4.5V-60V, 2.5A, High-Efficiency, Synchronous Step-Down DC-DC Converter With Internal Compensation

General Description
The MAX17503 high-efficiency, high-voltage, synchronously
rectified step-down converter with dual integrated
MOSFETs operates over a 4.5V to 60V input. It delivers
up to 2.5A and 0.9V to 90%VIN output voltage. Built-in
compensation across the output voltage range eliminates
the need for external components. The feedback (FB)
regulation accuracy over -40NC to +125NC is ±1.1%. The
device is available in a compact (4mm x 4mm) TQFN
lead(Pb)-free package with an exposed pad. Simulation
models are available.
The device features a peak-current-mode control
architecture with a MODE feature that can be used to
operate the device in pulse-width modulation (PWM),
pulse-frequency modulation (PFM), or discontinuousconduction
mode (DCM) control schemes. PWM operation
provides constant frequency operation at all loads, and is
useful in applications sensitive to switching frequency.
PFM operation disables negative inductor current and
additionally skips pulses at light loads for high efficiency.
DCM features constant frequency operation down to
lighter loads than PFM mode, by not skipping pulses but
only disabling negative inductor current at light loads.
DCM operation offers efficiency performance that lies
between PWM and PFM modes. The low-resistance,
on-chip MOSFETs ensure high efficiency at full load and
simplify the layout.
A programmable soft-start feature allows users to reduce
input inrush current. The device also incorporates an
output enable/undervoltage lockout pin (EN/UVLO) that
allows the user to turn on the part at the desired inputvoltage
level. An open-drain RESET pin provides a
delayed power-good signal to the system
upon achieving
successful regulation of the output voltage.

Applications
● Industrial Power Supplies
● Distributed Supply Regulation
● Base Station Power Supplies
● Wall Transformer Regulation
● High-Voltage Single-Board Systems
● General-Purpose Point-of-Load

Benefits and Features
● Eliminates External Components and Reduces Total
Cost
• No Schottky-Synchronous Operation for High
Efficiency and Reduced Cost
• Internal Compensation for Stable Operation at Any
Output Voltage
• All-Ceramic Capacitor Solution: Ultra-Compact
Layout with as Few as Eight External Components
● Reduces Number of DC-DC Regulators to Stock
• Wide 4.5V to 60V Input Voltage Range
• 0.9V to 90%VIN Output Voltage
• Delivers Up to 2.5A Over Temperature
• 200kHz to 2.2MHz Adjustable Frequency with
External Synchronization
• Available in a 20-Pin, 4mm x 4mm TQFN Package
● Reduces Power Dissipation
• Peak Efficiency > 90%
• PFM and DCM Modes for High Light-Load
Efficiency
• Shutdown Current = 2.8FA (typ)
● Operates Reliably
• Hiccup-Mode Current Limit and Autoretry Startup
• Built-In Output-Voltage Monitoring (Open-Drain
RESET Pin)
• Resistor-Programmable EN/UVLO Threshold
• Adjustable Soft-Start and Prebiased Power-Up
• -40NC to +125NC Operation