SC662 Datasheet

SC662
Backlight Driver for 6 LEDs
with SemPulse® Interface
POWER MANAGEMENT
Features
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Description
Input supply voltage range — 2.9V to 5.5V
Very high efficiency charge pump driver system with
three modes — 1x, 1.5x and 2x
Six programmable current sinks — 0mA to 25mA
Up to three LED grouping options
Fade-in/fade-out feature for main LED bank
Selectable charge pump frequency — 250kHz/1MHz
SemPulse® single wire interface
Backlight current accuracy — ±1.5% typical
Backlight current matching — ±0.5% typical
LED float detection
Automatic sleep mode with all LEDs off
Sleep mode quiescent current — 60µA typical
Shutdown current — 0.1µA typical
Ultra-thin package — 2 x 2 x 0.6 (mm)
Lead-free and halogen-free
WEEE and RoHS compliant
Applications
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The SC662 is a high efficiency charge pump LED driver
using Semtech’s proprietary charge pump technology.
Performance is optimized for use in single-cell Li-ion
battery applications.
The charge pump provides backlight current utilizing six
matched current sinks. The load and supply conditions
determine whether the charge pump operates in 1x, 1.5x,
or 2x mode. An optional fading feature that gradually
adjusts the backlight current is provided to simplify
control software.
®
The SC662 uses the proprietary SemPulse single wire
interface to control all functions of the device, including
backlight currents. The single wire interface minimizes
microcontroller and interface pin counts. The six LEDs can
be grouped in up to three separate banks that can be
independently controlled.
The charge pump switches at 1MHz or 250kHz, and the
frequency is selectable using the SemPulse interface. Both
1MHz and 250kHz frequencies are supported by 0402 size
(1005 metric) ceramic capacitors.
Cellular phones, smart phones, and PDAs
LCD modules
Portable media players
Digital cameras
Personal navigation devices
Display/keypad backlighting and LED indicators
The SC662 enters sleep mode when all the LED drivers are
disabled. In this mode, the quiescent current is reduced
while the device continues to monitor the SemPulse
interface.
Typical Application Circuit
CIN
1.0µF
IN
OUT
COUT
1.0µF
SC662
From
Microprocessor
SPIF
GND
C1+ C1-
C1
1.0µF
November 30, 2010
BL1
BL2
BL3
BL4
BL5
BL6
C2+ C2-
C2
1.0µF
© 2010 Semtech Corporation
SC662
Pin Configuration
Ordering Information
BL5
BL4
BL3
BL2
BL1
14
13
12
11
10
TOP VIEW
BL6
1
SPIF
2
T
9
IN
8
OUT
3
4
5
6
7
GND
C1-
C2-
C2+
C1+
Device
Package
SC662ULTRT(1)(2)
MLPQ-UT-14 2×2
SC662EVB
Evaluation Board
Notes:
(1) Available in tape and reel only. A reel contains 3,000 devices.
(2) Lead-free packaging only. Device is WEEE and RoHS compliant,
and halogen-free.
MLPQ-UT-14; 2x2, 14 LEAD
θJA = 78°C/W
Marking Information
...
FB
yw
FB = SC662ULTRT
yw = date code
SC662
Absolute Maximum Ratings
Recommended Operating Conditions
IN, OUT (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0
Ambient Temperature Range (°C). . . . . . . . . -40 ≤ TA ≤ +85
C1+, C2+ (V). . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (V OUT + 0.3)
Input Voltage (V). . . . . . . . . . . . . . . . . . . . . . . 2.9 ≤ VIN ≤ 5.5
Pin Voltage — All Other Pins (V). . . . . . . . . -0.3 to (V IN + 0.3)
Output Voltage (V). . . . . . . . . . . . . . . . . . . . . 2.5 ≤ VOUT ≤ 5.25
OUT Short Circuit Duration. . . . . . . . . . . . . . . . Continuous
Thermal Information
ESD Protection Level(1) (kV). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Thermal Resistance, Junction to Ambient(2) (°C/W) . . 78
Storage Temperature Range (°C). . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Tested according to JEDEC standard JESD22-A114
(2) Calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer FR4 PCB per JESD51 standards.
Electrical Characteristics
Unless otherwise noted, TA = +25°C for Typ, -40°C to +85°C for Min and Max, TJ(MAX) = 125°C, VIN = 3.7 V, CIN= C1= C2= COUT = 1.0µF (ESR = 0.03Ω)(1)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
0.1
2
µA
Supply Specifications
Shutdown Current
IQ(OFF)
Total Quiescent Current
IQ
All outputs disabled, SPIF = VIN(2)
60
1x mode, all LEDs on, IBLn = 0.5mA
0.9
1x mode, all LEDs on, IBLn = 25mA
1.5
1.5x or 2x charge pump mode, all LEDs on,
IBLn = 25mA
2
µA
mA
Charge Pump Electrical Specifications
Maximum Total Output Current
IOUT(MAX)
VIN > 2.9V, sum of all active LED currents, VOUT(MAX) = 4.2V
150
mA
Backlight Current Setting
IBLn
Nominal setting for BL1 thru BL6
0
Backlight Current Matching
IBL-BL
IBLn = 12mA(3)
-3.5
Backlight Current Accuracy
IBL_ACC
IBLn = 12mA
±1.5
%
Mode Transition (Falling) Input
Voltage — 1x Mode to 1.5x Mode
V TRANS1x
IOUT = 72mA, IBLn = 12mA, VOUT = 3.22V
3.28
V
1.5x Mode to 1x Mode Hysteresis
VHYST1x
IOUT = 72mA, IBLn = 12mA, VOUT = 3.22V, fPUMP = 250kHz
250
mV
±0.5
25
mA
+3.5
%
SC662
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Charge Pump Electrical Specifications (continued)
Mode Transition (Falling) Input
Voltage — 1.5x Mode to 2x Mode
V TRANS1.5x
IOUT = 72mA, IBLn = 12mA, VOUT = 4.2V(4), fPUMP = 250kHz
3.14
V
Current Sink Off-State
Leakage Current
IBLn(off )
VIN = VBLn = 4.2V
0.1
Bit FSEL = 0
250
kHz
Charge Pump Frequency
fPUMP
Bit FSEL = 1
1
MHz
OUT pin shorted to GND
125
VOUT > 2.5V
300
VUVLO-OFF
Increasing VIN
2.3
V
VUVLO-HYS
Hysteresis
75
mV
VOVP
OUT pin open circuit, VOUT = VOVP, rising threshold
5.7
TOT
Rising temperature
165
°C
TOT-HYS
Hysteresis
20
°C
1
µA
Fault Protection Specifications
Output Short Circuit
Current Limit
Under Voltage Lockout
Over-Voltage Protection
Over-Temperature Threshold
IOUT(SC)
mA
6.0
V
SC662
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Input High Threshold
VIH
VIN = 5.5V
1.4
Input Low Threshold
VIL
VIN = 2.9V
Input High Current
IIH
VIN = 5.5V
Input Low Current
IIL
Start up Time(5)
tSU
Bit Pulse Duration(6)
tHI
0.75
250
µs
Duration Between Pulses(6)
tLO
0.75
250
µs
Hold Time - Address(6)
tHOLDA
550
5000
µs
Hold Time - Data(6)
tHOLDD
550
µs
Bus Reset Time (6)
tBR
10
ms
Shutdown Time (7)
tSD
10
ms
SemPulse Interface
V
0.4
V
-1
+1
µA
VIN = 5.5V
-1
+1
µA
Only required when leaving shutdown mode
1
ms
Notes:
(1) Capacitors are MLCC of X5R type.
