EVALUATION KIT AVAILABLE
Inverting PWM Controller
MAX1846/MAX1847 high-efficiency PWM inverting
controllers allow designers to implement compact, low-
noise, negative-output DC-DC converters for telecom
and networking applications. Both devices operate
from +3V to +16.5V input and generate -500mV to
-200V output. To minimize switching noise, both devices
feature a current-mode, constant-frequency PWM control
scheme. The operating frequency can be set from 100kHz
to 500kHz through a resistor.
The MAX1846 is available in an ultra-compact 10-pin
µMAX® package. Operation at high frequency, com-
patibility with ceramic capacitors, and inverting topol-
ogy without transformers allow for a compact design.
Compatibility with electrolytic capacitors and flexibility to
operate down to 100kHz allow users to minimize the cost
of external components. The high-current output drivers
are designed to drive a P-channel MOSFET and allow the
converter to deliver up to 30W.
The MAX1847 features clock synchronization and shut-
down functions. The MAX1847 can also be configured to
operate as an inverting flyback controller with an N-channel
MOSFET and a transformer to deliver up to 70W. The
MAX1847 is available in a 16-pin QSOP package.
Current-mode control simplifies compensation and
provides good transient response. Accurate current-mode
control and over current protection are achieved through
low-side current sensing.
●● Cellular Base Stations
●● Networking Equipment
●● Optical Networking Equipment
●● SLIC Supplies
●● CO DSL Line Driver Supplies
●● Industrial Power Supplies
●● VOIP Supplies
Pin Configurations appear at end of data sheet.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
●● 90% Efficiency
●● +3.0V to +16.5V Input Range
●● -500mV to -200V Output
●● Drives High-Side P-Channel MOSFET
●● 100kHz to 500kHz Switching Frequency
●● Current-Mode, PWM Control
●● Internal Soft-Start
●● Electrolytic or Ceramic Output Capacitor
●● The MAX1847 also offers:
Synchronization to External Clock Shutdown
N-Channel Inverting Flyback Option
TEMP RANGE PIN-PACKAGE
-40°C to +85°C 10 µMAX
-40°C to +105°C 10 µMAX
-40°C to +85°C 16 QSOP
-40°C to +85°C 16 QSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
Typical Operating Circuit
19-2091; Rev 4; 7/16