LTC3646/LTC3646-1

3

36461fc

For more information www.linear.com/LTC3646

ELECTRICAL CHARACTERISTICS The

l

denotes the specifications which apply over the specified operating

junction temperature range, otherwise specifications are at TA = 25°C (Note 2), PVIN = SVIN = 12V unless otherwise noted.

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Input Supply (PVIN, SVIN)

VIN

Input Voltage Operating Range

l

4.0

40

V

VIN(OV)

Input Supply Overvoltage Lockout

VIN Rising

Hysteresis (VIN Falling)

l

l

43.5

2.0

46

2.5

2.9

V

V

VIN(UV)

Input Supply Undervoltage Lockout

VIN Falling

Hysteresis (VIN Rising)

3.2

3.35

250

3.5

V

mV

IQ

DC Supply Current (Note 3)

Forced Continuous

Sleep Mode

Shutdown Mode

VRUN = 0V

620

140

8

875

190

µA

µA

µA

Main Control Loop

VOUT

Output Voltage Range (Note 4)

LTC3646

LTC3646-1

2.0

0.6

30

15

V

V

VFB

Feedback Reference Voltage

–40°C < TA < 85°C

l

0.594

0.591

0.6

0.6

0.606

0.609

V

V

Feedback Voltage Line Regulation

VIN = 4.0V to 40V, ITH = 1.5V

0.05

%/V

Feedback Voltage Load Regulation

ITH = 1.0V to 1.8V

0.12

%

Feedback Input Current

VFB = 0.6V

l

0

±20

nA

gm(EA)

Error Amplifier Transconductance

External Comp

300

µS

tON(MIN)

Minimum On-Time

VIN = 40V, RRT = 30k, VON = 2V

30

ns

tOFF(MIN)

Minimum Off-Time

80

ns

ILIM

Valley Switch Current Limit

l

0.9

1.2

1.5

A

Negative Valley Switch Current Limit

–0.3

A

Internal Oscillator Frequency

VRT = VINTVCC

RRT = 450kΩ

RRT = 60kΩ

RRT = 30kΩ

1.6

0.19

1.25

2.55

2.25

0.2

1.5

3.0

2.95

0.27

1.75

3.45

MHz

MHz

MHz

MHz

External Clock Frequency Range

0.2

3.0

MHz

RDS(ON)

Top Switch On-Resistance (Note 5)

Bottom Switch On-Resistance (Note 5)

VIN = 5.5V

VIN = 5.5V

200

120

mΩ

mΩ

Switch Leakage

VIN = VSW = 40V, VRUN = 0V

VIN = 40V, VSW = 0V, VRUN = 0V

±1

±1

µA

µA

Internal VCC Regulator

VINTVCC

INTVCC Voltage

IINTVCC = 5mA

l

4.8

5.0

5.2

V

INTVCC Load Regulation (Note 6)

IINTVCC = 0mA to 5mA

0.5

%

INTVCC Undervoltage Lockout

INTVCC Falling

3.0

V

INTVCC UVLO Hysteresis

0.3

V

EXTVCC Switchover Voltage

EXTVCC Rising

4.25

4.5

4.65

V

EXTVCC Hysteresis

200

mV

Operation

VRUN

RUN Pin Threshold

RUN Rising

RUN Falling

Hysteresis

1.17

1.06

1.21

1.10

110

1.26

1.14

V

V

mV

RUN Pin Leakage Current

RUN = 1.3V

0

±1

µA

VPGOOD(UT)

PGOOD Overvoltage Threshold

FB Rising

FB Falling

5.0

3.5

7.5

5

10

%VFB

%VFB

VPGOOD(LT)

PGOOD Undervoltage Threshold

FB Falling

FB Rising

–5.0

–3.5

–7.5

–5

–10

%VFB

%VFB