1FEATURES
2• Power-up/Power-down Tracking
• Self-synchronization to Main Channel Output
• Leading Edge Pulse Width Modulation
• Valley Current Mode Control
• Standalone DC/DC Synchronous Buck Mode
• Operates from AC or DC Input up to 42V
• Wide 4.5V to 30V Bias Supply Range
• Wide 0.75V to 13.5V Output Range.
• Top and Bottom Gate Drivers Sink 2.5A Peak
• Adaptive Gate Driver Dead-time Control
• Wide Bandwidth Error Amplifier (4MHz)
• Programmable Soft-start
• Thermal Shutdown Protection
• TSSOP-16 package

DESCRIPTION
The LM25115A controller contains all of the features
necessary to produce multiple tracking outputs using
the Secondary Side Post Regulation (SSPR)
technique. The SSPR technique develops a highly
efficient and well regulated auxiliary output from the
secondary side switching waveform of an isolated power converter. LM25115A can be also used as a
standalone DC/DC synchronous buck controller
(Refer to Standalone DC/DC Synchronous Buck
Mode section). Regulation of the auxiliary output
voltage is achieved by leading edge pulse width
modulation (PWM) of the main channel duty cycle.
Leading edge modulation is compatible with either
current mode or voltage mode control of the main
output. The LM25115A drives external high-side and
low-side NMOS power switches configured as a
synchronous buck regulator. A current sense
amplifier provides overload protection and operates
over a wide common mode input range. Additional
features include a low dropout (LDO) bias regulator,
error amplifier, precision reference, adaptive dead
time control of the gate signals and thermal
shutdown.