NCV7681
100 mA Linear Current
Regulator and Controller for
Automotive LED Lighting
The NCV7681 consists of eight linear programmable constant
current sources. The part is designed for use in the regulation and
control of LED based Rear Combination Lamps and blinking
functions for automotive applications. System design with the
NCV7681 allows for two programmed levels for stop (100% Duty
Cycle) and tail illumination (programmable Duty Cycle), or an
optional external PWM control can be implemented.
LED brightness levels are easily programmed (stop is programmed
to the absolute current value, tail is programmed to the duty cycle)
with two external resistors. The use of an optional external ballast FET
allows for power distribution on designs requiring high currents. Set
back power limit reduces the drive current during overvoltage
conditions. This is most useful for low power applications when no
external FET is used.
The device is available in a SOIC−16 WB package with exposed pad.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Constant Current Outputs for LED String Drive
LED Drive Current up to 100 mA per Channel
Open LED String Diagnostic with Open−Drain Output in All Modes
Slew Rate Control Eliminates EMI Concerns
Low Dropout Operation for Pre−Regulator Applications
External Modulation Capable
On−chip 800 Hz Tail PWM Dimming
Single Resistor for Stop Current Set Point
Single Resistor for Tail Dimming Set Point
Overvoltage Set Back Power Limitation
AEC−Q100 Qualified and PPAP Capable
16 Lead SOICW Exposed Pad
Improved EMC Performance
Latch−Off Function on Open String (NCV7681L)
♦ Restart Option of Unaffected Strings
Over Temperature Fault Reporting
These are Pb−Free Devices
www.onsemi.com
MARKING
DIAGRAM
NCV7681x
AWLYYWWG
SOIC−16 WB
PW SUFFIX
CASE 751DW
NCV7681 = Specific Device Code
x
= A (No Latch−Off Function)
or L (Latch−Off Function)
A
= Assembly Location
WL = Wafer Lot
YY = Year
WW = Work Week
G = Pb−Free Device
ORDERING INFORMATION
Device
Package
Shipping†
NCV7681APWR2G SOIC−16WB
(Pb−Free)
1000 /
Tape & Reel
NCV7681LPWR2G SOIC−16WB
(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.
Applications
•
•
•
•
•
•
Rear Combination Lamps (RCL)
Daytime Running Lights (DRL)
Fog Lights
Center High Mounted Stop Lamps (CHMSL) Arrays
Turn Signal and Other Externally Modulated Applications
Signature Lamp
© Semiconductor Components Industries, LLC, 2016
November, 2016 − Rev. 1
1
Publication Order Number:
NCV7681/D
NCV7681
DIAG
Interface
VP
EMC Filter
Open Load
Detection
Latch−Off Control
CC
UVLO
Overvoltage
1 of 8
Vreg
Ballast
Drive
Soft Start,
Bias and
Reference
+
−
FB
FET Drive
200K
Out1
Output
Current
Drive
Channel
Control
Over temperature &
Over voltage sense
DIAG
Inverface
Control Logic
STOP
200K
Out3
Out4
Setback
Current
−20%
1V
Out2
Output
Latch−Off
Out5
Out6
50% IOUT
Open Load
Detect
Out7
Out8
DIAG
Oscillator
and PWM
2.2V
0.4V
V−I Converter
CC
Pin
Current
Limit
Vreg
Irstop
+
−
IRSTOP x 150
Rtail
+
−
1.8V Open
Circuit
Restart
RTAIL
RSTOP
Boxes with dotted lines signify NCV7681L only.
