MAX17498A/MAX17498B/MAX17498C

AC-DC and DC-DC Peak Current-Mode Converters

for Flyback/Boost Applications

19-6043; Rev 3; 4/13

General Description

The MAX17498A/MAX17498B/MAX17498C devices are

current-mode fixed-frequency flyback/boost converters

with a minimum number of external components. They

contain all the control circuitry required to design wide

input voltage isolated and nonisolated power supplies.

The MAX17498A has its rising/falling undervoltage lock-

out (UVLO) thresholds optimized for universal offline (85V

AC to 265V AC) applications, while the MAX17498B/

MAX17498C support UVLO thresholds suitable to low-

voltage DC-DC applications.

The switching frequency of the MAX17498A/MAX17498C

is 250kHz, while that of the MAX17498B is 500kHz. These

frequencies allow the use of tiny magnetic and filter com-

ponents, resulting in compact, cost-effective power sup-

plies. An EN/UVLO input allows the user to start the power

supply precisely at the desired input voltage, while also

functioning as an on/off pin. The OVI pin enables imple-

mentation of an input overvoltage-protection scheme that

ensures that the converter shuts down when the DC input

voltage exceeds the desired maximum value.

The devices incorporate a flexible error amplifier and an

accurate reference voltage (REF) to enable the end user to

regulate both positive and negative outputs. Programmable

current limit allows proper sizing and protection of the primary

switching FET. The devices support a maximum duty cycle

greater than 92% and provide programmable slope com-

pensation to allow optimization of control loop performance.

The devices provide an open-drain PGOOD pin that serves

as a power-good indicator and enters the high-impedance

state to indicate that the flyback/boost converter is in regu-

lation. An SS pin allows programmable soft-start time for the

flyback/boost converter. Hiccup-mode overcurrent pro-

tection and thermal shutdown are provided to minimize

dissipation under overcurrent and overtemperature fault

conditions. The devices are available in a space-saving,

16-pin (3mm x 3mm) TQFN package with 0.5mm lead

spacing.

Benefits and Features

S

Peak Current-Mode Converter

S

Current-Mode Control Provides Excellent

Transient Response

S

Fixed Switching Frequency



250kHz: MAX17498A/MAX17498C



500kHz: MAX17498B

S

Flexible Error Amplifier to Regulate Both Positive

and Negative Outputs

S

Programmable Soft-Start to Reduce Input Inrush

Current

S

Programmable Voltage or Current Soft-Start

S

Power-Good Signal (PGOOD)

S

Reduced Power Dissipation Under Fault



Overcurrent Protection



Thermal Shutdown with Hysteresis

S

Robust Protection Features



Programmable Current Limit



Input Overvoltage Protection

S

Optimized Loop Performance



Programmable Slope Compensation

S

High Efficiency



Low RDSON, 175mI, 65V Rated Internal

n-Channel MOSFET



No Current-Sense Resistor

S

Optional Spread Spectrum

S

Space-Saving, 16-Pin (3mm x 3mm) TQFN

Package

Applications

Front-End AC-DC Power Supplies for Industrial

Applications (Isolated and Nonisolated)

Telecom Power Supplies

Wide Input Range DC Input Flyback /Boost

Industrial Power Supplies

For related parts and recommended products to use with this part,

refer to www.maximintegrated.com/MAX17498A.related.

Ordering Information and Typical Application Circuits

appear at end of data sheet.

EVALUATION KIT AVAILABLE

For pricing, delivery, and ordering information, please contact Maxim Direct at

1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.