ONSEMI NSI50350AST3G

NSI50350AST3G
Constant Current Regulator
& LED Driver
50 V, 350 mA + 10%, 5.8 W Package
The linear constant current regulator (CCR) is a simple, economical
and robust device designed to provide a cost−effective solution for
regulating current in LEDs. The CCR is based on Self−Biased
Transistor (SBT) technology and regulates current over a wide voltage
range. It is designed with a negative temperature coefficient to protect
LEDs from thermal runaway at extreme voltages and currents.
The CCR turns on immediately and is at 20% of regulation with
only 0.5 V Vak. It requires no external components allowing it to be
designed as a high or low−side regulator. The high anode−cathode
voltage rating withstands surges common in Automotive, Industrial
and Commercial Signage applications. The CCR comes in thermally
robust packages and is qualified to AEC−Q101 standard and
UL94−V0 Certified.
Also available in DPAK: NSI50350ADT4G.
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Ireg(SS) = 350 mA
@ Vak = 7.5 V
Anode 2
Cathode 1
Features
•
•
•
•
•
•
•
•
Typical Applications
• Automobile: Chevron Side Mirror Markers, Cluster, Display &
Instrument Backlighting, CHMSL, Map Light
• AC Lighting Panels, Display Signage, Decorative Lighting, Channel
•
•
Lettering
Application Note AND8349/D − Automotive CHMSL
Application Notes AND8391/D, AND9008/D − Power Dissipation
Considerations
Mechanical Characteristics
• CASE: Void-free, transfer-molded, thermosetting plastic
•
•
•
•
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1
Robust Power Package: 5.8 W
Wide Operating Voltage Range
Immediate Turn−On
Voltage Surge Suppressing − Protecting LEDs
AEC−Q101 Qualified and PPAP Capable, UL94−V0 Certified
SBT (Self−Biased Transistor) Technology
Negative Temperature Coefficient
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
FINISH: All external surfaces are corrosion resistant and leads are
readily solderable
MAXIMUM CASE TEMPERATURE FOR SOLDERING PURPOSES:
260°C for 10 seconds
LEADS: Modified L−Bend providing more contact area to bond pads
POLARITY: Cathode indicated by molded polarity notch
MOUNTING POSITIONS: Any
© Semiconductor Components Industries, LLC, 2012
May, 2012 − Rev. 3
1
2
SMC
CASE 403
MARKING DIAGRAM
1
AYWW
350AG
G
2
350A
= Specific Device Code
A
= Assembly Location
Y
= Year
WW
= Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
ORDERING INFORMATION
Device
Package
Shipping†
NSI50350AST3G
SMC
(Pb−Free)
2500 / Tape & Reel
†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.
Publication Order Number:
NSI50350AS/D
NSI50350AST3G
MAXIMUM RATINGS (TA = 25°C unless otherwise noted)
Rating
Anode−Cathode Voltage
Reverse Voltage
Operating and Storage Junction Temperature Range
ESD Rating:
Human Body Model
Machine Model
Symbol
Value
Unit
Vak Max
50
V
VR
500
mV
TJ, Tstg
−55 to +175
°C
ESD
Class 3B (8000 V)
Class C (400 V)
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted)
Characteristic
Symbol
Min
Typ
Max
Unit
Steady State Current @ Vak = 7.5 V (Note 1)
Ireg(SS)
315
350
385
mA
405.5
460
516.5
mA
Voltage Overhead (Note 2)
Voverhead
Pulse Current @ Vak = 7.5 V (Note 3)
Ireg(P)
1.8
V
1. Ireg(SS) steady state is the voltage (Vak) applied for a time duration ≥ 300 sec, using 900 mm2 DENKA K1, 1.5 mm Al, 2kV Thermally
conductive dielectric, 2 oz. Cu (or equivalent), in still air.
2. Voverhead = Vin − VLEDs. Voverhead is typical value for 70% Ireg(SS).
3. Ireg(P) non−repetitive pulse test. Pulse width t ≤ 360 msec.
THERMAL CHARACTERISTICS
Characteristic
Symbol
Max
Unit
PD
3112
20.75
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 4)
RθJA
48.2
°C/W
Thermal Reference, Junction−to−Tab (Note 4)
RψJL
PD
8.7
°C/W
4225
28.17
mW
mW/°C
Total Device Dissipation (Note 4) TA = 25°C
Derate above 25°C
Total Device Dissipation (Note 5) TA = 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 5)
RθJA
35.5
°C/W
Thermal Reference, Junction−to−Tab (Note 5)
RψJL
8.0
°C/W
PD
5119
34.13
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 6)
RθJA
29.3
°C/W
Thermal Reference, Junction−to−Tab (Note 6)
RψJL
7.2
°C/W
PD
5859
39.06
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 7)
RθJA
25.6
°C/W
Thermal Reference, Junction−to−Tab (Note 7)
RψJL
6.9
°C/W
PD
3061
20.41
mW
mW/°C
Total Device Dissipation (Note 6) TA = 25°C
Derate above 25°C
Total Device Dissipation (Note 7) TA = 25°C
Derate above 25°C
Total Device Dissipation (Note 8) TA = 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 8)
RθJA
49
°C/W
Thermal Reference, Junction−to−Tab (Note 8)
RψJL
15.1
°C/W
NOTE: Lead measurements are made by non−contact methods such as IR with treated surface to increase emissivity to 0.9.