(2) SPIF is high for more than 10ms to place the serial bus in standby mode.
(3) Current matching is defined as ± [IBL(MAX) - IBL(MIN] / [IBL(MAX) + IBL(MIN)].
(4) Test voltage is VOUT = 4.2V — a relatively extreme LED voltage — to force a transition during test. Typically VF = 3.2V for white LEDs.
(5) The SemPulse start-up time is the minimum time that the SPIF pin must be held high to enable the part before starting communication.
(6) The source driver used to provide the SemPulse output must meet these limits.
(7) The SemPulse shutdown time is the minimum time that the SPIF pin must be pulled low to shut the part down.
SC662
Typical Characteristics
Charge Pump Efficiency (6 LEDs) — 25mA Each
Charge Pump Efficiency (6 LEDs) — 25mA Each
100
fPUMP = 1MHz, VOUT = 3.56V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
100
90
Efficiency (%)
Efficiency (%)
90
(1)
Charge Pump
80
70
80
50
4.2
3.9
3.6
VIN (V)
3.3
3
50
4.2
2.7
fPUMP = 1MHz, VOUT = 3.42V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
3.6
VIN (V)
3.3
3
2.7
100
fPUMP = 250kHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
90
Efficiency (%)
Efficiency (%)
80
(1)
Charge Pump
70
(1)
Backlight
60
4.2
3.9
3.6
VIN (V)
3.3
100
3
(1)
Charge Pump
70
50
2.7
(2)
(1)
Backlight
fPUMP = 1MHz, VOUT (see note), CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
Charge Pump Efficiency (6 LEDs) — 5mA Each
100
(2)
fPUMP = 250kHz, VOUT (see note), CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
90
Efficiency (%)
90
80
(1)
Charge Pump
70
(1)
Backlight
60
50
80
60
Charge Pump Efficiency (6 LEDs) — 5mA Each
Efficiency (%)
3.9
Charge Pump Efficiency (6 LEDs) — 12mA Each
90
Notes:
(1)
Backlight
60
Charge Pump Efficiency (6 LEDs) — 12mA Each
50
(1)
Charge Pump
70
(1)
Backlight
60
100
fPUMP = 250kHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
4.2
3.9
3.6
VIN (V)
3.3
3
80
(1)
Charge Pump
70
(1)
Backlight
60
2.7
50
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
(1) Efficiency labels “Charge Pump” and “Backlight” are defined on page 13 under the sub-heading Charge Pump Efficiency.
(2) Plots shown for 5mA data have — VOUT = 3.27V when in 1.5X and 2X modes, and VOUT = VIN - 55mV when in 1X mode. VOUT is connected internally to VIN only when the charge pump is in 1X mode and IBL ≤ 5mA.
SC662
Typical Characteristics (continued)
Backlight Matching (6 LEDs) — 25mA Each
Backlight Matching (6 LEDs) — 25mA Each
fPUMP = 1MHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
3
2
2
1
1
Matching (%)
Matching (%)
3
fPUMP = 250kHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
0
0
-1
-1
-2
-2
-3
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
-3
4.2
3
1
1
Matching (%)
Matching (%)
2
0
-1
-2
-2
3.6
VIN (V)
3.3
3
Backlight Matching (6 LEDs) — 5mA Each
2.7
4.2
(2)
3
2
2
1
1
0
2.7
3.9
3.6
VIN (V)
3.3
3
2.7
(2)
fPUMP = 250kHz, VOUT (see note), CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
0
-1
-2
-3
3
Backlight Matching (6 LEDs) — 5mA Each
fPUMP = 1MHz, VOUT (see note), CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
-1
Notes:
-3
Matching (%)
Matching (%)
3
3.3
0
-1
3.9
VIN (V)
fPUMP = 250kHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
2
-3
4.2
3.6
Backlight Matching (6 LEDs) — 12mA Each
Backlight Matching (6 LEDs) — 12mA Each
fPUMP = 1MHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
3
3.9
-2
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
-3
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
(1) Efficiency labels “Charge Pump” and “Backlight” are defined on page 13 under the sub-heading Charge Pump Efficiency.
(2) Plots shown for 5mA data have — VOUT = 3.27V when in 1.5X and 2X modes, and VOUT = VIN - 55mV when in 1X mode. VOUT is connected internally to VIN only when the charge pump is in 1X mode and IBL ≤ 5mA.
SC662
Typical Characteristics (continued)
Backlight Accuracy (6 LEDs) — 25mA Each
Backlight Accuracy (6 LEDs) — 25mA Each
fPUMP = 1MHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
8
6
6
4
4
2
2
0
Accuracy (%)
Accuracy (%)
8
fPUMP = 250kHz, VOUT = 3.55V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
ACC Max %
-2
ACC Max %
0
-2
-4
ACC Min %
-4
ACC Min %
-6
-6
-8
4.2
3.9
3.6
3.3
VIN (V)
3
2.7
-8
4.2
Backlight Accuracy (6 LEDs) — 12mA Each
4
4
2
2
Accuracy (%)
Accuracy (%)
6
0
ACC Max %
-4
ACC Min %
2.7
ACC Max %
ACC Min %
-6
4.2
3.9
3.6
3.3
VIN (V)
3
2.7
-8
6
6
4
4
2
2
ACC Max %
3.6
VIN (V)
3.3
3
2.7
(2)
fPUMP = 250kHz, VOUT (see note), CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
8
0
3.9
Backlight Accuracy (6 LEDs) — 5mA Each
fPUMP = 1MHz, VOUT (see note), CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
-2
4.2
(2)
Accuracy (%)
Accuracy (%)
3
0
-4
Backlight Accuracy (6 LEDs) — 5mA Each
8
3.3
-2
-6
-8
VIN (V)
fPUMP = 250kHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 1.0µF (0402), TA = 25°C
8
6
-2
3.6
Backlight Accuracy (6 LEDs) — 12mA Each
fPUMP = 1MHz, VOUT = 3.41V, CIN = COUT = C1 = C2 = 0.47µF (0402), TA = 25°C
8
3.9
ACC Max %
0
-2
ACC Min %
-4
-4
ACC Min %
-6
-6
-8
Notes:
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
-8
4.2
3.9
3.6
VIN (V)
3.3
3
2.7
(1) Efficiency labels “Charge Pump” and “Backlight” are defined on page 13 under the sub-heading Charge Pump Efficiency.
