SC668 EVB
Evaluation Board
User’s Guide
POWER MANAGEMENT
Description
Feature Content
SC668 EVB is the EVB (Evaluation Board) for the SC668
LMU (Light Management Unit). This EVB provides a
working demonstration the IC that allows the user to thoroughly evaluate the part’s features.
This guide contains information relating to the usage of
the EVB and should be used in conjunction with the datasheet for the device. The datasheet contains detailed
information including the electrical characteristics and
the detailed features of the device.
The EVB is supplied with a SC668 device and all necessary
support components. The schematics, board layouts, and
detailed instructions for operating the EVB are included in
this user’s guide.
•
•
•
•
EVB schematic
EVB bill of material and hardware notes
EVB layout
Software operation
Critical and Non-Critical Components
The critical components necessary for design-in are shown
in the image below next to the 3x3 (mm) SC668 device
(not to scale). The bill of materials includes many non-critical components that are useful for evaluation purposes.
SC668 EVB — R3
Rev 1.0
© 2011 Semtech Corporation
SC668 EVB
EVB Schematic 1 of 3
V560 OUT
V560_OUT
U1
2
C6
1.0μF
3
IN
GND
SC668
BL8
BL7
BL6
BL5
R9
10KΩ
15
R11
10KΩ
BL4
PWM
R10
10KΩ
16
668_EN
14
SDA
13
SCL
BL2
EN
SDA
D8
5
R7 ‒ 1.0Ω
D7
6
R6 ‒ 1.0Ω
D6
7
R5 ‒ 1.0Ω
D5
8
R4 ‒ 1.0Ω
D4
9
R3 ‒ 1.0Ω
D3
10
R2 ‒ 1.0Ω
D2
11
R1 ‒ 1.0Ω
D1
TP1
LDO1
1
C1
1μF
TP2
LDO2
20
C2
1μF
C8
0.1μF
LDO3
TP3
LDO3
19
C3
LDO4
1μF
Current
Amp
logic
BH1620FVC
LDO1
LDO2
U4
1
BL1
R8 ‒ 1.0Ω
SCL
LDO4
Photo-diode
BL3
4
12
5
R12
6.8kΩ
C7
2.2μF
ADI
LDO4
18
C4
1μF
2 3 4
BYP
TP4
LDO4
GND
TP5
GND
TP6
17
C5
22nF
SC668 EVB
EVB Schematic 2 of 3
5V_USB
5V_USB
R24
10kΩ
U2
15
16
17
18
19
20
21
22
P1.7
P1.6
P1.5
P1.4
P1.3
P1.2
P1.1
P1.0
P0.7
P0.6
P0.5
P0.4
P0.3
P0.2
P0.1
P0.0
23
24
25
26
27
28
1
2
P0.2
4
D+
5 D-
5V_USB
C9
4.7µF
3
1
2
Q6
2N7002
R22
10kΩ
11
12
13
14
R21
10kΩ
SC560_EN
668_LED_ENL
5V_USB 8
VBUS
7
REGIN
8051_P6 6
JP1
VDD
9 C2CK 1
RST/C2CK
C10
2
P3.0/C2D 10 C2DAT
0.1µF
3
GND Thermal
3
T1
Program
Port
3
1
2
R14
Q5_Dr
59kΩ
Q5
2N7002
2
R15
Q4
2N7002
118kΩ
5V_USB
R20
10kΩ
R13
Q3_Dr
3
1
2
R19
10kΩ
R18
10kΩ
1
P0.2
2
3
4
R27
9.76kΩ
237kΩ
Q3
2N7002
5V_USB
3
1A F1
R16
20kΩ
Q4_Dr
V560 OUT
R26
10kΩ
EN_NOT
USB_Type-A_Plug
J1
1 USB Power
2
3
1
FBA
Q7
2N7002
5V_USB
5V_USB
P2.3
P2.2
P2.1
P2.0
14.7kΩ
Q6_Dr
SCL
SDA
C 801 F 321
USB_D+
USB_D-
1
5V_USB
R23
10kΩ
R17
Q7_Dr
3
2
Q1
2N7002
3
5V_USB
1
2
668_EN
Q2
2N7002
USB_DUSB_D+
5V_USB
R25
300Ω
D9
668_LED_ENL
SC668 EVB
EVB Schematic 3 of 3
5V_USB
U3
2
5V_USB
R29
10kΩ
SC560_EN
D10
3
1
2
LDO EN
Q8
2N7002
5V_USB
R28
300Ω
C11
2.2µF
SC560_EN
VIN
OUTA
S C 60
FBA
6
7
EN
OUTB
ENB
FBB
GND
C13
5
22nF
3
4
1
8
SC560V_OUT
R30
9.53kΩ
C12
1.0µF
V560_OUT
FBA
R31
4.99kΩ
SC668 EVB
EVB Bill of Material List
Reference(1)
Value
Footprint
Hardware Notes(2)
C1, C2, C3, C4
1µF
0603
LDO output capacitors
C5
22nF
0603
LDO bypass capacitor
C6
1µF
0603
IN pin bypass capacitor
C7
2.2µF
0603
Prevents 60Hz lighting fluctuations from introducing ripple
on the light sensor output.
