Texas Instruments LP8861-Q1 User manual

Using the LP8861-Q1EVM Evaluation Module
User's Guide
Literature Number: SNVU456
July 2015

Contents
1 Preface ............................................................................................................................... 4
1.1 About this Manual........................................................................................................ 4
1.2 Related Documentation from Texas Instruments .................................................................... 4
1.3 FCC Warning ............................................................................................................. 4
1.4 If You Need Assistance ................................................................................................. 4
2 Introduction......................................................................................................................... 4
3 Description of the LP8861-Q1 Device...................................................................................... 5
3.1 Features................................................................................................................... 5
3.2 Applications ............................................................................................................... 5
4 Hardware Setup ................................................................................................................... 6
5 Board Layout....................................................................................................................... 7
6 Start-Up of the EVM and Power Sequences............................................................................. 8
6.1 PWM Input to Initiate Start-up Sequence............................................................................. 8
6.2 Shutdown Sequence..................................................................................................... 9
7 Boost Converter................................................................................................................. 10
7.1 Switching Frequency .................................................................................................. 10
7.2 Spread Spectrum and Synchronization.............................................................................. 10
7.3 Voltage Control.......................................................................................................... 11
8 LED Current Sinks.............................................................................................................. 12
8.1 Output Configuration ................................................................................................... 12
8.2 Current Setting.......................................................................................................... 12
8.3 Brightness Control...................................................................................................... 12
9 External Temperature Sensor Functionality .......................................................................... 13
9.1 Overview................................................................................................................. 13
9.2 Calculator................................................................................................................ 13
10 Fault Detection................................................................................................................... 13
10.1 Fault Indicator........................................................................................................... 13
11 Evaluation Board Schematic................................................................................................ 14
12 Bill of Materials .................................................................................................................. 15
13 Appendix A: LED Load Board .............................................................................................. 17
2Table of Contents SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com
List of Figures
1 Evaluation Board Connectors and Setup................................................................................. 6
2 Top Layer .................................................................................................................... 7
3 Bottom Layer (GND)......................................................................................................... 7
4 Evaluation Board Stackup .................................................................................................. 8
5 Typical Start-up Sequence ................................................................................................. 9
6 Switching Frequency vs RFSET............................................................................................. 10
7 Converter Maximum Output Voltage vs R12 ........................................................................... 11
8 Output Current vs RISET ................................................................................................... 12
9 Temperature Compensation Calculator ................................................................................. 13
10 Evaluation Board Schematic.............................................................................................. 14
11 LED Load Board - Top Side .............................................................................................. 17
12 LED Load Board - Bottom View.......................................................................................... 17
13 LED Load Board - Schematic Diagram.................................................................................. 18
14 Forward Voltage for Cree Xlamp ML-B LEDs ......................................................................... 19
Excel is a registered trademark of Microsoft Corporation.
All other trademarks are the property of their respective owners.
3
SNVU456–July 2015 List of Figures
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