(2) Plots shown for 5mA data have — VOUT = 3.27V when in 1.5X and 2X modes, and VOUT = VIN - 55mV when in 1X mode. VOUT is connected internally to VIN only when the charge pump is in 1X mode and IBL ≤ 5mA.
SC662
Typical Characteristics (continued)
All data taken with TA = 25°C, 6 LEDs @ 15mA each unless otherwise noted.
Ripple — 1x Mode
Ripple — 1x Mode
fPUMP = 250kHz, CIN = COUT = C1 = C2 = 1.0µF (0402)
fPUMP = 1MHz, CIN = COUT = C1 = C2 = 0.47µF (0402)
VIN (100mV/div)
VIN (100mV/div)
VOUT (100mV/div)
VOUT (100mV/div)
IBL (20mA/div)
IBL (20mA/div)
0mA
0mA
Time (2µ������
s�����
/div)
Time (1µ������
s�����
/div)
Ripple — 1.5x Mode
Ripple — 1.5x Mode
fPUMP = 1MHz, CIN = COUT = C1 = C2 = 0.47µF (0402)
fPUMP = 250kHz, CIN = COUT = C1 = C2 = 1.0µF (0402)
VIN (100mV/div)
VIN (100mV/div)
VOUT (100mV/div)
VOUT (100mV/div)
IBL (20mA/div)
IBL (20mA/div)
0mA
0mA
Time (1µ������
s�����
/div)
Time (2µ������
s�����
/div)
Ripple — 2x Mode
Ripple — 2x Mode
fPUMP = 1MHz, CIN = COUT = C1 = C2 = 0.47µF (0402)
VIN (100mV/div)
fPUMP = 250kHz, CIN = COUT = C1 = C2 = 1.0µF (0402)
VIN (100mV/div)
VOUT (100mV/div)
VOUT (100mV/div)
IBL (20mA/div)
IBL (20mA/div)
0mA
0mA
Time (1µ������
s�����
/div)
Time (2µ������
s�����
/div)
SC662
Pin Descriptions
Pin #
Pin Name
Pin Function
1
BL6
Current sink output for backlight LED 6 — leave this pin open if unused
2
SPIF
SemPulse single wire interface pin — used to enable/disable the device and to configure all registers (refer to Register Map and SemPulse Interface sections)
3
GND
Ground pin
4
C1-
Negative connection to bucket capacitor C1
5
C2-
Negative connection to bucket capacitor C2
6
C2+
Positive connection to bucket capacitor C2
7
C1+
Positive connection to bucket capacitor C1
8
OUT
Charge pump output — all LED anode pins should be connected to this pin
9
IN
10
BL1
Current sink output for backlight LED 1 — leave this pin open if unused
11
BL2
Current sink output for backlight LED 2 — leave this pin open if unused
12
BL3
Current sink output for backlight LED 3 — leave this pin open if unused
13
BL4
Current sink output for backlight LED 4 — leave this pin open if unused
14
BL5
Current sink output for backlight LED 5 — leave this pin open if unused
T
THERMAL PAD
Battery voltage input
Thermal pad for heatsinking purposes — connect to ground plane using multiple vias — not connected internally
10
SC662
Block Diagram
IN
SPIF
GND
3
C1-
C2+
C2-
7
4
6
5
Fractional Charge Pump
(1x, 1.5x, 2x)
9
2
C1+
SemPulse
Digital
Interface
and Logic
Control
Oscillator
Current
Setting
DAC
8
OUT
10
BL1
11
BL2
12
BL3
13
BL4
14
BL5
1
BL6
11
SC662
Applications Information
General Description
This design is optimized for handheld applications supplied from a single Li-ion cell and includes the following
key features:
•
•
•
•
A high efficiency fractional charge pump that
supplies power to all LEDs.
Six matched current sinks that control LED backlighting current, providing 0mA to 25mA per LED.
Up to three independently controlled LED
banks.
Selectable charge pump frequency — 250kHz or
1MHz options.
High Current Fractional Charge Pump
The backlight outputs are supported by a high efficiency,
high current fractional charge pump output. The charge
pump multiplies the input voltage by 1x, 1.5x, or 2x. The
output of the charge pump is delivered to the LED anodes.
The charge pump switches only in 1.5x and 2x modes and
is disabled in 1x mode to save power and improve
efficiency.
The charge pump switches at a fixed frequency of either
250kHz or 1MHz. The charge pump switching frequency
is set via the SemPulse interface by the FSEL bit. The
250kHz setting is selected by setting FSEL = 0, while the
1MHz setting is selected when FSEL = 1.
The mode selection circuit automatically selects one of
the following modes; 1x, 1.5x, or 2x based on circuit conditions such as LED voltage, input voltage, and load current.
The 1x mode is the most efficient of the three modes, followed by 1.5x and 2x modes. Circuit conditions such as
low input voltage, high output current, or high LED
voltage place a higher demand on the charge pump
output. A higher numerical mode (1.5x or 2x) may be
needed momentarily to maintain regulation at the OUT
pin during intervals of high demand. The charge pump
responds to momentary high demands, setting the charge
pump to the optimum mode to deliver the output voltage
and load current while optimizing efficiency. Hysteresis is
provided to prevent mode toggling.
The charge pump requires two bucket capacitors. One
capacitor must be connected between the C1+ and C1pins and the other must be connected between the C2+
and C2- pins as shown in the Typical Application Circuit
diagram. Bucket capacitors should be equal in value to
support current sharing between C1 and C2.
COUT , CIN , C1 , and C2 capacitors with X7R or X5R ceramic
dielectric are strongly recommended for their low ESR and
superior temperature and voltage characteristics. Y5V
capacitors should not be used as their temperature coefficients make them unsuitable for this application.
LED Backlight Current Sinks
The backlight current is set via the SemPulse interface. The
current is regulated to one of 32 values between 0mA and
25mA. The step size varies depending upon the current
setting. The lowest settings are 0, 50, 100, and 200µA.
From 0.5mA to 5mA, the step size is 0.5mA. The step size
increases to 1mA for settings between 5mA and 21mA.
Steps are 2mA between 21mA and 25mA. The variation in
step size allows finer adjustment for dimming functions in
the low current setting range and coarse adjustment at
higher current settings where small current changes are
not visibly noticeable in LED brightness. A zero setting is
also included to allow the current sink to be disabled by
writing to either the enable bit or the current setting register for maximum flexibility.
All backlight current sinks have matched currents. When
there is a variation in the forward voltages (∆VF ) of the
LEDs, mis-matched LED voltages do not degrade the accuracy of the backlight currents. The voltages of all BLn pins
are compared, and the lowest of these voltages is used as
feedback for setting the voltage regulation at the OUT pin.
This is done to ensure that sufficient bias exists for all
LEDs.
The backlight LEDs default to the off state upon power-up.
For backlight applications using less than six LEDs, any
unused output must be left open and the unused LED
must remain disabled. When writing to the backlight
enable register, a zero (0) must be written to the corresponding bit of any unused output. Detailed information
about programming of the registers is provided in later
sections, beginning at SemPulse Interface on page 21.
