Low-Cost, Wide Input Range, Step-Down

Controllers with Foldback Current Limit

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3

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

ERROR AMPLIFIER

°C to +85°C

0.787

0.800

0.815

FB Regulation Voltage

°C to +85°C

0.782

0.800

0.815

V

FB to COMP/EN Gain

4000

V / V

FB to COMP/EN

Transconductance

70

108

160

µS

FB Input Bias Current

1

2

µA

COMP/EN Source Current

15

46

100

µA

LX to GND, MAX8545, MAX8548,

-355

-320

-280

Current-Limit Threshold Voltage

(Across Low-Side MOSFET)

-185

-165

-140

mV

MAX8545, MAX8548

-105

-75

-45

Foldback Current-Limit Threshold

Voltage (Across Low-Side

MOSFET) When Output is Short

-53

-38

-22

mV

MOSFET DRIVERS

Rising edge, DH going low to DL going high

96

Break-Before-Make Time

Falling edge, DL going low to DH going high

28

ns

DH On-Resistance in Low State

1.6

4

Ω

DH On-Resistance in High State

2.5

5.5

Ω

DL On-Resistance in Low State

1.1

2.5

Ω

DL On-Resistance in High State

2.5

5.5

Ω

BST Leakage Current

0

50

µA

LX Leakage Current

33

100

µA

Note 1: Thermal shutdown disables the buck regulator when the die reaches this temperature. Soft-start is reset but the VL regulator

remains on.