AS1108-WL ams, AS1108-WL Datasheet - Page 13

• 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
9 Typical Application
Supply Bypassing and Wiring
In order to achieve optimal performance the AS1108 should be placed very close to the LED display to minimize
effects of electromagnetic interference and wiring inductance.
Furthermore, a 10µF electrolytic and a 0.1µF ceramic capacitor should be connected between pins V
avoid power supply ripple (see Figure 12 on page 15).
Note: Both GND pins must be connected to ground.
Selecting R
Brightness of the display segments is controlled via R
current that flows through the LEDs.
Segment current is about 200 times the current in I
ing voltages, and LED voltage drop (V
40mA. If higher currents are needed, external drivers must be used, in which case it is no longer necessary that the
device drive high currents.
In cases where the device drives only a few digits, Table 16 specifies the maximum currents, and R
accordingly.
Note: The display brightness can also be logically controlled (see Selecting RSET Resistor Value and Using External
Table 19. R
Table 20. R
Table 21. R
Table 22. R
www.austriamicrosystems.com/LED-Driver-ICs/AS1108
I
I
I
I
SEG
SEG
SEG
SEG
40
30
20
10
40
30
20
10
40
30
20
10
40
30
(mA)
(mA)
(mA)
(mA)
Drivers on page 13).
SET
SET
SET
SET
vs. Segment Current and LED Forward Voltage, V
vs. Segment Current and LED Forward Voltage, V
vs. Segment Current and LED Forward Voltage, V
vs. Segment Current and LED Forward Voltage, V
SET
11.6kΩ
10.18kΩ
8.6kΩ
10.7kΩ
22.2kΩ
13.9kΩ
28.8kΩ
15.6kΩ
31.9kΩ
6.9kΩ
6.7kΩ
9.1kΩ
7.5kΩ
Resistor Value and Using External Drivers
1.5
5kΩ
1.5
1.5
1.5
V
LED
(V)
LED
11.2kΩ
8.3kΩ
2.0
V
) are given in Tables 19 - 23. The maximum current the AS1108 can drive is
20.7kΩ
13.3kΩ
27.7kΩ
4.4kΩ
5.9kΩ
9.6kΩ
6.4kΩ
8.8kΩ
7.2kΩ
9.8kΩ
15kΩ
31kΩ
LED
2.0
2.0
2.0
(V)
SET
V
LED
SET
. Typical values for R
Revision 2.12
(V)
V
. The current that flows between V
10.8kΩ
7.9kΩ
LED
2.5
(V)
12.6kΩ
14.3kΩ
29.5kΩ
5.7kΩ
8.1kΩ
6.6kΩ
9.2kΩ
26kΩ
2.5
2.5
DD
DD
DD
DD
= 2.7V
= 3.3V
= 3.6V
= 4.0V
SET
7.6kΩ
9.9kΩ
3.0
for different segment currents, operat-
27.3kΩ
5.5kΩ
7.5kΩ
13kΩ
3.0
DD
and I
5.2kΩ
7.8kΩ
3.5
SET
SET
DD
must be set
defines the
and GND to
13 - 19