© Semiconductor Components Industries, LLC, 2011
October, 2011 − Rev. 1
1Publication Order Number:
NSI45035JZ/D
NSI45035JZT1G
Adjustable Constant Current
Regulator & LED Driver
45 V, 35 − 70 mA + 15%, 1.5 W Package
The adjustable constant current regulator (CCR) is a simple,
economical and robust device designed to provide a cost effective
solution for regulating current in LEDs (similar to Constant Current
Diode, CCD). 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. The Radj pin allows Ireg(SS) to be adjusted to higher
currents by attaching a resistor between Radj (Pin 3) and the Cathode
(Pin 4). The Radj pin can also be left open (No Connect) if no
adjustment is required. 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. This device is
available in a thermally robust package and is qualified to stringent
AEC−Q101 standard, which is lead-free RoHS compliant and uses
halogen-free molding compound, and UL94−V0 certified.
Features
•Robust Power Package: 1.5 Watts
•Adjustable up to 70 mA
•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
•Eliminates Additional Regulation
•These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Applications
•Automobile: Chevron Side Mirror Markers, Cluster, Display &
Instrument Backlighting, CHMSL, Map Light
•AC Lighting Panels, Display Signage, Decorative Lighting, Channel
Lettering
•Switch Contact Wetting
•Application Note AND8391/D − Power Dissipation Considerations
•Application Note AND8349/D − Automotive CHMSL
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Device Package Shipping†
ORDERING INFORMATION
NSI45035JZT1G SOT−223
(Pb−Free)
1000/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.
Anode
1
2/4
Cathode
Ireg(SS) = 35 − 70 mA
@ Vak = 7.5 V
3
Radj
SOT−223
CASE 318E
STYLE 2
MARKING DIAGRAM
(Note: Microdot may be in either location)
1
AYW
AAKG
G
A = Assembly Location
Y = Year
W = Work Week
AAK = Specific Device Code
G= Pb−Free Package
C
CA Radj
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2
MAXIMUM RATINGS (TA = 25°C unless otherwise noted)
Rating Symbol Value Unit
Anode−Cathode Voltage Vak Max 45 V
Reverse Voltage VR500 mV
Operating and Storage Junction Temperature Range TJ, Tstg −55 to +150 °C
ESD Rating: Human Body Model
Machine Model
ESD Class 2
Class C
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) 29.75 35 40.25 mA
Voltage Overhead (Note 2) Voverhead 1.8 V
Pulse Current @ Vak = 7.5 V (Note 3) Ireg(P) 30.9 42.5 mA
Capacitance @ Vak = 7.5 V (Note 4) C 7.4 pF
Capacitance @ Vak = 0 V (Note 4) C 31 pF
1. Ireg(SS) steady state is the voltage (Vak) applied for a time duration ≥ 35 sec, using FR−4 @ 300 mm2 2 oz. Copper traces, in still air.
2. Voverhead = Vin − VLEDs. Voverhead is typical value for 75% Ireg(SS).
3. Ireg(P) non−repetitive pulse test. Pulse width t ≤ 1.0 msec.
4. f = 1 MHz, 0.02 V RMS.
THERMAL CHARACTERISTICS
Characteristic Symbol Max Unit
Total Device Dissipation (Note 5) TA = 25°C
Derate above 25°C
PD1008
8.06
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 5) RθJA 124 °C/W
Thermal Reference, Junction−to−Lead 4 (Note 5) RψJL4 33.3 °C/W
Total Device Dissipation (Note 6) TA = 25°C
Derate above 25°C
PD1136
9.09
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 6) RθJA 110 °C/W
Thermal Reference, Junction−to−Lead 4 (Note 6) RψJL4 33.3 °C/W
Total Device Dissipation (Note 7) TA = 25°C
Derate above 25°C
PD1238
9.9
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 7) RθJA 101 °C/W
Thermal Reference, Junction−to−Lead 4 (Note 7) RψJL4 33.7 °C/W
Total Device Dissipation (Note 8) TA = 25°C
Derate above 25°C
PD1420
11.36
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 8) RθJA 88 °C/W
Thermal Reference, Junction−to−Lead 4 (Note 8) RψJL4 32.1 °C/W
Total Device Dissipation (Note 9) TA = 25°C
Derate above 25°C
PD1316
10.53
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 9) RθJA 95 °C/W
Thermal Reference, Junction−to−Lead 4 (Note 9) RψJL4 32.4 °C/W
Total Device Dissipation (Note 10) TA = 25°C
Derate above 25°C
PD1506
12.05
mW
mW/°C
Thermal Resistance, Junction−to−Ambient (Note 10) RθJA 83 °C/W
Thermal Reference, Junction−to−Lead 4 (Note 10) RψJL4 30.8 °C/W
Junction and Storage Temperature Range TJ, Tstg −55 to +150 °C
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.
5. FR−4 @ 300 mm2, 1 oz. copper traces, still air.
6. FR−4 @ 300 mm2, 2 oz. copper traces, still air.
7. FR−4 @ 500 mm2, 1 oz. copper traces, still air.
8. FR−4 @ 500 mm2, 2 oz. copper traces, still air.
9. FR−4 @ 700 mm2, 1 oz. copper traces, still air.
10.FR−4 @ 700 mm2, 2 oz. copper traces, still air.
