beautypg.com

Max8727 tft-lcd step-up dc-dc converter, Electrical characteristics (continued), Electrical characteristics – Rainbow Electronics MAX8727 User Manual

Page 3

background image

MAX8727

TFT-LCD Step-Up DC-DC Converter

_______________________________________________________________________________________

3

ELECTRICAL CHARACTERISTICS (continued)

(V

IN

= V

SHDN

= 3V, FREQ = GND, T

A

= 0°C to +85°C. Typical values are at T

A

= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

CONTROL INPUTS

SHDN, FREQ Input Low Voltage

V

IN

= 2.6V to 5.5V

0.3

×

V

IN

V

SHDN, FREQ Input High Voltage

V

IN

= 2.6V to 5.5V

0.7

×

V

IN

V

SHDN, FREQ Input Hysteresis

V

IN

= 2.6V to 5.5V

0.1

×

V

IN

V

FREQ Pulldown Current

2.3

6.0

9.5

µA

SHDN Input Current

SHDN = GND

0.001

1

µA

ELECTRICAL CHARACTERISTICS

(V

IN

= V

SHDN

= 3V, FREQ = GND, T

A

= -40°C to +85°C, unless otherwise noted.) (Note 1)

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

V

OUT

< 18V

2.6

5.5

Input Voltage Range

18V < V

OUT

< 24V

4.0

5.5

V

Output Voltage Range

24

V

IN Undervoltage-Lockout
Threshold

V

IN

rising, typical hysteresis is 50mV

2.20

2.57

V

V

FB

= 1.3V, not switching

0.44

IN Quiescent Current

V

FB

= 1.0V, switching

5

mA

IN Shutdown Current

SHDN = GND

10

µA

ERROR AMPLIFIER

FB Regulation Voltage

Level to produce V

COMP

= 1.24V

1.215

1.260

V

FB Input Bias Current

V

FB

= 1.24V

250

nA

FB Line Regulation

Level to produce V

COMP

= 1.24V, V

IN

= 2.6V to 5.5V

0.15

%/V

Transconductance

100

300

µS

Shutdown FB Input Voltage

SHDN = GND

0.05

0.15

V

OSCILLATOR

FREQ = GND

490

770

Frequency

FREQ = IN

900

1600

kHz

Maximum Duty Cycle

86

94

%

n-CHANNEL MOSFET

Current Limit

V

FB

= 1V, 75% duty cycle

3.0

5.1

A

On-Resistance

250

m

Current-Sense Transresistance

0.11

0.31

V/A

SOFT-START

Reset Switch Resistance

100

Charge Current

V

SS

= 1.2V

2.5

7.5

µA