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Typical operating characteristics (continued), Pin descriptions, Max5094 – Rainbow Electronics MAX5095A User Manual

Page 9

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MAX5094A/B/C/D/MAX5095A/B/C

High-Performance, Single-Ended, Current-Mode

PWM Controllers

_______________________________________________________________________________________

9

Typical Operating Characteristics (continued)

(V

CC

= 15V, T

A

= +25°C, unless otherwise noted.)

Pin Descriptions

PIN

NAME

FUNCTION

1

COMP

Error-Amplifier Output. COMP can be used for soft-start.

2

FB

Error-Amplifier Inverting Input

3

CS

PWM Comparator and Overcurrent Protection Comparator Input. The current-sense signal is
compared to a signal proportional to the error-amplifier output voltage.

4

R

T

/C

T

Timing Resistor/Capacitor Connection. A resistor R

T

from R

T

/C

T

to REF and capacitor C

T

from R

T

/C

T

to GND set the oscillator frequency.

5

GND

Power-Supply Ground. Place the V

CC

and REF bypass capacitors close to the IC to minimize ground

loops.

6

OUT

MOSFET Driver Output. OUT connects to the gate of the external n-channel MOSFET.

7

V

CC

Power-Supply Input. Bypass V

CC

to GND with a 0.1µF ceramic capacitor or a parallel combination of

a 0.1µF and a higher value ceramic capacitor.

8

REF

5V Reference Output. Bypass REF to GND with a 0.1µF ceramic capacitor or a parallel combination
of a 0.1µF and a higher value ceramic capacitor no larger then 4.7µF.

MAX5094_

t = 400ns/div

OUT SOURCE AND SINK CURRENTS

I

OUT

4A/div

V

OUT

10V/div

MAX5094/95 toc20

V

CC

= 15V

C

OUT

= 10nF

2.0

3.0

2.5

4.0

3.5

5.0

4.5

5.5

6.5

6.0

7.0

20

220 320 420

120

520 620 720

920

820

1020

SUPPLY CURRENT

vs. OSCILLATOR FREQUENCY

MAX5094/95 toc21

FREQUENCY (kHz)

I

CC

(mA)

T

A

= +125

°C

MAX5095C
C

T

= 100pF

T

A

= -40

°C

MAXIMUM DUTY CYCLE

vs. R

T

MAX5094A/MAX5095A

MAX5094/95 toc22

R

T

(

Ω)

DUTY CYCLE (%)

10,000

1000

30

40

50

60

70

80

90

100

20

100

100,000

C

T

= 100nF

C

T

= 560pF

C

T

= 220pF

C

T

= 1000pF