NCV7681APWR2G [ONSEMI]
LED 驱动器，汽车，八路，100 mA;
| 型号： | NCV7681APWR2G |
| 厂家： | 
ONSEMI |
| 描述： | LED 驱动器，汽车，八路，100 mA 驱动 驱动器 |
| 文件： | 总16页 (文件大小：197K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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.
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MARKING
DIAGRAM
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.
NCV7681x
AWLYYWWG
SOIC−16 WB
PW SUFFIX
CASE 751DW
NCV7681 = Specific Device Code
x
= A (No Latch−Off Function)
or L (Latch−Off Function)
= Assembly Location
The device is available in a SOIC−16 WB package with exposed pad.
A
Features
WL = Wafer Lot
YY = Year
WW = Work Week
• 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
G
= Pb−Free Device
ORDERING INFORMATION
†
Device
Package
Shipping
• 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
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.
• Improved EMC Performance
• Latch−Off Function on Open String (NCV7681L)
♦ Restart Option of Unaffected Strings
• Over Temperature Fault Reporting
• These are Pb−Free Devices
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
1
Publication Order Number:
November, 2016 − Rev. 1
NCV7681/D
NCV7681
Open Load
Detection
Latch−Off Control
DIAG
Interface
CC
VP
EMC Filter
UVLO
Vreg
Overvoltage
1 of 8
Ballast
Drive
Soft Start,
Bias and
Out1
Out2
Out3
Out4
Out5
Out6
Out7
Out8
−
+
Reference
Output
Current
Drive
FB
Channel
Control
FET Drive
200K
200K
Over temperature &
Over voltage sense
Setback
Current
−20%
1V
Control Logic
50% IOUT
Open Load
Detect
Output
Latch−Off
STOP
DIAG
Vreg
x 150
Oscillator
and PWM
I
GND
RSTOP
Irstop
−
+
2.2V
0.4V
V−I Converter
CC
Rtail
Pin
Current
Limit
−
+
Open
1.8V
Circuit
Restart
RTAIL
RSTOP
Boxes with dotted lines signify NCV7681L only.
Figure 1. Block Diagram
OUT1
VP
Ballast Drive
FB
OUT2
OUT3
OUT4
GND
EP
STOP
DIAG
RSTOP
RTAIL
OUT5
OUT6
OUT7
OUT8
Figure 2. Pinout Diagram
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2
NCV7681
V
MRA4003T3G
MRA4003T3G
STRING
TAIL
NVD2955
STOP
C2
R3
1K
0.22uF
C3
100nF
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
C1
R1
VP
10K
0.68uF
Ballast
Drive
FB
STOP
DIAG
RSTOP
RTAIL
R4, 3.01K
R5, 1.62K
OUT7
OUT8
C4
10nF
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 V
C1 is for line noise and stability considerations.
C3 is for EMC considerations.
.
STRING
Unused OUTx channels should be shorted to ground as OUT7 shows in this example.
MRA4003T3G
V
STRING
TAIL
MRA4003T3G
STOP
C3
100nF
OUT1
C1
R1
VP
0.68uF
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
10K
Ballast
Drive
FB
STOP
DIAG
R4, 3.01K
RSTOP
RTAIL
C4
10nF
R5, 1.62K
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.
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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
1
1
1
0
0
0
X
X
X
1
NCV7681A
NCV7681A
NCV7681A
NCV7681L
NCV7681A
NCV7681A
OFF
−
1
I
I
NORMAL
0
STOP
STOP
OPEN CIRCUIT***
OPEN CIRCUIT***
NORMAL
1
1
OFF
PWM
PWM
0
1
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
Open String Removed
on
OUTx
on
OUTx
Current
Current
off
off
on
OUTx
on
OUTx
Outputs with no open string.
Current
Current
Outputs with no open string.
off
off
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.
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NCV7681
Table 2. PIN FUNCTION DESCRIPTION (16 Pin SO Wide Exposed Pad Package)
Pin #
Label
Description
1
OUT1
Channel 1 constant current output to LED.
Unused pin should be grounded.
Supply Voltage Input.
2
3
VP
Ballast Drive
Gate drive for external power distribution PFET.