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TYPICAL PERFORMANCE CURVES
Minimum FR−4 @ 300 mm2, 2 oz Copper Trace, Still Air
Figure 1. General Performance Curve for CCR Figure 2. Steady State Current (Ireg(SS)) vs.
Anode−Cathode Voltage (Vak)
Figure 3. Pulse Current (Ireg(P)) vs.
Anode−Cathode Voltage (Vak)
Figure 4. Steady State Current vs. Pulse
Current Testing
Vak, ANODE−CATHODE VOLTAGE (V) Ireg(P), PULSE CURRENT (mA)
109.08.07.06.05.04.0
31
33
34
36
34333230
29
30
31
Ireg(P), PULSE CURRENT (mA)
Ireg(SS), STEADY STATE CURRENT (mA)
31
35
35 36
32
33
3.0
32
Figure 5. Current Regulation vs. Time
34
35
39
37
37
Non−Repetitive Pulse Test
Figure 6. Ireg(SS) vs. Radj
Vak, ANODE−CATHODE VOLTAGE (V)
403020 70100−10
−20
0
10
30
60
Ireg, CURRENT REGULATION (mA)
−10
20
40
TA = 25°C, Radj = Open
50
TIME (s)
201050
Ireg, CURRENT REGULATION (mA)
15
34
35
Vak @ 7.5 V
TA = 25°C
Radj = Open
Radj (W), MAX POWER 50 mW
101
30
35
40
Ireg(SS), STEADY STATE CURRENT (mA)
100
45
50
55
1000
60
36
37
3525 30
50
60
65
70
Vak @ 7.5 V
TA = 25°C
Vak, ANODE−CATHODE VOLTAGE (V)
96543
0
5
15
20
25
Ireg(SS), STEADY STATE CURRENT (mA)
710
DC Test Steady State, Still Air
8
10
TA = −40°C
TA = 25°C
TA = 85°C
−0.0302 mA/°C
210
−0.0290 mA/°C
−0.0278 mA/°C
TA = 125°C
35
40
45
30
36
37
38
39
40
41
41403938 42 43 44
38
TA = 25°C
Vak @ 7.5 V
TA = 25°C
Radj = Open
Radj = Open
Radj = Open
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4
Figure 7. Power Dissipation vs. Ambient
Temperature @ TJ = 1505C
TA, AMBIENT TEMPERATURE (°C)
8060200−20−40
700
900
1300
1500
POWER DISSIPATION (mW)
40
500 mm2/2 oz
500 mm2/1 oz
300 mm2/1 oz
1100
1700
500
100 mm2/1 oz
300 mm2/2 oz
1900
2100
2300
100 mm2/2 oz
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 45 V so long as the die temperature does
not exceed 150°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 8 and 9).
Figure 8.
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Other Currents
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 11).
Figure 11.
Dimming using PWM
The dimming of an LED string can be easily achieved by
placing a BJT in series with the CCR (Figure 12).
Figure 12.
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
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 13).
Figure 13.
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 14 is a typical response of Luminance vs Duty Cycle.
Figure 14. Luminous Emmitance vs. Duty Cycle
DUTY CYCLE (%)
100908070605040
0
1000
3000
ILLUMINANCE (lx)
2000
30
4000
6000
20100
5000
Lux
Linear
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 12) 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.
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Thermal Considerations
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:
PD(MAX) +TJ(MAX) *TA
RqJA
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 15 shows the basic
circuit configuration.
Figure 15. Basic AC Application
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8
PACKAGE DIMENSIONS
SOT−223 (TO−261)
CASE 318E−04
ISSUE N
1.5
0.059 ǒmm
inchesǓ
SCALE 6:1
3.8
0.15
2.0
0.079
6.3
0.248
2.3
0.091
2.3
0.091
2.0
0.079
SOLDERING FOOTPRINT
STYLE 2:
PIN 1. ANODE
2. CATHODE
3. NC
4. CATHODE
A1
b1
D
E
b
e
e1
4
123
0.08 (0003)
A
L1
C
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: INCH.
HE
DIM
A
MIN NOM MAX MIN
MILLIMETERS
1.50 1.63 1.75 0.060
INCHES
A1 0.02 0.06 0.10 0.001
b0.60 0.75 0.89 0.024
b1 2.90 3.06 3.20 0.115
c0.24 0.29 0.35 0.009
D6.30 6.50 6.70 0.249
E3.30 3.50 3.70 0.130
e2.20 2.30 2.40 0.087
0.85 0.94 1.05 0.033
0.064 0.068
0.002 0.004
0.030 0.035
0.121 0.126
0.012 0.014
0.256 0.263
0.138 0.145
0.091 0.094
0.037 0.041
NOM MAX
L1 1.50 1.75 2.00 0.060
6.70 7.00 7.30 0.264
0.069 0.078
0.276 0.287
HE
− −
e1
0°10°0°10°
q
q
L
L0.20 −−− −−− 0.008 −−− −−−
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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
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