User's Guide
SNVU456–July 2015
LP8861-Q1EVM Evaluation Module
1 Preface
1.1 About this Manual
This user’s guide describes the module used to evaluate characteristics, operation, and use of the
LP8861-Q1 low EMI, high-performance 4-channel LED driver for automotive lighting. This document
includes a schematic diagram, PCB layout, and bill of materials (BOM).
1.2 Related Documentation from Texas Instruments
LP8861-Q1 data sheet
1.3 FCC Warning
This equipment is intended for use in a laboratory test environment only. It generates, uses, and can
radiate radio frequency energy and has not been tested for compliance with the limits of computing
devices pursuant to subpart J of part 15 of FCC rules, which are designed to provide reasonable
protection against radio frequency interference. Operation of this equipment in other environments may
cause interference with radio communications, in which case the user, at their own expense, will be
required to take whatever measures may be required to correct this interference.
1.4 If You Need Assistance
Contact your local TI sales representative.
2 Introduction
The Texas Instruments LP8861-Q1EVM evaluation module (EVM) helps designers to evaluate the
operation and performance of the LP8861-Q1 device. The LP8861-Q1EVM uses the LP8861-Q1 to drive
up to 4 LED strings for LCD backlighting with high efficiency. Information about output voltage and current
ratings of the LP8861-Q1 can also be found in the device data sheet (SNVSA50).
A power supply connection for the VIN and test points for each signal can be found on the evaluation
board. A separate LED board can be used as a load; it is also possible to connect LCD panel to the output
connectors.
For evaluation purposes, the EVM has been tested over a 4.5-V to 40-V input range. This voltage range is
within the recommended operating range for input voltage of the LP8861-Q1. Users are cautioned to
evaluate their specific operating conditions and choose components with the appropriate voltage ratings
before designing this circuitry into a final product.
4LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com Description of the LP8861-Q1 Device
3 Description of the LP8861-Q1 Device
The LP8861-Q1 is an automotive high-efficiency LED driver with integrated boost/SEPIC converter. It has
4 high-precision current sinks that can be controlled by a PWM input signal.
The boost converter has adaptive output voltage control based on the LED current sink headroom
voltages. This feature minimizes the power consumption by adjusting the voltage to lowest sufficient level
in all conditions. Boost controller supports spread spectrum for switching frequency and an external
synchronization with dedicated pin. The high switching frequency allows the LP8861-Q1 to avoid
disturbance for AM radio band.
The LP8861-Q1 can drive an external p-FET to disconnect the input supply from the system in the event
of a fault, reduce inrush current and standby power consumption. The LP8861-Q1 has ability to reduce
LED current based on temperature measured with an external NTC sensor to protect LEDs from
overheating and extend LED life time.
The input voltage range for LP8861-Q1 is from 4.5 V to 40 V to support car stop/start and load dump
condition. The LP8861-Q1 device supports PWM brightness dimming ratio up to 10 000:1 for input PWM
frequency of 200 Hz. The device integrates extensive safety and protection features.
3.1 Features
• Four High-Precision Current Sinks
– Current Matching 1% (typ.)
– Output Current up to 100 mA/Channel
– Dimming Ratio 10 000:1 at 200-Hz PWM input
• Integrated Boost/SEPIC for LED String Power
– Output Voltage up to 45 V
– Switching Frequency 300 kHz to 2.2 MHz
– Boost Synchronization Input
– Spread Spectrum
• Input Voltage Operating Range 4.5 V to 40 V
• Power-Line FET Control for Inrush Current Protection and Standby Energy Saving
• Extensive Safety and Fault Tolerance Features
– Fault Output
– Input Voltage OVP, UVLO, and OCP
– Open and Shorted LED Fault Detection
– Automatic LED Current Reduction with External Temperature Sensor
– Thermal Shutdown
• Minimum Number of External Components
3.2 Applications
Automotive Infotainment, Instrument Cluster and Backlighting Systems
5
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

INPUT
VOLTAGE
OUTPUT
CONFIGURATION
LED
CONNECTOR
CONTROL
POINTS
FAULT
LED
CONTROL
POINTS SHUNTS
CONTROL
POINTS
CONTROL
POINTS
Hardware Setup www.ti.com
4 Hardware Setup
Figure 1 shows connectors and main components on the LP8861-Q1 board.
Figure 1. Evaluation Board Connectors and Setup
6LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com Board Layout
5 Board Layout
Figure 2. Top Layer
Figure 3. Bottom Layer (GND)
See the LP8861-Q1 datasheet (SNVSA50) for PCB layout guidelines.
7
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

