Datasheet MM5450, MM5451 Datasheet (Micrel)

General Description

MM5450/5451

LED Display Driver

Features

The MM5450 and MM5451 LED display drivers are
monolithic MOS IC’s fabricated in an N-Channel, metal­gate process. The technology produces low-threshold,
enhancement-mode, and ion-implanted depletion-mode
devices.

A single pin controls the LED display brightness by setting
a reference current through a variable resistor connected
to the supply.

Applications

• Industrial control indicator

• Relay driver

• Digital clock, thermometer, counter, voltmeter

• Instrumentation readouts

• Continuous brightness control

• Serial data input

• No load signal requirement

• Enable (on MM5450)

• Wide power supply operation

• TTL compatibility

• 34 or 35 outputs, 15mA capability

• Alphanumeric capability

Ordering Information

Part Number

Standard Pb-Free

MM5450BN MM5450YN –40°C to+85°C 40-pin PDIP

MM5451BN MM5451YN –40°C to+85°C 40-pin PDIP

Junction

Temp. Range

Package

MM5450BV MM5450YV –40°C to+85°C 44-pin PLCC

MM5451BV MM5451YV –40°C to+85°C 44-pin PLCC

____________________________________________________________________________________________________________

Block Diagram

BRIGHTNESS

CONTROL

19

VDD

OUT 34

20 24

35 OUTPUT BUFFERS

OUT 1

18

DATA ENABLE/OUT 35

SuperSwitcher and Super ßeta PNP are trademarks of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

February 2006

(See Note 1)

SERIAL DATA

CLOCK

23

22

21

Note 1: Pin 23 is Data Enable in MM5450

Pin 23 is Output 35 in MM5451

35 LATCHES

35-BIT SHIFT

REGISTER

Figure 1.

408

LOAD

RESET

1

RESET
(only available
in die form)

) 944-0800 • fax + 1 [phone] • http://www.micrel.com

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Connection Diagram: Die

Figure 2.

Connection Diagram: Dual-in-line Package

V

OUTPUT BIT 17

OUTPUT BIT 16

OUTPUT BIT 15

OUTPUT BIT 14

OUTPUT BIT 13

OUTPUT BIT 12

OUTPUT BIT 11

OUTPUT BIT 10

OUTPUT BIT 9

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

1 40

SS

2 39

3 38

4 37

5 36

6 35

7 34

8 33

9 32

10 31

11 30

12 29

13 28

14 27

15 26

16 25

17 24

18 23

19 22

20 21

DD

MM5450BN/YN

OUTPUT BIT 18

OUTPUT BIT 19

OUTPUT BIT 20

OUTPUT BIT 21

OUTPUT BIT 22

OUTPUT BIT 23

OUTPUT BIT 24

OUTPUT BIT 25

OUTPUT BIT 26

OUTPUT BIT 27

OUTPUT BIT 28

OUTPUT BIT 29

OUTPUT BIT 30

OUTPUT BIT 31

OUTPUT BIT 32

OUTPUT BIT 33

OUTPUT BIT 34

DATA ENABLE

DATA IN

CLOCK IN

Figure 3a, 3b.

V

OUTPUT BIT 17

OUTPUT BIT 16

OUTPUT BIT 15

OUTPUT BIT 14

OUTPUT BIT 13

OUTPUT BIT 12

OUTPUT BIT 11

OUTPUT BIT 10

OUTPUT BIT 9

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

1 40

SS

2 39

3 38

4 37

5 36

6 35

7 34

8 33

9 32

10 31

11 30

12 29

13 28

14 27

15 26

16 25

17 24

18 23

19 22

20 21

DD

MM5451BN/YN

OUTPUT BIT 18

OUTPUT BIT 19

OUTPUT BIT 20

OUTPUT BIT 21

OUTPUT BIT 22

OUTPUT BIT 23

OUTPUT BIT 24

OUTPUT BIT 25

OUTPUT BIT 26

OUTPUT BIT 27

OUTPUT BIT 28

OUTPUT BIT 29

OUTPUT BIT 30

OUTPUT BIT 31

OUTPUT BIT 32

OUTPUT BIT 33

OUTPUT BIT 34

OUTPUT BIT 35

DATA IN

CLOCK IN

February 2006

2

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Connection Diagram: Plastic Leaded Chip Carrier

