ITT - Index of

ITT
ITT503
QUAD SEGMENT DRIVER
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SEMICONDUCTORS
QUAD SEGMENT
DRIVER
PACKAGE 16 Pin Dual-in-line
• MOS to LED. segment driver
• Constant current source, programmable.
• Suitable for pocket calculators
• "Chip enable" for extended battery life
• High gain Darlington Outputs
The ITT 503 is a monolithic integrated circuit
which provides the interface between MOS
integrated circuits and Light Emitting Diode
(LE.P) displays. The ITT 503 is designed to be
used in serially addressed multi-digit displays.
This time-multiplexed system, using a segment
address and digit scan method of LED drive,
minimizes the number of drivers required. This
circuit, together~with the ITT 502 was designed
to operated with:two different power supplies.
The first being a battery, (Vee) where the
voltage may vary from 3.5 to 9 volts and
supplies the majority of the load currents
(display currents). The second, (Vss) supply,
being a D.C. to D.C. converter or regulator
which maintains the voltage between 7 and 9
volts. By connecting a resistor in series with
the VOUT terminal and the LED anode (i.e.
resistor across VOUT and VREF) an adequate
current source is generated. The voltage across
the resistor is equivalent to a diode forward
voltage drop (+ 0.6V), thus in order to control
20 mA, a resistor value of 300 is required. The
"chip enable" circuit allows turning the load
(display) "off" independently of the input
signals.
Pin Configuration (Top View)
SCHEMATIC
Vas
5K
Vee
VOUT
ABSOLUTE MAXIMUM RATINGS
(Measurements with respect to GND)
Characteristics
Unit
Vss (Vss VIN orVeE) 9 V
Vee
9V
Continuous total power
dissipation
800 mW
Storage temperature range -55°C to + 1250C
Operating temperature range O°C to + 50°C
(Each Driver, 4 per package)