AS1100PL austriamicrosystems, AS1100PL Datasheet - Page 12

• Manufacturer Part Number: AS1100PL
• Description: IC LED 8-DIGIT DRIVER 24-PDIP
• Manufacturer: austriamicrosystems

Specifications of AS1100PL

• Display Type: LED
• Configuration: 7 Segment + DP
• Interface: Serial
• Digits Or Characters: 8 Digits
• Current - Supply: 330mA
• Voltage - Supply: 4 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 24-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AS1100
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9.4 Calculating the Power Dissipation
The upper limit for power dissipation (PD) for the AS1100 is determined from the following equation:
Where:
V
DUTY = duty cycle set by intensity register
N = number of segments driven (worst case is 8)
V
I
Dissipation Example:
I
PD = 5.25V(0.5mA) + (5.25V - 1.8V)(31/32 x 40mA x 8) = 1.07W
Thus, for a PDIP package θ
Where:
T
The T
Table 16. Package Thermal Resistance Data
www.austriamicrosystems.com/LED-Driver-ICs/AS1100
SEG
SEG
A
DD
LED
T
= +69.7°C.
J,MAX
= supply voltage
= segment current set by R
= 40mA, N = 8, DUTY = 31/32, VLED = 1.8V at 40mA, V
A
= LED forward voltage
limit for SO Packages in the dissipation example above is +59.0°C.
= T
A
+ PD x θ
JA
= 150°C = T
JA
24 Narrow DIP
24 Wide SO
= +75°C/W (from Table 13), the maximum allowed ambient temperature T
Package
SET
A
PD = (V
+1.07W x 75°C/W.
DD
Maximum Junction Temperature (T
Maximum Ambient Temperature (T
x 0.5mA) + (V
DD
DD
= 5.25V
Revision 1.36
- V
LED
)(DUTY x I
J
A
) = +150ºC
) = +85ºC
SEG
x N)
Thermal Resistance (θ
+75ºC/W
+85ºC/w
A
is given by:
JA
)
(EQ 1)
12 - 17