Prepreg
Core
Prepreg
Top Layer
Bottom Layer
PGND
GND
Start-Up of the EVM and Power Sequences www.ti.com
Figure 4. Evaluation Board Stackup
• 4-layer board FR4
• Material thickness 1.616 ± 10% mm
• Surface finish immersion gold
6 Start-Up of the EVM and Power Sequences
The LP8861-Q1 EVM is set up for easy start-up:
• Connect LEDs to OUT1 - OUT4 of connector J16. (Note: LED current default is 100 mA and maximum
boost voltage default is 37 V. LED outputs that are not used must be grounded via jumpers J11 to
J14.)
• Connect input (BATTERY) voltage 12 V to connector J25.
LEDs will turned on immediately because the jumpers on the EVM are set up for PWM input of 100% duty
cycle. For connector and jumper positions, see Figure 1 and Figure 10.
Input (BATTERY) voltage range is 4.5 V to 40 V.
The LP8861-Q1 has a dual function VDDIO/EN pin. By default, VDDIO/EN = 3.3 V is generated
automatically on the EVM from battery input voltage via jumpers J1 and J26. VDDIO/EN acts as enable for
the device as well as supply/reference voltage for IO logic. Device starts when VIN voltage is present and
above the VIN UVLO voltage level (4 V), and the VDDIO/EN voltage is set above threshold voltage (1.2
V).
By default, boost switching frequency is 400 kHz (jumper J4 connecting R3 = 160 kΩto FSET) and boost
maximum voltage is 37 V (R12 = 750 kΩand R13 = 130 kΩ). See Section 7.1 and Section 7.3 for
description on how to change boost settings.
By default, LED current is 100 mA per string (jumper J5 connecting R4= 24 kΩto ISET). See Section 8.2
for the description on how to change LED current setting.
Alternatively to internal LDO, device circuitry can be powered from external power supply (4.4 V to 5.25 V)
connected to the LDO pin. Internal LDO will be disabled in this case.
6.1 PWM Input to Initiate Start-up Sequence
The backlight is started by setting PWM input high. By default, the LP8861-Q1EVM has PWM input set
high (100% duty cycle), which is connected to VDDIO through jumper J2. Alternatively, an external PWM
signal can be connected by removing jumper J2 , shorting pins 3 and 4 on jumper J17, and connecting the
external PWM to connector J18.
8LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com Start-Up of the EVM and Power Sequences
Figure 5. Typical Start-up Sequence
6.2 Shutdown Sequence
The backlight is shut down (LEDs turned off) by setting PWM input low or when VDDIO/EN = 0. If
VDDIO/EN is set low, the LP8861-Q1 will enter low power mode with internal LDO disabled.
9
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

200
400
600
800
1000
1200
1400
1600
1800
2000
2200
20 40 60 80 100 120 140 160 180 200 220
fSW (kHz)
RFSET (k)
C010
Boost Converter www.ti.com
7 Boost Converter
7.1 Switching Frequency
Switching frequency for boost is defined as 300 kHz to 2.2 MHz. However, frequency from 250 kHz to 2.2
MHz can be set by the external resistor connected to the FSET pin, thus allowing the device to be
synchronized with the lowest external frequency of 300 kHz (see details in Section 7.2).
Switching frequency is defined by resistor R3 connected to FSET pin:
fSW = 67600/(RFSET +6.4)
where
• fSW - switching frequency, kHz
• RFSET – frequency setting resistor, kΩ(1)
Figure 6. Switching Frequency vs RFSET
By default, jumper J4 is installed on the board connecting R3 = 160 kΩto the FSET pin which sets the
boost at 400 kHz. An external resistor can be connected to change the switching frequency: remove
jumper J4, short pins 7 and 8 on jumper J17, and connect the external resistor to connector J18. Boost
internal parameters will be adjusted automatically according to chosen frequency during start-up.
7.2 Spread Spectrum and Synchronization
The SYNC pin is used to enable boost spread spectrum or, alternatively, to synchronize boost switching
with an external frequency. To disable spread spectrum functionality this pin should be connected to
ground; to enable spread spectrum SYNC should be connected to VDDIO/EN. Selection is done with
jumper J3. When spread spectrum is enabled, boost switching frequency is modulated ±3% from set
frequency with 1.875 kHz modulation frequency.
If an external frequency is detected at SYNC pin, the LP8861-Q1 starts to synchronize boost with this
frequency. Frequency should be higher than the switching frequency set by RFSET resistor and be in range
1.2 V to 1.5 V × fSW SET.
10 LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

10
15
20
25
30
35
40
45
200 300 400 500 600 700 800 900 1000
Maximum converter output voltage (V)
R12 (k)
C011
VMAX BOOST = ( VBG
R13 + 0.0387 ) x R12 + VBG
www.ti.com Boost Converter
7.3 Voltage Control
Maximum boost converter voltage is defined by the feedback voltage divider R12 and R13.
Recommended value for R13 is 130 kΩ. R12 value can be calculated with the following equation:
where
• VBG = 1.2 V
• R12, R13 values are in kΩ(2)
Figure 7. Converter Maximum Output Voltage vs R12
Maximum voltage should be chosen based on the maximum voltage required for LED strings.
Recommended maximum voltage is about 30% higher than maximum LED string voltage. Initial boost
voltage is about 88% of maximum voltage. Boost output voltage is adjusted automatically based on LED
current sink headroom voltage.
Default setting for boost maximum voltage is 37 V (R12 is 750 kΩ).
11
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
20 40 60 80 100 120 140
IOUT (mA)
RISET (k)
C012
ILED=2000îVBG
RISET
LED Current Sinks www.ti.com
8 LED Current Sinks
8.1 Output Configuration
The LP8861-Q1 detects LED output configuration during start-up. Any output connected to ground is
disabled and excluded from adaptive boost control and fault detections. Non-used LED outputs must be
grounded with jumpers J11 through J14.
8.2 Current Setting
Maximum current for the LED outputs is controlled with an external resistor (R4) connected to the ISET
pin. Maximum current can be calculated as follows:
where
• VBG = 1.2 V
• RISET: current setting resistor (R4), kΩ
• ILED: output current per output, mA (3)
Figure 8. Output Current vs RISET
8.3 Brightness Control
The LP8861-Q1 controls the brightness of the display with conventional PWM. Output PWM will directly
follow the input PWM. Input PWM frequency can be in the range of 100 Hz to 20 kHz.
An external digital PWM signal can be connected to connector J18. For test purposes the PWM input of
the LP8861-Q1 can be connected to ground to turn off LEDs or connected to VDDIO/EN to set up 100%
brightness using jumper J2.
12 LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

