AN874 Maxim Integrated Products, AN874 Datasheet - Page 4

• Manufacturer Part Number: AN874
• Description: Using the MAX6950 and the MAX6951 LED Display Drivers with Multiplex Dual-Digit Displays
• Manufacturer: Maxim Integrated Products

*These digits are not available for the MAX6950.
The second solution can be used if all digits' segments are required. This time, hexadecimal-decode
operation can be selected because the standard segment connection pattern is used (Table 4). The
penalty for this configuration is that one diode is required per digit (Figure 2). Each diode is passing
only one segment's current, so it can be a low-cost single signal diode like 1N4148, BAS16 (silicon), or
BAT54, BAR43 (Schottky). Better still, use surface mount dual common-cathode diodes like BAV70
(silicon) and BAT54C (Schottky). The minimum supply voltage to the MAX6950/MAX6951 must also be
raised by the selected diode's forward voltage drop: typically 1.0V for a silicon signal diode or 0.4V for
a Schottky signal diode at 50mA.
LED
Digit
1
LED
Digit
2
LED
Digit
3
LED
Digit
4
LED
Digit
5*
LED
Digit
6*
LED
Digit
7*
LED anode
(cathode to
Discrete
SEG d
SEG d
SEG b
SEG b
SEG f
SEG f
CC0)
SEG g
SEG g
SEG g
SEG g
SEG g
SEG g
CC1
LED anode
(cathode to
Discrete
SEG g
CC2)
SEG f
SEG f
SEG f
SEG f
CC2
LED anode
(cathode to
Discrete
SEG e
SEG e
SEG e
SEG e
SEG f
CC3)
CC3
LED anode
(cathode to
Discrete
SEG e
SEG e
SEG e
SEG d
SEG d
CC4)
CC4
LED anode
(cathode to
Discrete
SEG d
SEG d
SEG d
SEG c
SEG c
CC5)
CC5
LED anode
(cathode to
Discrete
SEG c
SEG c
SEG c
SEG c
SEG c
CC6)
CC6
LED anode
(cathode to
Discrete
SEG b
SEG b
SEG b
SEG b
SEG b
CC7 )
CC7
SEG
SEG
SEG
SEG
SEG
SEG
SEG
a
a
a
a
a
a
a