Figure 1. Block Diagram
OUT1
VP
Ballast Drive
FB
STOP
DIAG
RSTOP
RTAIL
EP
OUT2
OUT3
OUT4
GND
OUT5
OUT6
OUT7
OUT8
Figure 2. Pinout Diagram
www.onsemi.com
2
GND
NCV7681
VSTRING
MRA4003T3G
TAIL
NVD2955
STOP
MRA4003T3G
C1
0.68uF
R1
10K
C2
0.22uF
C3
100nF
R3
1K
R4, 3.01K
C4
10nF
VP
Ballast
Drive
FB
STOP
DIAG
RSTOP
RTAIL
R5, 1.62K
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
R6
9.53K
GND
R7
1K
NCV7681
Figure 3. Application Diagram with External FET Ballast Transistor
R6 and R7 values shown yield 10.5 V regulation on VSTRING.
C1 is for line noise and stability considerations.
C3 is for EMC considerations.
Unused OUTx channels should be shorted to ground as OUT7 shows in this example.
VSTRING
MRA4003T3G
TAIL
STOP
MRA4003T3G
C3
100nF
R1
10K
C4
10nF
C1
0.68uF
VP
Ballast
Drive
FB
STOP
DIAG
R4, 3.01K
RSTOP
RTAIL
R5, 1.62K
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
GND
NCV7681
Figure 4. Application Diagram without the FET Ballast Transistor
When using the NCV7681 without the FET ballast transistor, tie the FB pin and Ballast Drive pin to GND.
www.onsemi.com
3
NCV7681
Table 1. APPLICATION I/O TRUTH TABLE
STOP
INPUT
TAIL
MODE
OUTx LATCH OFF
(w/ LO = GND)
OUTX
CURRENT
FAULT
STATE*
DIAG
STATE**
0
0
NCV7681A
OFF
−
1
1
X
NCV7681A
ISTOP
NORMAL
0
1
X
NCV7681A
ISTOP
OPEN CIRCUIT***
1
1
X
NCV7681L
OFF
OPEN CIRCUIT***
1
0
1
NCV7681A
PWM
NORMAL
0
0
1
NCV7681A
PWM
OPEN CIRCUIT***
PWM
Reference Figures below.
X = don’t care
0 = LOW
1 = HIGH
* Open Circuit, RSTOP Current Limit, Set Back Current Limit down 20%, and thermal shutdown
**Pull−up resistor to DIAG required.
*** OPEN CIRCUIT = Any string open.
DIAG
DIAG
Open String Occurs
Open String Removed
Open String Occurs
on
OUTx
Current
OUTx
Current
off
off
on
OUTx
Current
Open String Removed
on
on
Outputs with no open string.
OUTx
Current
off
off
Outputs with no open string.
NCV7681L
NCV7681A
Figure 5. DIAG timing diagram WITH
Open String Latch Active
All outputs latch off.
Figure 6. DIAG timing diagram WITHOUT
Open String Latch Active
No outputs are turned off.
DIAG will report the state.
www.onsemi.com
4
NCV7681
Table 2. PIN FUNCTION DESCRIPTION (16 Pin SO Wide Exposed Pad Package)
Pin #
Label
1
OUT1
Description
Channel 1 constant current output to LED.
Unused pin should be grounded.
2
VP
3
Ballast Drive
Supply Voltage Input.
4
FB
5
STOP
Stop Logic Input. External Modulation Input.
6
DIAG
Open−drain diagnostic output.
Reporting Open Circuit, RSTOP Current Limit,
and Overvoltage Set Back Current down 20%.
Normal Operation = LOW.
Ground if not used.
7
RSTOP
8
RTAIL
Tail current duty cycle PWM program resistor.
Ground if using external modulation.
9
OUT8
Channel 8 constant current output to LED.
Unused pin should be grounded.
10
OUT7
Channel 7 constant current output to LED.
Unused pin should be grounded.
11
OUT6
Channel 6 constant current output to LED.
Unused pin should be grounded.
12
OUT5
Channel 5 constant current output to LED.
Unused pin should be grounded.
13
GND
Ground.
14
OUT4
Channel 4 constant current output to LED.
Unused pin should be grounded.
15
OUT3
Channel 3 constant current output to LED.
Unused pin should be grounded.