USER INPUT CALCULATED COMPENSATION
USER INPUT
FOR NTC
www.ti.com External Temperature Sensor Functionality
9 External Temperature Sensor Functionality
9.1 Overview
The LP8861-Q1 has an optional feature to decrease automatically LED current when LED overheating is
detected with an external NTC sensor. See the LP8861-Q1 data sheet (SNVSA50) for details.
9.2 Calculator
An Excel®calculator is available to choose components for the temperature compensation with an
external NTC. Contact your local TI sales representative.
Figure 9. Temperature Compensation Calculator
10 Fault Detection
10.1 Fault Indicator
The LP8861-Q1 has fault detection for LED open and short, VIN input overvoltage, VIN undervoltage
lockout, power line overcurrent, boost overcurrent, and thermal shutdown. Open-drain FAULT pin
indicates faults. Fault pin can be connected to LED D2 for indication (jumper J10).
13
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

Evaluation Board Schematic www.ti.com
11 Evaluation Board Schematic
Figure 10. Evaluation Board Schematic
14 LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com Bill of Materials
12 Bill of Materials
The following is the bill of materials for the LP8861-Q1EVM:
DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER Qty
C1, C4, C6, C7 CAP, CERM, 10uF, 50V, +/-10%, X5R, TDK CGA5L3X5R1H106K160AB 5
1206_190
C2, C8 CAP, AL, 33uF, 50V, +/-20%, 40 mohm, Panasonic EEHZC1H330XP 2
SMD
C3 CAP, CERM, 1uF, 10V, +/-10%, X5R, Kemet C0603C105K8PACTU 1
0603
C9 CAP, CERM, 15pF, 50V, +/-5%, C0G/NP0, Kemet C0603C150J5GACTU 1
0603
C15 CAP, CERM, 47pF, 50V, +/-5%, C0G/NP0, Kemet C0603C470J5GACTU 1
0603
C10, C11, C12, C13 CAP, CERM, 2200pF, 50V, +/-10%, X7R, Kemet C0603C222K5RACTU 4
0603
C14 CAP, CERM, 0.1uF, 50V, +/-10%, X7R, MuRata GRM188R71H104KA93D 1
0603
C16 CAP, CERM, 1 µF, 50 V, +/- 10%, X7R, Taiyo Yuden UMK107AB7105KA-T 1
0603
D1 Diode, Schottky, 60V, 4A, ON Semiconductor NRVB460MFST3G 1
6.15x1.00x5.15mm
D2 LED, Red, SMD Rohm SML-311UTT86 1
J1, J4, J5, J7, J8, J11, Header, TH, 100mil, 2x1, Gold plated, 230 Samtec TSW-102-07-G-S 12
J12, J13, J14, J26, J28, mil above insulator
J29
J2, J3, J6, J10 Header, TH, 100mil, 3x1, Gold plated, 230 Samtec TSW-103-07-G-S 4
mil above insulator
J9, J19, J20, J21, J22, CONN HEADER 1POS .100" SNGL TIN, Samtec TSW-101-17-T-S 9
J23, J24, J27, J30 TH
J15, J17 Header, TH, 100mil, 8x2, Gold plated, 230 Samtec TSW-108-07-G-D 2
mil above insulator
J16 Header, TH, 100mil, 10x2, Gold plated, Samtec TSW-110-07-G-D 1
230 mil above insulator
J18 Header, TH, 100mil, 10x1, Gold plated, Samtec TSW-110-07-G-S 1
230 mil above insulator
J25 Conn Term Block, 2POS, 3.81mm, TH Phoenix Contact 1727010 1
L1 Inductor, Shielded, 22uH, 3.7A, 0.103 Vishay-Dale IHLP3232DZER220M5A 1
ohm, SMD
Q1 MOSFET, P-CH, -60V, 30A, Vishay-Siliconix SQJ461EP 1
PowerPAK_SO-8L
R1 RES, 0.05 ohm, 1%, 3W, 2512 Bourns CRA2512-FZ-R050ELF 1
R2 RES, 20k ohm, 5%, 0.1W, 0603 Vishay-Dale CRCW060320K0JNEA 1
R3 RES, 160 k, 1%, 0.1 W, 0603 Vishay-Dale CRCW0603160KFKEA 1
R4 RES, 24.0k ohm, 1%, 0.1W, 0603 Yageo America RC0603FR-0724KL 1
R5 RES, 1.80 k, 1%, 0.1 W, 0603 Yageo America RC0603FR-071K8L 1
15
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