Lead temperature measurement by attaching a T/C may yield values as high as 30% higher °C/W values based upon empirical
measurements and method of attachment.
4. 400 mm2, see below PCB description, still air.
5. 900 mm2, see below PCB description, still air.
6. 1600 mm2, see below PCB description, still air.
7. 2500 mm2, see below PCB description, still air.
(For NOTES 4−7: PCB is DENKA K1, 1.5 mm Al, 2kV Thermally conductive dielectric, 2 oz. Cu, or equivalent).
8. 1000 mm2, FR4, 3 oz Cu, still air.
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2
NSI50350AST3G
TYPICAL PERFORMANCE CURVES
(Minimum DENKA K1 @ 900 mm2, 1.5 mm Al, 2kV Thermally conductive dielectric, 2 oz. Cu, or equivalent)
Ireg(SS), STEADY STATE CURRENT (mA)
Ireg, CURRENT REGULATION (mA)
400
350
300
250
200
150
100
50
0
TA = 25°C
−50
−10
0
10
20
30
50
40
60
Ireg(SS), STEADY STATE CURRENT (mA)
Ireg(P), PULSE CURRENT (mA)
TA = 85°C
300
350
300
250
200
Non−Repetitive Pulse Test
TJ, maximum die temperature limit 175°C
200
150
100
50
0
DC Test Steady State, Still Air
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
380
3
4
5
6
8
7
9 10 11 12 13 14 15
Vak @ 7.5 V
TA = 25°C
370
360
350
340
330
320
310
400 410 420 430 440 450 460 470 480 490 500 510 520
Ireg(P), PULSE CURRENT (mA)
Figure 3. Pulse Current (Ireg(P)) vs.
Anode−Cathode Voltage (Vak)
Figure 4. Steady State Current vs. Pulse
Current Testing
450
9000
Vak @ 7.5 V
TA = 25°C
440
430
PD, POWER DISSIPATION (mW)
Ireg, CURRENT REGULATION (mA)
2
390
Vak, ANODE−CATHODE VOLTAGE (V)
420
410
400
390
380
370
360
350
0
≈−0.847 mA/°C typ
250
Figure 2. Steady State Current (Ireg(SS)) vs.
Anode−Cathode Voltage (Vak)
400
340
≈−0.773 mA/°C typ
Figure 1. General Performance Curve for CCR
TA = 25°C
1
TA = 25°C
350
Vak, ANODE−CATHODE VOLTAGE (V)
450
150
TA = −40°C
400
Vak, ANODE−CATHODE VOLTAGE (V)
550
500
450
50
100
150
200
250
300
2500 mm2, Denka K1, 2 oz
8000
7000
1600 mm2, Denka K1, 2 oz
6000
5000
4000
3000
2000
900 mm2, Denka K1, 2 oz
1000
0
−40
350
400 mm2, Denka K1, 2 oz
1000 mm2, FR4, 3 oz
0
40
80
TIME (s)
TA, AMBIENT TEMPERATURE (°C)
Figure 5. Current Regulation vs. Time
Figure 6. Power Dissipation vs. Ambient
Temperature @ TJ = 1755C
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120
NSI50350AST3G
APPLICATIONS INFORMATION
The CCR is a self biased transistor designed to regulate the
current through itself and any devices in series with it. The
device has a slight negative temperature coefficient, as
shown in Figure 2 – Tri Temp. (i.e. if the temperature
increases the current will decrease). This negative
temperature coefficient will protect the LEDS by reducing
the current as temperature rises.
The CCR turns on immediately and is typically at 20% of
regulation with only 0.5 V across it.
The device is capable of handling voltage for short
durations of up to 50 V so long as the die temperature does
not exceed 175°C. The determination will depend on the
thermal pad it is mounted on, the ambient temperature, the
pulse duration, pulse shape and repetition.
Single LED String
The CCR can be placed in series with LEDs as a High Side
or a Low Side Driver. The number of the LEDs can vary
from one to an unlimited number. The designer needs to
calculate the maximum voltage across the CCR by taking
the maximum input voltage less the voltage across the LED
string (Figures 7 and 8).
Figure 8.
Higher Current LED Strings
Two or more fixed current CCRs can be connected in
parallel. The current through them is additive (Figure 9).
