Rainbow Electronics MAX5051 - Manual

General Description
The MAX5051 is a clamped, two-switch power-supply
controller IC. This device can be used both in forward or
flyback configurations with input voltage ranges from 11V
to 76V. It provides comprehensive protection mech-
anisms against possible faults, resulting in very high relia-
bility power supplies. When used in conjunction with sec-
ondary-side synchronous rectification, power-supply
efficiencies can easily reach 92% for a +3.3V output
power supply operated from a 48V bus. The integrated
high- and low-side gate drivers provide more than 2A of
peak gate-drive current to two external N-channel
MOSFETs. Low startup current reduces the power loss
across the bootstrap resistor. A feed-forward voltage-
mode topology provides excellent line rejection while
avoiding the pitfalls of traditional current-mode control.
The MAX5051 power-supply controller is primary as
well as secondary-side parallelable, allowing the
design of scaleable power systems when necessary.
When paralleling the primary side, dedicated pins allow
for simultaneous wakeup or shutdown of all paralleled
units, thus preventing current-hogging during startup or
fault conditions.
The MAX5051 generates a lookahead signal for driving
secondary-side synchronous MOSFETs. Special
primary-side synchronization inputs/outputs allow two
primaries to be operated 180° out of phase for increased
output power and lower input ripple currents.
The MAX5051 is available in a 28-pin TSSOP-EP
package and operates over a wide -40°C to +125°C
temperature range.
Warning: The MAX5051 is designed to work with
high voltages. Exercise caution.
Applications
High-Efficiency, Isolated Telecom/Datacom
Power Supplies
48V and 12V Server Power Supplies
48V Power-Supply Modules
42V Automotive Power Systems
Industrial Power Supplies
Features
♦ Wide Input Voltage Range, 11V to 76V
♦ Voltage Mode with Input Voltage Feed-Forward
♦ Ripple-Phased Parallel Topology for High
Current/Power Output
♦ 2A Integrated High- and Low-Side MOSFET
Drivers
♦ SYNCIN And SYNCOUT Pins Enable 180° Out-Of-
Phase Operation
♦ Programmable Brownout and Bootstrap UVLOs
♦ High-Side Driver Bootstrap Capacitor Precharge
Driver
♦ Low Current-Limit Threshold for High Efficiency
♦ Programmable Switching Frequency
♦ Reference Voltage Soft-Start for Startup Without
Overshoots
♦ Startup Synchronization with Multiple Paralleled
Primaries
♦ Programmable Integrating Current-Limit Fault
Protection
♦ Look-Ahead PWM Signal for Secondary-Side
Synchronous Rectifier Drivers
♦ Look-Ahead Drivers for Either A High-Speed
Optocoupler or Pulse Transformer
♦ Wide -40°C to +125°C Operating Range
♦ Thermally Enhanced 28-Pin TSSOP Package
MAX5051
Parallelable, Clamped Two-Switch
Power-Supply Controller IC
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-2964; Rev 0; 8/03
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX5051AUI -40°C to +125°C 28-TSSOP-EP*
*EP = Exposed pad.
Pin Configuration appears at end of data sheet.