12
SC662
Applications Information (continued)
Charge Pump Efficiency
Efficiency of the charge pump is defined as
K
VOUT u IOUT
VIN u IIN
The input current is equal to the output current multiplied
by the charge pump mode plus the quiescent current IIN =
IOUT x Mode + IQ, and the output current is equal to the sum
of all backlight currents.
LED Banks
The LEDs can be grouped in up to three independently
controlled LED banks. Using the SemPulse interface, the
six LED drivers can be grouped as described in the
Backlight Grouping Configuration subsection. The banks
can be used to provide up to three different current
options. This can be useful for controlling keypad, display,
and auxiliary backlight operation from one SC662 device.
VOUT, IOUT, VIN, IIN, IQ, and IBLn are terms from the electrical
characteristics section. “Mode” is the active boost ratio of
the charge pump, equal to 1, 1.5, or 2. Efficiency plots in
the Typical Characteristics section provide charge pump
efficiency data labeled with “Charge Pump”.
The LED banks provide versatility by allowing backlights
to be controlled independently. For example, applications
that have a main and sub display may also need to supply
an indicator LED. The three bank option allows the SC662
to control each function with different current settings.
Another application involves backlighting two displays
and a keypad, each requiring different brightness settings.
A third scenario requires supplying different brightness
levels to different types of LEDs (such as RGB) to create
display effects. In all applications, the brightness level for
each LED can be set independently.
Efficiency of the power conversion to the LEDs is defined as
Backlight Fade-in / Fade-out Function
6
¦I
IOUT
n 1
6
K
¦
n 1
BLn
u Mode
( VFn u IBLn )
VIN u IIN
VF1 through VF6 are the forward voltages of the LEDs. IBL1
through IBL6 are the regulated backlight sink currents
flowing in the LEDs. Efficiency plots in the Typical
Characteristics section provide LED backlight efficiency
data labeled with “Backlight”.
Backlight Quiescent Current
The quiescent current required to operate all backlights is
reduced when each backlight current is set to 5.0mA or
less. This low-current mode feature results in improved
efficiency under light-load conditions, saving approximately 350µA of bias current. Low-current mode disables
and bypasses the internal LDO when the charge pump is
in 1x mode, connecting the LED anodes to the supply at
VIN. Further reduction in quiescent current will result from
using fewer than the maximum number of LEDs.
The SC662 contains register bits that control the fade state
of the main bank. When enabled, the fade function causes
the main backlights to change brightness by stepping the
current incrementally until the target backlight current is
reached. Fade begins immediately after the target backlight current is stored in its register. Fade may be enabled
for the main bank only. Sub and third banks do not fade.
In addition to the 32 programmable backlight current
values, there are also 75 non-programmable current steps.
The non-programmable steps are active only during a fade
operation to provide for a very smooth change in backlight
brightness. Backlight current steps proceed at a programmable fade rate of 2, 4, or 6ms. The exact length of time used
to fade between any two backlight values is determined by
multiplying the fade rate by the number of steps between
the old and new backlight values. The fade time can be calculated from the data provided in Table 1 on page 15.
Figures 2 through 6 on page 16 provide additional information about the fade process. Each figure represents
one linear segment of the overall fade range shown in
13
SC662
Applications Information (continued)
Figure 7. The overall fade range is a piece-wise linear, logrithmic type of function which provides for a very smooth
visual fading effect.
The fade rate may be changed dynamically when a fade
operation is active by writing new values to the fade register. When a new backlight level is written during an
ongoing fade operation, the fade will be redirected to the
new value from the present state. An ongoing fade operation may be cancelled by disabling fade, which will result
in the backlight current changing immediately to the final
value. If fade is disabled, the current level will change
immediately without the fade delay.
The terms BLEN and FADE are used for bits which are
defined in a later section of the datasheet. The reader may
choose to skip ahead to the Register Map and Register
and Bit Definitions sections for a better understanding of
these terms before continuing with this section’s explanation of the fade function and fade state diagram.
Fade State Diagram
If the main BLEN bits are disabled during an ongoing fade,
the main bank will turn off immediately. When the main
BLEN bits are re-enabled and FADE = 1, the main backlight
currents will begin at 0mA and fade to the target value. If
the main BLEN bits are re-enabled and FADE = 0, the main
backlights will proceed immediately to the target value.
The state diagram in Figure 1 describes the fade operation.
More details can be found in the Register Map section.
No change
Write either
MFADE
bit = 0
Immediate
change to
new bright
level
Fade is disabled:
Immediate
change to new
bright level
Write new
bright level
MFADE1
and
MFADE0
=0
Write
either
MFADE
bit = 1
Write
either
MFADE
bit = 0
No change
Fade is enabled:
MFADE1
and/or
MFADE0
=1
Write
MFADE1
and
MFADE0
=0
New rate
is used for all
remaining steps
Write a different
non-zero value
to MFADE bits
Write either or
both MFADE
bit(s) = 1
Write new
bright
level
Fade
ends
Fade begins
at 0mA
Fade
begins
Fade
processing
Fade is
redirected toward
the new value
from current
state
Write any
main bank
enable bit(s) = 1
Write new
brightness level
Fade
Re-write
continues the same
unchanged value to
MFADE
bits
Main bank
disabled
Bank
turns off
immediately
Write all main bank
enable bits = 0
Figure 1 — Fade Function State Diagram
Shutdown Mode
The device is disabled when the SPIF pin is held low for
the shutdown time specified in the electrical characteristics section. All registers are reset to default condition at
shutdown.
