The MAX6950/MAX6951 are compact common-cathode display drivers that interface microprocessors to individual 7-segment numeric LED digits, bar graph, or discrete LEDs through an SPI™-, QSPI™-, MICROWIRE™-compatible serial interface. The supply voltage can be as low as 2.7V.
The MAX6950 drives up to five 7-segment digits or 40 discrete LEDs. The MAX6951 drives up to eight 7-segment digits or 64 discrete LEDs.
Included on-chip are hexadecimal character decoders (0-9, A-F), multiplex scan circuitry, segment and digit drivers, and a static RAM that stores each digit. The user may select hexadecimal decoding or no-decode for each digit to allow any mix of 7-segment digits, bar graph, or discrete LEDs to be driven. The segment current for the LEDs is set by an internal digital brightness control. The segment drivers are slew-rate limited to reduce EMI.
Individual digits may be addressed and updated without rewriting the entire display. The devices include a low-power shutdown mode, digital brightness control, a scan-limit register that allows the user to display from one to eight digits, segment blinking that can be synchronized across drivers, and a test mode that forces all LEDs on.