MAX8648ETE+T ,Ultra-Efficient Charge Pumps for Six White/RGB LEDs in 3mm x 3mm Thin QFNApplicationstemperature range.+Denotes a lead-free package.White LED Backlighting, Single or Dual D ..
MAX8648ETE+T ,Ultra-Efficient Charge Pumps for Six White/RGB LEDs in 3mm x 3mm Thin QFNELECTRICAL CHARACTERISTICS(V = V = 3.6V, V = 0V, T = -40°C to +85°C, unless otherwise noted. Typica ..
MAX864EEE ,Dual-Output Charge Pump with ShutdownApplicationsMAX864C/D 0°C to +70°C Dice*Low-Voltage GaAsFET Bias in Wireless HandsetsMAX864EEE -40° ..
MAX864EEE ,Dual-Output Charge Pump with ShutdownFeaturesThe MAX864 CMOS, charge-pump, DC-DC voltage' Requires Only Four Capacitorsconverter produce ..
MAX864EEE+ ,Dual-Output Charge Pump with ShutdownApplicationsMAX864C/D 0°C to +70°C Dice*Low-Voltage GaAsFET Bias in Wireless HandsetsMAX864EEE -40° ..
MAX864EEE+ ,Dual-Output Charge Pump with ShutdownFeaturesThe MAX864 CMOS, charge-pump, DC-DC voltage♦ Requires Only Four Capacitorsconverter produce ..
MB84256A-10LLP , CMOS 256K-BIT LOW POWER SRAM
MB84256A-10LPF , CMOS 256K-BIT LOW POWER SRAM
MB84VD21183EM-70PBS , Stacked MCP (Multi-Chip Package) FLASH MEMORY & SRAM CMOS
MB84VD21194EM-70PBS , Stacked MCP (Multi-Chip Package) FLASH MEMORY & SRAM CMOS
MB84VD22181FM-70PBS , 32M (X16) FLASH MEMORY & 4M (X16) STATIC RAM
MB84VD22182EE-90 ,32M (x 8/x16) FLASH MEMORY & 4M (x 8/x16) STATIC RAMFUJITSU SEMICONDUCTORDS05-50204-2EDATA SHEETStacked MCP (Multi-Chip Package) FLASH MEMORY & SRAMCMO ..
MAX8648ETE+-MAX8648ETE+T
Ultra-Efficient Charge Pumps for Six White/RGB LEDs in 3mm x 3mm Thin QFN
General DescriptionThe MAX8647/MAX8648 drive up to six white LEDs or
two sets of RGB LEDs with regulated constant current
for display backlight and fun light applications. By utiliz-
ing an inverting charge pump and extremely low-
dropout adaptive current regulators, these ICs achieve
very high efficiency over the full 1-cell Li+ battery volt-
age range and even with large LED forward voltage
mismatch. The 1MHz fixed-frequency switching allows
for tiny external components. The regulation scheme is
optimized to ensure low EMI and low input ripple. The
MAX8647/MAX8648 include thermal shutdown, open-
and short-circuit protection.
The MAX8647 features an I2C serial port, while the
MAX8648 features a three-wire serial-pulse logic inter-
face. Both devices support independent on/off and
dimming for main and subbacklights. The dimming
ranges are pseudo-logarithmic from 24mA to 0.1mA
and off in 32 steps. Both devices include a temperature
derating function to safely allow bright 24mA full-scale
output current setting while automatically reducing cur-
rent to protect LEDs at high ambient temperatures
above +60°C.
The MAX8647/MAX8648 are available in a 16-pin, 3mm
x 3mm thin QFN package (0.8mm max height).
