NTE NTE1509 Datasheet
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 impedance input buffer accepts signals down to GND and up to within 1.5V of the positive supply. Further, it needs no protection against inputs of ±35V. The in p u t 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 independent 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:
D 3dB/Step, 30dB Range
D Drives LEDs, LCDs or vacuum fluorescents
D Bar or dot display mode externally selectable
by user
D Expandable to displays of 90dB
D Internal voltage reference from 1.2V to 12V
D Operates with single supply of 3V to 25V
D Inputs operate down to GND
D Output current programmable from 1 to 30mA
D Input withstands ±35V without damage or false
outputs
D Outputs are current regulated, open–collectors
D Directly Drives TTL or CMOS
D The internal 10–step divider is floating and can
be referenced to a wide range of voltages
Absolute Maximum Ratings:
Power Dissipation (Note 1) 1365mW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Voltage 25V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage on Output Drivers 25V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input Signal Overvoltage (Note 2) ±35V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Divider Voltage –100mV to V+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference Load Current 10mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage Temperature Range –55° to +150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead Temperature (During soldering, 10sec) +260°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Note 1. The maximum junction temperature of the NTE1509 is +100°C. Device must be derated for
operation at elevated temperatures. Junction to ambient thermal resistance is 55°C/W.
Note 2. Pin5 input current must be limited to ±3mA. The addition of a 39kΩ resistor in series with
Pin5 allows ±100V signals without damage.
Electrical Characteristics: (Note 2, unless otherwise specified, all specifications apply with the
following conditions:
Comparator
3VDC ≤ V+ ≤ 20V
3VDC ≤ V
LED
–0.015V ≤ V
–0.015V ≤ V
Parameter Test Conditions Min Typ Max Unit
DC
≤ V+ 0V ≤ VIN ≤ V+ –1.5V
≤ 12V
RLO
RHI
≤ 12V
DC
DC
V
, V
REF
TA +25°C, I
RHI
, V
RLO
L(REF)
≤ (V+ –1.5V)
= 0.2mA,
Pin9 connected to Pin3 (Bar Mode)
Offset Voltage, Buffer, and First Comparator 0V ≤ V
Offset Voltage, Buffer, and Any Other
Comparator
Gain (∆I
Input Bias Current (At Pin5) 0V ≤ VIN ≤ V+ =1.5V – 25 100 nA
Input Signal Overdrive No Change is Display –35 – +35 V
Voltage Divider
Divider Resistance Total, Pin6 to Pin4 16 28 36
Relative Accuracy (Input Change Between
Any Two Threshold Points)
Absolute Accuracy at Each Threshold Point VIN = –3, –6dB, Note 3 –0.5 – +0.5 dB
Voltage Reference
Output Voltage 0.1mA ≤ I
Line Regulation 3V ≤ V+ ≤ 18V – 0.01 0.03 %/V
Load Regulation 0.1mA ≤ I
Output Voltage Change with Temperature 0° ≤ TA ≤ +70°C, I
Adjust Pin Current – 75 120 µA
/∆VIN) I
LED
0V ≤ V
L(REF)
Note 3 2.0 3.0 4.0 dB
VIN = –9dB, Note 3 –0.5 – +0.65 dB
VIN = –12, –15, –18dB, Note 3 –0.5 – +1.0 dB
VIN = –21, –24, –27dB, Note 3 –0.5 – +1.5 dB
= V
RLO
= V
RLO
= 2mA, I
L(REF)
L(REF)
≤ 12V, I
RHI
≤ 12V, I
RHI
= 10mA 3 8 – mA/mV
LED
≤ 4m A, V+ = V
≤ 4m A, V+ = V
L(REF)
= 1mA – 3 10 mV
LED
= 1mA – 3 15 mV
LED
= 5V 1.2 1.28 1.34 V
LED
= 5V – 0.4 2.0 %
LED
= 1mA, V+ = 5V – 1 – %
kΩ
Note 2. Pin5 input current must be limited to ±3mA. The addition of a 39kΩ resistor in series with
Pin5 allows ±100V signals without damage.
Note 3. Accuracy is measured referred to +10.000VDC at Pin5, with + 10.000VDC at Pin6, and
0.000VDC at Pin4. At lower full–scale voltages, buffer and comparator offset voltage may
add significant error. See table for threshold voltages.
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