PCA9622 Datasheet, PDF(24/40 Page) NXP Semiconductors – 16-bit Fm+ I2C-bus 100 mA 40 V LED driver

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PCA9622 Datasheet, PDF (24/40 Pages) NXP Semiconductors – 16-bit Fm+ I2C-bus 100 mA 40 V LED driver

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NXP Semiconductors

PCA9622

16-bit Fm+ I2C-bus 100 mA 40 V LED driver

10.1.1 Example 1: Tj calculation of PCA9622DR, in TSSOP32 package, when Tamb

is known

Rth(j-a) = 83 ï°C/W

Tamb = 50 ï°C

LED output low voltage (LED VOL) = 0.5 V

LED output current per channel = 80 mA

Number of outputs = 16

IDD(max) = 12 mA

VDD(max) = 5.5 V

I2C-bus clock (SCL) maximum sink current = 25 mA

I2C-bus data (SDA) maximum sink current = 25 mA

1. Find Ptot (device total power dissipation):

â output total power = 80 mA ï´ 16 ï´ 0.5 V = 640 mW

â chip core power consumption = 12 mA ï´ 5.5 V = 66 mW

â SCL power dissipation = 25 mA ï´ 0.4 V = 10 mW

â SDA power dissipation = 25 mA ï´ 0.4 V = 10 mW

Ptot = (640 + 66 + 10 + 10) mW = 726 mW

2. Find Tj (junction temperature):

Tj = (Tamb + Rth(j-a) ï´ Ptot) = (50 ï°C + 83 ï°C/W ï´ 726 mW) = 110.26 ï°C

10.1.2 Example 2: Tj calculation where only Tcase is known

This example uses a customerâs specific application of the PCA9622DR, 16-channel LED

controller in the TSSOP32 package, where only the case temperature (Tcase) is known.

Tj = Tcase + Rth(j-c) ï´ Ptot, where:

Rth(j-c) = 23 ï°C/W

Tcase (measured) = 94.6 ï°C

VOL of LED ~ 0.5 V

IDD(max) = 12 mA

VDD(max) = 5.5 V

LED output voltage LOW = 0.5 V

LED output current:

60 mA on 1 port = (60 mA ï´ 1)

50 mA on 6 ports = (50 mA ï´ 6)

40 mA on 2 ports = (40 mA ï´ 2)

20 mA on 7 ports = (20 mA ï´ 7)

I2C-bus maximum sink current on clock line = 25 mA

I2C-bus maximum sink current on data line = 25 mA

PCA9622

Product data sheet

All information provided in this document is subject to legal disclaimers.

Rev. 5 â 2 June 2014

24 of 40

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