the precision divider. Accuracy is typically better than 1dB.
The NTE1509’s 3dB/step display is suited for signals with wide dynamic range, such as audio level,
power, light intensity, or vibration. Audio applications include average or peak level indicators, power
meters, and RF signal strength meters. Replacing conventional meters with an LED bar graph results
in a faster responding, more rugged display with high visibility that retains the ease of interpretation
of an analog display.
The NTE1509 is extremely easy to apply. A 1.2V full–scale meter requires only 1 resistor in addition
to the 10 display LEDs. One more resistor programs the full–scale anywhere from 1.2V to 12V inde-
pendent of supply voltage. LED brightness is easily controlled with a single pot.
The NTE1509 is very versitile. The outputs can drive LCDs, vacuum fluorescents, and incandescent
bulbs as well as LEDs of any color. Multiple devices can be cascaded for a dot or bar mode display
with a range of 60 or 90dB. NTE1509s can also be cascaded with NTE1508s for a linear/log display
or with NTE1549s for an extended–range VU meter.
Features:
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3dB/Step, 30dB Range
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Drives LEDs, LCDs or vacuum fluorescents
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Bar or dot display mode externally selectable
by user
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Expandable to displays of 90dB
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Internal voltage reference from 1.2V to 12V
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Operates with single supply of 3V to 25V
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Inputs operate down to GND
Output current programmable from 1 to 30mA
Input withstands
±35V
without damage or false
outputs
Outputs are current regulated, open–collectors
Directly Drives TTL or CMOS
The internal 10–step divider is floating and can
be referenced to a wide range of voltages
NTE [ NTE ELECTRONICS ]
