ZETEX ZXSC300 Technical data
SINGLE OR MULTI CELL LED DRIVER SOLUTION
DESCRIPTION
The ZXSC300 is a single or multi cell LED driver
designed for applications where step-up voltage
conversion from very low input voltages is required.
These applicationsmainly operate from single 1.5V or
1.2V battery cells. The circuit generates constant
current pulses that are ideal for driving single or
multipleLED’soverawide rangeofoperating voltages.
The ZXSC300 is a PFM controller IC that drives an
external Zetex switching transistor with a very low
saturation resistance. These transistors are the best
switching devices available for this type of switching
conversion enabling high efficiency conversion with
input voltages below 1 volt. The drive output of the
ZXSC controller generates a dynamic drive signal for
the switching transistor.
The circuit can start up under full load and operates
down to an input voltage of 0.8 volts. The solution
configuration ensures optimum efficiency over a wide
range of load currents, several circuit configurations
are possible depending on battery life versus
brightness considerations.
TheZXSC300isofferedintheSOT23-5packagewhich,
when combined with a SOT23 switching transistor,
generates a high efficiency small size circuit solution.
The IC and discrete combination offers the ultimate
costvsperformance solution forsinglecell LED driving
applications.
ZXSC300
FEATURES
94% efficiency
•
• Minimum operating input voltage 0.8V
•
Fixed output current
•
Low saturation voltage switching transistor
•
SOT23-5 package
TYPICAL APPLICATION CIRCUIT
V
BATT
L1
100µH
U1
V
cc
V
drive
I
sense
Gnd
ZXSC300
Q1
FMMT617
R1
0.33R
LED1
WHITE LED
APPLICATIONS
LED flashlights and torches
•
• LED backlights
•
White LED driving
•
Multiple LED driving
•
Solar Equipment
ORDERING INFORMATION
DEVICE Reel Tapewidth Quantity
ZXSC300E5TA 7” 8mm 3,000
per reel
DEVICE MARKING C300
Package SOT23-5
ISSUE 2 - FEBRUARY 2004
1
SEMICONDUCTORS
ZXSC300
ABSOLUTE MAXIMUM RATING
Supply Voltage -0.3 to 10V
Maximum Voltage Other Pins -0.3 to V
Power Dissipation 450mW
CC
+0.3V
Operating Temperature -40 to 85°C
Storage Temperature -55 to 150°C
ELECTRICAL CHARACTERISTICS: Test conditions unless otherwise stated: V
=1.5V, T
CC
AMB
=25°C
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS
η
V
CC
V
CC(min)
I
Q
I
VDRIVE
I
CC
V
VDRIVE(high)
V
VDRIVE(low)
V
ISENSE
(threshold)
T
CVISENSE
I
ISENSE
T
DRV
Efficiency
Recommended
1
0.8 8 V
supply voltage range
Minimum startup
and operating
voltage
Quiescent current
Base drive current V
Supply current
3
High level drive
voltage
Low level drive
voltage
Output current
I
=-600µA, V
DRIVE
=-600µA, V
I
DRIVE
T
AMB
2
DRIVE
V
DRIVE
V
ISENSE
V
ISENSE
=-10°C
= 0.7V, V
= 0.7V, V
=0V,I
= 50mV, I
3
=0.7V
DRIVE
=0.7V,
DRIVE
= 0V 1.5 3.6 mA
ISENSE
=0V 2 4 mA
ISENSE
=-0.5mA VCC-0.3 VCCV
VDRIVE
= 5mA 0 0.2 V
VDRIVE
14 19 24 mV
reference voltage
I
SENSE
voltage temp co.
I
input current V
SENSE
2
= 0V 0 -30 -65 µA
ISENSE
Discharge pulse width 1.2 1.7 3.2 µ s
94 %
0.8
0.92 V
0.9
0.2 mA
0.4 %/°C
OPERATING CONDITIONS
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNITS
F
OSC
1
Application dependent, see reference designs.
2
These parameters guaranteed by design and characterisation
3
Total supply current =IQ+ I
4
Operating frequency is application circuit dependent. See applications section.
SEMICONDUCTORS
Recommended operating frequency
, see typical characteristics
VDRIVE
4
200 kHz
ISSUE 2 - FEBRUARY 2004
2
ZXSC300
FMMT617
For the circuits described in the applications section, Zetex FMMT617 is the recommended pass transistor. The
following indicates outline data for the transistor, more detailed information can be found in the Zetex surface
mount data book or at www.zetex.com
ELECTRICAL CHARACTERISTICS (at TA= 25°C unless otherwise stated).
PARAMETER SYMBOL MIN. TYP. MAX. UNIT CONDITIONS
Collector-Emitter
Saturation Voltage
Collector-Emitter
Breakdown Voltage
V
CE(sat)
V
(BR)CEO
15 18 V IC=10mA*
8
70
150
*Measured under pulsed conditions. Pulse width=300µs. Duty cycle ≤ 2%
ZHCS1000
For the circuits described in the applications section Zetex ZHCS1000 is the recommended Schottky diode. The
following indicates outline data for the diode, more detailed information is available at www.zetex.com
14
100
200
mV
mV
mV
IC=0.1A, IB=10mA*
I
=1A, IB=10mA*
C
I
=3A, IB=40mA*
C
ELECTRICAL CHARACTERISTICS (at T
PARAMETER SYMBOL MIN. TYP. MAX. UNIT CONDITIONS
Forward Voltage V
Reverse Current I
Reverse Recovery
Time
F
R
t
rr
= 25°C unless otherwise stated).
amb
400
500
50 100
12 ns Switched from IF= 500mA
mV
mV
µA
IF=500mA
I
=1A
F
VR=30V
to I
= 500mA. Measured at
R
I
=50mA
R
*Measured under pulsed conditions. Pulse width=300µs. Duty cycle ≤ 2%
ISSUE 2 - FEBRUARY 2004
3
SEMICONDUCTORS
ZXSC300
TYPICAL CHARACTERISTICS
SEMICONDUCTORS
ISSUE 2 - FEBRUARY 2004
4
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