User guide

MAX1846/MAX1847
High-Efficiency, Current-Mode,
Inverting PWM Controller
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
SHDN
= V
IN
= +12V, SYNC = GND, PGND = GND, R
FREQ
= 147kΩ ±1%, C
VL
= 0.47µF, C
REF
= 0.1µF, T
A
= 0°C to +85°C, unless
otherwise noted.)
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, SHDN to GND ...................................................-0.3V to +20V
PGND to GND .......................................................-0.3V to +0.3V
VL to PGND for V
IN
≤ 5.7V...........................-0.3V to (V
IN
+ 0.3V)
VL to PGND for V
IN
> 5.7V .......................................-0.3V to +6V
EXT to PGND ...............................................-0.3V to (V
IN
+ 0.3V)
REF, COMP to GND......................................-0.3V to (VL + 0.3V)
CS, FB, FREQ, POL, SYNC to GND .........................-0.3V to +6V
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
16-Pin QSOP (derate 8.3mW/°C above +70°C)...........696mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER CONDITIONS MIN TYP MAX UNITS
PWM CONTROLLER
Operating Input Voltage Range 3.0 16.5 V
V
IN
rising 2.8 2.95
UVLO Threshold
V
IN
falling 2.6 2.74
V
UVLO Hysteresis 60 mV
FB Threshold No load -12 0 12 mV
FB Input Current V
FB
= -0.1V -50 -6 50 nA
Load Regulation
C
COMP
= 0.068µF, V
OUT
= -48V,
I
OUT
= 20mA to 200mA (Note 1)
-1 0 %
Line Regulation
C
COMP
= 0.068µF, V
OUT
= -48V,
V
IN
= +8V to +16.5V, I
OUT
= 100mA
0.04 %
Current-Limit Threshold 85 100 115 mV
CS Input Current CS = GND 10 20 µA
Supply Current V
FB
= -0.1V, V
IN
= +3.0V to +16.5V 0.75 1.2 mA
Shutdown Supply Current
SHDN = GND, V
IN
= +3.0V to +16.5V
10 25 µA
REFERENCE AND VL REGULATOR
REF Output Voltage I
REF
= 50µA 1.236 1.25 1.264 V
REF Load Regulation I
REF
= 0 to 500µA -2 -15 mV
VL Output Voltage I
VL
= 100µA 3.85 4.25 4.65 V
VL Load Regulation I
VL
= 0.1mA to 2.0mA -20 -60 mV