Max8727 tft-lcd step-up dc-dc converter – Rainbow Electronics MAX8727 User Manual
Page 2
MAX8727
TFT-LCD Step-Up DC-DC Converter
2
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ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(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)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
LX to GND ..............................................................-0.3V to +26V
IN, SHDN, FREQ, FB to GND ...................................-0.3V to +6V
COMP, SS to GND .........................................-0.3V to V
IN
+ 0.3V
LX Switch Maximum Continuous RMS Current .....................2.4A
Continuous Power Dissipation (T
A
= +70
°C)
10-Pin Thin DFN (derate 24.4mW/
°C above +70°C) ....1951mW
Operating Temperature Range ...........................-40
°C to +85°C
Junction Temperature ......................................................+150
°C
Storage Temperature Range .............................-65
°C to +160°C
Lead Temperature (soldering, 10s) .................................+300
°C
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
2.38
2.57
V
V
FB
= 1.3V, not switching
0.225
0.440
IN Quiescent Current
V
FB
= 1.0V, switching
2
5
mA
IN Shutdown Current
SHDN = GND
0.1
10.0
µA
ERROR AMPLIFIER
FB Regulation Voltage
Level to produce V
COMP
= 1.24V
1.22
1.24
1.26
V
FB Input Bias Current
V
FB
= 1.24V
50
125
250
nA
FB Line Regulation
Level to produce V
COMP
= 1.24V, V
IN
= 2.6V to 5.5V
0.05
0.15
%/V
Transconductance
100
200
300
µS
Voltage Gain
700
V/V
Shutdown FB Input Voltage
SHDN = GND
0.05
0.10
0.15
V
OSCILLATOR
FREQ = GND
540
640
740
Frequency
FREQ = IN
1000
1220
1500
kHz
Maximum Duty Cycle
87
90
93
%
n-CHANNEL MOSFET
Current Limit
V
FB
= 1V, 75% duty cycle
3.0
3.8
4.6
A
On-Resistance
125
250
Ω
Leakage Current
V
LX
= 24V
30
45
µA
Current-Sense Transresistance
0.11
0.21
0.31
V/A
SOFT-START
Reset Switch Resistance
100
Ω
Charge Current
V
SS
= 1.2V
2.5
4.5
7.5
µA