ADP191ACBZ-R7 datasheet(14/16 Pages) AD

14 / 16 page

ADP190/ADP191

Rev. D | Page 14 of 16

In cases where the board temperature is known, use the thermal

characterization parameter, ΨJB, to estimate the junction temper-

ature rise. Maximum junction temperature (TJ) is calculated

from the board temperature (TB) and power dissipation (PD)

using the formula

TJ = TB + (PD × ΨJB)

(4)

140

120

100

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

VIN – VOUT (V)

MAX JUNCTION TEMPERATURE

LOAD CURRENT = 1mA

LOAD CURRENT = 10mA

LOAD CURRENT = 25mA

LOAD CURRENT = 50mA

LOAD CURRENT = 75mA

LOAD CURRENT = 100mA

LOAD CURRENT = 150mA

Figure 37. ADP190 PCB Layout

Figure 36. TB = 85°C

PCB LAYOUT CONSIDERATIONS

Improve heat dissipation from the package by increasing the

amount of copper attached to the pins of the ADP190/ADP191.

However, as listed in Table 6, a point of diminishing returns is

eventually reached, beyond which an increase in the copper size

does not yield significant heat dissipation benefits.

It is critical to keep the input and output traces as wide and as

short as possible to minimize the circuit board trace resistance.

Figure 38. ADP191 PCB Layout

ADP191ACBZ-R7 Datasheet(PDF) 14 Page - Analog Devices