ZXSC100 Datasheet, PDF (1/19 Pages) Zetex Semiconductors – SINGLE CELL DC-DC CONVERTER SOLUTION

SINGLE CELL DC-DC CONVERTER SOLUTION
ZXSC100
DESCRIPTION
The ZXSC100 series is designed for DC-DC
applications where step-up voltage conversion from
very low input voltages is required. These applications
mainly operate from single nickel cadmium or nickel
metal hydride battery cells.
The ZXSC100 devices are non-synchronous PFM,
DC-DC controller ICs which drive an external
transistor. Zetex SuperSOT4^™ switching transistors,
with saturation resistance as low as 13mΩ, are
recommended as the external switching element.
These bipolar transistors are the best switching
devices available for this type of DC-DC conversion,
enabling high efficiency conversion with input
voltages down to below 1 volt.
The circuit can start up under full load with regulation
maintained down to an input voltage of only 0.926
volts. The solution configuration ensures optimum
efficiency over a wider range of load currents, several
circuit configurations are possible with power
dissipation up to 2W. The step up output voltage is
easily programmed with external resistors, the
non-synchronous architecture and SuperSOT4™
device enabling an output voltage down to the input
voltage level. For best performance the ZXSC100
quiescent current is a small 150µA ensuring minimum
battery drain in no load conditions.
For the best in space saving the ZXSC100 is offered in
the MSOP8 package, however the devices are also
available in SO8 packaging for applications where
space saving is not so critical.
The IC and discrete combination offers the ultimate
cost vs performance solution for single cell DC-DC
conversion.
FEATURES
• SuperSOT4™ switching transistor
ZXT14N20DX:V_CE(sat) 45mV max @ 1A load
• Efficiency maintained over a wide range of input
voltages and load currents
82% efficiency @ V_BATT=1V
• Startup under full load
• Minimum operating input voltage V_BATT=0.926V
• Adjustable output voltage down to V_BATT
• Quiescent current typically 150µA referred to
input voltage
• MSOP8 Package
• SO8 Package
• Demonstration boards available
APPLICATIONS
• Cordless Telephones
• MP3 Players
• PDA
• Pagers
• Battery Backup Supplies
• Electronic toothbrush
• GPS Receivers
• Digital Camera
• Palmtop Computers
APPLICATIONS(continued)
• Hand Held Instruments
• Portable Medical Equipment
• Solar Powered Equipment
• LED Flashlight
• LED Backlight
TYPICAL APPLICATION CIRCUIT
L1
VBATT
R1
U1
EM
VDRIVE
BAS ISENSE
RE
FB
VCC
GND
ZXSC100
C1
D1
ZHCS2000
3.3V/0.1A
Q1
R3
ZXT14N20DX
C3
C2
R2
R4
ISSUE 1 - JANUARY 2001
1