PCA9626B NXP Semiconductors, PCA9626B Datasheet - Page 32

• Manufacturer Part Number: PCA9626B
• Description: IC, LED DRIVER, RGBA, 48-LQFP
• Manufacturer: NXP Semiconductors

Specifications of PCA9626B

• No. Of Outputs: 24
• Output Current: 100mA
• Output Voltage: 40V
• Input Voltage: 2.3V To 5.5V
• Dimming Control Type: PWM
• Driver Case Style: LQFP
• Switching Frequency: 1MHz
• Base Number: 9626
• Operating: RoHS Compliant
• Led Driver Application: RGB Or RGBA LED Drivers, LED Status Information, Displays, Backlights
• Rohs Compliant: Yes
• Lead Free Status / Rohs Status: Details

NXP Semiconductors
1.
PCA9626_2
Product data sheet
50 C is a typical temperature inside an enclosed system. The designers should feel free, as needed, to perform their own
calculation using the examples.
10.1 Junction temperature calculation
T
T
A device junction temperature can be calculated when the ambient temperature or the
case temperature is known.
When the ambient temperature is known, the junction temperature is calculated using
Equation 4
power dissipation.
where:
When the case temperature is known, the junction temperature is calculated using
Equation 5
dissipation.
where:
Here are two examples regarding how to calculate the junction temperature using junction
to case and junction to ambient thermal resistance. In the first example
given the operating condition and the junction to ambient thermal resistance, the junction
temperature of PCA9626B, in the LQFP48 package, is calculated for a system operating
condition in 50 C
on a specific customer application requirement where only the case temperature is
known, applying the junction to case thermal resistance equation, the junction
temperature of the PCA9626B, in the LQFP48 package, is calculated.
j
j
T
T
R
P
T
T
R
P
=
=
j
amb
j
case
tot
tot
th(j-a)
th(j-c)
= junction temperature
= junction temperature
T
T
= (device) total power dissipation
= (device) total power dissipation
amb
case
= ambient temperature
= case temperature
= junction to case thermal resistance
= junction to ambient thermal resistance
+
+
and the ambient temperature, junction to ambient thermal resistance and
and the case temperature, junction to case thermal resistance and power
R
R
th j-a
th j-c
1
ambient temperature. In the second example
P
P
Rev. 02 — 31 August 2009
tot
tot
24-bit Fm+ I
2
C-bus 100 mA 40 V LED driver
(Section
PCA9626
© NXP B.V. 2009. All rights reserved.
(Section
10.1.2), based
10.1.1),
32 of 47
(4)
(5)