LT8686S

8

Rev. 0

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TYPICAL PERFORMANCE CHARACTERISTICS

Switching Waveform

Burst Mode Operation

Switching Waveform Pulse-

Skipping Operation

HV Channel Load Step

LV Channel Load Step

Conducted EMI Performance

Switching Waveform Continuous

Full Frequency Operation

12VIN TO 5VOUT AT 0.5A

SYNC/MODE = GND

2µs/DIV

VSW

5V/DIV

IL

500mA/DIV

8686S G28

12VIN TO 5VOUT AT 20mA

SYNC/MODE = GND

1µs/DIV

VSW

5V/DIV

IL

200mA/DIV

8686S G29

12VIN TO 5VOUT AT 20mA

SYNC/MODE = FLOATING

1µs/DIV

VSW

5V/DIV

IL

200mA/DIV

8686S G30

0.5A TO 1.5A STEP

5VOUT

COUT = 47µF

Burst Mode OPERATION, fSW = 2MHz

50µs/DIV

VOUT

200mV/DIV

ILOAD

1A/DIV

8686S G31

0.5A TO 1.5A STEP

1.8VOUT

COUT = 47µF ×2

Burst Mode OPERATION, fSW = 2MHz

50µs/DIV

VOUT

100mV/DIV

ILOAD

1A/DIV

8686S G32

DC3126A DEMO BOARD

(WITH EMI FILTER INSTALLED)

CLASS 5 PEAK LIMIT

SPREAD SPECTRUM MODE

FIXED FREQUENCY MODE

FREQUENCY (MHz)

0

3

6

9

12

15

18

21

24

27

30

–20

–10

0

10

20

30

40

50

60

8686S G33

VEMI = 14V, VOUT1 = 5V, VOUT2 = 3.3V, VOUT3 = 1.8V, VOUT4 = 1.2V

IOUT1 = 2A – IVIN3 – IVIN4 – IBIAS, IOUT2 = IOUT3 = IOUT4 = 2A, fSW = 2MHz

LV Channel Switching Frequency

vs Load, RT = 22.6kΩ

VIN = 5V

VOUT = 1.8V

L = 0.78µH

Burst Mode OPERATION

PULSE-SKIPPING MODE

LOAD CURRENT (A)

0.0001

0.001

0.01

0.1

1

10

0.001

0.01

0.1

1

10

8686S G27

TA = 25°C, VIN1 = VIN2 = 12V, VIN3 = VIN4 = 3.3V,

fSW = 2MHz, unless otherwise noted.