Product specifications
The MxL76508 is a fully integrated, high-efficiency
synchronous step-down converter that requires a minimum
number of external components. It offers a very compact
solution with up to 8A continuous output current over a wide
input range.
The MxL76508 uses a proprietary constant on-time (COT)
control scheme that provides a superior transient response
and maintains a constant switching frequency during
continuous conduction mode (CCM) operation. The external
ramp compensation network enables stable operation
with ultra-low equivalent series resistance (ESR) output
ceramic capacitors. An internal compensated error amplifier
in the control loop provides excellent line and load regulation.
The MxL76508 integrates extensive protection functions,
including 2.85V input under-voltage lockout (UVLO),
thermal shutdown, input over-voltage protection (OVP),
cycle-by-cycle current limiting, and short-circuit protection.
An open-drain power good signal indicates that the output
is within its regulation voltage range.
The MxL76508 offers three modes of operation, PFM
(MxL76508N), UA (MxL76508U), and forced
PWM—FPWM—(MxL76508A), to suit different applications.
PFM mode provides high efficiency at light loads and low
standby power. UA mode can operate in DCM at light load
and in CCM at higher output power, and the lowest frequency
at light load is limited to a frequency not lower than that of the
sound wave to avoid buzzing noise. FPWM mode provides
low ripple voltage and fast transient, even at light loads.
The converter is available in a small 16-pin 3mm×3mm
QFN package.
Features
■ Input voltage range: 3V to 18V
■ 1% feedback voltage accuracy
■ 8A continuous output current
■ Supports 100% duty cycle low-dropout operation
■ Stable operation with low ESR ceramic output capacitors
■ Fast pulse-width modulation (PWM) COT control with superior transient performance
■ Constant 700KHz switching frequency
■ 14mW/8mW integrated high-side (HS)/low-side (LS) power switches
■ Accurate 1.26V EN threshold with 260mV hysteresis
■ High-efficiency operation at light load (MxL76508N)
■ Ultra-sonic (UA) mode of operation (MxL76508U)
■ FPWM mode of operation (MxL76508A)
■ Low quiescent current of 200mA for MxL76508U_UA mode,
low quiescent current of 150mA for MxL76508N_PFM mode
■ Internal fixed or external programmable soft-start time
■ Thermal shutdown
■ Hiccup mode short-circuit protection
■ Available in a 16-pin 3mm×3mm QFN package
Applications
■ USB Type-C/PD docking stations
■ Networking systems
■ Laptop computers
■ Flat panel television and monitors
■ Distributed power systems