OUTPUT BIT 13

OUTPUT BIT 12

OUTPUT BIT 11

OUTPUT BIT 10

OUTPUT BIT 9

NC

OUTPUT BIT 8

OUTPUT BIT 7

OUTPUT BIT 6

OUTPUT BIT 5

OUTPUT BIT 4

6 44 43 42 41 40

7

8

9

10

11

12

13

14

15

16

17

12393384375

MM5450BV/YV

232221201918 24 25 26 27 28

OUTPUT BIT 23

OUTPUT BIT 24

OUTPUT BIT 25

36

OUTPUT BIT 26

35

OUTPUT BIT 27

34

NC

33

OUTPUT BIT 28

32

OUTPUT BIT 29

31

OUTPUT BIT 30

30

OUTPUT BIT 31

29

OUTPUT BIT 32

February 2006

12393384375

MM5451BV/YV

232221201918 24 25 26 27 28

OUTPUT BIT 23

OUTPUT BIT 24

OUTPUT BIT 25

36

OUTPUT BIT 26

35

OUTPUT BIT 27

34

NC

33

OUTPUT BIT 28

32

OUTPUT BIT 29

31

OUTPUT BIT 30

30

OUTPUT BIT 31

29

OUTPUT BIT 32

OUTPUT BIT 13

OUTPUT BIT 12

OUTPUT BIT 11

OUTPUT BIT 10

OUTPUT BIT 9

NC

OUTPUT BIT 8

OUTPUT BIT 7

OUTPUT BIT 6

OUTPUT BIT 5

OUTPUT BIT 4

6 44 43 42 41 40

7

8

9

10

11

12

13

14

15

16

17

Figure 4a, 4b.

3

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Absolute Maximum Ratings

Operating Ratings

Voltage (any pin) ........................................VSS to VSS + 12V

Power Dissipation

+25°C........................................................................1W

+85°C................................................................. 560mW

Junction Temperature (T
Storage Temperature (T

) .......................................+150°C

J

).........................–65°C to +150°C

S

Lead Temperature (soldering, 10sec.)..................... +300°C

Supply voltage (VDD – VSS).......................... +4.75V to +11V

Ambient Temperature Range (T

) .............–40°C to +85°C

A

Electrical Characteristics

4.5V ≤ V

Symbol Parameter Condition Min Typ Max Units

Power Supply Current

V

L

V

H

Brightness Control Input Current

Brightness Control Input Voltage input current = 750 µA

Output Matching

fC Clock Input Frequency

tH Clock Input High Time

tL Clock Input Low Time

tDS Data Input Setup Time

tDH Data Input Hold Setup Time

t

DES

Reset Pad Current die

Notes:

1. Output matching is calculated as the percent variation (I

2. With a fixed resistor on the brightness input pin, some variation in brightness will occur among devices.

3. See Figures 7, 8 and 9 for recommended operating conditions and limits. Absolute maximum for each output should be limited to 40mA.

4. V

OUT

5. AC input waveform specification for test purpose: t

6. Clock input rise and fall times must not exceed 300ns.

≤ 11V, VSS = 0V; T

DD

Data Input Voltage

Data Enable Input Setup Time

should be regulated by user. See Figures 8 and 9 for allowable V

= 25°C, bold values indicate –40°C ≤ T

A

–25°C to +85°C, excluding output loads
–40°C to +85°C, excluding output loads

logic-0 level, ±10 µA input bias
logic-1 level, 4.75V ≤ VDD ≤ 5.25V
V

> 5.25V

DD

Note 2 0

segment off, V

segment on, V
brightness input = 0µA
brightness input = 100µA
brightness input = 750µA

Note 1
Notes 5, 6
Notes 5, 6 950
Notes 5, 6 950

+ I

MIN

) / 2.

MAX

≤ 200ns, tF ≤ 20ns, f = 500kHz, 50% ±10% duty cycle.

R

= 3.0V

OUT

= 1.8V, Note 3

OUT

vs. I

OUT

OUT

≤ +85°C, unless otherwise noted.

A

–0.3

2.2
–2

V

DD

0

2.0

15

3.0

300
300
100

8

operation.

2.7

8.5
10

0.8

V

DD

VDD

0.75
10

10

4

25

4.3
±20
500

mA
mA

V
V
V

mA

µA Output Sink Current

µA
mA
mA

V

%

kHz

ns

ns

ns
ns
ns

8 µA

February 2006

4

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Functional Description

The MM5450 and MM5451 were designed to drive either
4- or 5-digit alphanumeric LED displays with the added
benefit of requiring minimal interface with the display or
data source.

