Datasheet

MAX8795A
TFT-LCD DC-DC Converter with
Operational Amplifiers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
IN, CTL to AGND ...................................................-0.3V to +7.5V
COMP, FB, FBP, FBN, DEL, REF to AGND ....-0.3V to (V
IN
+ 0.3V)
PGND, BGND to AGND ......................................................±0.3V
LX to PGND ............................................................-0.3V to +20V
SUP to AGND .........................................................-0.3V to +20V
DRVP to AGND.......................................................-0.3V to +36V
POS_, NEG_, OUT_ to AGND ...................-0.3V to (V
SUP
+ 0.3V)
DRVN to AGND ...................................(V
IN
- 30V) to (V
IN
+ 0.3V)
SRC to AGND .........................................................-0.3V to +40V
COM, DRN to AGND ................................-0.3V to (V
SRC
+ 0.3V)
DRN to COM............................................................-30V to +30V
POS_ to NEG_ RMS Current ...................................5mA (Note 1)
OUT_ Maximum Continuous Output Current....................±75mA
LX Switch Maximum Continuous RMS Current .....................1.6A
Continuous Power Dissipation (T
A
= +70°C)
32-Pin Thin QFN (derate 34.5mW/°C above +70°C) 2758mW
32-Pin LQFP (derate 48.4mW/°C above +70°C)....1652.9mW
Operating Temperature Range, E Grade ............-40°C to +85°C
Operating Temperature Range, G Grade .........-40°C to +105°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
ELECTRICAL CHARACTERISTICS
(V
IN
= 3V, V
MAIN
= V
SUP
= 14V, V
PGND
= V
AGND
= V
BGND
= 0V, I
REF
= 25µA, T
A
= 0°C to +85°C. Typical values are at T
A
= +25°C,
unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IN Supply Range V
IN
(Note 2) 2.5 6.0 V
IN Undervoltage-Lockout
Threshold
V
UVLO
V
IN
rising, typical hysteresis = 50mV 2.05 2.25 2.45 V
V
FB
= V
FBP
= 1.3V, V
FBN
= 0V,
LX not switching
0.6 1.0
IN Quiescent Current I
IN
V
FB
= 1.2V, V
FBP
= 1.4V, V
FBN
= 0V,
LX switching
23
mA
Duration-to-Trigger Fault
Condition
FB or FBP below threshold or FBN above
threshold
200 ms
T
A
= +25°C to +85°C 1.238 1.250 1.262
REF Output Voltage No external load
T
A
= 0°C to +85°C 1.232 1.250 1.266
V
REF Load Regulation 0 < I
LOAD
< 50µA 10 mV
REF Sink Current In regulation 10 µA
REF Undervoltage Lockout
Threshold
Rising edge; typical hysteresis = 160mV 1.15 V
Temperature rising +160
Thermal Shutdown
Hysteresis 15
°C
MAIN STEP-UP REGULATOR
Output Voltage Range V
MAIN
V
IN
18 V
Operating Frequency f
OSC
1000 1200 1400 kHz
Oscillator Maximum Duty Cycle 86 90 93 %
T
A
= +25°C to +85°C 1.221 1.233 1.245
FB Regulation Voltage V
FB
No load
T
A
= 0°C to +85°C 1.212 1.233 1.248
V
FB Fault Trip Level V
FB
falling 1.10 1.14 1.17 V
FB Load Regulation 0 < I
MAIN
< full load, transient only -1 %
FB Line Regulation V
IN
= 2.5V to 6V 0.1 ±0.4 %/ V
FB Input Bias Current V
FB
= 1.233V +100 +200 nA
Note 1: See Figure 2 for the op amp clamp structure.