The NTE2028 is an integrated circuit in a 16鈥揕ead DIP type package custom designed to decode
four lines of BCD and drive a gas鈥揻illed seven鈥搒egment display tube.
Each output constitutes a switchable, adjustable current sink which provides constant current to the
tube segment, even with high tube anode supply tolerance or fluctuation. These current sinks have
a voltage compliance from 3V to at least 80V; typically the output current varies 1% for output voltage
changes of 3 to 50V. Each bit line of the decoder switches a current sink on or off as prescribed by
the input code. Each current sink is ratioed to the b鈥搊utput current as required for even illumination
of all segments.
Output currents may be varied over the 0.2 to 1.5 mA range for driving various tube types or multiplex
operation. The output current is adjusted by connecting an external program resistor (R
to the Program input in accordance with the programming curve. The circuit design provides a one鈥?/div>
to鈥搊ne correlation between program input current and b鈥搒egment output current.
The Blanking Input provides unconditional blanking of any output display, while the Ripple Blanking
pins allow simple leading or trailing zero blanking.
Features:
D
Current Sink Outputs
D
Adjustable Output Current: 0.2 to 1.5mA
D
High Output Breakdown Voltage: 110V Typ
D
Suitable for Multiplex Operation
D
Blanking and Ripple Blanking Provisions
D
Low Fan鈥揑n and Low Power
Absolute Maximum Raings:
(Note 1)
Supply Voltage, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Input Voltage (Except BI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6V
Input Voltage (BI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
CC
Segment Output Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80V
Power Dissipation, P
D
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600mW
Transient Segment Output Current (Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Storage Temperature Range, T
stg
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 鈥?5擄 to +150擄C
Lead Temperature (During Soldering, 10sec), T
L
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300擄C
Note 1. 鈥淎bsolute Maximum Ratings鈥?are those values beyond which the safety of the device cannot
be guaranteed. Except for 鈥淥perating Temperature Range鈥?they are not meant to imply that
the device should be operated at these limits. The table of 鈥淓lectrical Chracteristics鈥?pro-
vides conditions for actual device operation.
Note 2. In all applications transient segment output current must be limited to 50mA. This may be
accomplished in DC applications by connecting a 2.2k resistor from the anode鈥搒upply filter
capacitor to the display anode, or by current limiting the anode driver in multiplex applica-
tions.
1
2
3
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