Bill of Materials www.ti.com
DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER Qty
R6 RES, 10.0 k, 1%, 0.1 W, 0603 Vishay-Dale CRCW060310K0FKEA 1
R7 RES, 82.0 k, 1%, 0.1 W, 0603 Yageo America RC0603FR-0782KL 1
R8 RES, 8.2 k, 1%, 0.1 W, 0603 Yageo America RC0603FR-078K2L 1
R9 RES, 12.0 k, 1%, 0.1 W, 0603 Yageo America RC0603FR-0712KL 1
R10 RES, 1.00k ohm, 1%, 0.1W, 0603 Yageo America RC0603FR-071KL 1
R11, R14, R15, R16, R17 RES, 0 ohm, 5%, 0.1W, 0603 Rohm MCR03EZPJ000 5
R12 RES, 750 k, 1%, 0.1 W, 0603 Vishay-Dale CRCW0603750KFKEA 1
R13 RES, 130 k, 1%, 0.1 W, 0603 Vishay-Dale CRCW0603130KFKEA 1
R18 RES, 10.0 k, 1%, 0.1 W, 0603 Vishay-Dale CRCW060310K0FKEA 1
R20 RES, 100k ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW0603100KFKEA 1
R19 RES, 165 k, 1%, 0.1 W, 0603 Yageo America RC0603FR-07165KL 1
R21 RES, 10.0k ohm, 1%, 0.1W, 0603 Yageo America RC0603FR-0710KL 1
R22 RES, 0 ohm, 5%, 0.125W, 0805 Vishay-Dale CRCW08050000Z0EA 1
RT1 Thermistor NTC, 10.0k ohm, 1%, 0603 MuRata NCP18XH103F03RB 1
U1 Low-EMI, High-Performance 4-Channel Texas Instruments LP8861PWPQ1(1) 1
LED Driver for Automotive Lighting,
PWP0020B
U2 LOW-VOLTAGE ADJUSTABLE Texas Instruments TLVH431AQDBVRQ1 1
PRECISION SHUNT REGULATOR,
DBV0005A
(1) Some boards shipped with pre-production silicon marked as P8861Q1 53TG4 ES11 with adaptive SW pin current limit disabled.
16 LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com Appendix A: LED Load Board
13 Appendix A: LED Load Board
The LED board is intended to be used as the load for LED drivers and can configured for up to 6 strings
and up to 20 LEDs in the string (number of LEDs in use is defined by jumpers). Cree Xlamp ML-B LEDs
with maximum current 175 mA and maximum forward voltage 3.5 mA at 80 mA (3.3 V typical) are used on
the board. For theLP8861-Q1 4 strings are assembled.
NOTE: The LED board is not included with the EVM -- contact your local TI sales representative if
board is needed.
Figure 11. LED Load Board - Top Side
Figure 12. LED Load Board - Bottom View
17
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

