What Is the MAX7219? Serial LED Driver: 7-Segment/Matrix and Uses
The MAX7219 is a serial LED display driver that drives many LEDs with few pins. It drives an 8-digit 7-segment display or an 8×8 matrix over an SPI-like 3-wire bus (DIN/CLK/CS) and can be daisy-chained. A single Rset resistor sets the current (brightness) of all LEDs and scanning is done on-chip — unlike the 74HC595, no per-LED resistor is needed.
The MAX7219 is a serial LED display driver that drives many LEDs with few pins. It drives an 8-digit 7-segment display or an 8×8 LED matrix from one chip over a 3-wire SPI-like bus and can be daisy-chained. For the concept, see what is an LED driver.
What is the MAX7219 used for?
7-segment clock/counter displays and 8×8 LED matrix panels (scrolling text, icons). Only 3 MCU pins (DIN, CLK, CS/LOAD) are needed; chaining several MAX7219s builds large panels. A single external resistor (Rset) sets the current (brightness) of all LEDs — unlike the 74HC595, no per-LED resistor is needed.
Highlights
| Parameter | Value |
|---|---|
| Drives | 8-digit 7-segment or 8×8 matrix (64 LEDs) |
| Interface | SPI-like (DIN, CLK, LOAD/CS) |
| Current | Constant-current, set by one Rset |
| Brightness | Set in software (digital) |
| Chaining | DOUT → next DIN |
Limitations
- Drives common-cathode LEDs/matrix only.
- Not a color/graphic display (use OLED/TFT for that).
- The Rset resistor must be chosen for the LED type (wrong current = lifetime/brightness issues).
Equivalents and alternatives
- MAX7221: the SPI-compatible, lower-EMI version.
- HT16K33: an I2C LED matrix/segment driver.
- TM1637: a cheap 4-digit 7-segment driver.
- 74HC595: general-purpose output expansion.
Find it in our catalog
Use the MAX7219 search.