C8
0.1µF
0603
Noise decoupling of the supply pin on light sensor IC
C9
4.7µF
0603
VBUS decoupling for U2
C10
0.1µF
0603
VDD decoupling for U2
C11
2.2µF
0603
Input decoupling for U3
C12
1.0µF
0603
Output decoupling for U3
C13
22nF
0603
LDO bypass output for U3
D1, D2, D3, D4, D5, D6, D7, D8
AND4WB
0805
White LEDs for backlight functions
D9
0603
Green LED SC668 enable light
D10
0603
Green LED LDO power light
USB power fuse
F1
1A
1210
JP1
No-pop
3 pin conn.
Programming connections
J1
USB type A
USB type A
USB connector
Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8
2N7002
SC70_123
Q1 and Q2 provide a non-inverting level shift for enable
signal. Q3 through Q7 are switched to set the LDO voltage.
Q8 is used to switch the LDO enable indicator LED on/off.
R1, R2, R3, R4, R5, R6, R7, R8
1Ω, 1%
0603
Current sense resistor for backlight testing
R9, R10, R11, R18, R19, R20, R21,
R22, R23, R24, R26, R29
10kΩ
0603
Pull-up resistors
R12
6.8kΩ
0603
Load resistor for light sensor IC
R13
237kΩ
0603
R14
59kΩ
0603
R15
118kΩ
0603
R16
20kΩ
0603
R17
14.7kΩ
0603
LDO program resistors
SC668 EVB
EVB Bill of Material List (continued)
Reference(1)
Value
Footprint
Hardware Notes(2)
R25, R28
300Ω
0603
R27
9.76kΩ
0603
R30
9.53kΩ
0603
R31
4.99kΩ
0603
TP1, TP2, TP3, TP4, TP5, TP6
No_pop
40 mil
U1
SC668
U2
C8051F321
MLPQ-5 x 5
(MM)
USB to SemPulse interface plus GPIO
U3
SC560
MPOQ-UT8
Semtech Integrated circuit — Adjustable LDO
U4
BH1620
Ballast for LED indicators
LDO program resistors
Test points for LDO1,2,3,4, and GND
MLPQ-UT-20
Semtech integrated circuit — LMU
3 x 3 (mm)
1.6 x 1.6 (mm) Light Sensor Amplifier
Note:
(1) Component references in BOLD indicate critical components
(2) All capacitors are X5R type.
SC668 EVB
EVB Layout Drawings — Top Layer (top view)
EVB Layout Drawings — Bottom Layer (bottom view)
SC668 EVB
EVB Operation
SC668 EVB Software Installation
SC668 Software Interface Functions
The SC668 EVB uses a USB compatible microprocessor
on a separate board to communicate I2C commands to
the SC668. The software driver and executable program
included in the SC668 GUI kit should be installed before
connecting the USB interface board to a USB port.
The Semtech SC668 Evaluator GUI is illustrated for reference to the following list of functions. Differences for the
SC667 and SC668 are noted in the applicable sections.
The following sequence is recommended.
Run USBXpressinstaller.exe.
Place SiUSBXp.dll in the windows/system32
directory.
Place SC668_R1p01.xml in the same folder as
Semtech.exe.
Connect the USB A/B cable and confirm that
the USB device driver is found.
Run Semtech.exe to start the user interface.
•
•
•
1. Scenarios — contains the following buttons; Simple
Breathe, Simple Blink, Simple ALS w/Fade, Auto Dim
Full, Auto Dim Partial, and Mixed Demo. Each button
performs multiple write operations to configure and
demonstrate a function of the SC668. These buttons
provide a convenient way to quickly view some of the
basic lighting effect capabilities of the SC668.
Simple Breathe — Initiates cycling of the
breathe function on all LEDs.