D11
D10
D9
D8
D7
D6
D5
D4
1
2
3
J5 1
2
3
J6 1
2
3
J7 1
2
3
J8 1
2
3
J9 1
2
3
J10 1
2
3
J11 1
2
3
J12 D31
D30
D29
D28
D27
D26
D25
D24
1
2
3
J26 1
2
3
J27 1
2
3
J28 1
2
3
J29 1
2
3
J30 1
2
3
J31 1
2
3
J32 1
2
3
J33 D51
D50
D49
D48
D47
D46
D45
D44
1
2
3
J47 1
2
3
J48 1
2
3
J49 1
2
3
J50 1
2
3
J51 1
2
3
J52 1
2
3
J53 1
2
3
J54 D71
D70
D69
D68
D67
D66
D65
D64
1
2
3
J68 1
2
3
J69 1
2
3
J70 1
2
3
J71 1
2
3
J72 1
2
3
J73 1
2
3
J74 1
2
3
J75 D91
D90
D89
D88
D87
D86
D85
D84
1
2
3
J89 1
2
3
J90 1
2
3
J91 1
2
3
J92 1
2
3
J93 1
2
3
J94 1
2
3
J95 1
2
3
J96 D111
D110
D109
D108
D107
D106
D105
D104
1
2
3
J110 1
2
3
J111 1
2
3
J112 1
2
3
J113 1
2
3
J114 1
2
3
J115 1
2
3
J116 1
2
3
J117
D20
D19
D18
D17
D16
D15
D14
D13
1
2
3
J14 1
2
3
J15 1
2
3
J16 1
2
3
J17 1
2
3
J18 1
2
3
J19 1
2
3
J20 1
2
3
J21
GND
1 2 3 4
J22
D40
D39
D38
D37
D36
D35
D34
D33
1
2
3
J35 1
2
3
J36 1
2
3
J37 1
2
3
J38 1
2
3
J39 1
2
3
J40 1
2
3
J41 1
2
3
J42
GND
1 2 3 4
J43
D60
D59
D58
D57
D56
D55
D54
D53
1
2
3
J56 1
2
3
J57 1
2
3
J58 1
2
3
J59 1
2
3
J60 1
2
3
J61 1
2
3
J62 1
2
3
J63
GND
1 2 3 4
J64
D80
D79
D78
D77
D76
D75
D74
D73
1
2
3
J77 1
2
3
J78 1
2
3
J79 1
2
3
J80 1
2
3
J81 1
2
3
J82 1
2
3
J83 1
2
3
J84
GND
1 2 3 4
J85
D100
D99
D98
D97
D96
D95
D94
D93
1
2
3
J98 1
2
3
J99 1
2
3
J100 1
2
3
J101 1
2
3
J102 1
2
3
J103 1
2
3
J104 1
2
3
J105
GND
1 2 3 4
J106
D120
D119
D118
D117
D116
D115
D114
D113
1
2
3
J119 1
2
3
J120 1
2
3
J121 1
2
3
J122 1
2
3
J123 1
2
3
J124 1
2
3
J125 1
2
3
J126
GND
1 2 3 4
J127
LED1 LED2 LED3 LED4 LED5 LED6
12 34
J1
BOOST1
BOOST1
LED1
LED2
LED3
LED4
LED5
LED6
1
2
3
J129
GND
10.0
R1 10.0 R2 10.0 R3 10.0 R4 10.0 R5 10.0 R6
D12
1
2
3
J13 D32 D52 D72 D92 D112
1
2
3
J34
1
2
3
J55
1
2
3
J76
1
2
3
J97
1
2
3
J118
1
2
3
J4 D3
1
2
3
J25
1
2
3
J46
1
2
3
J67
1
2
3
J88
1
2
3
J109
D23 D43 D63 D83 D103
1
2
3
J3
1
2
3
J24
1
2
3
J45
1
2
3
J66
1
2
3
J87
1
2
3
J108
1
2
3
J2 D1
1
2
3
J23
1
2
3
J44
1
2
3
J65
1
2
3
J86
1
2
3
J107
D21 D41 D61 D81 D101
D2 D22 D42 D62 D82 D102
5
4
1
2
3
6
7
J130
Appendix A: LED Load Board www.ti.com
Figure 13. LED Load Board - Schematic Diagram
18 LP8861-Q1EVM Evaluation Module SNVU456–July 2015
Submit Documentation Feedback
Copyright © 2015, Texas Instruments Incorporated

