1 Features
1• Space-Saving SOT-23 Package
• Input Voltage Range of 3 V to 5.5 V
• Output Voltage Range of 0.6 V to 4.5 V
• 1.5-A Output Current
• High Switching Frequencie
– 1.6 MHz (LM2831X)
– 0.55 MHz (LM2831Y)
– 3 MHz (LM2831Z)
• 130-mΩ PMOS Switch
• 0.6-V, 2% Internal Voltage Reference
• Internal Soft Start
• Current Mode, PWM Operation
• Thermal Shutdown
• Overvoltage Protection

2 Applications
• Local 5 V to Vcore Step-Down Converters
• Core Power in HDDs
• Set-Top Boxes
• USB Powered Devices
• DSL Modems

3 Description
The LM2831 regulator is a monolithic, high-
frequency, PWM step-down DC-DC converter in a 5- pin SOT-23 and a 6-Pin WSON package. The
LM2831 provides all the active functions to provide
local DC-DC conversion with fast transient response
and accurate regulation in the smallest possible PCB area. With a minimum of external components, the
LM2831 is easy to use. The ability to drive 1.5-A
loads with an internal 130-mΩ PMOS switch using
state-of-the-art 0.5-μm BiCMOS technology results in
the best power density available. The world-class
control circuitry allows on-times as low as 30 ns, thus
supporting exceptionally high frequency conversion
over the entire 3 V to 5.5 V input operating range,
down to the minimum output voltage of 0.6 V. Switching frequency is internally set to 550 kHz, 1.6
MHz, or 3 MHz, allowing the use of extremely small
surface mount inductors and chip capacitors. Even
though the operating frequency is high, efficiencies of
up to 93% are easy to achieve. External shutdown is included, featuring an ultra-low standby current of 30
nA. The LM2831 utilizes current-mode control and
internal compensation to provide high-performance
regulation over a wide range of operating conditions.
Additional features include internal soft-start circuitry
to reduce inrush current, pulse-by-pulse current limit,
thermal shutdown, and output overvoltage protection.