•
•
•
50 51
11
11
11
11
11
11
12
13
14
15
16
17
18
19
34
20
21
35
22
23
36
2
24
25
37
3
26
27
38
4
28
29
39
5
30
31
40
32
33
41
1
6
7
43
8
44
42
47 52 53
45
9
10
46
48
49
54
55
SC668 EVB
EVB Operation (continued)
•
•
•
•
•
Simple Blink — Initiates the blink function on all
LEDs with a 4 second delay time between
blinks.
Simple ALS with Fade — Enables the ALS function on all LEDs and provides fading at the same
time. All LEDs should fade to a lower brightness
when the light sensor U2 on the EVB is covered
up to prevent light from reaching it. Cover U2
for at least 1 second to give the ADC time to
process the change in ambient lighting.
Mixed Demo — This button enables several
features simultaneously. BL1 pin provides DC
current for LED D1. BL2 pin provides the blink
function for LED D2. BL3 and BL4 pins provide
the breathe function for LEDs D3 and D4. BL5,
BL6, BL7, and BL8 pins provide a DC current
with fade, ALS and ADP functions for LEDs D5,
D6, D7, and D8 on bank #1.
Auto Dim Full — This button sets bank #1 to
12mA for 4 seconds and then automatically
dims bank #1 to 1mA. Another 4 seconds
elapses and bank #1 turns off. The fade option
is enabled during this scenario.
Auto Dim Partial — This button sets bank #1 to
12mA for 4 seconds and then automatically
dims bank #1 to 1mA. Bank #1 will remain at
1mA. Auto Dim Partial does not automatically
turn off bank #1. The fade option is enabled
during this scenario.
2. LDO Supply Voltage — An adjustable voltage supply
for the SC668 is provided by an on-board SC560A LDO.
The LDO is programmable between 4.13V and 2.89V in
increments of 40mV — the approximate range provided
by a typical Li-ion battery. Typical LDO output accuracy is
1%. The LDO output is provided as a tool to demonstrate
performance of the SC668 and the ADP (Automatic
Dropout Protection). This output provides voltage (VIN)
to the anodes of D1 through D8.
3. AD Out — A value may be selected from this list to be
written directly to the ADC output (value of register
13h).
4. AD Rise (threshold) — A value may be selected from
this list to set the the ADC rising threshold (value in
register 14h). When AD Out is greater than AD Rise,
backlight bank #1 changes to the “Bank#1 Target”
value (the value of register 06h).
5. AD Fall (threshold) — A value may be selected
from this list to set the ADC falling threshold (value
in register 15h). When AD Out is less than AD Fall,
backlight bank #1 changes to the “Bank#1 Current”
value (the value of register 02h).
6. AD_SAT — When enabled, this button allows an
interrupt to be generated if AD Out (register 13h)
reaches overflow or underflow.
7. AD_AUTO — When this button is enabled, the
comparison of AD_OUT with AD_RISE and AD_FALL
is used to control the brightness of the bank #1
backlights.
8. AD_EN — When enabled, the ADC is activated, and
the result of each conversion is stored in register 13h.
9. Automatic Dropout Protection — When enabled,
ADP (Automatic Dropout Protection) reduces the
current in bank #1 to ensure accurate current matching
in the LEDs. When this button is enabled, ADP will
become active when the supply voltage is too low to
provide the required LED anode voltage.
10. ADP Delay(µs) — This button is used to select the delay
time for ADP. The options are 256µs and 4000µs. When
a reduction in bank #1 backlight current becomes
necessary, the first step change is delayed for the time
selected by this button. If further reductions in current
are needed, the second and all subsequent reductions
occur at a faster rate equal to 1/4 of the initial delay time.
When 4000µs is selected:
1st delay = 4000µs
2nd and all subsequent delays = 1000µs
When 256µs is selected:
1st delay = 256µs
2nd and all subsequent delays = 64µs
Further reductions in current will stop when the backlight
accuracy and matching have normalized.
11. BL1 through BL6 Enable — These buttons are used
to individually enable and disable backlights BL1
through BL6.
SC668 EVB
EVB Operation (continued)
12. DIS — This button is used in combination with the EN
button to control the multi-function bits DIS and EN.
When DIS is enabled and EN is disabled, DIS disables
the banks selected with buttons 13 though 16.
13. EN — This button is used in combination with the DIS
button to control the multi-function bits DIS and EN.
When EN is enabled and DIS is disabled, EN enables
the banks selected with buttons 13 though 16.
