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Typical operating characteristics – Rainbow Electronics MAX1638 User Manual

Page 5

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MAX1638

High-Speed Step-Down Controller with

Synchronous Rectification for CPU Power

_______________________________________________________________________________________

5

FOLDBACK CURRENT LIMIT

MAX1638-04

V

O

= 2.0V NOMINAL

A: V

OUT

= 0.5V/div

B: INDUCTOR CURRENT, 5A/div

A

B

10

µ

s/div

START-UP WAVEFORMS

MAX1638-05

A: V

OUT

= 0.5V/div

B: INDUCTOR CURRENT, 5A/div

A

B

400

µ

s/div

1

µ

s/div

SWITCHING WAVEFORMS

C

0

MAX1638-06

V

IN

= 5V, V

OUT

= 2.5V, LOAD = 5A

A: LX, 5V/div

C: INDUCTOR CURRENT,

B: V

OUT

, 20mV/div, AC COUPLED

5A/div

B

A

LOAD-TRANSIENT RESPONSE

WITHOUT GLITCHCATCHER (C

OUT

= 880

µ

F)

MAX1638-01

V

IN

= 5V, V

OUT

= 2.0V, LOAD = 14A, 3A/

µ

s

A: V

OUT

, 50mV/div, AC COUPLED

B: INDUCTOR CURRENT, 10A/div

A

B

10

µ

s/div

LOAD-TRANSIENT RESPONSE

WITHOUT GLITCHCATCHER (C

OUT

= 440

µ

F)

MAX1638-02

V

IN

= 5V, V

OUT

= 2.0V, LOAD = 14A, 3A/

µ

s

A: V

OUT

, 100mV/div, AC COUPLED

B: INDUCTOR CURRENT, 10A/div

A

B

10

µ

s/div

LOAD-TRANSIENT RESPONSE

WITH GLITCHCATCHER

MAX1638-03

C

OUT

= 440

µ

F, V

IN

= 5V, V

OUT

= 2.0V, LOAD = 14A, 30A/

µ

s

A: V

OUT

, 100mV/div,

C: NDRV, 5V/div

AC COUPLED

D: INDUCTOR CURRENT,

B: PDRV, 5V/div

10A/div

A

D

B

C

10

µ

s/div

__________________________________________Typical Operating Characteristics

(T

A

= +25°C, using the MAX1638 evaluation kit, unless otherwise noted.)

100

90

30

0.1

10

100

EFFICIENCY vs. OUTPUT CURRENT

50

40

80

70

60

MAX1638-07

OUTPUT CURRENT (A)

EFFICIENCY (%)

1

V

OUT

= 2.0V

V

OUT

= 1.3V

V

OUT

= 3.5V

5.094

1.094

0.001

0.1

1

0.01

10

REFERENCE VOLTAGE

vs. OUTPUT CURRENT

1.594

2.094

MAX1638-08

OUTPUT CURRENT (mA)

REFERENCE VOLTAGE (V)

2.594

3.594

3.094

4.094

4.594

SOURCING

CURRENT

SINKING

CURRENT

50

55

0

MAXIMUM DUTY CYCLE

vs. SWITCHING FREQUENCY

65

60

70

MAX1638-09

SWITCHING FREQUENCY (kHz)

MAXIMUM DUTY CYCLE (%)

85

95

90

75

80

200

800

1000

1200

100

600

400