LM3914 Datasheet, PDF (4/19 Pages) National Semiconductor (TI) – Dot/Bar Display Driver

Electrical Characteristics (Notes 2, 4) (Continued)
Note 2: Unless otherwise stated, all specifications apply with the following conditions:
3 V_DC ≤ V⁺ ≤ 20 V_DC V_REF, V_RHI, V_RLO ≤ (V⁺ − 1.5V)
3 V_DC ≤ V_LED ≤ V⁺ 0V ≤ V_IN ≤ V⁺ − 1.5V
−0.015V ≤ V_RLO ≤ 12 V_DC T_A = +25˚C, I_L(REF) = 0.2 mA, V_LED = 3.0V, pin 9 connected to pin 3 (Bar Mode).
−0.015V ≤ V_RHI ≤ 12 V_DC
For higher power dissipations, pulse testing is used.
Note 3: Accuracy is measured referred to +10.000 V_DC at pin 6, with 0.000 V_DC at pin 4. At lower full-scale voltages, buffer and comparator offset voltage may add
significant error.
Note 4: Pin 5 input current must be limited to ±3 mA. The addition of a 39k resistor in series with pin 5 allows ±100V signals without damage.
Note 5: Bar mode results when pin 9 is within 20 mV of V⁺. Dot mode results when pin 9 is pulled at least 200 mV below V⁺ or left open circuit. LED No. 10 (pin
10 output current) is disabled if pin 9 is pulled 0.9V or more below V_LED.
Note 6: The maximum junction temperature of the LM3914 is 100˚C. Devices must be derated for operation at elevated temperatures. Junction to ambient thermal
resistance is 55˚C/W for the molded DIP (N package).
Definition of Terms
Accuracy: The difference between the observed threshold
voltage and the ideal threshold voltage for each comparator.
Specified and tested with 10V across the internal voltage di-
vider so that resistor ratio matching error predominates over
comparator offset voltage.
Adjust Pin Current: Current flowing out of the reference ad-
just pin when the reference amplifier is in the linear region.
Comparator Gain: The ratio of the change in output current
(I_LED) to the change in input voltage (V_IN) required to pro-
duce it for a comparator in the linear region.
Dropout Voltage: The voltage measured at the current
source outputs required to make the output current fall by
10%.
Input Bias Current: Current flowing out of the signal input
when the input buffer is in the linear region.
Typical Performance Characteristics
LED Current Regulation: The change in output current
over the specified range of LED supply voltage (V_LED) as
measured at the current source outputs. As the forward volt-
age of an LED does not change significantly with a small
change in forward current, this is equivalent to changing the
voltage at the LED anodes by the same amount.
Line Regulation: The average change in reference output
voltage over the specified range of supply voltage (V⁺).
Load Regulation: The change in reference output voltage
(V_REF) over the specified range of load current (I_L(REF)).
Offset Voltage: The differential input voltage which must be
applied to each comparator to bias the output in the linear re-
gion. Most significant error when the voltage across the in-
ternal voltage divider is small. Specified and tested with pin
6 voltage (V_RHI) equal to pin 4 voltage (V_RLO).
Supply Current vs
Temperature
Operating Input Bias
Current vs Temperature
Reference Voltage vs
Temperature
DS007970-2
DS007970-20
DS007970-21
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