Ground if not used.
4
FB
Feedback Sense node for V regulation.
P
Use feedback resistor divider or connect to V with a 10k resistor.
P
5
6
STOP
DIAG
Stop Logic Input. External Modulation Input.
Open−drain diagnostic output.
Reporting Open Circuit, R
Current Limit,
STOP
and Overvoltage Set Back Current down 20%.
Normal Operation = LOW.
Ground if not used.
7
8
RSTOP
RTAIL
Stop current bias program resistor.
Tail current duty cycle PWM program resistor.
Ground if using external modulation.
9
OUT8
OUT7
OUT6
OUT5
Channel 8 constant current output to LED.
Unused pin should be grounded.
10
11
12
Channel 7 constant current output to LED.
Unused pin should be grounded.
Channel 6 constant current output to LED.
Unused pin should be grounded.
Channel 5 constant current output to LED.
Unused pin should be grounded.
13
14
GND
Ground.
OUT4
Channel 4 constant current output to LED.
Unused pin should be grounded.
15
16
OUT3
OUT2
epad
Channel 3 constant current output to LED.
Unused pin should be grounded.
Channel 2 constant current output to LED.
Unused pin should be grounded.
epad*
Ground. Do not connect to pcb traces other than GND.
*Grounding will provide better thermal and electrical performance.
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NCV7681
Table 3. MAXIMUM RATINGS (Voltages are with respect to device substrate.)
Rating
Value
Unit
Supply Input (VP, Ballast Drive, STOP, DIAG)
V
DC
−0.3 to 40
40
Peak Transient
Output Pin Voltage (OUTX)
Output Pin Current (OUTX)
DIAG Pin Current
−0.3 to 40
200
V
mA
mA
V
10
Input Voltage (RTAIL, RSTOP, FB)
−0.3 to 3.6
−40 to 150
260 peak
Junction Temperature, T
°C
°C
J
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)
Storage Temperature
MSL3
−55 to 150°C
Package Thermal Resistance (Note 2)
SOIC−16 WB EP
Junction−to−Board (R
)
15°C/W
73°C/W
43°C/W
Y
JB
Junction−to−Ambient (R
)
q
JA
Junction−to−Pin (R
)
Y
JL
1. For additional information, see or download ON Semiconductor’s Soldering and Mounting Techniques Reference Manual, SOLDERRM/D,
and Application Note AND8003/D.
2
2. Values represent typical still air steady−state thermal performance on 1 oz. copper FR4 PCB with 650 mm copper area with OUT1−OUT8
dissipating 50 mW each.
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NCV7681
Table 5. ELECTRICAL CHARACTERISTICS
(4.5 V < VP < 16 V, STOP = VP, RSTOP = 3.01 kW, RTAIL = 1.62 kW, −40°C ≤ T ≤ 150°C, unless otherwise specified.)
J
Characteristic
Conditions
Min
Typ
Max
Unit
GENERAL PARAMETERS
Quiescent Current (IOUTx = 50 mA)
STOP mode
Tail mode
mA
VP = 16 V
VP = 16 V
VP = 16 V, STOP = 0 V, OUTx = 0 mA,
−
−
−
6
5
−
12
12
2.0
Fault mode (Note 5)
Disconnected output
Driver Ground Pin Current (pin12)
Output Under Voltage Lockout
IOUT1 to IOUT8 = 50 mA
VP Rising
−
3.8
−
400
4.1
500
4.4
−
mA
V
Output Under Voltage Lockout
Hysteresis
200
mV
Open Load Disable Threshold
Open Load Disable Hysteresis
THERMAL LIMIT
7.2
−
7.7
8.2
−
V
200
mV
Thermal Shutdown
(Note 3)
(Note 3)
150
−
175
15
−
−
°C
°C
Thermal Hysteresis
CURRENT SOURCE OUTPUTS
Output Current
OUTX = 0.5 V, T = 25°C, 150°C
45
90
50
100
55
110
mA
J
OUTX = 1 V, R
= 1.5 K
STOP
Maximum Regulated Output Current
Current Matching
0.5V to 16V
100
−4
−
0
−
4
mA
%
2IOUTx(min)
ƪ
ƪ
* 1ƫ
* 1ƫ
100
100
IOUTx(min) ) IOUTx(max)
2IOUTx(max)
IOUTx(min) ) IOUTx(max)
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
@ 99% Iout
−
16.0
−
6
17.2
78
80
−
15
18.4
−
mA/ms
V
Overvoltage Set Back Threshold
Overvoltage Set Back Current
Diag Reporting of Set Back Current
Output Off Leakage
VP = 20 V (Note 4)
%Iout
%Iout
mA
−
−
EN = high
−
1
FET DRIVER
Ballast Drive
DC Bias
Sink Current
mA
V
FB = 1.5 V, Ballast Drive = 3 V
FB = 0.5 V, Ballast Drive = 3 V
−
4
1.0
13
2.4
20
Ballast Drive Reference Voltage
STOP LOGIC
0.92
1.00
1.08
Input High Threshold
Input Low Threshold
0.75
0.70
100
120
1.25
1.00
250
200
1.75
1.44
400
300
V
V
V
IN
Hysteresis
mV
kW
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.
