19-2590; Rev 0; 10/02
KIT
ATION
EVALU
BLE
AVAILA
Current-Mode PWM Controllers with an Error
Amplifier for Isolated/Nonisolated Power Supplies
General Description
The MAX5052/MAX5053 current-mode PWM controllers
contain all the control circuitry required for the design of
wide-input-voltage isolated and nonisolated power
supplies. The MAX5052 is well suited for universal input
(rectified 85VAC to 265VAC) or telecom (-36VDC to
-72VDC) power supplies. The MAX5053 is well suited for
low-input-voltage (10.8VDC to 24VDC) power supplies.
The MAX5052/MAX5053 contain an internal error ampli-
fier that regulates the tertiary winding output voltage.
This implements a primary-side regulated, isolated
power supply, eliminating the need for an optocoupler.
An input undervoltage lockout (UVLO) is provided for
programming the input-supply start voltage and to
ensure proper operation during brownout conditions.
The input-supply start voltage is externally programma-
ble with a voltage-divider. To shutdown the device, the
UVLO pin is pulled low. Internal digital soft-start
reduces output voltage overshoot. The internal thermal
shutdown circuit protects the device in the event the
junction temperature exceeds +130擄C.
The MAX5052 has an internal bootstrap UVLO with
large hysteresis that requires a minimum voltage of
23.6V for startup. The MAX5053 does not have the
internal bootstrap UVLO and can be biased directly
from a minimum voltage of 10.8V.
The 262kHz switching frequency is internally trimmed to
鹵12% accuracy; this allows the optimization of the
magnetic and filter components resulting in compact,
cost-effective power supplies. The MAX5052A/
MAX5053A are offered with a 50% maximum duty-cycle
limit. The MAX5052B/MAX5053B are offered with a 75%
maximum duty-cycle limit. These devices are available
in 8-pin 碌MAX packages and operate over the -40擄C to
+85擄C temperature range.
o
Current-Mode Control
o
50W Output Power
o
Universal Offline Input Voltage Range
Rectified 85VAC to 265VAC (MAX5052)
o
V
IN
Directly Driven from 10.8V to 24V Input
(MAX5053)
o
Digital Soft-Start
o
Programmable Input Startup Voltage
o
Internal Bootstrap UVLO with Large Hysteresis
(MAX5052)
o
Internal Error Amplifier with 1% Accurate
Reference
o
Thermal Shutdown
o
45碌A(chǔ) (typ) Startup Supply Current
o
1.4mA (typ) Operating Supply Current
o
Fixed Switching Frequency of 262kHz 鹵12%
o
50% Maximum Duty-Cycle Limit
(MAX5052A/MAX5053A)
o
75% Maximum Duty-Cycle Limit
(MAX5052B/MAX5053B)
o
60ns Cycle-by-Cycle Current-Limit Response Time
Features
o
Available in a Tiny 8-Pin 碌MAX Package
MAX5052/MAX5053
Ordering Information
PART
MAX5052AEUA
MAX5052BEUA
MAX5053AEUA
MAX5053BEUA
TEMP RANGE
-40擄C to +85擄C
-40擄C to +85擄C
-40擄C to +85擄C
-40擄C to +85擄C
PIN-PACKAGE
8 碌MAX
8 碌MAX
8 碌MAX
8 碌MAX
Applications
Universal Input AC
Power Supplies
Isolated Telecom Power
Supplies
Networking Systems
Computer Systems/
Servers
Industrial Power
Conversion
Isolated Keep-Alive
Circuits
12V Boost Regulators
12V SEPIC Regulators
Warning:
The MAX5052/MAX5053 are designed to work with
high voltages. Exercise caution.
Pin Configuration
TOP VIEW
UVLO/EN
1
FB
2
COMP
3
8
7
V
IN
V
CC
NDRV
GND
MAX5052
MAX5053
6
5
CS
4
Functional Diagram/Typical Operating Circuit/Selector
Guide appear at end of data sheet.
碌MAX
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________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim鈥檚 website at www.maxim-ic.com.
Maxim
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