AS1108-WL ams, AS1108-WL Datasheet - Page 15

• Manufacturer Part Number: AS1108-WL
• Description: LED Display Drivers
• Manufacturer: ams

Specifications of AS1108-WL

• Rohs: yes
• Number Of Digits: 4
• Number Of Segments: 7
• Mounting Style: SMD/SMT
• Package / Case: SOIC-20
• Operating Supply Voltage: 5 V
• Maximum Supply Current: 1 mA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Number Of Leds: 1
• Power Dissipation: 941 mW

AS1108
Datasheet - Ty p i c a l A p p l i c a t i o n
4x8 LED Dot Matrix Driver
The application example in Figure 12 shows the AS1108 as a 4x8 LED dot matrix driver.
The LED columns have common cathodes and are connected to the DIG0:3 outputs. The rows are connected to the
segment drivers. Each of the 32 LEDs can be addressed separately. The columns are selected via the digits as listed
in Table 7 on page 8.
The Decode Enable Register (see page 9) must be set to ‘00000000’ as described in Table 9 on page 9. Single LEDs
in a column can be addressed as described in Table 12 on page 10, where bit D0 corresponds to segment G and bit
D7 corresponds to segment DP.
Note: For a multiple-digit dot matrix, multiple AS1108 devices must be cascaded.
Figure 12. Application Example as LED Dot Matrix Driver
Cascading Drivers
If more than 4 digits or 32 LEDs are needed, it is recommended to use the AS1106/AS1107, although several AS1108
devices can be cascaded.
The example in Figure 4 drives 2 dot matrix digits using a 4-wire microprocessor interface. All Scan-Limit Registers
should be set to the same value so that one display will not appear brighter than the other.
For example, to display 6 digits, set both Scan-Limit Registers to display 3 digits so that both displays have a 1/3 duty
cycle per digit. If 5 digits are needed, set both Scan-Limit Registers to display 3 digits and leave one digit unconnected.
Otherwise, if one driver is set to display 3 digits and the other to display 2 digits one display will appear brighter
because its duty cycle per digit will be 1/2 and the other display’s duty cycle will be 1/3.
Note: Refer to No-Op Register (0xX0) on page 12 for additional information.
www.austriamicrosystems.com/LED-Driver-ICs/AS1108
Processor
Diode Arrangement
Micro-
SEG A:G
SEG DP
GND
LOAD/CSN
CLK
DIN
SEG DP
AS1108
SEG G
SEG D
SEG C
SEG F
SEG E
SEG B
SEG A
GND
DIG0:3
DOUT
ISET
VDD
Dot Matrix
4x8 LED
9.53kΩ
Revision 2.12
V
BAT
SEG A:G
SEG DP
GND
CLK
DIN
LOAD/CSN
AS1108
SEG DP
SEG G
SEG D
SEG C
SEG E
SEG B
SEG A
SEG F
GND
DIG0:3
ISET
VDD
Dot Matrix
4x8 LED
9.53kΩ
V
BAT
15 - 19