16
OUT2
Channel 2 constant current output to LED.
Unused pin should be grounded.
epad*
epad
Ground. Do not connect to pcb traces other than GND.
Gate drive for external power distribution PFET.
Ground if not used.
Feedback Sense node for VP regulation.
Use feedback resistor divider or connect to VP with a 10k resistor.
Stop current bias program resistor.
*Grounding will provide better thermal and electrical performance.
www.onsemi.com
5
NCV7681
Table 3. MAXIMUM RATINGS (Voltages are with respect to device substrate.)
Value
Rating
Unit
Supply Input (VP, Ballast Drive, STOP, DIAG)
DC
Peak Transient
−0.3 to 40
40
V
Output Pin Voltage (OUTX)
−0.3 to 40
V
Output Pin Current (OUTX)
200
mA
DIAG Pin Current
10
mA
Input Voltage (RTAIL, RSTOP, FB)
−0.3 to 3.6
V
Junction Temperature, TJ
−40 to 150
°C
260 peak
°C
Peak Reflow Soldering Temperature: Lead−free
60 to 150 seconds at 217°C (Note 1)
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
Table 4. ATTRIBUTES
Characteristic
Value
ESD Capability
Human Body Model
Machine Model
≥ ± 4.0 kV
≥ ± 200 V
Moisture Sensitivity (Note 1)
MSL3
Storage Temperature
−55 to 150°C
Package Thermal Resistance (Note 2)
SOIC−16 WB EP
Junction−to−Board (RYJB)
Junction−to−Ambient (RqJA)
Junction−to−Pin (RYJL)
15°C/W
73°C/W
43°C/W
1. For additional information, see or download ON Semiconductor’s Soldering and Mounting Techniques Reference Manual, SOLDERRM/D,
and Application Note AND8003/D.
2. Values represent typical still air steady−state thermal performance on 1 oz. copper FR4 PCB with 650 mm2 copper area with OUT1−OUT8
dissipating 50 mW each.
www.onsemi.com
6
NCV7681
Table 5. ELECTRICAL CHARACTERISTICS
(4.5 V < VP < 16 V, STOP = VP, RSTOP = 3.01 kW, RTAIL = 1.62 kW, −40°C ≤ TJ ≤ 150°C, unless otherwise specified.)
Characteristic
Conditions
Min
Typ
Max
Unit
VP = 16 V
VP = 16 V
VP = 16 V, STOP = 0 V, OUTx = 0 mA,
Disconnected output
−
−
−
6
5
−
12
12
2.0
Driver Ground Pin Current (pin12)
IOUT1 to IOUT8 = 50 mA
−
400
500
mA
Output Under Voltage Lockout
VP Rising
3.8
4.1
4.4
V
Output Under Voltage Lockout
Hysteresis
−
200
−
mV
Open Load Disable Threshold
7.2
7.7
8.2
V
Open Load Disable Hysteresis
−
200
−
mV
GENERAL PARAMETERS
Quiescent Current (IOUTx = 50 mA)
STOP mode
Tail mode
Fault mode (Note 5)
mA
THERMAL LIMIT
Thermal Shutdown
(Note 3)
150
175
−
°C
Thermal Hysteresis
(Note 3)
−
15
−
°C
Output Current
OUTX = 0.5 V, TJ = 25°C, 150°C
OUTX = 1 V, RSTOP = 1.5 K
45
90
50
100
55
110
mA
Maximum Regulated Output Current
0.5V to 16V
100
−
−
mA
−4
0
4
%
CURRENT SOURCE OUTPUTS
Current Matching
2IOUTx(min)
ƪIOUTx(min)
* 1ƫ
) IOUTx(max)
2IOUTx(max)
ƪIOUTx(min)
* 1ƫ
) IOUTx(max)
100
100
Line Regulation
9 V ≤ VP ≤ 16 V
–
1.2
6.0
mA
Open Circuit Detection Threshold
25 mA
50 mA
25
35
50
50
75
65
% of Output
Current
Current Slew Rate
Iout = 44 mA, 10% to 90% points
−
6
15
mA/ms
Overvoltage Set Back Threshold
@ 99% Iout
16.0
17.2
18.4
V
Overvoltage Set Back Current
VP = 20 V (Note 4)
−
78
−
%Iout
−
80
−
%Iout
EN = high
−
−
1
mA
FB = 1.5 V, Ballast Drive = 3 V
FB = 0.5 V, Ballast Drive = 3 V
−
4
1.0
13
2.4
20
0.92
1.00
1.08
V
Input High Threshold
0.75
1.25
1.75
V
Input Low Threshold
0.70
1.00
1.44
V
VIN Hysteresis
100
250
400
mV
120
200
300
kW
Diag Reporting of Set Back Current
Output Off Leakage
FET DRIVER
Ballast Drive
DC Bias
Sink Current
mA
Ballast Drive Reference Voltage
STOP LOGIC
Input Impedance
Vin = 14 V
3. Designed to meet these characteristics over the stated voltage and temperature recommended operating ranges, though may not be 100%
parametrically tested in production.
