MM58341 National Semiconductor, MM58341 Datasheet - Page 3

• Manufacturer Part Number: MM58341
• Description: High Voltage Display Driver
• Manufacturer: National Semiconductor

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AC Electrical Characteristics
Note 2 Note that for timing purposes the signals ENABLE and BLANK can be considered to be totally independent of each other
Note 3 AC input waveform specification for test purpose t
Note 4 Clock input rise and fall times must not exceed 5 s
Connection Diagrams
Symbol
f
t
t
t
t
t
t
t
C
H
L
DS
DH
ES
EH
CDO
See NS Package Number N40A
Order Number MM58341N
See NS Package Number V44A
Dual-In-Line Package
Order Number MM58341V
Plastic Chip Carrier
Clock Input Frequency
Clock Input High Time
Clock Input Low Time
Data Input Setup Time
Data Input Hold Time
Enable Input Setup Time
Enable Input Hold Time
Data Output Clock Low to
Data Out Time
Top View
Top View
Parameter
r s
T
TL F 5603– 2
TL F 5603– 8
A
20 ns t
e b
(Notes 3 4)
C
Conditions
f s
L
40 C to
e
20 ns f
50 pF
3
a
e
Figure 2 shows the pinout of the MM58341 device where
Figure 4 demonstrates the critical timing requirements be-
Figure 6 shows a schematic diagram of a microprocessor-
Functional Description
This product is specifically designed to drive multiplexed or
non-multiplexed high voltage alphanumeric or dot matrix
vacuum fluorescent (VF) displays Character generation is
done externally in the microprocessor with a serial data
path to the display driver The MM58341 uses three signals
DATA IN CLOCK and ENABLE where ENABLE acts as an
external load signal Display blanking can be achieved by
means of the BLANKING CONTROL input and a logic ‘1’
will turn off all sections of the display A block diagram of
the MM58341 is shown in Figure 1
output 1 (pin 18) is equivalent to bit 1 (i e the first bit of data
to be loaded into the shift register following ENABLE high)
A logic ‘1’ at the input will turn on the corresponding display
digit segment dot output
A significant reduction in discrete board components can be
achieved by use of the MM58341 because external pull-
down resistors are not required Due to the nature of the
output stage both its on and off impedance values vary as a
function of the display voltage applied However Figures 3a
and 3b show that this output impedance will remain con-
stant for a fixed value of display voltage
tween CLOCK and DATA IN for the MM58341
To clear (reset) the display driver at power on or any time
the following flushing routine may be used With the enable
signal high clock in 32 zeroes Drive the enable signal low
and the display will be blank It is recommended to clear the
driver at power on
In Figure 5 the ENABLE signal acts as an envelope and
only while this signal is at a logic ‘1’ does the circuit accept
CLOCK input signals Data is transferred and shifted in the
internal shift register on the rising clock edge i e ‘0’ – ‘1’
transition When the ENABLE signal goes low the contents
of the shift registers are latched and the display will show
new data During data transfer the display will show old
data DATA OUT is also provided on the MM58341 being
output on the falling edge At any time the display may be
blanked under processor control using the BLANKING
CONTROL input
based system where the MM58341 is used to provide the
grid drive for a 32-digit 5 x 7 dot matrix vacuum fluorescent
(VF) display The anode drive in this example is provided by
another member of the high voltage display driver family
namely the MM58348 which does not require an externally
generated load signal
85 C V
800 kHz 50%
DD
Min
300
300
100
100
100
100
e
g
5V
10% duty cycle
g
0 5V
Typ
Max
800
500
Units
kHz
ns
ns
ns
ns
ns
ns
ns