MAX7221 Datasheet

• 10MHz Serial Interface
• Individual LED Segment Control
• Decode/No-Decode Digit Selection
• 150µA Low-Power Shutdown (Data Retained)
• Digital and Analog Brightness Control
• Display Blanked on Power-Up
• Drive Common-Cathode LED Display
• Slew-Rate Limited Segment Drivers for Lower EMI (MAX7221)
• SPI, QSPI, MICROWIRE Serial Interface (MAX7221)
• 24-Pin DIP and SO Packages

• Bar Graph Displays
• Industrial Controllers
• LED Matrix Displays
• Panel Meters

The MAX7221 are compact, serial input/output common-cathode display drivers that interface microprocessors (µPs) to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. Included on-chip are a BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8x8 static RAM that stores each digit. Only one external resistor is required to set the segment current for all LEDs. The MAX7221 is compatible with SPI™, QSPI™, and MICROWIRE™, and has slew-rate-limited segment drivers to reduce EMI.

A convenient 4-wire serial interface connects to all common µPs. Individual digits may be addressed and updated without rewriting the entire display. The MAX7221 also allow the user to select code-B decoding or no-decode for each digit.

The devices include a 150µA low-power shutdown mode, analog and digital brightness control, a scan-limit register that allows the user to display from 1 to 8 digits, and a test mode that forces all LEDs on.

For applications requiring 3V operation or segment blinking, refer to the MAX6951 data sheet.