4. The output current degrades at a rate of 8%/V.
5. This test parameter applies only to the NCV7681LPWR2G.
www.onsemi.com
7
NCV7681
Table 5. ELECTRICAL CHARACTERISTICS
(4.5 V < VP < 16 V, STOP = VP, RSTOP = 3.01 kW, RTAIL = 1.62 kW, −40°C ≤ TJ ≤ 150°C, unless otherwise specified.)
Characteristic
Conditions
Min
Typ
Max
Unit
0.94
1.00
1.06
V
−
150
−
−
CURRENT PROGRAMMING
RSTOP Bias Voltage
Stop current programming voltage
RSTOP K multiplier
IOUTX/IRSTOP
RSTOP Over Current Detection
RSTOP = 0 V
0.70
1.00
1.45
mA
RTAIL Bias Current
Tail duty cycle programming current
290
330
370
mA
Duty Cycle
RTAIL = 0.49 V
RTAIL = 0.76 V
RTAIL = 1.66 V
3.5
17
59.5
5
20
70
6.5
23
80.5
%
DIAG OUTPUT
Output Low Voltage
DIAG Active, IDIAG = 1 mA
–
0.1
0.40
V
DIAG Output Leakage
VDIAG = 5 V
−
−
10
mA
Open Load Reset Voltage on DIAG
(Note 5)
1.6
1.8
2.0
V
−
14
45
msec
AC CHARACTERISTICS
Stop Turn−on Delay Time
V(STOP) > 1.75 V to I(OUTx) = 90%
Stop Turn−off Delay Time
V(STOP) < 0.75 V to I(OUTx) = 10%
PWM Frequency
STOP = 0 V
Open Circuit to DIAG Reporting
4.8 mA pull−up to VP, V(DIAG) >1.5 V
VP Turn−on Time
−
14
45
msec
400
800
1200
Hz
1
2
4
ms
0.55
0.80
1.2
msec
3. Designed to meet these characteristics over the stated voltage and temperature recommended operating ranges, though may not be 100%
parametrically tested in production.