Figure 7.
Figure 9.
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NSI50350AST3G
Other Currents
LEDs on and off for a portion of a single cycle. This on/off
cycle is called the Duty cycle (D) and is expressed by the
amount of time the LEDs are on (Ton) divided by the total
time of an on/off cycle (Ts) (Figure 12).
The adjustable CCR can be placed in parallel with any
other CCR to obtain a desired current. The adjustable CCR
provides the ability to adjust the current as LED efficiency
increases to obtain the same light output (Figure 10).
Figure 12.
The current through the LEDs is constant during the period
they are turned on resulting in the light being consistent with
no shift in chromaticity (color). The brightness is in proportion
to the percentage of time that the LEDs are turned on.
Figure 13 is a typical response of Luminance vs Duty Cycle.
6000
5000
ILLUMINANCE (lx)
Figure 10.
4000
Dimming using PWM
The dimming of an LED string can be easily achieved by
placing a BJT in series with the CCR (Figure 11).
3000
2000
Lux
Linear
1000
0
0
10
20
30
40 50
60 70
DUTY CYCLE (%)
80
90 100
Figure 13. Luminous Emmitance vs. Duty Cycle
Reducing EMI
Designers creating circuits switching medium to high
currents need to be concerned about Electromagnetic
Interference (EMI). The LEDs and the CCR switch
extremely fast, less than 100 nanoseconds. To help eliminate
EMI, a capacitor can be added to the circuit across R2.
(Figure 11) This will cause the slope on the rising and falling
edge on the current through the circuit to be extended. The
slope of the CCR on/off current can be controlled by the
values of R1 and C1.
The selected delay / slope will impact the frequency that
is selected to operate the dimming circuit. The longer the
delay, the lower the frequency will be. The delay time should
not be less than a 10:1 ratio of the minimum on time. The
frequency is also impacted by the resolution and dimming
steps that are required. With a delay of 1.5 microseconds on
the rise and the fall edges, the minimum on time would be
30 microseconds. If the design called for a resolution of 100
dimming steps, then a total duty cycle time (Ts) of
3 milliseconds or a frequency of 333 Hz will be required.
Figure 11.
The method of pulsing the current through the LEDs is
known as Pulse Width Modulation (PWM) and has become
the preferred method of changing the light level. LEDs being
a silicon device, turn on and off rapidly in response to the
current through them being turned on and off. The switching
time is in the order of 100 nanoseconds, this equates to a
maximum frequency of 10 MHz, and applications will
typically operate from a 100 Hz to 100 kHz. Below 100 Hz
the human eye will detect a flicker from the light emitted
from the LEDs. Between 500 Hz and 20 kHz the circuit may
generate audible sound. Dimming is achieved by turning the
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NSI50350AST3G
Thermal Considerations
P D(MAX) +
As power in the CCR increases, it might become
necessary to provide some thermal relief. The maximum
power dissipation supported by the device is dependent
upon board design and layout. Mounting pad configuration
on the PCB, the board material, and the ambient temperature
affect the rate of junction temperature rise for the part. When
the device has good thermal conductivity through the PCB,
the junction temperature will be relatively low with high
power applications. The maximum dissipation the device
can handle is given by:
T J(MAX) * T A
R qJA
Referring to the thermal table on page 2 the appropriate
RqJA for the circuit board can be selected.
AC Applications
The CCR is a DC device; however, it can be used with full
wave rectified AC as shown in application notes
AND8433/D and AND8492/D and design notes
DN05013/D and DN06065/D. Figure 14 shows the basic
circuit configuration.
Figure 14. Basic AC Application
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NSI50350AST3G
PACKAGE DIMENSIONS
SMC
CASE 403−03
ISSUE E
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. D DIMENSION SHALL BE MEASURED WITHIN DIMENSION P.
4. 403-01 THRU -02 OBSOLETE, NEW STANDARD 403-03.
HE
E
b
DIM
A
A1
b
c
D
E
HE
L
L1
D
MIN
1.90
0.05
2.92
0.15
5.59
6.60
7.75
0.76
MILLIMETERS
NOM
MAX
2.13
2.41
0.10
0.15
3.00
3.07
0.23
0.30
5.84
6.10
6.86
7.11
7.94
8.13
1.02
1.27
0.51 REF
MIN
0.075
0.002
0.115
0.006
0.220
0.260
0.305
0.030
INCHES
NOM
0.084
0.004
0.118
0.009
0.230
0.270
0.313
0.040
0.020 REF
MAX
0.095
0.006
0.121
0.012
0.240
0.280
0.320
0.050
A
L
L1
c
A1
SOLDERING FOOTPRINT*
4.343
0.171
3.810
0.150
2.794
0.110
SCALE 4:1
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent
rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other
applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur.
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NSI50350AS/D