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NCV7681
Table 5. ELECTRICAL CHARACTERISTICS
(4.5 V < VP < 16 V, STOP = VP, RSTOP = 3.01 kW, RTAIL = 1.62 kW, −40°C ≤ T ≤ 150°C, unless otherwise specified.)
J
Characteristic
CURRENT PROGRAMMING
RSTOP Bias Voltage
Conditions
Min
Typ
Max
Unit
Stop current programming voltage
0.94
−
1.00
150
1.06
−
V
−
RSTOP K multiplier
I
/I
OUTX RSTOP
RSTOP Over Current Detection
RTAIL Bias Current
Duty Cycle
RSTOP = 0 V
0.70
290
1.00
330
1.45
370
mA
mA
%
Tail duty cycle programming current
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, I
= 1 mA
–
−
0.1
−
0.40
10
V
mA
V
DIAG
DIAG Output Leakage
Open Load Reset Voltage on DIAG
AC CHARACTERISTICS
Stop Turn−on Delay Time
Stop Turn−off Delay Time
PWM Frequency
V
DIAG
= 5 V
(Note 5)
1.6
1.8
2.0
V(STOP) > 1.75 V to I(OUTx) = 90%
V(STOP) < 0.75 V to I(OUTx) = 10%
STOP = 0 V
−
−
14
14
45
45
msec
msec
Hz
400
1
800
2
1200
4
Open Circuit to DIAG Reporting
VP Turn−on Time
4.8 mA pull−up to VP, V(DIAG) >1.5 V
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.
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NCV7681
TYPICAL CHARACTERISTICS
100
90
80
70
60
50
40
30
20
53
52
51
50
49
48
10
0
T = 25°C
RSTOP = 3.01 kW
47
0
1
2
3
4
5
6
7
8
9
10
−40 −20
0
20 40 60 80 100 120 140 160
RSTOP (kW)
TEMPERATURE (°C)
Figure 7. Iout vs. RSTOP
Figure 8. Iout vs. Temperature
100
90
100
90
80
80
70
70
60
50
40
30
20
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
2.5
RTAIL (kW)
V(RTAIL)
Figure 9. Duty Cycle vs. RTAIL
Figure 10. Duty Cycle vs. V(RTAIL)
80
70
60
50
40
30
20
RTAIL = 5 kW
RTAIL = 2.3 kW
RTAIL = 1.5 kW
10
0
−40 −20
0
20
40 60 80 100 120 140 160
TEMPERATURE (°C)
Figure 11. Duty Cycle vs. Temperature
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NCV7681
TYPICAL CHARACTERISTICS
60
50
40
30
20
51.0
50.8
50.6
50.4
50.2
50.0
49.8
49.6
49.4
49.2
10
0
R
= 3.01 k
STOP
49.0
9
11
13
15
17
19
21
23
25
27
6
7
8
9
10 11 12
(V)
13 14 15 16
VP (V)
V
OUT
Figure 12. IOUT vs. VP
Figure 13. IOUT Line Regulation
60
50
40
30
20
60
50
40
30
20
10
0
10
0
0
2
4
6
8
10
12
14
16
0
0.1
0.2
0.3
0.4
0.5
V
OUT
(V)
V
OUT
(V)
Figure 14. IOUT vs. VOUT
Figure 15. IOUT vs. VOUT
14
12
10
8
6
4
per eq. 1
R7 = 1 kW
2
0
0
2K
4K
6K
8K
10K
12K 14K
R6 (W)
Figure 16. VSTRING vs. R6
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NCV7681
TYPICAL PERFORMANCE CHARACTERISTICS
160
140
120
100
80
1 oz
2 oz
60
40
20
0
0
100
200
300
400
500
600
700
2
COPPER HEAT SPREADER AREA (mm )
Figure 17. qJA vs. Copper Spreader Area
100
D = 0.5
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
2
100 mm
2
50 mm
2
500 mm
10
1
0.000001 0.00001
0.0001
0.001
0.01
0.1
1
10
100
1000
PULSE TIME (s)
Figure 19. Single Pulse Heating Curve
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NCV7681
DETAILED OPERATING DESCRIPTION
General
module will either display all LED strings or no LED strings
The NCV7681 device is an eight channel LED driver
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.
