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Typical operating characteristics (continued) – Rainbow Electronics MAX8621Z User Manual

Page 8

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MAX8621Y/MAX8621Z

Dual Step-Down DC-DC Power-Management ICs
for Portable Devices

8

_______________________________________________________________________________________

SWITCHING FREQUENCY

vs. LOAD CURRENT

MAX8621 toc11

LOAD CURRENT (mA)

FREQUENCY (MHz)

100

200

300

400

1

10

0.1

0

500

1

µH

2.2

µH

4.7

µH

BUCK1 OUTPUT VOLTAGE

vs. LOAD CURRENT (VOLTAGE POSITIONING)

MAX8621 toc15

LOAD CURRENT (mA)

OUTPUT VOLTAGE (V)

400

300

200

100

1.32

1.34

1.36

1.38

1.40

1.42

1.44

1.30

0

500

BUCK1 LIGHT-LOAD WAVEFORMS

MAX8621 toc12

200ns/div

10mV/div
AC-COUPLED

V

BUCK1

I

LX1

V

LX1

200mA/div

0

5V/div
0

LOAD = 50mA

BUCK1 LOAD-TRANSIENT RESPONSE

MAX8621 toc14

5

µs/div

50mV/div
AC-COUPLED

V

BUCK1

I

LX1

I

BUCK1

500mA/div
0

500mA/div
0

400mA LOAD

BUCK1 HEAVY-LOAD WAVEFORMS

MAX8621 toc13

200ns/div

10mV/div
AC-COUPLED

V

BUCK1

I

LX1

V

LX1

200mA/div

0

5V/div
0

LOAD = 300mA

Typical Operating Characteristics (continued)

(Circuit of Figure 3, V

IN1

= V

IN2

= V

IN3

= 3.6V, PWRON = IN, V

BUCK1

= 1.375V, V

BUCK2

= 1.8V, V

OUT1

= 2.6V, V

OUT2

= 2.6V, V

OUT3

= 1.8V, V

OUT4

= 3.0V, SEL1 = SEL2 = open, LX1 = LX2 = Murata LQH32CN2R2M53, T

A

= +25°C, unless otherwise noted.)