bd6222 ROHM Co. Ltd., bd6222 Datasheet - Page 12

• Manufacturer Part Number: bd6222
• Description: H-bridge Drivers For Brush Motors
• Manufacturer: ROHM Co. Ltd.

 Thermal design
○
BD6220, BD6221, BD6222, BD6225, BD6226, BD6227
c
www.rohm.com
2009 ROHM Co., Ltd. All rights reserved.
1.5
1.0
0.5
0.0
10.0
8.0
6.0
4.0
2.0
0.0
0
Thermal design needs to meet the following operating conditions.
In creating the thermal design, sufficient margin must be provided to guarantee the temperature conditions below.
The junction temperature Tj can be determined using the following equation.
The power consumption Pc can be determined using the following equation. Refer to page 4 about V
Example using the BD6221F
Fig.42 Thermal derating curve
Fig.45 Thermal derating curve
0
iv)7.3W
iii)5.5W
ii)2.3W
i)1.4W
i) 0.562W
1. The ambient temperature Ta must be 85°C or below
2. The junction temperature Tj must be 150°C or below
Tj ≈ Ta + θ
Pc ≈ (I
Conditions: Ta=50°C, VCC=VREF=12V, Iout=0.1A.
The power consumption of the IC and the junction temperature are as follows:
Where the Tjmax parameter is 150°C and the derating is set to 80 percents, the maximum ambient temperature
Tamax is determined as follows.
In this example, thermal design can be considered satisfactory (meaning that there are no problems in thermal
design), since the system meets the operating temperature conditions.
ii) Mounted on ROHM standard PCB
i) Package only
25
AMBIENT TEMPERATURE [°C]
(70mm x 70mm x 1.6mm FR4 glas s-epox y board)
25
AMBIENT TEMPERATURE [°C]
Pc ≈ 0.1
Tj ≈ 50 + 182 x 30.6m = 55.6 [°C]
Ta ≤ Tjmax x 0.8 - θ
ii) 0.687W
iv ) 4 layers PCB(c opper foil: 70mm x 70mm)
iii) 2 lay ers PCB (c opper foil: 70mm x 70mm)
ii) 2 layers PCB (copper foil: 15mm x 15mm)
i) 1 lay er PCB (copper foil: 10.5mm x 10.5mm)
50
50
OUT
Mounted on ROHM standard PCB
(70mm x 70mm x 1.6mm FR4 glass-epoxy board)
(SOP8)
(HRP7)
2
j-a
75
x R
2
75
x 1.5 + 12 x 1.3m = 30.6mW
x Pc [°C]
ON
100
100
) x (V
125
125
REF
j-a
x Pc ≈ 113 [°C]
/ V
150
150
CC
) + I
OUT
3.0
2.0
1.0
0.0
Fig.43 Thermal derating curve
x (V
0
i)0.85W
ON(H)
ii) Mounted on ROHM standard PCB
i) Package only
25
(70mm x 70mm x 1.6mm FR4 glas s -epox y board)
AMBIENT TEMPERATURE [°C]
ii)1.45W
+ V
12/15
50
(HSOP25)
F(H)
75
) x (1 - V
100
REF
125
/ V
150
CC
) + V
CC
3.0
2.0
1.0
0.0
x I
Mounted on a 70mmx70mmx1.6mm FR4 glass-epoxy
board with less than 3% copper foil.
Fig.44 Thermal derating curve
CC
0
Table 8 Thermal resistance
HSOP-M28
i)1.80W
HSOP25
Package
[W]
SOP8
HRP7
ii) Mounted on ROHM standard PCB
i) Package only
25
(70mm x 70mm x 1.6mm FR4 glas s -epox y board)
AMBIENT TEMPERATURE [°C]
(HSOP-M28)
ii)2.20W
50
Technical Note
2009.04 - Rev.B
ON(H)
75
θ
100
and V
j-a
86.2
56.8
89.3
182
[°C/W]
125
F(H)
.
150