bd6232fp ROHM Co. Ltd., bd6232fp Datasheet - Page 12

• Manufacturer Part Number: bd6232fp
• Description: H-bridge Driver For Dc Brush Motor
• Manufacturer: ROHM Co. Ltd.

Thermal design
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 BD6232FP
1.5
1.0
0.5
0.0
3
2
1
0
1. The ambient temperature Ta must be 85°C or below
2. The junction temperature Tj must be 150°C or below
Tj ≈ Ta +
Pc ≈ (I
Conditions: Ta=50°C, VCC=VREF=24V, Iout=0.5A.
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.
0
0
Fig.43 Thermal derating curve
Fig.46 Thermal derating curve
i) 0.85W
AMBIENT TEMPERATURE [°C]
AMBIENT TEMPERATURE [°C]
Pc ≈ 0.5
Tj ≈ 50 + 86.2 x 281m = 74 [°C]
Ta ≤ Tjmax x 0.8 -
i) 0.562W
i) Package only
ii) Mounted on ROHM standard PCB
(70mm x 70mm x 1.6mm FR4 glas s-epox y board)
25
OUT
i) Package only
ii) Mounted on ROHM standard PCB
25
(70mm x 70mm x 1.6mm FR4 glass -epoxy board)
θ
2
j-a
ii) 0.687W
x R
ii) 1.45W
50
50
x Pc [°C]
(HSOP25)
2
ON
(SOP8)
x 1.0 + 24 x 1.3m = 281mW
75
) x (V
75
100
100
REF
θ
j-a
/ V
125
125
x Pc ≈ 96 [°C]
CC
) + I
150
150
OUT
x (V
1.5
1.0
0.5
0.0
3
2
1
0
0
ON(H)
0
Fig.44 Thermal derating curve
Fig.47 Thermal derating curve
i) 1.80W
AMBIENT TEMPERATURE [°C]
AMBIENT TEMPERATURE [°C]
i) Package only
ii) Mounted on ROHM standard PCB
i) 0.787W
(70mm x 70mm x 1.6mm FR4 glas s-epox y board)
25
i) Package only
ii) Mounted on ROHM standard PCB
25
+ V
(70mm x 70mm x 1.6mm FR4 glass -epox y board)
ii) 2.20W
12/16
F(H)
50
ii) 0.976W
50
(HSOPM28)
(SSOPB24)
) x (1 - V
75
75
100
100
REF
/ V
125
125
CC
) + V
150
150
CC
x I
10.0
8.0
6.0
4.0
2.0
0.0
CC
Mounted on a 70mmx70mmx1.6mm FR4 glass-epoxy
board with less than 3% copper foil.
Fig.45 Thermal derating curve
0
Table 9 Thermal resistance
[W]
AMBIENT TEMPERATURE [°C]
iv) 7.3W
iii) 5.5W
ii) 2.3W
i) 1.4W
SSOPB24
HSOP25
HSOP28
Package
SOP8
HRP7
25
i) Pac kage only (c opper foil: 10.5mm x 10.5mm)
ii) 2 layers PCB (copper foil: 15mm x 15mm)
iii) 2 lay ers PCB (c opper foil: :70mm x 70mm)
iv ) 4 layers PCB (copper foil: 70mm x 70mm)
50
ON(H)
(HRP7)
75
and V
θ
100
j-a
89.3
86.2
56.8
182
122
F(H)
[°C/W]
125
.
150