ApplicationsWhite LED Backlighting, Single or Dual Display
Wide-Gamut RGB LED Display Backlighting
Camera Flash or RGB Indicators
Cellular Phones and Smartphones
PDAs, Digital Cameras, and Camcorders
FeaturesSix Adaptive Current RegulatorsIndependent Voltage Supply for Each LEDIndividual LED Brightness Control (MAX8647)24mA to 0.1mA Dimming Range2C Interface (MAX8647)
Serial-Pulse Dimming Logic (MAX8648)±2% Accuracy, ±0.4% Matching (typ)Low 70µA Quiescent CurrentLow 1µA Shutdown CurrentInrush Current LimitTADerating Function Protects LEDs16-Pin, 3mm x 3mm Thin QFN Package
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFNC1PC2P
LED4LED5LED2
SDA (ENC)
( ) DESIGNATE PINS ON THE MAX8648109
SCL (ENB)
VDD (ENA)
LED6
NEG
C1N
C2N
MAX8647ETE
MAX8648ETE
GND
LED3
LED1
THIN QFNTOP VIEW
Pin Configuration19-0790; Rev 1; 9/07
EVALUATION KIT
AVAILABLE
Ordering Information
Note:All devices are specified over the -40°C to +85°C extended
temperature range.
+Denotes a lead-free package.
*EP = Exposed paddle.
PARTDIMMINGPIN
PACKAGE
TOP
MARK
PKG
CODEA X8 6 4 7 E TE + I2C interface16 Thi n QFN- E P *AFDT1633- 5
A X8 6 4 8 E TE + S eri al -p ul seogi c16 Thi n QFN- E P *AFET1633- 5
WHITE
OR RGB LED
LED3
1μF
GND
LED4
LED5
LED6D6
LED2
MAX8648LED1
NEGINPUT
2.7V TO 5.5V
1μF
C1PC1N
1μF
C2PC2N
1μF
SERIAL-
PULSE
INTERFACE
ENA
ENB
ENC
Typical Operating Circuit
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VVDD= VIN= 3.6V, VGND= 0V, TA= -40°C to +85°C,unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
VDD, IN, SCL, SDA, ENA, ENB, ENC to GND........-0.3V to +6.0V
VDD, IN, SCL, SDA, ENA, ENB, ENC to NEG........-0.3V to +6.0V
NEG to GND.............................................................-6V to +0.3V
C2N to GND.............................................................-6V to +0.3V
C1P, C2P to GND .......................................-0.3V to (VIN+ 0.3V)
C2P to C1N..................................................-0.3V to (VIN+ 0.3V)
LED_, C1N, C2N to NEG.............................-0.3V to (VIN+ 0.3V)
Continuous Power Dissipation (TA= +70°C)
16-Pin Thin QFN 3mm x 3mm (derate 20.8mW/°C
above +70°C).............................................................1667mW
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERCONDITIONSMINTYPMAXUNITSIN Operating Voltage2.75.5V
VDD Operating Voltage1.75.5V
Undervoltage-Lockout (UVLO)
ThresholdVIN rising2.352.452.55V
Undervoltage-Lockout Hysteresis100mV
TA = +25°C0.42.5IN Shutdown Supply Current
(All Outputs Off)
VSCL = VSDA = VDD (MAX8647),
VEN_ = 0V (MAX8648)TA = +85°C0.4µA
TA = +25°C0.11.0VDD Shutdown Supply CurrentTA = +85°C0.1µA
Charge pump inactive, two LEDs enabled at 0.1mA
setting70100µA
IN Operating Supply CurrentCharge pump active, 1MHz switching, all LEDs
enabled at 0.1mA setting1.6mA
Charge pump inactive, two LEDs enabled at 0.1mA
setting, TA = +25°C0.11.0
VDD Operating Supply CurrentCharge pump active, 1MHz switching, all LEDs
enabled at 0.1mA setting, TA = +85°C0.1
Thermal-Shutdown Threshold+160°C
Thermal-Shutdown Hysteresis20°C