4. The output current degrades at a rate of 8%/V.
5. This test parameter applies only to the NCV7681LPWR2G.
www.onsemi.com
8
NCV7681
TYPICAL CHARACTERISTICS
53
80
70
60
50
40
30
20
10
0
T = 25°C
0
1
2
3
4
5
6
7
8
9
52
51
50
49
48
RSTOP = 3.01 kW
47
−40 −20
0
20 40
10
60
80
100
120 140 160
RSTOP (kW)
TEMPERATURE (°C)
Figure 7. Iout vs. RSTOP
Figure 8. Iout vs. Temperature
100
100
90
90
80
80
DUTY CYCLE (%)
DUTY CYCLE (%)
Iout, OUTPUT CURRENT (mA)
90
70
60
50
40
30
20
70
60
50
40
30
20
10
0
10
0
RSTOP = 3.01 kW
0
1
2
3
4
5
6
7
0
0.5
1.0
1.5
2.0
RTAIL (kW)
V(RTAIL)
Figure 9. Duty Cycle vs. RTAIL
Figure 10. Duty Cycle vs. V(RTAIL)
80
RTAIL = 5 kW
70
DUTY CYCLE (%)
Iout OUTPUT CURRENT (mA)
100
60
50
40
30
RTAIL = 2.3 kW
20
10
RTAIL = 1.5 kW
0
−40 −20
0
20
40
60
80
100 120 140 160
TEMPERATURE (°C)
Figure 11. Duty Cycle vs. Temperature
www.onsemi.com
9
2.5
NCV7681
TYPICAL CHARACTERISTICS
51.0
IOUT, OUTPUT CURRENT (mA)
IOUT, OUTPUT CURRENT (mA)
60
50
40
30
20
10
RSTOP = 3.01 k
0
9
11
13
15
19
17
21
23
25
50.8
50.6
50.4
50.2
50.0
49.8
49.6
49.4
49.2
49.0
27
6
9
8
10
11
12
13
14
VP (V)
VOUT (V)
Figure 12. IOUT vs. VP
Figure 13. IOUT Line Regulation
15
16
60
IOUT, OUTPUT CURRENT (mA)
60
50
40
30
20
10
0
50
40
30
20
10
0
0
2
4
6
8
10
12
14
16
0
0.1
0.2
0.3
VOUT (V)
VOUT (V)
Figure 14. IOUT vs. VOUT
Figure 15. IOUT vs. VOUT
14
12
10
VSTRING (V)
IOUT, OUTPUT CURRENT (mA)
7
8
6
4
per eq. 1
R7 = 1 kW
2
0
0
2K
4K
6K
8K
10K
R6 (W)
Figure 16. VSTRING vs. R6
www.onsemi.com
10
12K
14K
0.4
0.5
NCV7681
TYPICAL PERFORMANCE CHARACTERISTICS
160
140
qJA (°C/W)
120
100
1 oz
80
2 oz
60
40
20
0
0
100
200
300
400
500
COPPER HEAT SPREADER AREA
600
700
(mm2)
Figure 17. qJA vs. Copper Spreader Area
100
D = 0.5
R(t) (°C/W)
0.2
0.1
10 0.05
0.02
0.01
SINGLE PULSE
1
0.000001
0.00001
0.0001
0.001
0.01
0.1
1
10
100
1000
PULSE TIME (s)
Figure 18. Thermal Duty Cycle Curves on 500 mm2 Spreader Test Board
1000
100 mm2
50 mm2
100
R(t) (°C/W)
500 mm2
10
1
0.000001
0.00001
0.0001
0.001
0.01
0.1
1
PULSE TIME (s)
Figure 19. Single Pulse Heating Curve
www.onsemi.com
11
10
100
1000
NCV7681
DETAILED OPERATING DESCRIPTION
General
module will either display all LED strings or no LED strings
at all. This function is designed into the NCV7681L.
Each output has its own sensing circuitry. An open string
detection on any output latches off all 8 outputs. There are
three means to reinitiate the IC drivers.
1. Forcing the DIAG pin below the Open Circuit
Reset Voltage (1.8 V typical).
2. Toggling the ENABLE input
3. A complete power down of the device below the
Under Voltage Lockout threshold including
hysteresis (3.9 V typical).
The NCV7681 device is an eight channel LED driver
whose output currents up to 100 mA/channel are
programmed by an external resistor. The target application
for the device is in automotive Rear Combination Lighting
(RCL) systems.
The STOP logic input switches the two modes of the IC.
While in the STOP mode (high), the duty cycle of the outputs
is at 100%. When STOP is low, the duty cycle of the outputs
is programmed via an external resistor on the RTAIL pin.
