Dual, 4A/2A, 4MHz, Step-Down DC-DC

Regulator with Dual LDO Controllers

_______________________________________________________________________________________

3

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

LDO CONTROLLERS

FB3, FB4 Input Bias Current

-250

+250

nA

FB3, FB4 Voltage Set-point

0.585

0.600

0.615

V

FB3, FB4 to B3, B4

Transconductance

2.5mA to 10mA sink current,

0.56

1.20

2.30

S

B3, B4 Driver Sink Current

20

mA

LDO Soft-Start Duration

512

Clock

Cycles

LDO Reference Voltage Steps

64

Steps

POWER MOSFETS

Regulator 1 p-Channel MOSFET

50

90

m

Ω

Regulator 1 n-Channel MOSFET

30

50

m

Ω

Regulator 1 Gate Charge

8

nC

Maximum LX1 RMS Current

4A

Regulator 2 p-Channel MOSFET

100

180

m

Ω

Regulator 2 n-Channel MOSFET

60

100

m

Ω

Regulator 2 Gate Charge

4

nC

Maximum LX2 RMS Current

2A

PWM CURRENT LIMIT AND HICCUP MODE

4.5

4.9

5.3

Regulator 1 Peak Current Limit

3.40

3.65

3.95

A

4.0

5.0

5.65

Regulator 1 Valley Current Limit

3.0

3.7

4.25

A

2.25

2.45

2.65

Regulator 2 Peak Current Limit

1.70

1.85

1.98

A

2.0

2.5

2.83

Regulator 2 Valley Current Limit

1.5

1.85

2.13

A

Number of Cumulative Current-

Limit Events to Hiccup

4

Clock

Cycles

Number of Consecutive Noncurrent

3

Clock

Cycles

Hiccup Timeout

8192

Clock

Cycles