I2C INTERFACE (MAX8647)Logic-Input High Voltage (SDA, SCL)VDD = 1.7V to 5.5V, hysteresis = 0.2 x VDD (typ)0.7 x
VDDV
Logic-Input Low Voltage (SDA, SCL)VDD = 1.7V to 5.5V, hysteresis = 0.2 x VDD (typ)0.3 x
VDDV
Filtered Pulse Width (tSP)VIN = 2.7V to 5.5V, VDD = 1.7V to 5.5V (Note 2)50ns
TA = +25°C-10.01+1Logic-Input Current (SDA, SCL)VIL = 0V or VIH = 5.5VTA = +85°C0.1µA
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
ELECTRICAL CHARACTERISTICS (continued)(VVDD= VIN= 3.6V, VGND= 0V, TA= -40°C to +85°C,unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERCONDITIONSMINTYPMAXUNITSSDA Output Low VoltageISDA = 3mA, for acknowledge (Note 2)0.030.40V
I2C Clock Frequency400kHz
Bus Free Time Between START and
STOP (tBUF)(Note 2)1.3µs
Hold Time Repeated START Condition
(tHD_STA)(Note 2)0.60.1µs
SCL Low Period (tLOW)(Note 2)1.30.2µs
SCL High Period (tHIGH)(Note 2)0.60.2µs
Setup Time Repeated START
Condition (tSU_STA)(Note 2)0.60.1µs
SDA Hold Time (tHD_DAT)(Note 2)0-0.01µs
SDA Setup Time (tSU_DAT)(Note 2)10050ns
Setup Time for STOP Condition
(tSU_STO)(Note 2)0.60.1µs
SERIAL-PULSE LOGIC (EN_) (MAX8648)Logic-Input High VoltageVIN = 2.7V to 5.5V1.4V
Logic-Input Low VoltageVIN = 2.7V to 5.5V0.4V
TA = +25°C-10.01+1Logic-Input CurrentVIL = 0V or VIH = 5.5VTA = +85°C0.1µA
EN Low Shutdown Delay tSHDN
See Figure 3 and the Shutdown Mode section; EN_
needs to be longer than 4ms to ensure LED is
powered off
4ms
tLO (Figure 3)1500µs
tHI (Figure 3)1µs
Initial tHI (Figure 3)First EN_ high pulse120µs
CHARGE PUMPSwitching Frequency1MHz
Soft-Start Time0.5ms
Charge-Pump Regulation Voltage(VIN - VNEG)4.35.0V
Open-Loop NEG Output Resistance(VNEG - 0.5 x VIN) / INEG2.55Ω
NEG Discharge Resistance in
Shutdown or When the Charge Pump
is Inactive
All LEDs off, EN_ = GND10kΩ
LED1–LED6 CURRENT REGULATORCurrent Setting RangeThrough an I2C or serial-pulse interface0.124.0mA
24mA setting, TA = +25°C-2±1+2
24mA setting, TA = -40°C
to derating function start
temperature (Note 2)+5Current Accuracy
VLED_ = 0.5V for
charge-pump inactive,
VLED_ = -0.9V,
VNEG_ = -1.4V1.6mA setting, TA = +25°C-15±5+15
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
Note 1:Limits are 100% production tested at TA= +25°C. Specifications over the operating temperature range are guaranteed by design.
Note 2:Guaranteed by design.
Note 3:LED dropout voltage is defined as the LED_ to GND voltage at which current into LED_ drops 10% from the value at VLED_= 0.5V.
ELECTRICAL CHARACTERISTICS (continued)(VVDD= VIN= 3.6V, VGND= 0V, TA= -40°C to +85°C,unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERCONDITIONSMINTYPMAXUNITSDerating-Function Start Temperature+60°C
Derating-Function SlopeFrom derating-function start temperature-2.5%/°C
Not utilizing the charge pump3LED_ RDSONUtilizing the charge pump4Ω
Not utilizing the charge pump60120LED_ Dropout24mA setting
(Note 3)Utilizing the charge pump90200mV
LED_ Current Regulator Switchover
Threshold (Inactive to Active)VLED_ falling125150175mV
LED_ Current Regulator Switchover
