The MAX6958/MAX6959 compact multiplexed common-
cathode display drivers interface microprocessors
to seven-segment numeric LED digits, or discrete LEDs
through an SMBus™- and I²C-compatible 2-wire serial
interface. The 2-wire serial interface uses fixed
0.8V/2.1V logic thresholds for compatibility with 2.5V
and 3.3V systems when the display driver is powered
from a 5V supply.
The MAX6958/MAX6959 drive up to four 7-segment
digits, with decimal points, plus four discrete LEDs, or
four 7-segment digits and eight discrete LEDs if the
digits' decimal points are not used, or up to 36 discrete
LEDs. The MAX6959 also includes two input ports, one
or both of which may be configured as a key-switch
reader, which automatically scans and debounces a
matrix of up to eight switches. Key-switch status is
obtained by polling internal status registers or by configuring
the MAX6959 interrupt output.
Other on-chip features include a hexadecimal font for
seven-segment displays, multiplex scan circuitry,
anode and cathode drivers, and static RAM that stores
each digit. The peak segment current for the display
digits is set internally to 23mA. Display intensity is
adjusted using a 64-step internal digital brightness control.
The MAX6958/MAX6959 include a low-power shutdown
mode, a scan-limit register that allows the user to
display from one to four digits, and a test mode, which
forces all LEDs on. The LED drivers are slew-rate-limited
to reduce EMI.
The MAX6958/MAX6959 are available in 16-pin PDIP
and QSOP packages and are fully specified over the
-40°C to +125°C automotive temperature range.
Key Features
Applications/Uses
400kbps 2-Wire Serial Interface
3V to 5.5V Operation
Drive 4 Digits plus 4 or 8 Discrete LEDs
Drive Common-Cathode LED Digits
23mA Constant-Current LED Segment Drive
Hexadecimal Decode/No-Decode Digit Selection
64-Step Digital Brightness Control
Slew-Rate-Limited Segment Drivers Reduced EMI
Debounces Up to Eight Switches with n-Key
Rollover (MAX6959 Only)
IRQ Output When a Key Input Is Debounced
(MAX6959 Only)
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