4.5V to 28V Input, Synchronous PWM Buck Controllers

for DDR Termination and Point-of-Load Applications

4

_______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

CURRENT LIMIT

LX to PGND, ILIM = VL

80

100

115

Ω

35

50

65

Current-Limit Threshold (Positive

Direction)

Ω

160

200

230

mV

Current-Limit Threshold (Negative

Direction)

LX to PGND, ILIM = VL, with respect to positive

current-limit threshold

-130

-110

-90

%

ILIM Input Current

5µA

FAULT DETECTION

57

60

63

≤ +1V)

0.576

0.600

0.624

Overvoltage Threshold

MAX8554

0.696

0.720

0.744

V

VL REGULATOR

Output Voltage

4.80

5.0

5.33

V

Line Regulation

0.2

%

RMS Output Current

35

mA

Bypass Capacitor

ESR < 100m

Ω

2.2

µF

DRIVER

DH Gate-Driver On-Resistance

1.4

2.5

Ω

DL Gate-Driver On-Resistance

(Source)

DL high state

1.6

3.0

Ω

DL Gate-Driver On-Resistance

(Sink)

DL low state

0.75

1.25

Ω

DL rising

32

Dead Time

DL falling

30

ns

FSEL LOGIC

Logic Input Current

-3

+3

µA

Logic Low (GND)

0.5

V

Logic REF Level

FSEL = REF

1.65

2.35

V

Logic Float Level

FSEL unconnected

3.15

3.85

V

Logic VL Level

FSEL = VL

V

EN/HSD OR EN LOGIC

EN/HSD or EN Shutdown Current

0.5

3.0

µA

Logic High

1.5

V

Logic Low

0.8

V