NSI45030ZT1G
Constant Current Regulator
& LED Driver
45 V, 30 mA
+
15%, 1.4 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 (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 25% 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.
Features
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I
reg(SS)
= 30 mA
@ Vak = 7.5 V
Anode 1
Cathode 2/4
•
•
•
•
•
•
•
•
Robust Power Package: 1.4 Watts
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
SOT−223
CASE 318E
STYLE 2
MARKING DIAGRAM
C
AYW
AAGG
G
1
A
C
NC
A
= Assembly Location
Y
= Year
W
= Work Week
AAG
= Specific Device Code
G
= Pb−Free Package
(Note: Microdot may be in either location)
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
Rating
Symbol
Vak Max
V
R
T
J
, T
stg
ESD
Value
45
500
−55
to +150
Class 1C
Class B
Unit
V
mV
°C
MAXIMUM RATINGS
(T
A
= 25°C unless otherwise noted)
Anode−Cathode Voltage
Reverse Voltage
Operating and Storage Junction
Temperature Range
ESD Rating:
Human Body Model
Machine Model
ORDERING INFORMATION
Device
NSI45030ZT1G
Package
SOT−223
(Pb−Free)
Shipping
†
1000/Tape & Reel
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.
©
Semiconductor Components Industries, LLC, 2011
†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.
October, 2011
−
Rev. 2
1
Publication Order Number:
NSI45030Z/D
NSI45030ZT1G
ELECTRICAL CHARACTERISTICS
(T
A
= 25°C unless otherwise noted)
Characteristic
Steady State Current @ Vak = 7.5 V (Note 1)
Voltage Overhead (Note 2)
Pulse Current @ Vak = 7.5 V (Note 3)
Capacitance @ Vak = 7.5 V (Note 4)
Capacitance @ Vak = 0 V (Note 4)
1.
2.
3.
4.
Symbol
I
reg(SS)
V
overhead
I
reg(P)
C
C
26.7
Min
25.5
Typ
30
1.8
31.55
2.6
6.9
36.4
Max
34.5
Unit
mA
V
mA
pF
pF
I
reg(SS)
steady state is the voltage (Vak) applied for a time duration
≥
10 sec, using FR−4 @ 300 mm
2
2 oz. Copper traces, in still air.
V
overhead
= V
in
−
V
LEDs
. V
overhead
is typical value for 70% I
reg(SS)
.
I
reg(P)
non−repetitive pulse test. Pulse width t
≤
300
msec.
f = 1 MHz, 0.02 V RMS.
THERMAL CHARACTERISTICS
Characteristic
Total Device Dissipation (Note 5) T
A
= 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 5)
Thermal Reference, Junction−to−Lead 4 (Note 5)
Total Device Dissipation (Note 6) T
A
= 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 6)
Thermal Reference, Junction−to−Lead 4 (Note 6)
Total Device Dissipation (Note 7) T
A
= 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 7)
Thermal Reference, Junction−to−Lead 4 (Note 7)
Total Device Dissipation (Note 8) T
A
= 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 8)
Thermal Reference, Junction−to−Lead 4 (Note 8)
Total Device Dissipation (Note 9) T
A
= 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 9)
Thermal Reference, Junction−to−Lead 4 (Note 9)
Total Device Dissipation (Note 10) T
A
= 25°C
Derate above 25°C
Thermal Resistance, Junction−to−Ambient (Note 10)
Thermal Reference, Junction−to−Lead 4 (Note 10)
Junction and Storage Temperature Range
Symbol
P
D
R
θ
JA
R
ψ
JL4
P
D
R
θ
JA
R
ψ
JL4
P
D
R
θ
JA
R
ψ
JL4
P
D
R
θ
JA
R
ψ
JL4
P
D
R
θ
JA
R
ψ
JL4
P
D
R
θ
JA
R
ψ
JL4
T
J
, T
stg
Max
954
7.6
131
40.8
1074
8.6
116
39.9
1150
9.2
109
42
1300
10.4
96
39.4
1214
9.7
103
40.2
1389
11.1
90
37.7
−55
to +150
Unit
mW
mW/°C
°C/W
°C/W
mW
mW/°C
°C/W
°C/W
mW
mW/°C
°C/W
°C/W
mW
mW/°C
°C/W
°C/W
mW
mW/°C
°C/W
°C/W
mW
mW/°C
°C/W
°C/W
°C
5. FR−4 @ 100 mm
2
, 1 oz. copper traces, still air.
