LM3485_16 Datasheet, PDF (1/28 Pages) Texas Instruments – Hysteretic PFET Buck Controller

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LM3485
SNVS178H – JANUARY 2002 – REVISED DECEMBER 2015
LM3485 Hysteretic PFET Buck Controller
1 Features
•1 Easy-to-Use Control Methodology
• No Control-Loop Compensation Required
• 4.5-V to 35-V Wide Input Range
• 1.242-V to V_IN Adjustable Output Range
• High Efficiency 93%
• ±1.3% (±2% Over Temp) Internal Reference
• 100% Duty Cycle
• Maximum Operating Frequency > 1 MHz
• Current Limit Protection
2 Applications
• Set-Top Box
• DSL or Cable Modem
• PC/IA
• Auto PC
• TFT Monitor
• Battery-Powered Portable Applications
• Distributed Power Systems
• Always On Power
3 Description
The LM3485 is a high-efficiency PFET switching
regulator controller that can be used to quickly and
easily develop a small, low-cost, switching buck
regulator for a wide range of applications. The
hysteretic control architecture provides for simple
design without any control-loop stability concerns
using a wide variety of external components. The
PFET architecture also allows for low component
count as well as ultralow dropout, 100% duty cycle
operation. Another benefit is high efficiency operation
at light loads without an increase in output ripple.
Current limit protection is provided by measuring the
voltage across the R_DS(ON) of the PFET, thus
eliminating the need for a sense resistor. The cycle-
by-cycle current limit can be adjusted with a single
resistor, ensuring safe operation over a range of
output currents.
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM3485
VSSOP (8)
3.0 mm × 3.0 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.