A logic output (DIAG) communicates open circuit of the
LED driver outputs back to the microprocessor. DIAG
requires a pull−up resistor for proper operation.
An optional external control for a ballast transistor helps
distribute the system power.
Open Load Detection
Open load detection has an under voltage lockout feature
to remove the possibility of turning off the device while it is
powering up. The Open Load Disable Threshold is 7.7 V
(typ). Open load detection becomes active above this
threshold. Current is monitored internal to the NCV7681
device and an open load is flagged when the current is 1/2
of the targeted output current.
Latch Off (NCV7681L)
The Latch Off feature applies only to the NCV7681L.
Automotive requirements sometime dictate all outputs
turn off if one of the outputs is an open circuit. This
eliminates driving with partial illuminated lights. The
TAIL
D1
MRA4003T3G
Q1
STOP
D2
MRA4003T3G
C1
0.68uF
Q2
NVD2955
NVD2955
R1
C2
1K 0.22uF
R2
C4
1K 0.22uF
C3
0.68uF
VSTRING
C5
100nF
D3
D6
D9
D12
D4
D7
D10
D13
D5
D8
D11
D14
1 -8
C6
100nF
OUT1-OUT8
OUT1-OUT8
OUT1
VP
Ballast Drive
---------
---------
OUT1
VP
Ballast Drive
OUT8
OUT8
R3
9.53K
FB
FB
R4
1K
NCV7681 U1
GND
GND
NCV7681 U2
Figure 20.
www.onsemi.com
12
NCV7681
DIAG
brightness level for tail. The PWM generator’s fixed
frequency (800 Hz typ.) oscillator allows flicker−free
illumination. PWM control is the preferred method for
dimming LEDs.
The diagnostic function allows the detection of an open in
any one of the output circuits. The active−low diagnostic
output (DIAG) is coincident with the STOP input and the ON
state in the tail mode. DIAG remains high (pulled up) if an
open load is detected in any LED string when STOP is high.
The logic DIAG pin’s main function is to alert the
controlling microprocessor an open string has occurred on
one of the outputs (DIAG high = open string). Reference
Table 1 for details on logic performance.
Open circuit conditions are reported when the outputs are
actively driven. When operating in STOP mode the DIAG
signal is a DC signal. When operating in TAIL the DIAG
signal is a PWM signal reporting open circuit when the
output drive is active.
Output Current Programming
Ballast Drive
Reference Figure 7 (typ performance graph) to choose
programming resistor (RSTOP) value for stop current.
Reference Figure 9 Typical Performance Graph (Duty Cycle
vs. RTAIL) to choose a typical value programming resistor
for output duty cycle (with a typical RSTOP value of
3.01 kW). Note the duty cycle is dependent on both RSTOP
and RTAIL values. RSTOP should always be chosen first as
the stop current is only dependent on this value.
Alternatively, the equations below can be used to calculate
a typical value and used for worst case analysis.
Set the Stop Current using RSTOP
The use of an external FET device (NVD2955) helps
distribute the system power. A DC voltage regulation system
is used which regulates the voltage at the top (anode) of the
LED strings (Vstring). This has the effect of limiting the
power in the NCV7681 by setting the voltage on the IOUTx
pins specific to each customer application. The Ballast Drive
pin provides the drive in the feedback loop from the FB pin.
In steady state, the voltage is regulated at the feedback
voltage (FB). A simple voltage divider helps set the voltage
at Vstring. Unlike other systems, the ballast drive current
does not turn off in a leakage state when turned off (FB high),
but instead provides 1 mA of current providing a faster
response of the system loop. This sets the gate voltage of the
NVD2955 to 1 V at 25°C.
