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MAX7219CNG

MAX7219CNG - 8-Digit LED Display Driver, 24-PDIP | Maxim

The Analog Devices (formerly Maxim Integrated) MAX7219CNG is a compact, serial-input/output common-cathode LED display driver that interfaces microprocessors to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Housed in a 24-pin PDIP (narrow, 0.300 inch / 7.62 mm) through-hole package, the device operates from a single +4.0 V to +5.5 V supply and includes on-chip BCD Code-B decoder, multiplex scan circuitry, segment and digit drivers, plus an 8x8 static RAM that stores the display state. A serial-in/serial-out LED driver is an interface IC that translates a high-speed synchronous serial data stream (SPI/QSPI/Microwire compatible on MAX7219) into multiplexed constant-current segment and digit outputs, eliminating the need for external current-limiting resistors on every LED. The MAX7219 belongs to the broader hierarchy LED display driver > display driver IC > interface IC > integrated circuit > semiconductor. Its integrated BCD decoder, multiplexing scan engine, and per-segment current control place it in the same functional family as the MAX7221 (SPI-only variant) and competitors such as Holtek HT16K33 and Titan Micro TM1637. Key features of the MAX7219CNG include an individual LED segment current programmable up to 40 mA per segment via a single external resistor (ISET), a 150 µA low-power shutdown mode (data retained), a scan-limit register that allows 1 to 8 digits, a digital brightness control (16 steps via 4-bit PWM duty cycle), and a display test mode that forces all segments on. The serial interface runs up to 10 MHz at +5 V, and the device cascades for additional digits by clocking the DOUT pin into the DIN of the next MAX7219. Typical applications are 8-digit 7-segment numeric readouts, 8x8 LED matrix modules (two cascaded MAX7219s drive a 64-LED matrix), bar-graph displays, industrial panel meters, scoreboard displays, and Arduino/AVR/PIC-based user interfaces. The MAX7219 is essentially the de-facto standard for hobbyist and educational LED matrix projects, with mature open-source libraries (LedControl, MD_MAX72XX, MD_Parola) supporting it. When designing with the MAX7219CNG, place a 0.1 µF bypass capacitor close to V+ and a 10 µF tantalum bulk capacitor on the supply rail, keep the ISET resistor within 9.53 kΩ (40 mA per segment) to 47 kΩ (10 mA per segment), and respect the 6 V absolute-maximum V+ rating. The narrow PDIP-24 footprint is identical to the MAX7221CNG and MAX7219CNG+ RoHS-compliant variant, so PCBs can be designed once and populated with either part.