Part Datasheet Search > Voltage References > TI > LM385M3-1.2/NOPB Datasheet PDF > LM385M3-1.2/NOPB Datasheet Pages 1/32
LM385M3-1.2/NOPBDatasheet PDF
Page:
of 32 Go
If the format of the manual is confusing, please download and read the original PDF file.
LM3914
www.ti.com
SNVS761B –JANUARY 2000–REVISED MARCH 2013
LM3914 Dot/Bar Display Driver
Check for Samples: LM3914
Versatility was designed into the LM3914 so that
1
FEATURES
controller, visual alarm, and expanded scale functions
2
• Drives LEDs, LCDs or Vacuum Fluorescents
are easily added on to the display system. The circuit
• Bar or Dot Display Mode Externally Selectable
can drive LEDs of many colors, or low-current
by User
incandescent lamps. Many LM3914s can be
“chained” to form displays of 20 to over 100
• Expandable to Displays of 100 Steps
segments. Both ends of the voltage divider are
• Internal Voltage Reference from 1.2V to 12V
externally available so that 2 drivers can be made
• Operates with Single Supply of Less than 3V
into a zero-center meter.
• Inputs Operate Down to Ground
The LM3914 is very easy to apply as an analog
• Output Current Programmable from 2 mA to 30
meter circuit. A 1.2V full-scale meter requires only 1
resistor and a single 3V to 15V supply in addition to
mA
the 10 display LEDs. If the 1 resistor is a pot, it
• No Multiplex Switching or Interaction Between
becomes the LED brightness control. The simplified
Outputs
block diagram illustrates this extremely simple
• Input Withstands ±35V without Damage or
external circuitry.
False Outputs
When in the dot mode, there is a small amount of
• LED Driver Outputs are Current Regulated,
overlap or “fade” (about 1 mV) between segments.
Open-collectors
This assures that at no time will all LEDs be “OFF”,
and thus any ambiguous display is avoided. Various
• Outputs can Interface with TTL or CMOS Logic
novel displays are possible.
• The Internal 10-step Divider is Floating and
can be Referenced to a Wide Range of
Much of the display flexibility derives from the fact
Voltages
that all outputs are individual, DC regulated currents.
Various effects can be achieved by modulating these
currents. The individual outputs can drive a transistor
DESCRIPTION
as well as a LED at the same time, so controller
The LM3914 is a monolithic integrated circuit that
functions including “staging” control can be
senses analog voltage levels and drives 10 LEDs,
performed. The LM3914 can also act as a
providing a linear analog display. A single pin
programmer, or sequencer.
changes the display from a moving dot to a bar
graph. Current drive to the LEDs is regulated and
The LM3914 is rated for operation from 0°C to +70°C.
programmable, eliminating the need for resistors.
The LM3914N-1 is available in an 18-lead PDIP
This feature is one that allows operation of the whole
(NFK) package.
system from less than 3V.
The following typical application illustrates adjusting
The circuit contains its own adjustable reference and
of the reference to a desired value, and proper
accurate 10-step voltage divider. The low-bias-current
grounding for accurate operation, and avoiding
input buffer accepts signals down to ground, or V
−
,
oscillations.
yet needs no protection against inputs of 35V above
or below ground. The buffer drives 10 individual
comparators referenced to the precision divider.
Indication non-linearity can thus be held typically to
½%, even over a wide temperature range.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2000–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.