14. BANK4 — BANK4 is used with EN or DIS to enable or
disable bank #4.
15. BANK3 — BANK3 is used with EN or DIS to enable or
disable bank #3.
16. BANK2 — BANK2 is used with EN or DIS to enable or
disable bank #2. This button also serves an alternate
function; BL8 — When EN and DIS are both disabled,
this button is used to enable or disable the indivual
backlight BL8.
17. BANK1 — BANK1 is used with EN or DIS to enable or
disable bank #1. This button also serves an alternate
function; BL7 — When EN and DIS are both disabled,
this button is used to enable or disable the individual
backlight BL7.
18. B1FEN — This button works in conjunction with
button B1BEN to set a lighting effect for bank #1 as
illustrated in the following figure.
B1BEN = 0
B1FEN = 1
Fade
B1BEN = 1
B1FEN = 0
Blink
Bank #1
Breathe
B1BEN = 1
B1FEN = 1
No Light Effect
B1BEN = 0
B1FEN = 0
19. Bank #1 Current — This menu is used to select a
value of current for LEDs in bank #1. This menu sets
the current to be used when fade or no lighting effect
is needed, and also provides the “starting” current for
blink and breathe effects.
20. B2FEN — This button works in conjunction with
button B2BEN to set a lighting effect for bank #2.
Lighting effect choices for bank #2 are the same as
illustrated previously for bank #1.
21. Bank #2 Current — This menu is used to select a
value of current for LEDs in bank #2. This menu sets
the current to be used when fade or no lighting effect
is needed, and also provides the “starting” current for
blink and breathe effects.
22. B3FEN — This button works in conjunction with
button B3BEN to set a lighting effect for bank #3.
Lighting effect choices for bank #3 are the same as
illustrated previously for bank #1.
23. Bank #3 Current — This menu is used to select a
value of current for LEDs in bank #3. This menu sets
the current to be used when fade or no lighting effect
is needed, and also provides the “starting” current for
blink and breathe effects.
24. B4FEN — This button works in conjunction with
button B4BEN to set a lighting effect for bank #4.
Lighting effect choices for bank #4 are the same as
illustrated previously for bank #1.
25. Bank #4 Current — This menu is used to select a
value of current for LEDs in bank #4. This menu sets
the current to be used when fade or no lighting effect
is needed, and also provides the “starting” current for
blink and breathe effects.
26. B1BEN — This button works in conjunction with
button B1FEN to select a lighting effect for bank #1.
27. Bank #1 Target — This menu is used to select a target
value of current for LEDs in bank #1 at the end of a
breathe or blink lighting effect cycle.
28. B2BEN — This button works in conjunction with
button B2FEN to select a lighting effect for bank #2.
29. Bank #2 Target — This menu is used to select a target
value of current for LEDs in bank #2 at the end of a
breathe or blink lighting effect cycle.
30. B3BEN — This button works in conjunction with
button B3FEN to select a lighting effect for bank #3.
10
SC668 EVB
EVB Operation (continued)
31. Bank #3 Target — This menu is used to select a target
value of current for LEDs in bank #3 at the end of a
breathe or blink lighting effect cycle.
32. B4BEN — This button works in conjunction with
button B4FEN to select a lighting effect for bank #4.
33. Bank #4 Target — This menu is used to select a target
value of current for LEDs in bank #4 at the end of a
breathe or blink lighting effect cycle.
34. Bank Assignments — This menu provides choices
for assigning LEDs to banks.
35. Group Assignments — This menu provides choices
for assigning banks into groups.
36. Group #1 Breathe/Fade Rates(ms) — This menu
provides choices for assigning the incremental step
rates for progressing through the breathe and fade
lighting effects. The rate will be assigned only to banks
associated with group #1.
37. Group #2 Breathe/Fade Rates(ms) — This menu
provides choices for assigning the incremental step
rates for progressing through the breathe and fade
lighting effects. The rate will be assigned only to banks
associated with group #2.
38. Group #1 Start-Time(ms) — The duration of time that
a bank will dwell at the start current during a breathe
or blink lighting effect. These menu selections apply
only to banks associated with group #1.
39. Group #1 Target-Time(ms) — The duration of time
that a bank will dwell at the target current during a
breathe or blink lighting effect. These menu selections
apply only to banks associated with group #1.
40. Group #2 Start-Time(ms) — The duration of time that
a bank will dwell at the start current during a breathe
or blink lighting effect. These menu selections apply
only to banks associated with group #2.
