LDF24E-xx-xxx
Series
S
Miniature, SMT
Constant Current Output
DC/DC LED Drivers
Electrical Specifications
Specifications typical @ +25°C, nominal input voltage & rated output current, unless otherwise noted. Specifications subject to change without notice.
Input
Parameter
•
300 - 700 mA Output Current
Input Voltage Range
Max Input Voltage
•
Constant Current Output
Input Filter
•
Miniature SMTCase
Output
Parameter
•
PWM & Analog Dimming
Output Current Accuracy
•
Wide 5.5V to 48V Input Range
Output Current Stability
Output Capacitive Load
•
Efficiency to 96%
Ripple & Noise
•
2.0 MHrs MTBF
Temperature Coefficient
Output Short Circuit
•
Low, Low Cost!
Environmental
Parameter
Key Features:
Conditions
Min.
5.5
See Note 1
Internal Capacitor
Typ.
24.0
Max.
48.0
55.0
Units
VDC
VDC
Conditions
Vin = 24V
Vin = 48V
Min.
Typ.
±2.0
Max.
±3.0
±1.0
1,000
120
±0.015
Units
%
%
µF
mV P-P
%/
º
C
Continuous
Conditions
300 mA, 350 mA Output Models
All Other Models
Case
Min.
-40
-40
Typ.
+25
+25
Max.
+85
+71
+100
+125
95
260
Units
º
C
º
C
º
C
Operating Temperature Range, Ambient
Operating Temperature Range, Case
Storage Temperature Range
Cooling
Humidity
Lead Temperature
Physical
Case Size
Case Material
Weight
Remote On/Off Control
Parameter
DC/DC On
DC/DC Off
Remote Pin Drive Current
Quiescent Input Current
(Shutdown Mode)
PWM Dimming
Parameter
Operation Frequency
Reliability Specifications
Parameter
MTBF
-55
Free Air Convection
RH, Non-condensing
1.5 mm From Case For 10 Sec
%
ºC
0.94 x 0.54 x 0.295 Inches (23.86 x 13.70 x 7.50 mm)
Non-Conductive Black Plastic (UL94-V0)
0.212 Oz (6.0g)
Conditions
Min.
Typ.
Max.
Units
Open Or 2.8 VDC < 6.0 VDC
<0.6 VDC
1
mA
400
µA
Typ.
Max.
10
Max.
Units
kHz
Units
MHours
Vcont = 5.0 VDC
Vin = 24V, Vcont = <0.6 VDC
Conditions
Min.
0.2
Min.
2.0
Conditions
MIL HDBK 217F, 25
º
C, Gnd Benign
Typ.
Typical Connection:
DC Input
MicroPower Direct
292 Page Street
Suite D
Stoughton, MA 02072
USA
T:
(781) 344-8226
F:
(781) 344-8481
E:
sales@micropowerdirect.com
W:
www.micropowerdirect.com
Typical Connection:
AC Input
Connection Notes:
1. Input filter components (C
1
, L
1
& C
2
) are
used to help meet the conducted emissions
requirements (EN 55022 B) for the unit.
Recommended values are:
C
2
- 2.2
µF
L
1
- 1.25 mH
C
3
- 1.0
µF
Other components added to the circuit
include an input storage capacitor to help
prevent problems due to input line sags and
an output capacitor to improve performance.
Recommended values are:
C
1
- 470
µF
C
4
- 1.0
µF
2
2. To comply with EN61000-4-5, a TVS should
be installed before the input filter compo-
nents. A SMCG51 is recommended.
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Model Selection Guide
Model
Number
LDF24E-10-300
LDF24E-12-350
LDF24E-18-500
LDF24E-21-600
LDF24E-25-700
Input
Voltage
(VDC)
Nominal
24
24
24
24
24
Range
5.5 - 48.0
5.5 - 48.0
5.5 - 48.0
5.5 - 48.0
5.5 - 48.0
Output
Voltage
(VDC)
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Current
(mA)
Dimming
Control
PWM/Analog
PWM/Analog
PWM/Analog
PWM/Analog
PWM/Analog
Efficiency
(%, Max)
96
96
96
96
96
3.3 - 36.0
3.3 - 36.0
3.3 - 36.0
3.3 - 36.0
3.3 - 36.0
0.0 - 300
0.0 - 350
0.0 - 500
0.0 - 600
0.0 - 700
Specification Notes:
1. Exceeding 55V on the unit input could damage the unit.
2. No connection should be made between input ground and
the output.
3. These are step-down devices, the maximum output open
voltage is equal to the input voltage.
4. When not used, the PWM/Cont input (Pin 3) or should be left
open if not used.
5. Exceeding the specified maximum output power could cause
damage to the unit.
PWM Output Current Control
Typical Connection:
Parallel Output
Output current may be adjusted
by using a pulse width modu-
lated (PWM) signal. By varying
the signal duty cycle (as shown
at right) the output current is
adjusted up or down.
Output current may be calcu-
lated by using the formula:
I
OUT
=
(DT - 0.6)
T
=
=
=
=
x I
RATED
Connection Notes:
1. A positive temperature coefficient PTC is connected to each parallel channel for protection.
Mechanical Dimensions
Where I
OUT
I
RATED
D
T
Required output current
Full rated output current for the unit
Pulse width of the he control signal
Cycle of the control signal
The T
ON
of the driver signal must be greater than 0.7 mS. An audible noise may be generated
during the digital dimming process of the driver, since the control circuit frequency is within the
is within the range of human hearing (20 Hz - 20 kHz).
Analog Output Current Control
Analog dimming is accomplished
by using a simple resistor divider
network, as illustrated above.
The output current is varied by
changing the voltage level pres-
ent at Pin 10. The amount varia-
tion is shown in chart at right.
The maximum voltage level that
can be applied to Pin 10 is 15V.
Exceeding this may damage
the driver.
Analog and PWM control of the
driver should not be attempted
at the same time. The control
pin not being used should be
left open.
Analog Control vs Output
Notes:
•
All dimensions are typical in inches (mm)
•
Tolerance x.xx = ±0.01 (±0.25)
•
Pin 1 is marked by a “dot” or indentation on
the top of the unit
Solder Layout
Pin Connections
Pin
1
7
8
Function
Gnd
PWM, On/Off
-V
OUT
Pin
9
10
16
Function
+V
OUT
Analog Dimming
+V
IN
MicroPower Direct
We Power Your Success - For Less!
292 Page Street Ste D Stoughton, MA 02072
•
TEL: (781) 344-8226
•
FAX: (781) 344-8481
•
E-Mail: sales@micropowerdirect.com
Embedded System
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