Data is transferred serially via 2 signals; clock and serial
data. Data transfer without the added inconvenience of
an external load signal is accomplished by using a
format of a leading “1”followed by the allowed 35 data
bits. These 35 data bits are latched after the 36th has
been transferred. This scheme provides non multiplexed,
direct drive to the LED display. Characters currently
displayed (thus, data output) changes only if the serial
data bits differ from those previously transferred.

The MIC37252 regulator is fully protected from damage
due to fault conditions. Current limiting is provided. This
limiting is linear; output current during overload
conditions is constant. Thermal shutdown disables the
device when the die temperature exceeds the maximum
safe operating temperature. Transient protection allows
device (and load) survival even when the input voltage
spikes above and below nominal. The output structure of
these regulators allows voltages in excess of the desired
output voltage to be applied without reverse current flow.

Control of the output current for LED displays provides
for the display brightness. To prevent oscillations, a 1nF
capacitor should be connected to pin 19, brightness
control.

The block diagram is shown in Figure 1. For the
MIC5450, the /DATA ENABLE is a metal option and is
used instead of the 35th output. The output current is
typically 20-times greater that the current into pin 19,
which is set by an external variable resistor.

There is an external reset connection shown which is
available on unpackaged (die) only. Figure 2 illustrates
the die pad locations for bonding in “chip on board”
applications.

Figure 5 shows the input data format. A leading “1” is
followed by 35 bits of data. After the 36th had been
transferred, a LOAD signal is generated synchronously
with the clock high state. This loads the 35 bits of data
into the latches. The low side of the clock is used to
generate a RESET signal which clears all shift registers
for the next set of data. All shift registers are static
master-slave, with no clear for the master portion of the
first register, allowing continuous operation.

There must be a complete set of 36 clocks or the shift
registers will not clear.

When the chip first powers ON, an internal power ON
reset signal is generated which resets all registers and
all latches. The START bit and the first clock return the
chip to its normal operation.

Figure 3 and 4 show the pinout of the MIC5450 and
MIC5451. Bit 1 is the first bit following the start bit and it
will appear on pin 18. A logical “1” at the input will turn
on the appropriate LED.

Figure 5 shows the timing relationships between data,
clock and /DATA ENABLE. A maximum clock frequency
of 0.5MHz is assumed.

For applications where a lesser number of outputs are
used, it is possible to either increase the current per
output, or operate the part at higher than 1V V

OUT

. The

following equation can be used for calculations.

T

= (V

J

OUT

) (I

) (No. of segments) (124°C/W) + TA

LED

where:
T

= junction temperature + 150°C max

J

V

= the voltage at the LED driver outputs

OUT

= the LED current

I

LED

124°C/W = thermal resistance of the package
T

= ambient temperature

A

February 2006

The above equation was used to plot Figures 7–9.

5

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Figure 5.

Figure 6. Input Data Format

February 2006

6

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Typical Performance Characteristics

A

J

2

0

S

E

G

M

Figure 7.

OTUO

LED

Figure 8.

Figure 9.

Typical Applications

240

5k

I19=

7V

1k

I

19

–

1K

LM324

+

5V

20

1

2N2907

PIN 19

MM5450

CD4046

(VCO)

7

5V

MM74HC123

10 µS

Q19

20

MM5450

1

M9999-021606

[phone]

RAW DC

> 9 V

LM317

Figure 10. Typical Application of Constant Current Figure 11. Brightness Control Varying the Duty Cycle
Brightness Control

February 2006

Micrel, Inc. MM5450/5451

Typical Applications

LED DISPLAY

AM

FM

34

MM5450

DISPLAY DRIVER

ELECTRONIC

KEYBOARD

TUNING

CONTROLLER

SYNTHESIZER

STATION DETECT, ETC.

Figure 12. Basic Electronically Tuned Radio System

V

=3.0V V

LED

V

LED

V

LED

PLL

LED

=3.0V

February 2006

CLOCK IN

DATA IN

9–16 2–8,40 32–39 24–31

MM5450

18

21 22 19 20 1 23 17

V

BRIGHTNESS

CONTROL

100k
TYP.

DD

Figure 13. Duplexing 8 Digits with One MM5450

8

M9999-021606

[phone]

Micrel, Inc. MM5450/5451

Package Information

40-Pin Plastic DIP (N)

44-Pin PLCC (V)

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL [phone] FAX [phone] WEB http:/www.micrel.com

The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product

can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant

into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A

Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully

February 2006

use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.

indemnify Micrel for any damages resulting from such use or sale.

© 2002 Micrel, Incorporated.

9

M9999-021606

[phone]