SGS Thomson Microelectronics M5481 Datasheet

FEATURES

■ 2 DIGIT LED DRIVER (14 segments)

■ CURRENT GENERATOR OUTPUTS (no

registor required)

■ CONTINUOU BRIGHTNESS CONTROL

■ SERIAL DATA INPUT

■ DATA ENABLE

■ WIDE SUPPLY VOLTAGE OPERATION

■ TLL COMPATIBILITY

■ APPLICATION EXAMPLES

■ MICROPROCESSOR DISPLAYS

■ INDUSTRIAL CONTROL INDICATOR

■ RELAY DRIVER

■ INSTRUMENTATI ON READ O U TS

DESCRIPTION

The M5481 is a monolithic MOS integrated circuit
produced with a N-channel silicon gate techn olo­gy. It uses the M54 50 die packaged in a 20-pin
plastic package copper frame, making it ideal for a
1-digit display. A single pin controls the LE D dis­play brightness by setting a reference current
through a variable resistor connected either to

V

DD

or to a separate supply of 13.2V maximum.
The M5481 is a pin-to-pin replacement of the NS

MM 5481.

PIN CONNECTIONS

M5481

LED DISPLAY DRIVER

DIP20

(Plastic package)

ORDER CODE: M54 81 B7

Output Bit 8
Output Bit 7
Output Bit 6
Output Bit 5
Output Bit 4
Output Bit 3
Output Bit 2
Output Bit 1

Brightness Control

V

DD

1
2
3
4

5
6
7
8
9

10

20
19
18
17

16

15

14
13
12

11

Output Bit 9
Output Bit 9
Output Bit 9
Output Bit 9
Output Bit 9
V

SS

Output Bit 9
Data Enable

Data In
Clock

Version 4.1

April 2000 1/8

1

M5481

1 - BLOC DIAGRAM

Figure 1.

Brightness

Control

100kΩ

V

10

DD

Output

Bit 14

14

Output

Bit 1

8

9

35 Output Buffers

1nF

Load

Data Enable

Serial Data

Clock

13

12

11

35 Latches

35-Bit Shift Register

Reset

15

2 - ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

DD

Vi Input Voltage -0.3 to 15 V

Vo(off) Off-state Output Voltage 15 V

Io Output Sink Current 40 mA

Supply Voltage -0.3 to 15 V

Total package power Dissipation

P

tot

T

j

T

oper

T

stg

Stresses exceed ing those list ed under “Ab solute Max imum Rating s” may caus e permanen t damage to the device a nd
affect its reliability.

2/8

Junction Temperatu re 150 °C
Operating Temperature Range -25, +85 °C
Staorage Temperature Range -65, +150 °C

at 25°C
t 85°C

1.5

800

W

mW

2

3 - STATIC ELECTRICAL CHARACTERISTICS

(T

within operational range, VDD=4.75V to 13.2V, VSS=0V, unless otherwise specified)

amb

Symbol Parameter Test Conditions Min Typ Max Unit

V

DD

Idd Supply Current V

Supply Voltage 4.5 13.2 V

=13.2V 7 mA

DD

M5481

Input Voltages

Vi

IB Brightness Input Current (Note 2) 0 0.75 mA

VB Brightness Input Voltage (pin9)

Vo(off) Off-state Output Voltage 13.2 V

Io

fclock

Io Output Matching (Note 1)

Note 1 Output matching is calculated as the percent variation from Imax+Imin/2
Note 2 With a fixed resistor on the brightness input some variation in brightness will occur from one device to another.
Note 3 Absolute maximum for each output should be limited to 40mA.
Note 4 the Vo voltage should be regulated by the user.

Logical “0” Level
Logical “1” Level

Output Sink Current (Note 3)
Segment OFF
Segment ON

Input Clock Frequency 0 0.5 MHz

+10µA Input Bias

4.75≤V
V

DD

Input Curren=750µA
T

amb

Vo=3V
Vo=1V (Note 4)
Brightness In.=0µA
Brightness In.=100µA
Brightness In.=750µA

DD

>5.25

=25°C

≤5.25

-0.3

2.2

V

-

DD

2

3 4.3 V

0
2

12

2.7
15

0.8

V

DD

V

DD

10
10

4

25

±20 %

V
V
V

µA
µA

mA
mA

4 - FUNCTIONAL DESCRIPTION

The M5481 uses the M5450 die which is packaged
to operate 2-digit alphanumeric displays with mini­mal interface with the display and the data source.

Serial data transfer from the data source to the dis­play driver is accom plished with 2 signals, serial

data and clock. using a format of a leadi ng “1” fol­lowed by the 35 data bits allows data transfer with­out an additional load signal.

The 35 data bits are latched after the 36th bit is
complete, thus providing non-multiplexed, direct
drive to the display. Outputs change only if the se­rial data bits differ from the previous time. Display
brightness is determined by control of the output
current for LED displays. A 1nF capacitor should

be connected to brightness c ontrol (pin 9) to pre­vent possible oscillations.

A bloc diagram is shown on F igure 1. The output
current is typically 20 times g reater than the cur­rent into pin 9, which is set by an external variable
resistor.

The latter is an internal limiting resistor of 400Ω
nominal value.

Figure 2 shows the input data format. A start bit of

logical “1” precedes the 35 bits of data. At the 36th
clock a LOAD is generated synchronously with the
high state of the clock, which l oads the 35 bits of
the shift registers into the latches.

3/8