Rainbow Electronics MAX5074 - Manual

General Description
The MAX5074 isolated PWM power IC features integrated
switching power MOSFETs connected in a voltage-
clamped, two-transistor, power-circuit configuration. This
device can be used in both forward and flyback configu-
rations with a wide input voltage range from 11V to 76V
and up to 15W of output power.
The voltage-clamped power topology enables full
recovery of stored magnetizing and leakage inductive
energy for enhanced efficiency and reliability. A look-
ahead signal for driving secondary-side synchronous
rectifiers can be used to increase efficiency.
A wide array of protection features includes UVLO,
overtemperature shutdown, and short-circuit protection
with hiccup current limit for enhanced performance and
reliability. Operation up to 500kHz allows smaller exter-
nal magnetics and capacitors.
The MAX5074 is rated for operation over the -40°C to
+125°C temperature range and is available in a 20-pin
TSSOP package.
Warning: The MAX5074 is designed to work with
high voltages. Exercise caution.
Applications
IEEE 802.3af PD Power Supplies
Isolated IP Phone Power Supplies
High-Efficiency Telecom/Datacom Power Supplies
48V Input, Isolated Power-Supply Modules
WLAN Access-Point Power Supplies
ADSL Line Cards
ADSL Line-Driver Power Supplies
Distributed Power Systems with 48V Bus
Features
♦ Clamped, Two-Switch Power IC for High Efficiency
♦ No Reset Winding Required
♦ Up to 15W Output Power
♦ Bias Voltage Regulator with Automatic High-
Voltage Supply Turn-Off
♦ 11V to 76V Wide Input Voltage Range
♦ Integrated High-Voltage 0.4Ω Power MOSFETs
♦ Feed-Forward Voltage-Mode Control For Fast
Input Transient Rejection
♦ Programmable Brownout Undervoltage Lockout
♦ Internal Overtemperature Shutdown
♦ Indefinite Short-Circuit Protection With
Programmable Fault Integration
♦ Integrated Look-Ahead Signal for Secondary-Side
Synchronous Rectification
♦ >90% Efficiency with Synchronous Rectification
♦ Up to 500kHz Switching Frequency
♦ High-Power (1.74W), Small-Footprint 20-Pin
Thermally Enhanced TSSOP Package
MAX5074
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
________________________________________________________________ Maxim Integrated Products 1
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
INBIAS
HVIN
UVLO
BST RCFF
FLTINT
RTCT
REGOUT
TOP VIEW
DRNH
XFRMRH
DRVIN
XFRMRL PPWM
CSS
OPTO
RAMP
12
11
9
10
SRC
PGND CS
GND
MAX5074
TSSOP
Pin Configuration
Ordering Information
MAX5074
DRNH
SRC
DRVL
DRVH QH
QL D2
D1
D3
T1
V IN
C IN
C OUT
V OUT
XFRMRH
XFRMRL
Simplified Application Circuit
19-3312; Rev 0; 7/04
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.
*EP = Exposed pad.
EVALUATION KIT AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX5074AUP -40 °C to +125°C 20-TSSOP-EP*