600 Ma Sync-rect Pfm Step-up Dc-dc Converter Step-up Dc-dc Converter With True-cutoff And Ring-killer

ON Semiconductor

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NCP1421 pinout,NCP1421 pin diagram
NCP1421
600 mA Sync−Rect PFM
Step−Up DC−DC Converter
with True−Cutoff and
Ring−Killer
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
provide value−added features for various battery−operated
applications. With all these functions on, the quiescent supply
current is typically only 8.5
mA.
This device is available in the
compact and low profile MICRO8T package.
Features
http://onsemi.com
MARKING
DIAGRAM
DM SUFFIX
CASE 846A
8
1
1421
AYW
1421
A
Y
W
= Device Code
= Assembly Location
= Year
= Work Week
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
mA
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
FB
LBI/EN
LBO
REF
PIN CONNECTIONS
1
2
3
4
(Top View)
8
7
6
5
OUT
LX
GND
BAT
ORDERING INFORMATION
Device
Package
(Pb−Free)
Shipping†
4000 Tape & Reel
4000 Tape & Reel
Typical Applications
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
©
Semiconductor Components Industries, LLC, 2004
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
1
October, 2004 − Rev. 6
Publication Order Number:
NCP1421 D