RSTOP Bias Voltage = 1 V (typ)
Parallel Outputs
Set the Duty Cycle (DC) using RTAIL
I OUTX + 150 @
RSTOP_Bias_Voltage
RSTOP
RTAIL + 1.8 @ RSTOP(DC ) 0.22)
The maximum rating per output is 100 mA. In order to
increase system level LED string current, parallel
combinations of any number of outputs is allowed.
Combining all 8 outputs will allow for a maximum system
level string current design of 800 mA.
(eq. 1)
(eq. 2)
DC = duty cycle expressed in fractional form. (e.g. 0.50
is equivalent to 50% duty cycle) (ground RTAIL when using
external modulation)
Output Current is directly tested per the electrical
parameter table to be ±10% (with RSTOP = 3.01 KW) or
45 mA (min), 50 mA (typ), 55 mA (max) at room and hot
temperature.
Duty Cycle will vary according to the changes in RTAIL
Voltage and RTAIL Bias Current (generated from the current
through RSTOP).
Voltage errors encompass generator errors (0.4 V to
2.2 V) and comparator errors and are included in testing as
the Duty Cycle. Typical duty cycle measurements are 5%
with RTAIL = 0.49 V and 70% with RTAIL = 1.66 V.
RTAIL Bias Current errors are measured as RTAIL Bias
Current and vary as 290 mA (min), 330 mA (typ), and 370 mA
(max) with RSTOP = 3.01 kW.
The error duality originating from both the internal current
source generated on the RSTOP pin and the comparator
voltage thresholds of the RTAIL pin combined with the
choice of duty cycle levels make it difficult to specify duty
cycle minimum and maximum limits, but worst case
conditions can be calculated when considering the variation
in the voltage threshold and current source. Duty Cycle
variation must include the direct duty cycle as specified in
the electrical parameter table plus an additional error due to
the Irstop current which generates this voltage in the system.
Unused Outputs
Unused outputs should be shorted to ground. The
NCV7681 detects the condition during power−up using the
open load disable threshold and disables the open circuit
detection circuitry.
Programmability
Strings of LEDs are a common configuration for RCL
applications. The NCV7681 provides eight matched outputs
allowing individual string drive with current set by a single
resistor. Output currents are mirrored and matched within
±4% at hot temperature.
A high STOP condition sets the output current using
equation 1 below.
A low STOP condition, modulates the output currents at
a duty cycle (DC) programmed using equation 2 below.
Note, current limiting on RSTOP limits the current which
can be referenced from the RSTOP Pin. Exceeding the
RSTOP Current Limit will set the output current to less than
100 mA, and the DIAG Pin will go high. This helps limit
output current (brightness and power) for this type of fault.
The average ISTOP Duty Cycle current provides the
dimmed tail illumination function and assures a fixed
www.onsemi.com
13
NCV7681
RSTOP Over Current Protection
consistent LED light output at low line voltage. Unlike
adjustable regulator based constant current source schemes
where the set point resistor resides in the load path, the
NCV7681’s set point resistor lies outside the LED load path,
and aids in the low dropout capability.
Setback Current Limit is employed during high voltage.
During a Setback Current Limit event, the drive current is
reduced resulting in lower power dissipation on the IC. This
occurs during high battery voltage (VP > 16 V). In this way
the NCV7681 can operate in extreme conditions and still
provide a controlled level of light output The Setback
Current (−20%) condition is reported on the DIAG Pin.
Activation of the set back current feature provides a
roll−off rate of −8%/V.
Over Current protection has been included for the RSTOP
pin. Without protection, the device performance could cause
excessive high current and potential damage to the external
LEDs. Detection of the RSTOP over current event (RSTOP
to ground) is 1 mA (typ) and is current limited to 2.2 mA
(typ). Output drive currents will limit to typically 65 mA.
Note – A feature of the NCV7681 device includes
operation of the device during a short circuit on the RSTOP
pin. Iout is decreased during the STOP condition and the
TAIL duty cycle is reduced to less than 40% by reducing the
voltage on the RTAIL pin to 2/3 of normal operation.
