MAX17498A_14 Datasheet, PDF (1/20 Pages) Maxim Integrated Products – AC-DC and DC-DC Peak Current-Mode Converters for Flyback/Boost Applicatio

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MAX17498A/MAX17498B/MAX17498C
AC-DC and DC-DC Peak Current-Mode Converters
for Flyback/Boost Applications
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.
Ordering Information and Typical Application Circuits
appear at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maximintegrated.com/MAX17498A.related.
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 pricing, delivery, and ordering information, please contact Maxim Direct at
1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
19-6043; Rev 3; 4/13