IMP38C/HC/42/3/4/5

IMP38C/HC/42/3/4/5

2

408-432-9100/www.impweb.com

S

Pin Descriptions

Pin Configuration

IMP38C4x

IMP38HC4x

1

COMP

2

FB

3

ISNS

4

RT/CT

OUT

GND

8

7

6

5

38C/HC_02.eps

SO/MicroSO/DIP

SO/DIP

IMP38C4x

IMP38HC4x

1

COMP

2

NC

3

FB

4

NC

NC

14

13

12

11

5

ISNS

OUT

10

6

NC

AGND

9

7

RT/CT

PGND

8

38C/HC_03.eps

r

e

b

m

u

N

n

i

P

e

m

a

Nn

o

i

t

c

n

u

F

e

g

a

k

c

a

P

n

i

P

-

8e

g

a

k

c

a

P

n

i

P

-

4

1

11

P

M

O

C

.

r

o

t

a

r

a

p

m

o

c

M

W

P

e

h

t

o

t

t

u

p

n

i

d

n

a

r

e

i

f

il

p

m

a

r

o

r

r

E

e

h

t

f

o

t

u

p

t

u

O

23

B

F.

r

e

i

f

il

p

m

A

r

o

r

r

E

e

h

t

f

o

t

u

p

n

i

g

n

i

t

r

e

v

n

I

35

S

N

S

I.

V

1

o

t

d

e

t

i

m

il

y

ll

a

n

r

e

t

n

i

s

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I

.

t

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p

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a

r

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p

m

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c

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s

n

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s

t

n

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r

r

u

C

47

T

C

/

T

R

o

t

d

e

t

c

e

n

n

o

c

s

i

T

R

r

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t

s

i

s

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R

.

n

o

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t

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c

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m

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c

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C

R

r

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a

ll

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V

F

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D

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C

r

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p

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d

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a

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l

c

y

c

y

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d

m

u

m

i

x

a

m

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h

t

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i

m

r

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d

T

C

58

D

N

G

P

/

D

N

G

r

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w

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p

d

n

a

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c

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v

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d

d

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a

k

c

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p

n

i

p

-

8

r

o

f

d

n

u

o

r

g

g

o

l

a

n

a

d

n

a

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w

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p

d

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C

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g

a

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c

a

p

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-

4

1

r

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f

d

n

u

o

r

g

60

1T

U

O

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e

h

w

W

O

L

d

l

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h

y

l

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v

i

t

c

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p

T

U

O

.

t

u

p

t

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v

i

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d

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l

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p

-

m

e

t

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,

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w

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p

-

h

g

i

H

C

.

d

l

o

h

s

e

r

h

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V

U

e

h

t

w

o

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b

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72

D

.

t

u

p

n

i

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g

a

t

l

o

v

y

l

p

p

u

S

84

1V

F

E

R

.

t

u

p

t

u

o

e

g

a

t

l

o

v

e

c

n

e

r

e

f

e

r

-

V

5

9D

N

G

A.

e

g

a

k

c

a

p

n

i

p

-

4

1

r

o

f

n

o

i

t

c

e

n

n

o

c

d

n

u

o

r

g

g

o

l

a

n

A

1

.

e

g

a

k

c

a

p

n

i

p

-

4

1

r

o

f

e

g

a

t

l

o

v

y

l

p

p

u

s

r

e

v

i

r

d

t

u

p

t

u

O

3

1

,

6

,

4

,

2C

N.

n

o

i

t

c

e

n

n

o

c

l

a

n

r

e

t

n

i

o

N

s

p

e

.

1

0

t

_

C

H

-

C

8

3

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.

For maximum application flexibility, start-up voltage ranges from

14.5V to 8.4V. Start-up current has been reduced to 120

µA 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.