14
SC662
Applications Information (continued)
Starting Value (mA)
Table 1 — Number of Backlight Fade Steps between Values (See Note)
25.0 106 105 104 102 96
90
88
84
80
76
72
68
64
60
52
47
42
38
34
30
26
24
22
20
18
16
14
12
10
8
4
0
23.0 102 101 100 98
92
86
84
80
76
72
68
64
60
56
48
43
38
34
30
26
22
20
18
16
14
12
10
8
6
4
0
4
21.0 98
97
96
94
88
82
80
76
72
68
64
60
56
52
44
39
34
30
26
22
18
16
14
12
10
8
6
4
2
0
4
8
20.0 96
95
94
92
86
80
78
74
70
66
62
58
54
50
42
37
32
28
24
20
16
14
12
10
8
6
4
2
0
2
6
10
19.0 94
93
92
90
84
78
76
72
68
64
60
56
52
48
40
35
30
26
22
18
14
12
10
8
6
4
2
0
2
4
8
12
18.0 92
91
90
88
82
76
74
70
66
62
58
54
50
46
38
33
28
24
20
16
12
10
8
6
4
2
0
2
4
6
10
14
17.0 90
89
88
86
80
74
72
68
36 31
26
22
18
14
10
8
6
4
2
0
2
4
6
8
12
16
16.0 88
87
86
84
78
72
70
66
62
58
54
50
46
42
34
29
24
20
16
12
8
6
4
2
0
2
4
6
8
10
14
18
15.0 86
85
84
82
76
70
68
64
60
56
52
48
44
40
32
27
22
18
14
10
6
4
2
0
2
4
6
8
10
12
16
20
14.0 84
83
82
80
74
68
66
62
58
54
50
46
42
38
30
25
20
16
12
8
4
2
0
2
4
6
8
10
12
14
18
22
13.0 82
81
80
78
72
66
64
60
56
52
48
44
40
36
28
23
18
14
10
6
2
0
2
4
6
8
10
12
14
16
20
24
12.0 80
79
78
76
70
64
62
58
54
50
46
42
38
34
26
21
16
12
8
4
0
2
4
6
8
10
12
14
16
18
22
26
11.0 76
75
74
72
66
62
58
54
50
46
42
38
34
30
22
17
12
8
4
0
4
6
8
10
12
14
16
18
20
22
26
30
10.0 72
71
70
68
62
58
54
50
46
42
38
34
30
26
18
13
8
4
0
4
8
10
12
14
16
18
20
22
24
26
30
34
9.0
68
67
66
64
58
54
50
46
42
38
34
30
26
22
14
9
4
0
4
8
12
14
16
18
20
22
24
26
28
30
34
38
8.0
64
63
62
60
54
50
46
42
38
34
30
26
22
18
10
5
0
4
8
12
16
18
20
22
24
26
28
30
32
34
38
42
7.0
59
58
57
55
49
45
41
37
33
29
25
21
17
13
5
0
5
9
13
17
21
23
25
27
29
31
33
35
37
39
43
47
6.0
54
53
52
50
44
40
36
32
28
24
20
16
12
8
0
5
10
14
18
22
26
28
30
32
34
36
38
40
42
44
48
52
5.0
46
45
44
42
36
32
28
24
20
16
12
8
4
0
8
13
18
22
26
30
34
36
38
40
42
44
46
48
50
52
56
60
4.5
42
41
40
38
32
28
24
20
16
12
8
4
0
4
12
17
22
26
30
34
38
40
42
44
46
48
50
52
54
56
60
64
4.0
38
37
36
34
28
24
20
16
12
8
4
0
4
8
16
21
26
30
34
38
42
44
46
48
50
52
54
56
58
60
64
68
3.5
34
33
32
30
24
20
16
12
8
4
0
4
8
12
20
25
30
34
38
42
46
48
50
52
54
56
58
60
62
64
68
72
3.0
30
29
28
26
20
16
12
8
4
0
4
8
12
16
24
29
34
38
42
46
50
52
54
56
58
60
62
64
66
68
72
76
2.5
26
25
24
22
16
12
8
4
0
4
8
12
16
20
28
33
38
42
46
50
54
56
58
60
62
64
66
68
70
72
76
80
2.0
22
21
20
18
12
8
4
0
4
8
12
16
20
24
32
37
42
46
50
54
58
60
62
64
66
68
70
72
74
76
80
84
1.5
18
17
16
14
8
4
0
4
8
12
16
20
24
28
36
41
46
50
54
58
62
64
66
68
70
72
74
76
78
80
84
88
1.0
14
13
12
10
4
0
4
8
12
16
20
24
28
32
40
45
50
54
58
62
64
66
68
70
72
74
76
78
80
82
86
90
0.5
10
9
8
6
0
4
8
12
16
20
24
28
32
36
44
49
54
58
62
66
70
72
74
76
78
80
82
84
86
88
92
96
0.2
4
3
2
0
6
10
14
18
22
26
30
34
38
42
50
55
60
64
68
72
76
78
80
82
84
86
88
90
92
94
98 102
0.1
2
1
0
2
8
12
16
20
24
28
32
36
40
44
52
57
62
66
70
74
78
80
82
84
86
88
90
92
94
96 100 104
0.05
1
0
1
3
9
13
17
21
25
29
33
37
41
45
53
58
63
67
71
75
79
81
83
85
87
89
91
93
95
97 101 105
0.0
0
1
2
4
10
14
18
22
26
30
34
38
42
46
54
59
64
68
72
76
80
82
84
86
88
90
92
94
96
98 102 106
64
60
56
52
48
44
0.0 0.05 0.1 0.2 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.0 23.0 25.0
Ending Value (mA)
NOTE:
The fade time is determined by multiplying the number of steps by the fade rate (fade steps × fade rate = fade time).
15
SC662
Applications Information (continued)
NOTES:
· = Programmable backlight steps, о = Non-programmable fade steps
0.5
12
0.4
11
IBL (mA)
IBL (mA)
0.3
10
0.2
9
0.1
0.0
0
2
4
Step Count
6
8
8
10
64
68
72
Step Count
76
80
Figure 5 — Backlight Fade Steps (8.0mA to 12.0mA)
Figure 2 — Backlight Fade Steps (0.0mA to 0.5mA)
6.0
27
5.0
24
IBL (mA)
IBL (mA)
4.0
3.0
18
2.0
15
1.0
0.0
10
21
20
30
40
Step Count
50
60
Figure 3 — Backlight Fade Steps (0.5mA to 6.0mA)
12
80
85
90
95
Step Count
100
105
110
Figure 6 — Backlight Fade Steps (12.0mA to 25.0mA)
25
8.0
20
7.5
IBL (mA)
IBL (mA)
15
7.0
10
6.5
6.0
54
5
56
58
60
Step Count
62
Figure 4 — Backlight Fade Steps (6.0mA to 8.0mA)
64
0
0
20
40
60
Step Count
80
100
120
Figure 7 — Backlight Fade Steps (0.0mA to 25.0mA)
16
SC662
Applications Information (continued)
Sleep Mode
When all LEDs are disabled, sleep mode is activated. This
is a reduced current mode that helps minimize overall
current consumption by disabling the clock and the
charge pump while continuing to monitor the serial interface for commands. An additional current savings can be
obtained by putting the serial interface in standby mode
(see SemPulse Interface, Standby Mode).
Protection Features
The SC662 provides several protection features to safeguard the device from catastrophic failures. These features
include:
•
•
•
•
Output Open Circuit Protection
Over-Temperature Protection
Charge Pump Output Current Limit
LED Float Detection
Output Open Circuit Protection
Over-Voltage Protection (OVP) at the OUT pin prevents the
charge pump from producing an excessively high output
voltage. In the event of an open circuit between the OUT
pin and all current sinks (no loads connected), the charge
pump runs in open loop and the voltage rises up to the
OVP limit. OVP operation is hysteretic, meaning the charge
pump will momentarily turn off until VOUT is sufficiently
reduced. The maximum OVP threshold is 6.0V, allowing
the use of a ceramic output capacitor rated at 6.3V.
Over-Temperature Protection
The OT (Over-Temperature) protection circuit prevents the
device from overheating and experiencing a catastrophic
failure. When the junction temperature exceeds 165­°C, the
device goes into thermal shutdown with all outputs disabled until the junction temperature is reduced. All
register information is retained during thermal shutdown.
Hysteresis of 20°C is provided to ensure that the device
cools sufficiently before re-enabling.
