an8049sh Panasonic Corporation of North America, an8049sh Datasheet - Page 12

• Manufacturer Part Number: an8049sh
• Description: 1.8-volt 3-channel Step-up, Step-down, And Polarity Inverting Dc-dc Converter Control Ic
• Manufacturer: Panasonic Corporation of North America

AN8049SH
I Usage Notes (continued)
I Application Notes
12
[3] Notes on MOS drive
[1] P
require care if this device is used to drive n-channel MOS transistors directly.
1. Use an n-channel MOS transistor with a low input capacitance.
2. Use an n-channel MOS transistor with a low gate-threshold voltage.
Since the AN8049SH channel 1 and 2 output circuits were designed to drive bipolar transistors, the following points
a circuit structure that can provide a constant-current (50 mA maxi-
mum) output source current. Furthermore, it has a sink current capac-
ity of 80 mA maximum. This means that designs must be concerned
about increased loss due to longer rise- and fall-times. If a problem
occurs, an inverter may be inserted as shown in figure 1 to provide
amplification.
voltage is V
adequately low on-resistance must be used. Also, if a large V
required, one solution is to use a transformer as shown in figure 2,
and apply a voltage that is twice the input voltage to the IC's V
D
 T
The AN8049SH is designed to drive bipolar transistors, and adopts
Since the AN8049SH OUT1 and OUT2 pin high-level output
a
curves of SSOP024-P-0300A
CC
− 1.0 V (minimum), low V
700
658
600
500
400
366
300
263
200
146
100
0
0
25
Ambient temperature T
T
MOS transistors with an
SDH00012BEB
50
P
Glass epoxy printed circuit board
(75 × 75 × t1.6 mm
R
P
D
D
th(j−a)
= 658 mW(25°C)
 T
= 152°C/W
75 85
a
Independent IC
without a heat sink
R
P
D
th(j−a)
a
= 366 mW(25°C)
(°C)
CC
= 273°C/W
3
)
100
GS
pin.
is
125
Figure 2. Gate drive voltage bootstrap
OUT1/2
OUT1/2
Figure 1. Output bootstrap circuit
V
V
V
IN
IN
CC
V
CC
≈ 2 × V
technique
IN
− VD
V
V
OUT
OUT