MAX17499 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – Current-Mode PWM Controllers with Programmable Switching Frequency

19-5485; Rev 1; 7/11
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Current-Mode PWM Controllers with
Programmable Switching Frequency
General Description
The MAX17499/MAX17500 current-mode PWM con-
trollers contain all the control circuitry required for the
design of wide-input-voltage isolated and nonisolated
power supplies. The MAX17499 is well suited for low
input voltage (9.5V DC to 24V DC) power supplies. The
MAX17500 is well suited for universal input (rectified
85V AC to 265V AC) or telecom (-36V DC to -72V DC)
power supplies.
The ICs contain an internal error amplifier that regulates
the tertiary winding output voltage that is used in prima-
ry-side-regulated isolated power supplies. Primary-side
regulation eliminates the need for an optocoupler. An
input undervoltage lockout (UVLO) is provided for pro-
gramming the input-supply start voltage and to ensure
proper operation during brownout conditions. An open-
drain UVLO flag output, with 210μs internal delay,
allows the sequencing of a secondary-side controller.
The input-supply start voltage is externally programma-
ble with a voltage-divider. A UVLO/EN input is used to
shut down the devices. Internal digital soft-start elimi-
nates output voltage overshoot.
The MAX17500 has an internal bootstrap UVLO with
large hysteresis that requires a minimum 23.6V for start-
up. The MAX17499 does not have the internal bootstrap
UVLO and can be biased directly from a minimum volt-
age of 9.5V.
The switching frequency for the ICs is programmable
with an external resistor. The MAX17499A/MAX17500A
provide a 50% maximum duty-cycle limit, while the
MAX17499B/MAX17500B provide a 75% maximum
duty-cycle limit. These devices are available in 10-pin
μMAX^® packages and are rated for operation over the
-40°C to +125°C temperature range.
Selector Guide appears at end of data sheet.
μMAX is a registered trademark of Maxim Integrated Products, Inc.
Features
o Current-Mode Control
o Programmable Switching Frequency Up to 625kHz
o Accurate UVLO Threshold (1%)
o Open-Drain UVLO Flag Output with Internal Delay
o 36V to 72V Telecom Voltage Range
o Universal Offline Input Voltage Range
Rectified 85V AC to 265V AC (MAX17500)
o 9.5V to 24V Input (MAX17499)
o Digital Soft-Start
o Internal Bootstrap UVLO with Large Hysteresis
(MAX17500)
o Internal Error Amplifier with 1.5% Accurate
Reference
o 50µA (typ) Startup Supply Current
o 50% Maximum Duty-Cycle Limit
(MAX17499A/MAX17500A)
o 75% Maximum Duty-Cycle Limit
(MAX17499B/MAX17500B)
o 60ns Cycle-by-Cycle Current-Limit Propagation
Delay
o Available in Tiny 10-Pin µMAX Packages
Applications
1/2, 1/4, and 1/8 Brick Power Modules
High-Efficiency, Isolated Telecom Power
Supplies
Networking/Servers
Isolated Keep-Alive Power Supplies
12V Boost and SEPIC Regulators
Isolated and Nonisolated High-Brightness LED
Power Supplies
Industrial Power Conversion
PART
D_MAX (%)
STARTUP VOLTAGE (V)
MAX17499AAUB+
50
9.5
MAX17499BAUB+
75
9.5
MAX17500AAUB+
50
22
MAX17500BAUB+
75
22
Warning: The ICs are designed to work with high voltages. Exercise caution.
+Denotes a lead(Pb)-free/RoHS-compliant package.
Ordering Information
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
10 μMAX
10 μMAX
10 μMAX
10 μMAX
________________________________________________________________ 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.