Charge Pump Output Current Limit
The device limits the charge pump current at the OUT pin.
If the OUT pin is shorted to ground, or VOUT is lower than
VUVLO, the typical output current limit is 60mA. The output
current is limited to 300mA when over loaded resistively
with VOUT greater than 2.4V.
LED Float Detection
Float detect is a fault detection feature of the LED backlight
outputs. If an output is programmed to be enabled and an
open circuit fault occurs at any backlight output, that
output will be disabled to prevent a sustained output OVP
condition from occurring due to the resulting open loop.
Float detect ensures device protection but does not ensure
optimum performance. Unused LED outputs must be disabled to prevent an open circuit fault from occurring.
Capacitor Selection
The SC662 is designed to use low-ESR ceramic capacitors for the input and output decoupling capacitors as
well as the charge pump bucket capacitors. The required
value of input and output capacitors can vary with supply and layout conditions, but typically 1µF 0402 (1005
metric) size X5R capacitors are sufficient for both CIN and
COUT when 250kHz is selected for the charge pump clock.
Typically 0.47µF 0402 size X5R capacitors are sufficient
for CIN and COUT when the charge pump clock is1MHz.
Table 1 — Recommended Capacitors
Cap
Value
μF
Case
Size
fPUMP
kHz
1.0
0402
250
Recommended for FSEL = 0,
Typical output VPP ≤ 40mV at
250kHz
0.47
0402
1000
Recommended for FSEL = 1,
Typical output VPP ≤ 40mV at
1MHz
250
Required to provide full rated
output current and maintain a
low 1.5x—2x mode transition
point for optimum efficiency.
1000
Required to provide full rated
output current and maintain a
low 1.5x—2x mode transition
point for optimum efficiency.
Notes
CIN , COUT
1.0
0402
C1 , C2
0.47
0402
NOTE: Use only X5R type capacitors, with a 6.3V rating or higher
17
SC662
Applications Information (continued)
Thermal Management
PCB (Printed Circuit Board) layout directly effects the junction to ambient thermal resistance (θJA). Layout performance may place limits on the SC662 performance. The
SC662 is capable of 150mA of total output current in an
ambient temperature of up to 85°C. Both of these parameters, maximum output current (IOUT(MAX) ), and maximum
ambient temperature (TA), may be reduced if the layout
does not provide for adequate heat dissipation. Layout
guidelines are recommended in the next section, PCB
Layout Considerations.
18
SC662
Applications Information (continued)
PCB Layout Considerations
Following fundamental layout rules is critical for achieving
the performance specified in the Electrical Characteristics
table. A recommended layout is illustrated in Figures 8, 9,
and 10. Figure 8 shows a composite view of the two
copper layers plus components, vias, and text descriptors.
Figure 9 shows the copper layer on the component side of
the board, and Figure 10 is the copper layer for ground
and routing.
The following guidelines are recommended when developing a PCB layout:
•
•
•
•
•
•
•
•
Place all capacitors (C1, C2, CIN, and COUT) as
close to the device as possible, and on the same
side of the board as the SC662.
CIN, COUT should have their grounds connected
at one point as shown in Figure 8, with multiple
vias to ground.
C1 and C2 should be placed so that they do not
require vias to connect to the SC662.
All charge pump current passes through pins IN,
OUT, C1-, C1+, C2+, and C2-. Ensure that all connections to these pins use wide traces. Layout
should minimize the resistance and inductance
of these traces.
Make all ground connections to a ground plane
as shown in the example layout. There should
be a short unobstructed path between all
ground vias on the ground plane.
The power trace connecting the battery to the
IN pin should be sized for 300mA of battery
current. The power trace should be on a layer
adjacent to the ground return. If possible, make
the power trace equal in width to the ground
return trace.
The output trace connecting the OUT pin to the
anode terminals of the LEDs should be sized for
150mA of DC current.
Up to six LED traces connect between the LED
cathodes and the BLn pins. Each LED trace width
should be sized for 25mA of DC current. The LED
traces route in parallel on one layer and serve as
•
•
•
•
the return current path from the LEDs to the BLn
pins.
Figure 8 is representative of a two layer design.
As shown in this figure, the OUT trace can be
placed next to the six LED traces on the same
layer. However, if more than two layers are available, the preferred method is to have the OUT
trace route underneath the LED traces on a different layer.
Double vias are preferred for grounding pin 3 of
the SC662, and also for grounding the ground
leads of CIN and COUT.
The SPIF trace should be routed away from
sources of noise to preserve the signal integrity
for the SemPulse interface.
Multiple vias are recommended for the thermal
pad at the center of the device.
Ground return to battery
Positive from battery
OUT to LED Anodes
To LED1
BL1
To LED2
BL2
11
To LED3
BL3
12
To LED4
BL4
13
To LED5
BL5
14
To LED6
BL6
To SPIF output
10
CIN
COUT
IN
OUT
9
8
SC662
1
2
Vias to
ground
plane
7
C1+
6
C2+
5
C2-
4
C1-
3
GND
C2
C1
SPIF
Ground Layer
Figure 8 — Recommended PCB Layout
19
SC662
Applications Information (continued)
Vias to
ground
plane
Figure 9 — Component Layer
Figure 10 — Ground Layer
20
SC662
SemPulseTM Interface
Introduction
SemPulse is a write-only single wire interface. It provides
the capability to access up to 32 registers that control
device functionality. Two sets of pulse trains are transmitted via the SPIF pin. The first pulse set is used to set the
desired address. After the bus is held high for the address
hold period, the next pulse set is used to write the data
value. After the data pulses are transmitted, the bus is
held high again for the data hold period to signify the data
write is complete. At this point the device latches the data
into the address that was selected by the first set of pulses.
See the SemPulse Timing Diagrams for descriptions of all
timing parameters.
register bits per register. Just like with the address write,
the data write is only accepted if the bus is held high for
tHOLDD when the pulse train is completed. If the proper
hold time is not received, the interface will keep counting
pulses until the hold time is detected. If the total exceeds
63 pulses, the write will be ignored and the bus will reset
after the next valid hold time is detected. After the bus
has been held high for tHOLDD, the bus will expect the next
pulse set to be an address write. Note that this is the same
effect as the bus reset that occurs when tHOLDA exceeds its
maximum specification. For this reason, there is no
maximum limit on tHOLDD — the bus simply waits for the
next valid address to be transmitted.
Chip Enable/Disable
Multiple Writes
The device is enabled when the SemPulse interface pin
(SPIF) is pulled high for greater than tSU. If the SPIF pin is
pulled low again for more than tSD, the device will be
disabled.
Address Writes
The first set of pulses can range between 0 and 31 (or 1 to
32 rising edges) to set the desired address. After the
pulses are transmitted, the SPIF pin must be held high for
tHOLDA to signal to the slave device that the address write is
finished. If the pulse count is between 0 and 31 and the
line is held high for tHOLDA, the address is latched as the
destination for the next data write. If the SPIF pin is not
held high for tHOLDA, the slave device will continue to count
pulses. Note that if tHOLDA exceeds its maximum specification, the bus will reset. This means that the communication
is ignored and the bus resumes monitoring the pin,
expecting the next pulse set to be an address. If the total
exceeds 31 pulses, SPIF must be held high until the bus
reset time t BR is exceeded before commencing
communication.
