Skip to main content


MAX7219 – 8-Digit LED Display Driver IC

[Click the image to enlarge it]

The MAX7219 is an IC designed to control a 8x8 LED MATRIX. The IC is serial input common-cathode (Common Negative) display drivers that interface microprocessors (or microcontroller) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs.

 

Pin configuration

MAX7219 is a 24-pin IC available in different packages and is selected depending on the requirements. The description for each pin is given below.

Pin Number

Description

COMMON CATHODE OF DISPLAY SEGMENTS

2

DIG0- Common ground for all eight segments of DIGIT0

11

DIG1- Common ground for all eight segments of DIGIT1

6

DIG2- Common ground for all eight segments of DIGIT2

7

DIG3- Common ground for all eight segments of DIGIT3

3

DIG4- Common ground for all eight segments of DIGIT4

10

DIG5- Common ground for all eight segments of DIGIT5

5

DIG6- Common ground for all eight segments of DIGIT6

8

DIG7- Common ground for all eight segments of DIGIT7

SHARED TERMINALS

4

GND

19

V+- Power Supply

SHARED SEGMENT TERMINAL OF ALL EIGHT DIGITS

14

SEG A – SEGEMTENT A  of all DIGITS

16

SEG B – SEGEMTENT B  of all DIGITS

20

SEG C – SEGEMTENT C  of all DIGITS

23

SEG D – SEGEMTENT D  of all DIGITS

21

SEG E – SEGEMTENT E  of all DIGITS

15

SEG F – SEGEMTENT F  of all DIGITS

17

SEG G – SEGEMTENT G  of all DIGITS

22

SEG DP – SEGEMTENT DOT of all DIGITS

FUNCTION PINS

1

DIN -  Serial Data Input Pin

12

LOAD(CS) – Chip Select or Data shift pin

13

CLK -  Clock Pin

24

DOUT -  Pin used to Connect Second chip serially

18

ISET -  current output adjust pin

 

Features and Specifications

  • Operating voltage range: +4.0 to +5.5V
  • Recommended operating voltage: +5V
  • Maximum supply voltage: 6V
  • Maximum current allowed to draw through each segment pin: 100mA
  • Maximum current allowed to  through each DIGIT ground pin: 500mA
  • Low power consumption
  • Data-to-Segment Delay Time: 2.2mSec
  • Operating temperature: 0°C  to +70°C
  • Storage Temperature: -65°C  to +150°C

 

Similar ICs

74HC595

 

Where to use MAX7219 IC

1. Thsis IC is basically used where you want to convert serial data to parallel data.

2. The chip is used to reduce I/O pin usage of controller or processor.

3. Used to control 64 LEDs using only 3 PINS

4. Preferred when controller 7 Segment Displays. The chip can control up to 8 DIGIT.

5. Can be used to control more display segments by connecting more chips in serial.

 

How to use MAX7219 IC

The chip is used similar to any shift register. First we will send serial data to chip bit by bit .once all data is sent we will tell chip to shift this serial data to output by enabling CS pin. The step by step procedure of working goes as below.

  • First connect DIN, CS and CLK pin. These three pins are important to controlling chip.
  • Next is selecting resistor for ISET pin. As we know that there is no standard parameter for segment displays in market. They have different voltage and current setting. In order to drive the display without error we will choose the appropriate resistor by using the following table.

Forward voltage

ISeg

1.5V

2.0V

2.5V

3.0V

3.5V

40mA

12.2kΩ

11.8kΩ

11.0kΩ

10.6kΩ

9.69kΩ

30mA

17.8kΩ

17.1kΩ

15.8kΩ

15.0kΩ

14.0kΩ

20mA

29.8kΩ

28.0kΩ

25.9kΩ

24.5kΩ

22.6kΩ

10mA

66.7kΩ

63.7kΩ

59.3kΩ

55.4kΩ

51.2kΩ

  • There are two ways to use this chip. One is to follow the instructions given in datasheet to send the data bit by bit. Second way is to use libraries previously written for this chip. Using the libraries is easiest way to get the required result.With libraries you can just enter the required data to send without worrying anything.
  • We will send data to the chip through DIN pin. The data is sent BIT by BIT by setting the clock of chip for each bit. The Chip stores the serial data its registers until all data is received. After completing data sending we will set the CS pin for the chip to shift all data stored in its register to the output.
  • Once the data is put out by the chip it will light up the corresponding LEDs to display the result.

                                                                                     

Applications

  • General purpose SHIFT operation
  • Measuring Instruments
  • Digital Electronics
  • Servers
  • Memory units
  • Networking
  • Digital systems

 

Dimensions

Measurements in (Inches/millimeters)

MAX7219 IC Dimensions




Download Datasheet PDF:
MAX7219 IC Datasheet