AS1115 DB-YELLOW austriamicrosystems, AS1115 DB-YELLOW Datasheet - Page 19

• Manufacturer Part Number: AS1115 DB-YELLOW
• Description: BOARD DEMO AS1115 YELLOW
• Manufacturer: austriamicrosystems

Specifications of AS1115 DB-YELLOW

• Current - Output / Channel: *
• Outputs And Type: 8, Non-Isolated
• Voltage - Output: *
• Features: 64 LED + 16 keys, I⊃2C
• Voltage - Input: 2.7 ~ 5.5 V
• Utilized Ic / Part: AS1115
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption

AS1115
Datasheet - Ty p i c a l A p p l i c a t i o n
9 Typical Application
Selecting R
Brightness of the display segments is controlled via R
through the LEDs.
Segment current is about 200 times the current in I
ing voltages, and LED voltage drop (V
drive is 47mA. If higher currents are needed, external drivers must be used, in which case it is no longer necessary
that the devices drive high currents.
Note: The display brightness can also be logically controlled
Table 22. R
Table 23. R
Calculating Power Dissipation
The upper limit for power dissipation (PD) for the AS1115 is determined from the following equation:
Where:
V
DUTY is the duty cycle set by intensity register
N is the number of segments driven (worst case is 8)
V
I
Dissipation Example:
Thus, for a TQFN(4x4)-24 package
In this example the maximum ambient temperature must stay below 123.61°C.
www.austriamicrosystems.com/LED-Driver-ICs/AS1115
SEG
(mA)
I
I
DD
LED
SEG
SEG
40
30
20
10
is the supply voltage.
= segment current set by RSET
40
30
20
10
is the LED forward voltage
(mA)
36.89k Ω 35.7k Ω
17.7k Ω
11.6k Ω
8.6k Ω
SET
SET
1.5V
vs. Segment Current and LED Forward Voltage, V
vs. Segment Current and LED Forward Voltage, V
SET
10.7k Ω
22.2k Ω
6.9k Ω
1.5V
5k Ω
Resistor Value and Using External Drivers
17.3k Ω
11.2k Ω
I
8.3k Ω
SEG
2.0V
T
J,MAX
V
LED
= 40mA, N = 8, DUTY = 15/16, V
PD = 5V(5mA) + (5V - 2.2V)(15/16 x 40mA x 8) = 0.865W
20.7k Ω
4.4k Ω
5.9k Ω
9.6k Ω
PD = (V
= T
2.0V
10.8k Ω
16.6k Ω 15.6k Ω 13.6k Ω
34.5k Ω 32.5k Ω 29.1k Ω
V
7.9k Ω
2.5V
LED
AMB
Θ
DD
JA
+ PD x
LED
= +30.5°C/W, the maximum allowed T
x 5mA) + (V
7.6k Ω
9.9k Ω
) are given in
3.0V
13.9k Ω
28.8k Ω
6.7k Ω
9.1k Ω
1.5V
Θ
JA
(page
= 150°C = T
5.2k Ω
7.8k Ω
SET
3.5V
DD
SET
17).
. Typical values for R
13.3k Ω
27.7k Ω
6.4k Ω
8.8k Ω
Table 22
Revision 1.07
V
2.0V
- V
. The current that flows into I
LED
LED
LED
AMB
11.35k Ω 11.12k Ω 10.84k Ω 10.49k Ω 10.2k Ω 9.9k Ω
)(DUTY x I
(see Intensity Control Register (0x0A) on page
15.4k Ω
23.6k Ω
48.9k Ω
= 2.2V at 40mA, V
1.5V
&
12.6k Ω
5.7k Ω
8.1k Ω
26k Ω
DD
DD
+ 0.865W x 30.5°C/W
Table
2.5V
= 2.7V & 3.3V & 3.6V
= 4.0V & 5.0V
15.1k Ω
23.1k Ω
47.8k Ω
23. The maximum current the AS1115 can
SEG
2.0V
SET
x N)
10.18k Ω
AMB
15.6k Ω
31.9k Ω
for different segment currents, operat-
7.5k Ω
1.5V
DD
14.7k Ω
22.6k Ω
46.9k Ω
is given by:
2.5V
SET
= 5V
V
defines the current that flows
LED
7.2k Ω
9.8k Ω
15k Ω
31k Ω
2.0V
14.4k Ω 13.6k Ω 13.1k Ω
45.4k Ω 43.8k Ω 42k Ω
22k Ω
3.0V
V
LED
14.3k Ω
29.5k Ω
6.6k Ω
9.2k Ω
21.1k Ω 20.2k Ω
2.5V
3.5V
16).
27.3k Ω
5.5k Ω
7.5k Ω
13k Ω
(EQ 1)
(EQ 2)
(EQ 3)
(EQ 4)
3.0V
4.0V
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