Data Writes
After the bus has been held high for the minimum address
hold period, the next set of pulses are used to write the
data value. The total number of pulses can range from 0
to 63 (or 1 to 64 rising edges) since there are a total of 6
It is important to note that this single-wire interface
requires the address to be paired with its corresponding
data. If it is desired to write multiple times to the same
address, the address must always be re-transmitted prior
to the corresponding data. If it is only transmitted one
time and followed by multiple data transmissions, every
other block of data will be treated like a new address. The
result will be invalid data writes to incorrect addresses.
Note that multiple writes only need to be separated by
the minimum tHOLDD for the slave to interpret them correctly. As long as tHOLDA between the address pulse set and
the data pulse set is less than its maximum specification
but greater than its minimum, multiple pairs of address
and data pulse counts can be made with no detrimental
effects.
Standby Mode
Once data transfer is completed, the SPIF line must be
returned to the high state for at least 10ms to return to the
standby mode. In this mode, the SPIF line remains idle
while monitoring for the next command. This mode
allows the device to minimize current consumption
between commands. Once the device has returned to
standby mode, the bus is automatically reset to expect the
address pulses as the next data block. This safeguard is
intended to reset the bus to a known state (waiting for the
beginning of a write sequence) if the delay exceeds the
reset threshold.
21
SC662
SemPulseTM Interface (continued)
SemPulse Timing Diagrams
The SemPulse single wire interface is used to enable or disable the device and configure all registers (see Figure 11). The
timing parameters refer to the digital I/O electrical specifications.
Address is set
Up to 32 rising edges
(0 to 31 pulses)
Up to 64 rising edges
(0 to 63 pulses)
Data is written
SPIF
t = tSU
t = tHOLDA
t = tHOLDD
tHI
tLO
Figure 11 — Uniform Timing Diagram for SemPulse Communication
Timing Example 1
In this example (see Figure 12), the slave chip receives two sets of pulses to set the address and data, and the pulses
experience interrupts that cause the pulse width to be nonuniform. Note that as long as the maximum high and low
times are satisfied and the hold times are within specification, the data transfer is completed regardless of the number
of interrupts that delay the transmission.
Address is set to
register 02h
Data written is
000011
SPIF
t = tSU
tHI
tLO
t = tHOLDA
t < tHImax
t = tHOLDD
t < tLOmax
Figure 12 — SemPulse Data Write with Non-Uniform Pulse Widths
Timing Example 2
In this example (see Figure 13), the slave chip receives two sets of pulses to set the address and data, but an interrupt
occurs during a pulse that causes it to exceed the minimum address hold time. The write is meant to be the value 03h
in register 05h, but instead it is interpreted as the value 02h written to register 02h. The extended pulse that is delayed
by the interrupt triggers a false address detection, causing the next pulse set to be interpreted as the data set. To avoid
any problems with timing, make sure that all pulse widths comply with their timing requirements as outlined in this
datasheet.
Address is set to
register 02h
SPIF
Data written is
000010
Address is set to register
03h (address and data are
now out of order)
Interrupt
duration
t > tHImax
t = tHOLDA
t = tHOLDD
Figure 13 — Faulty SemPulse Data Write Due to Extended Interrupt Duration
22
SC662
Register Map(1)
Address
D5
D4
D3
D2
D1
D0
Reset
Value
Description
00h
BLEN6
BLEN5
BLEN4
BLEN3
BLEN2
BLEN1
00h
Backlight Enable
01h
0(2)
MBL4
MBL3
MBL2
MBL1
MBL0
00h
Main Backlight Current
02h
0(2)
SBL4
SBL3
SBL2
SBL1
SBL0
00h
Sub Backlight Current
03h
0(2)
TBL4
TBL3
TBL2
TBL1
TBL0
00h
Third Backlight Current
04h
0(2)
0(2)
0(2)
0(2)
MFADE1
MFADE0
00h
Main Fade
05h
0(2)
0(2)
FSEL
MB2
MB1
MB0
00h
Frequency and Banking Configurations
Notes:
(1) All registers are write-only.
(2) 0 = always write a 0 to these bits
Registers and Bit Definitions
BL Enable Control Register (00h)
This register enables each individual LED.
BLEN6 — BLEN1 [D5:D0]
These active high bits enable the six backlight drivers.
Each LED can be controlled independently.
23
SC662
Register and Bit Definitions (continued)
Main Backlight Current Control Register (01h)
This register is used to set the currents for the backlight
current sinks assigned to the Main Backlight Group. This
group can also be used to control red LEDs for limited RGB
control. These current sinks need to be enabled in the
Backlight Enable Control register to be active.
Bit D5
This bit is unused and is always a zero, so the maximum
pulse count for this register is 31.
MBL4 — MBL0 [D4:D0]
These bits are used to set the current for the main backlight current sinks. All enabled main backlight current
sinks will sink the same current, as shown in Table 2.
Table 2 — Main Backlight Current Settings
MBL4
MBL3
MBL2
MBL1
MBL0
Backlight
Current (mA)
0
0
0
0
0
0
0
0
0
0
1
0.05
0
0
0
1
0
0.1
0
0
0
1
1
0.2
0
0
1
0
0
0.5
0
0
1
0
1
1.0
0
0
1
1
0
1.5
0
0
1
1
1
2.0
0
1
0
0
0
2.5
0
1
0
0
1
3.0
0
1
0
1
0
3.5
0
1
0
1
1
4.0
0
1
1
0
0
4.5
0
1
1
0
1
5.0
0
1
1
1
0
6.0
0
1
1
1
1
7.0
1
0
0
0
0
8.0
1
0
0
0
1
9.0
1
0
0
1
0
10
1
0
0
1
1
11
1
0
1
0
0
12
1
0
1
0
1
13
1
0
1
1
0
14
1
0
1
1
1
15
1
1
0
0
0
16
1
1
0
0
1
17
1
1
0
1
0
18
1
1
0
1
1
19
1
1
1
0
0
20
1
1
1
0
1
21
1
1
1
1
0
23
1
1
1
1
1
25
24
SC662
Register and Bit Definitions (continued)
Sub Backlight Current Control Register (02h)
This register is used to set the currents for the backlight
current sinks assigned to the Sub Backlight Group. This
group can also be used to control green LEDs for limited
RGB control. These current sinks need to be enabled in the
Backlight Enable Control register to be active.
Bit D5
This bit is unused and is always a zero, so the maximum
pulse count for this register is 31.
SBL4 — SBL0 [D4:D0]
These bits are used to set the current for the sub backlight
current sinks. All enabled sub backlight current sinks will
sink the same current, as shown in Table 3.
