2-Wire Interfaced, 3V to 5.5V, 4-Digit, 9-Segment LED Display Drivers with Keyscan

 

Part Number	Replacement	Explanation

Description

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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.

MAX6958, MAX6959: Typical Operating Circuit Enlarge+

Key Features

• 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)
• 20µA Low-Power Shutdown (Data Retained)
• Automotive Temperature Range (-40°C to +125°C)
• Compact 16-Pin PDIP and QSOP Packages

Applications/Uses

• Audio/Video Equipment
• Industrial Controls
• Panel Meters
• Set-Top Boxes
• Vending Machine
• White Goods