Set Back Current
Automotive battery systems have wide variations in line
supply voltage. Low dropout is a key attribute for providing
www.onsemi.com
14
MECHANICAL CASE OUTLINE
PACKAGE DIMENSIONS
SOIC−16 WB, EP
CASE 751DW
ISSUE A
DATE 23 OCT 2015
SCALE 1:1
D
0.25
M
B
M
A
B
9
16
H
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME
Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b DOES NOT INCLUDE DAMBAR
PROTRUSION. DAMBAR PROTRUSION SHALL
BE 0.13 TOTAL IN EXCESS OF b DIMENSION AT
MAXIMUM MATERIAL CONDITION.
4. DIMENSIONS D AND E DO NOT INCLUDE MOLD
PROTRUSIONS.
5. MAXIMUM MOLD PROTRUSION OR FLASH TO
BE 0.15 PER SIDE.
M
E
1
PIN 1
INDICATOR
8
16X
e
b
0.25
h
x 45
M
T A
S
B
S
DIM
A
A1
b
c
D
D1
E
E1
e
H
h
L
M
DETAIL A
END VIEW
TOP VIEW
16X
L
T
SEATING
PLANE
A1
A
SIDE VIEW
c
DETAIL A
D1
GENERIC
MARKING DIAGRAM*
xxxxxxxxxx
xxxxxxxxxx
xxxxxxxxxx
AWLYYWWG
E1
BOTTOM VIEW
RECOMMENDED
SOLDERING FOOTPRINT
16X
0.58
2.50
11.00
MILLIMETERS
MIN
MAX
2.65
2.35
0.00
0.10
0.35
0.49
0.25
0.32
10.15
10.45
1.79
2.00
7.40
7.60
2.27
2.47
1.27 BSC
10.05
10.55
0.53 REF
0.50
0.90
0_
7_
xxx
A
WL
YY
WW
G
= Specific Device Code
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
*This information is generic. Please refer to
device data sheet for actual part marking.
Pb−Free indicator, “G” or microdot “ G”,
may or may not be present.
2.87
16X
1.62
1
1.27
PITCH
DIMENSIONS: MILLIMETERS
DOCUMENT NUMBER:
DESCRIPTION:
98AON96277F
SOIC−16 WB, EP
Electronic versions are uncontrolled except when accessed directly from the Document Repository.
Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
PAGE 1 OF 1
ON Semiconductor and
are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.
ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding
the suitability of its products for any particular purpose, nor does ON Semiconductor 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. ON Semiconductor does not convey any license under its patent rights nor the
rights of others.
© Semiconductor Components Industries, LLC, 2019
www.onsemi.com
onsemi,
, and other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliates
and/or subsidiaries in the United States and/or other countries. onsemi owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property.
A listing of onsemi’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. onsemi reserves the right to make changes at any time to any
products or information herein, without notice. The information herein is provided “as−is” and onsemi makes no warranty, representation or guarantee regarding the accuracy of the
information, product features, availability, functionality, or suitability of its products for any particular purpose, nor does onsemi 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. Buyer is responsible for its products
and applications using onsemi products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information
provided by onsemi. “Typical” parameters which may be provided in onsemi 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. onsemi does not convey any license
under any of its intellectual property rights nor the rights of others. onsemi products are not designed, intended, or authorized for use as a critical component in life support systems
or any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should
Buyer purchase or use onsemi products for any such unintended or unauthorized application, Buyer shall indemnify and hold onsemi and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that onsemi was negligent regarding the design or manufacture of the part. onsemi is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT:
Email Requests to: orderlit@onsemi.com
onsemi Website: www.onsemi.com
◊
TECHNICAL SUPPORT
North American Technical Support:
Voice Mail: 1 800−282−9855 Toll Free USA/Canada
Phone: 011 421 33 790 2910
Europe, Middle East and Africa Technical Support:
Phone: 00421 33 790 2910
For additional information, please contact your local Sales Representative