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.
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).
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
D1
TAIL
MRA4003T3G
Q1
NVD2955
Q2
NVD2955
VSTRING
D2
MRA4003T3G
STOP
R1
1K
R2
D3
D4
D5
D6
D7
D8
D9
D12
D13
D14
C2
0.22uF
C4
0.22uF
1K
1 -8
D10
D11
C1
0.68uF
C3
0.68uF
C6
100nF
C5
100nF
OUT1-OUT8
OUT1-OUT8
OUT1
OUT1
Ballast Drive
VP
VP
Ballast Drive
OUT8
OUT8
R3
9.53K
FB
FB
R4
1K
GND
GND
NCV7681 U2
NCV7681 U1
Figure 20.
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NCV7681
DIAG
brightness level for tail. The PWM generator’s fixed
The logic DIAG pin’s main function is to alert the
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.
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
(eq. 1)
IOUTX + 150 @
RSTOP
RSTOP Bias Voltage = 1 V (typ)
Set the Duty Cycle (DC) using RTAIL
Parallel Outputs
RTAIL + 1.8 @ RSTOP(DC ) 0.22)
(eq. 2)
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.
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).
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.
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.
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
NOTES:
D
A
B
1. DIMENSIONING AND TOLERANCING PER ASME
Y14.5M, 1994.
M
M
B
0.25
16
9
M
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.
H
E
5. MAXIMUM MOLD PROTRUSION OR FLASH TO
BE 0.15 PER SIDE.
MILLIMETERS
h
DIM MIN
MAX
2.65
0.10
0.49
0.32
10.45
2.00
7.60
2.47
1
8
PIN 1
INDICATOR
x 45
A
A1
b
2.35
0.00
0.35
0.25
10.15
1.79
7.40
2.27
DETAIL A
16X b
e
M
S
S
0.25
T A
B
END VIEW
c
TOP VIEW
D
D1
E
16X
E1
e
L
1.27 BSC
H
10.05
10.55
h
0.53 REF
A1
A
SEATING
PLANE
L
0.50
0.90
T
M
0
7
_
_
SIDE VIEW
D1
c
DETAIL A
GENERIC
MARKING DIAGRAM*
xxxxxxxxxx
xxxxxxxxxx
xxxxxxxxxx
AWLYYWWG
E1
xxx
A
WL
YY
WW
G
= Specific Device Code
= Assembly Location
= Wafer Lot
= Year
= Work Week
BOTTOM VIEW
RECOMMENDED
SOLDERING FOOTPRINT
16X
0.58
= Pb−Free Package
2.50
*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.
11.00
2.87
1
1.27
PITCH
16X
1.62
DIMENSIONS: MILLIMETERS
Electronic versions are uncontrolled except when accessed directly from the Document Repository.
Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
DOCUMENT NUMBER:
DESCRIPTION:
98AON96277F
SOIC−16 WB, EP
PAGE 1 OF 1
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