Step-Down Converters

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3

Note 3: For the MAX1556, 3.3V output accuracy is specified with a 4.2V input.

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

-0.37

MAX1556,

D1 = IN, D2 = GND;

MAX1556A

D1 = D2 = IN

0.33

-0.1

Line Regulation

MAX1557,

D1 = IN, D2 = GND

0.09

%

0.19

0.35

MAX1556/MAX1556A

0.23

0.35

0.7

p-Channel On-Resistance

MAX1557

0.42

Ω

0.27

0.48

n-Channel On-Resistance

0.33

Ω

MAX1556/MAX1556A

1.5

1.8

2.1

p-Channel Current-Limit

Threshold

MAX1557

0.8

1.0

1.2

A

n-Channel Zero Crossing

Threshold

20

35

45

mA

MAX1556/MAX1556A

1.8

RMS LX Output Current

MAX1557

1.0

0.1

10

LX Leakage Current

GND or IN

0.1

µA

Maximum Duty Cycle

100

%

Minimum Duty Cycle

0%

Internal Oscillator Frequency

0.9

1

1.1

MHz

SS Output Impedance

130

200

300

k

Ω

SS Discharge Resistance

SHDN = GND, 1mA sink current

90

200

Ω

Thermal-Shutdown Threshold

+160

°C

Thermal-Shutdown Hysteresis

15

°C

LOGIC INPUTS (D1, D2,

SHDN)

Input-Voltage High

2.6V

1.4

V

Input-Voltage Low

0.4

V

0.1

1

Input Leakage

0.1

µA