6. FR−4 @ 100 mm
2
, 2 oz. copper traces, still air.
7. FR−4 @ 300 mm
2
, 1 oz. copper traces, still air.
8. FR−4 @ 300 mm
2
, 2 oz. copper traces, still air.
9. FR−4 @ 500 mm
2
, 1 oz. copper traces, still air.
10. FR−4 @ 500 mm
2
, 2 oz. copper traces, still air.
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.
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2
NSI45030ZT1G
Minimum FR−4 @ 300 mm
2
, 2 oz Copper Trace, Still Air
I
reg(SS)
, STEADY STATE CURRENT (mA)
60
I
reg
, CURRENT REGULATION (mA)
50
40
30
20
10
0
−10
−20
−10
VR
40
35
30
25
20
15
10
5
0
DC Test Steady State, Still Air
0
1
2
3
4
5
6
7
8
9
10
Vak, ANODE−CATHODE VOLTAGE (V)
T
A
=
−40°C
T
A
= 25°C
T
A
= 85°C
T
A
= 125°C
[
−0.088
mA/°C
typ @ Vak = 7.5 V
[
−0.072
mA/°C
typ @ Vak = 7.5 V
[
−0.061
mA/°C
typ @ Vak = 7.5 V
TYPICAL PERFORMANCE CURVES
0
10
20
30
40
50
60
Vak, ANODE−CATHODE VOLTAGE (V)
Figure 1. General Performance Curve for CCR
I
reg(SS)
, STEADY STATE CURRENT (mA)
33
I
reg(P)
, PULSE CURRENT (mA)
32
31
30
29
28
27
26
3.0
Non−Repetitive Pulse Test
4.0
5.0
6.0
7.0
8.0
9.0
10
T
A
= 25°C
35
34
33
32
31
30
29
28
27
26
25
26
Figure 2. Steady State Current (I
reg(SS)
) vs.
Anode−Cathode Voltage (Vak)
Vak @ 7.5 V
T
A
= 25°C
27
28
29
30
31
32
33
34
35
36
37
Vak, ANODE−CATHODE VOLTAGE (V)
I
reg(P)
, PULSE CURRENT (mA)
Figure 3. Pulse Current (I
reg(P)
) vs.
Anode−Cathode Voltage (Vak)
32
I
reg
, CURRENT REGULATION (mA)
POWER DISSIPATION (mW)
Vak @ 7.5 V
T
A
= 25°C
31
2200
2000
1800
1600
1400
1200
1000
800
600
400
−40
Figure 4. Steady State Current vs. Pulse
Current Testing
500 mm
2
/2 oz
300 mm
2
/2 oz
100 mm
2
/2 oz
30
500 mm
2
/1 oz
300 mm
2
/1 oz
100 mm
2
/1 oz
−20
0
20
40
60
80
29
0
5
10
15
20
25
30
35
TIME (s)
T
A
, AMBIENT TEMPERATURE (°C)
Figure 5. Current Regulation vs. Time
Figure 6. Power Dissipation vs. Ambient
Temperature @ T
J
= 1505C
APPLICATIONS INFORMATION
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3
NSI45030ZT1G
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 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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4
NSI45030ZT1G
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 10).
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).
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
Figure 10.
Dimming using PWM
The dimming of an LED string can be easily achieved by
placing a BJT in series with the CCR (Figure 11).
ILLUMINANCE (lx)
4000
3000
2000
1000
0
0
Lux
Linear
10
20
30
40 50
60 70
DUTY CYCLE (%)
80
90 100
Figure 13. Luminous Emmitance vs. Duty Cycle
Reducing EMI
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
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.
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