NCP1500

Features:

Current Mode Control with Cycle-by-Cycle Current Limit
Nominal Synchronization Frequency of 270 to 630 kHz
Built-in Slope Compensation
Low Output Noise
Thermal Shutdown with Hysteresis
Digitally Programmable Output Voltage Between 4 Voltages:1.0, 1.3, 1.5, and 1.8
Fast Transient Response
Input Voltage Range From 2.7 V to 5.4 V
Space Saving Micro8 Package
Low Shutdown Current of 0.18 A Typical
Pb-Free Package is Available


Application

Baseband Supplies for Portable Handsets
PDAs
Supplies for DSP Circuitry


Pinout




Specifications

Rating	Symbol	Value	Unit
Device Power Supply (Pin 8)	VOUT	-0.3 to 6.0	V
Input/Output Pins (Pins 1-5, Pin 7)	VIO	-0.3 to 6.0	V
Thermal Characteristics                            - Micro8 Plastic Package                            Thermal Resistance, Junction-to-Air	PD RJA	520 240	Mw /W
Operating Junction Temperature Range	TJ	-40 to +150
Operating Ambient Temperature Range	TA	-40 to +85
Storage Temperature Range	Tstg	-55 to +150

Description

The NCP1500 is a dual mode converter that operates as either a pulse width modulated (PWM) buck converter or as a linear regulator. The converter automatically transitions between the two modes. The NCP1500 converter operates as a PWM when a synchronization signal is present at the sync input. The NCP1500 converter operates as a linear regulator in the absence of a synchronization signal. The PWM mode offers excellent performance at normal to heavy loads at the sacrifice of output ripple voltage. The linear mode offers excellent noise rejection at the sacrifice of system efficiency. The user is able to select which mode will give the best performance for a given operating condition. Internal protection features include thermal shutdown with hysteresis and cycle-by-cycle current limit in the PWM mode. Additionally, the converter transitions into PFM mode at very light loads if a synchronization signal is present and an output overvoltage condition is detected.