NTE1509
Integrated Circuit
10Step Dot/Bar Display Driver
for Logarithmic Scale
Description:
The NTE1509 is a monolithic integrated circuit in an 18Lead 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 10step 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 fullscale meter requires only 1 resistor in addition
to the 10 display LEDs. One more resistor programs the fullscale 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 extendedrange 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, opencollectors
D
Directly Drives TTL or CMOS
D
The internal 10step 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 39k
resistor in series with
Pin5 allows
100V signals without damage.
Electrical Characteristics:
(Note 2, unless otherwise specified, all specifications apply with the
following conditions:
3V
DC
V+
20V
DC
V
REF
, V
RHI
, V
RLO
(V+ 1.5V)
3V
DC
V
LED
V+
0V
V
IN
V+ 1.5V
0.015V
V
RLO
12V
DC
T
A
+25
C, I
L(REF)
= 0.2mA,
0.015V
V
RHI
12V
DC
Pin9 connected to Pin3 (Bar Mode)
Parameter
Test Conditions
Min
Typ
Max
Unit
Comparator
Offset Voltage, Buffer, and First Comparator
0V
V
RLO
= V
RHI
12V, I
LED
= 1mA
3
10
mV
Offset Voltage, Buffer, and Any Other
Comparator
0V
V
RLO
= V
RHI
12V, I
LED
= 1mA
3
15
mV
Gain (
I
LED
/
V
IN
)
I
L(REF)
= 2mA, I
LED
= 10mA
3
8
mA/mV
Input Bias Current (At Pin5)
0V
V
IN
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
k
Relative Accuracy (Input Change Between
Any Two Threshold Points)
Note 3
2.0
3.0
4.0
dB
Absolute Accuracy at Each Threshold Point
V
IN
= 3, 6dB, Note 3
0.5
+0.5
dB
V
IN
= 9dB, Note 3
0.5
+0.65
dB
V
IN
= 12, 15, 18dB, Note 3
0.5
+1.0
dB
V
IN
= 21, 24, 27dB, Note 3
0.5
+1.5
dB
Voltage Reference
Output Voltage
0.1mA
I
L(REF)
4mA, V+ = V
LED
= 5V
1.2
1.28
1.34
V
Line Regulation
3V
V+
18V
0.01
0.03
%/V
Load Regulation
0.1mA
I
L(REF)
4mA, V+ = V
LED
= 5V
0.4
2.0
%
Output Voltage Change with Temperature
0
T
A
+70
C, I
L(REF)
= 1mA, V+ = 5V
1
%
Adjust Pin Current
75
120
A
Note 2. Pin5 input current must be limited to
3mA. The addition of a 39k
resistor in series with
Pin5 allows
100V signals without damage.
Note 3. Accuracy is measured referred to +10.000V
DC
at Pin5, with + 10.000V
DC
at Pin6, and
0.000V
DC
at Pin4. At lower fullscale voltages, buffer and comparator offset voltage may
add significant error. See table for threshold voltages.
Electrical Characteristics (Cont'd): (Note 2, unless otherwise specified, all specifications apply
with the following conditions:
3V
DC
V+
20V
DC
V
REF
, V
RHI
, V
RLO
(V+ 1.5V)
3V
DC
V
LED
V+
0V
V
IN
V+ 1.5V
0.015V
V
RLO
12V
DC
T
A
+25
C, I
L(REF)
= 0.2mA,
0.015V
V
RHI
12V
DC
V
LED
= 3V, Pin9 connected to Pin3
(Bar Mode)
Parameter
Test Conditions
Min
Typ
Max
Unit
Output Drivers
LED Current
V+ = V
LED
= 5V, I
L(REF)
= 1mA
7
10
13
mA
LED Current Difference (Between Largest
V
LED
= 5V
I
LED
= 2mA
0.12
0.4
mA
and Smallest LED Currents)
I
LED
= 20mA
1.2
3.0
mA
LED Current Regulation
2V
V
LED
17V
I
LED
= 2mA
0.1
0.25
mA
I
LED
= 20mA
1
3
mA
Dropout Voltage
I
LED(ON)
= 20mA, V
LED
= 5V,
I
LED
= 2mA
1.5
V
Saturation Voltage
I
LED
= 2mA, I
L(REF)
= 0.4mA
0.15
0.4
V
Output Leakage, Each Collector
Bar Mode, Note 4
0.1
10
A
Output Leakage
Dot Mode, Note 4
Pin10 to Pin18
0.1
10
A
Pin1
60
150
450
A
Supply Current
Standby Supply Current (All Outputs OFF)
V+ = 5V, I
L(REF)
= 0.2mA
2.4
4.2
A
V+ = 20V, I
L(REF)
= 1mA
6.1
9.2
A
Note 2. Pin5 input current must be limited to
3mA. The addition of a 39k
resistor in series with
Pin5 allows
100V signals without damage.
Note 4. Bar mode results when Pin9 is within 20mV of V+. Dot mode results when Pin9 is pulled at
least 200mV below V+ or left open circuit. LED No. 10 (Pin10 output current) is disabled if
Pin9 is pulled 0.9V or more below V
LED
.
Threshold Voltage: (Note 3)
Output
dB
Min
Typ
Max
Output
dB
Min
Typ
Max
1
27
0.422
0.447
0.531
6
12
2.372
2.512
2.819
1
24
0.596
0.631
0.750
7
9
3.350
3.548
3.825
3
21
0.841
0.891
1.059
8
6
4.732
5.012
5.309
4
18
1.189
1.259
1.413
9
3
6.683
7.079
7.498
5
15
1.679
1.778
1.995
10
0
9.985
10.000
10.015
Note 3. Accuracy is measured referred to +10.000V
DC
at Pin5, with + 10.000V
DC
at Pin6, and
0.000V
DC
at Pin4. At lower fullscale voltages, buffer and comparator offset voltage may
add significant error. See table for threshold voltages.
1
9
18
10
.870 (22.1) Max
.800 (20.3)
.100 (2.54)
.125 (3.17) Min
.250
(6.35)
.150
(3.8)
Pin Connection Diagram
1
2
3
4
LED1
V ()
V (+)
Divider Low
5
Signal Input
6
Divider High
7
Reference Output
18
17
16
15
LED2
LED3
LED4
LED5
14
LED6
13
LED7
12
LED8
8
Reference Adjust
11
LED9
9
Mode
10
LED10
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