MAX1846EUB-T Datasheet, PDF (1/20 Pages) Maxim Integrated Products – High-Efficiency, Current-Mode, Inverting PWM Controller

19-2091; Rev 2; 9/10
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High-Efficiency, Current-Mode,
Inverting PWM Controller
General Description
MAX1846/MAX1847 high-efficiency PWM inverting con-
trollers 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, compat-
ibility with ceramic capacitors, and inverting topology
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 pro-
vides good transient response. Accurate current-mode
control and over current protection are achieved
through low-side current sensing.
Applications
Cellular Base Stations
Networking Equipment
Optical Networking Equipment
SLIC Supplies
CO DSL Line Driver Supplies
Industrial Power Supplies
Automotive Electronic Power Supplies
Servers
VOIP Supplies
Pin Configurations appear at end of data sheet.
Features
o 90% Efficiency
o +3.0V to +16.5V Input Range
o -500mV to -200V Output
o Drives High-Side P-Channel MOSFET
o 100kHz to 500kHz Switching Frequency
o Current-Mode, PWM Control
o Internal Soft-Start
o Electrolytic or Ceramic Output Capacitor
o The MAX1847 also offers:
Synchronization to External Clock
Shutdown
N-Channel Inverting Flyback Option
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX1846EUB
-40°C to +85°C 10 µMAX
MAX1846EUB+
-40°C to +85°C 10 µMAX
MAX1847EEE
-40°C to +85°C 16 QSOP
MAX1847EEE+
-40°C to +85°C 16 QSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
Typical Operating Circuit
POSITIVE
V_IN
VL
IN
EXT
MAX1846
MAX1847
COMP
CS
FREQ
PGND
REF
GND
FB
P
NEGATIVE
V_OUT
µMAX is a registered trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.