41. Group #2 Target-Time — The duration of time that a
bank will dwell at the target current during a breathe
or blink lighting effect. These menu selections apply
only to banks associated with group #2.
42. Auto-dim Options for Group #1 — This menu is
used to select lighting effects auto-dim full, autodim partial, or no effect. Auto-dim full provides a
time-out and dim function followed by a time-out
and turn-off function. Auto-dim partial provides the
time-out and dim function, but does not turn off
backlights. Auto-dim is only available for group #1.
After selecting an auto-dim option, the bank’s blink
effect must be enabled to enable auto-dim. The bank
must be enabled or re-enabled to begin the auto-dim.
Auto-dim Full — The cycle begins when the bank
is enabled (or re-enabled). The bank will first go to
the target current and wait for a count of 8 times
the group #1 target time. The bank will then dim
to the “start” current and wait for a count of 8 times
the group #1 start time. The bank will then turn off.
Auto-dim Partial — The cycle begins when the bank
is enabled (or re-enabled). The bank will first go to
the target current and wait for a count of 8 times the
group #1 target time. The bank will then dim to the
“start” current. The bank will not turn off automatically.
43. LDO1 Control — This menu is used to select a voltage
for LDO1 or turn it off.
44. LDO2 Control — This menu is used to select a voltage
for LDO2 or turn it off.
45. LDO3 Control — This menu is used to select a voltage
for LDO3 or turn it off.
46. LDO4 Control — This menu is used to select a voltage
for LDO4 or turn it off. Note that LDO4 must be turned
on for the ADC to function.
47. PWM Bypass — This menu is used to select between
normal and bypass mode. Normal — provides normal
PWM function at the PWM pin. Bypass — provides no
function at the PWM pin, so that a high or low at the
pin serves no function.
48. I2C Speed — This menu is used for setting the data
rate of I2C to either 100kbit/s or 400kbit/s.
49. Hardware Status — A link status activity indicator
flashes green continuously while USB is connected.
The green light gives no indication of I2C activity.
50. Register Address (in hexadecimal notation) — One
mouse click in this box will send the 8 bits of data
located in the field to the right of register address
field. Data color is red if in the cue and green after
sending.
51. Register Data (8 bit binary data) — Data color is red
if in the cue and green after sending.
11
SC668 EVB
EVB Operation (continued)
52. Write All — One mouse click initiates writing of all
registers.
53. Read All — One mouse click initiates reading of all
registers.
54. Device Enable/Disable — This button is used to
enable and disable the SC668.
55. Exit — This button is used to exit the program and
close the window.
SC668 Evaluation and Measurement Tips
This section provides setup information about the EVB.
•
•
•
Install the software and plug the EVB into a USB
port. Suggestion: A USB A to A cable may be
used to relocate the EVB away from the USB port
for easier access to the board while taking
measurements.
Resistors R1, R2, R3, R4, R5, R6, R7, and R8 are in
series between the sink pins (BL1 through BL8)
and the LED cathodes of D1 through D8. The
resistors are 1Ω 1% sense resistors for measuring
current with a voltmeter at 1mV/1mA.
Test points are provided for voltage measurement at the right edge of the card (as shown on
page 1) for LDO1, LDO2, LDO3, LDO4, and GND.
12
SC668 EVB
© Semtech 2011
All rights reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright
owner. The information presented in this document does not form part of any quotation or contract, is believed to be
accurate and reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use. Publication thereof does not convey nor imply any license under patent or other industrial or
intellectual property rights. Semtech assumes no responsibility or liability whatsoever for any failure or unexpected
operation resulting from misuse, neglect improper installation, repair or improper handling or unusual physical or electrical stress including, but not limited to, exposure to parameters beyond the specified maximum ratings or operation
outside the specified range.
SEMTECH PRODUCTS ARE NOT DESIGNED, INTENDED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN LIFESUPPORT APPLICATIONS, DEVICES OR SYSTEMS OR OTHER CRITICAL APPLICATIONS. INCLUSION OF SEMTECH PRODUCTS
IN SUCH APPLICATIONS IS UNDERSTOOD TO BE UNDERTAKEN SOLELY AT THE CUSTOMER’S OWN RISK. Should a customer
purchase or use Semtech products for any such unauthorized application, the customer shall indemnify and hold
Semtech and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs damages
and attorney fees which could arise.
Notice: All referenced brands, product names, service names and trademarks are the property of their respective
owners.
Contact Information
Semtech Corporation
Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
13