NCP1421

Features:

Pb-Free Package is Available
High Efficiency: 94% for 3.3 V Output at 200 mA from 2.5 V Input
                           88% for 3.3 V Output at 500 mA from 2.5 V Input
High Switching Frequency, up to 1.2 MHz (not hitting current limit)
Output Current up to 600 mA at V_IN = 2.5 V and V_OUT = 3.3 V
True-Cutoff Function Reduces Device Shutdown Current to typically 50 nA
Anti-Ringing Ring-Killer for Discontinuous Conduction Mode
High Accuracy Reference Output, 1.20 V 1.5%, can Supply 2.5 mA Loading Current when V_OUT > 3.3 V
Low Quiescent Current of 8.5 A
Integrated Low-Battery Detector
Open Drain Low-Battery Detector Output
1.0 V Startup at No Load Guaranteed
Output Voltage from 1.5 V to 5.0 V Adjustable
1.5 A Cycle-by-Cycle Current Limit
Multi-function Logic-Controlled Shutdown Pin
On Chip Thermal Shutdown with Hysteresis


Application

Personal Digital Assistants (PDA)
Handheld Digital Audio Products
Camcorders and Digital Still Cameras
Hand-held Instruments
Conversion from one to two Alkaline, NiMH, NiCd Battery Cells to 3.0-5.0 V or one Lithium-ion cells to 5.0 V
White LED Flash for Digital Cameras


Pinout




Specifications

Rating	Symbol	Value	Unit
Device Power Supply (Pin 8)	VOUT	-0.3 to 5.5	V
Input/Output Pins (Pins 1-5, Pin 7)	VIO	-0.3 to 5.5	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

NCP1421 is a monolithic micropower high-frequency step-up switching converter IC specially designed for battery-operated hand-held electronic products up to 600 mA loading. It integrates Sync-Rect to improve efficiency and to eliminate the external Schottky Diode. High switching frequency (up to 1.2 MHz) allows for a low profile, small-sized inductor and output capacitor to be used. When the device is disabled, the internal conduction path from LX or BAT to OUT is fully blocked and the OUT pin is isolated from the battery. This True-Cutoff function reduces the shutdown current
to typically only 50 nA. Ring-Killer is also integrated to eliminate the high-frequency ringing in discontinuous conduction mode. In addition to the above, Low-Battery Detector, Logic-Controlled Shutdown, Cycle-by-Cycle Current Limit and Thermal Shutdown of the NCP1421 provide value-added features for various battery-operated applications. With all these functions on, the quiescent supply current is typically only 8.5 A. This device is available in the
compact and low profile Micro8 package.