IMP38C4X IMP Inc, IMP38C4X Datasheet - Page 2

• Manufacturer Part Number: IMP38C4X
• Description: BiCMOS Current-Mode PWM Controllers
• Manufacturer: IMP Inc

powered through the out pin. Leakage current from the external
power MOSFETs will not force the PWM output to rise and turn
the external MOSFETs on.
Current-sense propagation delay time is 35ns typical, 65ns maxi-
mum, representing an up to 75 percent reduction over other 38xx
implementations.
Output stage drive is 0.5A for IMP38C4x devices. The high-drive
IMP38HC4x family is rated at 1.0A peak current drive.
Like conventional 384x controllers, the IMP38C4x and
IMP38HC4x controllers use the current-mode architecture for
superior load regulation, pulse-by-pulse current limiting and out-
put MOSFET protection. All versions operate up to 20 volts.
2
Pin Configuration
Pin Descriptions
I M P 3 8 C / H C / 4 2 / 3 / 4 / 5
I M P 3 8 C / H C / 4 2 / 3 / 4 / 5
1
2
3
4
5
6
7
8
COMP
RT/CT
ISNS
FB
1
2
3
4
, 2
, 4
IMP38HC4x
1
1
1
1
IMP38C4x
1
3
5
7
8
9
0
2
4
1
, 6
1
3
8
7
6
5
V
V
OUT
GND
G
38C/HC_02.eps
REF
DD
N
C
R
A
S I
D
O
V
V
O
T
G
N
F
V
P /
R
U
N
D
C /
M
B
N
C
D
E
D
T
S
G
F
D
P
T
N
D
408-432-9100/www.impweb.com
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For maximum application flexibility, start-up voltage ranges from
14.5V to 8.4V. Start-up current has been reduced to 120µA maxi-
mum and operating current has been reduced to 1.5mA maximum.
The IMP38C4x/IMP38HC4x are available in 8-pin and 14-pin DIP
and SO packages as well as the 8-pin MicroSO package. The 14-
pin devices provide separate pins for the controller power supply
and the output driver supply. This configuration maximizes
application flexibility and performance. The 14-pin package can
also dissipate more power. Devices in the compact 8-pin packages
do not have separate output drive supply connections.
The IMP38C4x and IMP38HC4x families operate over the –40°C
to +85°C temperature range.
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NC
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IMP38HC4x
n r
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IMP38C4x
T
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14
13
12
11
10
v i t
9
8
e r
o
d
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m
R
e
e
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38C/HC_03.eps
V
NC
V
V
OUT
AGND
PGND
d
T
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p
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DD
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© 2000 IMP, Inc.
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