www.ti.com Appendix A: LED Load Board
Table 1. Bill of Materials for LED Load Board
DESIGNATOR DESCRIPTION MANUFACTURER PART NUMBER QTY
R1, R2, R3, R4, Resistor 10.0 ohm, 1%, 0.1W, 0603 Vishay-Dale CRCW060310R0FKEA 6
R5, R6 (not assembled)
J1, J22, J43, J64, Header, 100mi, 2x2 Samtec TSW-102-07-G-D 7
J85,J106, J127
J2...J21,
J23...J42,
J44...J63, Header, 100mi, 3x1 Samtec TSW-103-07-G-S 121
J65...J84 ,
J86...J105,
J107...J126, J129
J130 Header, 100mi, 7x1 Samtec TSW-107-07-G-S 1
D1...D120 Cool White SMD LED XLamp mL-B Cree MLBAWT-A1-0000-000W51 120
Figure 14. Forward Voltage for Cree Xlamp ML-B LEDs
19
SNVU456–July 2015 LP8861-Q1EVM Evaluation Module
Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated

STANDARD TERMS AND CONDITIONS FOR EVALUATION MODULES
1. Delivery: TI delivers TI evaluation boards, kits, or modules, including any accompanying demonstration software, components, or
documentation (collectively, an “EVM” or “EVMs”) to the User (“User”) in accordance with the terms and conditions set forth herein.
Acceptance of the EVM is expressly subject to the following terms and conditions.
1.1 EVMs are intended solely for product or software developers for use in a research and development setting to facilitate feasibility
evaluation, experimentation, or scientific analysis of TI semiconductors products. EVMs have no direct function and are not
finished products. EVMs shall not be directly or indirectly assembled as a part or subassembly in any finished product. For
clarification, any software or software tools provided with the EVM (“Software”) shall not be subject to the terms and conditions
set forth herein but rather shall be subject to the applicable terms and conditions that accompany such Software
1.2 EVMs are not intended for consumer or household use. EVMs may not be sold, sublicensed, leased, rented, loaned, assigned,
or otherwise distributed for commercial purposes by Users, in whole or in part, or used in any finished product or production
system.
2Limited Warranty and Related Remedies/Disclaimers:
2.1 These terms and conditions do not apply to Software. The warranty, if any, for Software is covered in the applicable Software
License Agreement.
2.2 TI warrants that the TI EVM will conform to TI's published specifications for ninety (90) days after the date TI delivers such EVM
to User. Notwithstanding the foregoing, TI shall not be liable for any defects that are caused by neglect, misuse or mistreatment
by an entity other than TI, including improper installation or testing, or for any EVMs that have been altered or modified in any
way by an entity other than TI. Moreover, TI shall not be liable for any defects that result from User's design, specifications or
instructions for such EVMs. Testing and other quality control techniques are used to the extent TI deems necessary or as
mandated by government requirements. TI does not test all parameters of each EVM.
2.3 If any EVM fails to conform to the warranty set forth above, TI's sole liability shall be at its option to repair or replace such EVM,
or credit User's account for such EVM. TI's liability under this warranty shall be limited to EVMs that are returned during the
warranty period to the address designated by TI and that are determined by TI not to conform to such warranty. If TI elects to
repair or replace such EVM, TI shall have a reasonable time to repair such EVM or provide replacements. Repaired EVMs shall
be warranted for the remainder of the original warranty period. Replaced EVMs shall be warranted for a new full ninety (90) day
warranty period.
3Regulatory Notices:
3.1 United States
3.1.1 Notice applicable to EVMs not FCC-Approved:
This kit is designed to allow product developers to evaluate electronic components, circuitry, or software associated with the kit
to determine whether to incorporate such items in a finished product and software developers to write software applications for
use with the end product. This kit is not a finished product and when assembled may not be resold or otherwise marketed unless
all required FCC equipment authorizations are first obtained. Operation is subject to the condition that this product not cause
harmful interference to licensed radio stations and that this product accept harmful interference. Unless the assembled kit is
designed to operate under part 15, part 18 or part 95 of this chapter, the operator of the kit must operate under the authority of
an FCC license holder or must secure an experimental authorization under part 5 of this chapter.
3.1.2 For EVMs annotated as FCC – FEDERAL COMMUNICATIONS COMMISSION Part 15 Compliant:
CAUTION
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not
cause harmful interference, and (2) this device must accept any interference received, including interference that may cause
undesired operation.
Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to
operate the equipment.
FCC Interference Statement for Class A EVM devices
NOTE: This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of
the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not
installed and used in accordance with the instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to
correct the interference at his own expense.
SPACER
SPACER
SPACER
SPACER
SPACER
SPACER
SPACER
SPACER