Table 3 — Sub Backlight Current Settings
SBL4
SBL3
SBL2
SBL1
SBL0
Backlight
Current (mA)
0
0
0
0
0
0
0
0
0
0
1
0.05
0
0
0
1
0
0.1
0
0
0
1
1
0.2
0
0
1
0
0
0.5
0
0
1
0
1
1.0
0
0
1
1
0
1.5
0
0
1
1
1
2.0
0
1
0
0
0
2.5
0
1
0
0
1
3.0
0
1
0
1
0
3.5
0
1
0
1
1
4.0
0
1
1
0
0
4.5
0
1
1
0
1
5.0
0
1
1
1
0
6.0
0
1
1
1
1
7.0
1
0
0
0
0
8.0
1
0
0
0
1
9.0
1
0
0
1
0
10
1
0
0
1
1
11
1
0
1
0
0
12
1
0
1
0
1
13
1
0
1
1
0
14
1
0
1
1
1
15
1
1
0
0
0
16
1
1
0
0
1
17
1
1
0
1
0
18
1
1
0
1
1
19
1
1
1
0
0
20
1
1
1
0
1
21
1
1
1
1
0
23
1
1
1
1
1
25
25
SC662
Register and Bit Definitions (continued)
Third Backlight Current Control Register (03h)
This register is used to set the currents for the backlight
current sinks assigned to the Third Backlight Group. This
group can also be used to control blue LEDs for limited
RGB control. These current sinks need to be enabled in the
Backlight Enable Control register to be active.
Bit D5
This bit is unused and is always a zero, so the maximum
pulse count for this register is 31.
TBL4 — TBL0 [D4:D0]
These bits are used to set the current for the third backlight current sinks. All enabled third backlight current
sinks will sink the same current, as shown in Table 4.
Table 4 — Third Backlight Current Control Bits
TBL4
TBL3
TBL2
TBL1
TBL0
Backlight
Current (mA)
0
0
0
0
0
0
0
0
0
0
1
0.05
0
0
0
1
0
0.1
0
0
0
1
1
0.2
0
0
1
0
0
0.5
0
0
1
0
1
1.0
0
0
1
1
0
1.5
0
0
1
1
1
2.0
0
1
0
0
0
2.5
0
1
0
0
1
3.0
0
1
0
1
0
3.5
0
1
0
1
1
4.0
0
1
1
0
0
4.5
0
1
1
0
1
5.0
0
1
1
1
0
6.0
0
1
1
1
1
7.0
1
0
0
0
0
8.0
1
0
0
0
1
9.0
1
0
0
1
0
10
1
0
0
1
1
11
1
0
1
0
0
12
1
0
1
0
1
13
1
0
1
1
0
14
1
0
1
1
1
15
1
1
0
0
0
16
1
1
0
0
1
17
1
1
0
1
0
18
1
1
0
1
1
19
1
1
1
0
0
20
1
1
1
0
1
21
1
1
1
1
0
23
1
1
1
1
1
25
26
SC662
Register and Bit Definitions (continued)
Main Fade Control (04h)
Backlight Grouping Configuration (05h)
This register sets the fade status and rate for the main
backlight group.
This register assigns the LEDs to the backlight bank
configurations.
Bits [D5:D2]
These bits are unused and are always zeros, so the
maximum pulse count for this register is 3.
Bits [D5:D4]
These bits are unused and are always zeros, so the
maximum pulse count for this register is 16.
MFADE1, MFADE0[D1:D0]
These bits are used to enable fade and set the fade rate
between two backlight currents as shown in Table 5.
FSEL [D3]
This bit sets the charge pump clock frequency. FSEL = 0
for 250kHz, and FSEL = 1 for 1MHz. The default state for
this bit is zero.
Table 5 — Main Display Fade Control Bits
MFADE1
MFADE0
Fade Feature Rise/Fall Rate
(ms/step)
0
0
OFF
0
1
2
1
0
4
1
1
6
When the fade rate is set to 2, 4, or 6ms and then a new
backlight current is set, the backlight current will change
from its current value to the new value in steps, pausing at
each step for the duration of the fade rate before proceeding to the next step. The exact length of time used to fade
between any two backlight values is determined by multiplying the fade rate by the number of steps between the old
and new backlight values. The fade time can be calculated
from the data provided in Table 1 on page 15.
MB2 and MB0 [D2:D0]
These bits are used to set the number of LED drivers dedicated to each backlight group. This allows the device to
drive up to three different sets of LEDs with different
current settings. Note that any driver assigned to any LED
group can still be disabled independently if not needed.
The code set by these bits determines how the LED drivers
are assigned among the three LED groups according to
the assignments listed in Table 6. Default state for each of
these three bits is zero (all LEDs assigned to main
display).
Table 6 — Backlight Grouping Configuration
MB2
MB1
MB0
Main
Display
LED
Drivers
Sub
Display
LED
Drivers
Third
Display
LED
Drivers
0
0
0
BL1-BL6
0
0
1
BL1-BL3
BL4-BL6
0
1
0
BL1-BL2
BL3-BL4
BL5-BL6
0
1
1
BL1-BL2,
BL5-BL6
BL3
BL4
1
0
0
BL1-BL3
BL4-BL5
BL6
1
0
1
BL1-BL4
BL5-BL6
1
1
X
BL1-BL5
BL6
27
SC662
Outline Drawing — MLPQ-UT-14 2x2
B
D
A
DIMENSIONS
DIM
PIN 1
INDICATOR
(LASER MARK)
A
A1
A2
b
D
D1
E
E1
e
E
L
N
aaa
A2
A
aaa
bbb
MILLIMETERS
MIN
0.50
0.00
0.15
1.90
0.65
1.90
0.65
NOM
(0.152)
0.20
2.00
0.80
2.00
0.80
0.40 BSC
0.30
0.35
14
0.08
0.10
MAX
0.60
0.05
0.25
2.10
0.90
2.10
0.90
0.40
SEATING
PLANE
C
C
A1
D1
LxN
E/2
2
0.68
E1
0.34
1
N
bxN
bbb
C
A
B
e
D/2
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.
28
SC662
Land Pattern — MLPQ-UT-14 2x2
K
DIMENSIONS
(C)
0.68
H
0.34
G
Z
Y
X
DIM
MILLIMETERS
C
(1.95)
G
1.30
H
0.80
K
0.80
P
0.40
X
0.20
Y
0.65
Z
2.60
P
NOTES:
1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).
2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY.
CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR
COMPANY'S MANUFACTURING GUIDELINES ARE MET.
3. THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD
SHALL BE CONNECTED TO A SYSTEM GROUND PLANE.
FAILURE TO DO SO MAY COMPROMISE THE THERMAL AND/OR
FUNCTIONAL PERFORMANCE OF THE DEVICE.
4.
SQUARE PACKAGE - DIMENSIONS APPLY IN BOTH " X " AND " Y " DIRECTIONS.
29
SC662
© Semtech 2010
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Contact Information
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Power Management Products Division
200 Flynn Road, Camarillo, CA 93012
Phone: (805) 498-2111 Fax: (805) 498-3804
www.semtech.com
30