Step-Down Controllers with Prebias Startup,

Lossless Sensing, Synchronization, and OVP

_______________________________________________________________________________________

5

ELECTRICAL CHARACTERISTICS (continued)

PARAMETER

CONDITIONS

MIN

MAX

UNITS

CURRENT-SENSE AMPLIFIER

8.8

13.2

4.8

7.2

3.2

4.8

Voltage Gain

2.4

3.6

V/V

CURRENT LIMIT

ILIM2 Output Current (MAX8544 Only)

Ω to 200kΩ

4.2

5.5

µA

ILIM1 Input Current

-1

+1

µA

38.5

56.5

85

115

127.5

172.5

170

230

Ω (MAX8544 only)

-40

-60

Ω (MAX8544 only)

-160

-240

-110

-150

Current-Limit Threshold

-20

-40

mV

Negative Current-Limit Threshold

-25

-85

%

CS+, CS- Input Current

-40

+40

µA

CS+, CS- Input Common-Mode Range

0

13.2

V

OSCILLATOR

Switching Frequency

Ω

800

1200

kHz

Minimum Off-Time

Measured at DH

150

270

ns

Minimum On-Time

Measured at DH

140

ns

FSYNC Synchronization Range

160

1200

kHz

FSYNC Input High Pulse Width

100

ns

FSYNC Input Low Pulse Width

100

ns

FSYNC Rise/Fall Time

100

ns

SYNCO Phase Shift from DH Rising

Ω

165

195

Degrees

SYNCO Output Low Level

0.4

V

SYNCO Output High Level

V

MOSFET DRIVERS

DH On-Resistance, High State

2.5

Ω

DH On-Resistance, Low State

2.5

Ω

DL On-Resistance, High State

2.5

Ω

DL On-Resistance, Low State

1.7

Ω

LX, BST, IN Leakage Current

5

µA