Hysteresis100mV
TA = +25°C0.015LED_ Leakage in ShutdownAll LEDs offTA = +85°C0.1µA
Typical Operating Characteristics(VIN= 3.6V, VEN_= VIN, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
EFFICIENCY vs. SUPPLY VOLTAGE
(DRIVING SIX MATCHED LEDs)MAX8647/48 toc01
INPUT VOLTAGE (V)
EFFICIENCY (%)
1.6mA/LED16mA/LED
20.8mA/LED
6.4mA/LED
EFFICIENCY vs. Li+ BATTERY VOLTAGE
(DRIVING SIX MATCHED LEDs)MAX8647/48 toc02
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
EFFICIENCY P
LED
BATT
(%)
1.6mA/LED
20.8mA/LED
16mA/LED
6.4mA/LED
EFFICIENCY vs. SUPPLY VOLTAGE
(DRIVING SIX LEDs)MAX8647/48 toc03
INPUT VOLTAGE (V)
EFFICIENCY (%)
1.6mA/LED
16mA/LED
LEDs HAVE MISMATCHED VF
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
EFFICIENCY vs. SUPPLY VOLTAGE
(DRIVING SIX LEDs)MAX8647/48 toc04
INPUT VOLTAGE (V)
EFFICIENCY (%)
6.4mA/LED
20.8mA/LED
LEDs HAVE MISMATCHED VF
EFFICIENCY vs. Li+ BATTERY VOLTAGE
(DRIVING SIX LEDs)MAX8647/48 toc05
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
EFFICIENCY P
LED
BATT
(%)
1.6mA/LED
16mA/LED
LEDs HAVE MISMATCHED VF
EFFICIENCY vs. Li+ BATTERY VOLTAGE
(DRIVING SIX LEDs)MAX8647/48 toc06
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
EFFICIENCY P
LED
BATT
(%)
6.4mA/LED
20.8mA/LED
LEDs HAVE MISMATCHED VF
INPUT CURRENT vs. INPUT VOLTAGE
(DRIVING SIX LEDs)MAX8647/48 toc07
INPUT VOLTAGE (V)
INPUT CURRENT (mA)
LEDs HAVE MISMATCHED VF
ILED = 16mA
ILED = 20.8mA
ILED = 6.4mA
ILED = 1.6mA
INPUT CURRENT vs. Li+ BATTERY
VOLTAGE (DRIVING SIX LEDs)MAX8647/48 toc08
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
INPUT CURRENT (mA)
1.6mA/LED
6.4mA/LED
16mA/LED
20.8mA/LED
LEDs HAVE MISMATCHED VF
INPUT CURRENT
vs. INPUT VOLTAGE (RGB MODULE)MAX8647/48 toc09
INPUT VOLTAGE (V)
INPUT CURRENT (mA)
ILED = 20.8mA
ILED = 16mA
ILED = 4.8mA
ILED = 1.6mA
RGB MODULE: LUMEX SML-LX3632SISUGSBC
INPUT CURRENT vs. Li+ BATTERY
VOLTAGE (RGB MODULE)MAX8647/48 toc10
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
INPUT CURRENT (mA)
1.6mA/LED
6.4mA/LED
16mA/LED
20.8mA/LED
RGB MODULE: LUMEX SML-LX3632SISUGSBC
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE (DRIVING SIX WHITE LEDs)MAX8647/48 toc11
SUPPLY VOLTAGE (V)
INPUT RIPPLE VOLTAGE (mV
RMS
20.8mA/LED
16mA/LED
6.4mA/LED
1.6mA/LED
LEDs HAVE
MISMATCHED VF
LED CURRENT MATCHING
vs. INPUT VOLTAGE (16mA/LED)
MAX8647/48 toc12
INPUT VOLTAGE (V)
LED CURRENT (mA)
Typical Operating Characteristics (continued)(VIN= 3.6V, VEN_= VIN, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFNLED CURRENT vs. TEMPERATURE
MAX8647/48 toc13
TEMPERATURE (°C)
LED CURRENT (mA)
400ns/div
1x MODE OPERATING WAVEFORMS
(VIN = 4V)VIN
IIN100mA/div
AC-COUPLED
100mV/div
20mA/div
MAX8647/48 toc14
ILEDALL LEDs ON
ILED = 24mA
400ns/div
1.5x MODE OPERATING WAVEFORMS
(VIN = 3V)VIN
IIN100mA/div
AC-COUPLED
100mV/div
20mA/div
MAX8647/48 toc15
ILEDALL LEDs ON
ILED = 24mA
1ms/div
STARTUP AND SHUTDOWN
(MAX8648)VEN_
VIN
IIN200mA/div
AC-COUPLED
20mV/div
2V/div
MAX8647/48 toc16
ILED5
2V/divENA = ENB = ENC
10ms/div
SINGLE-WIRE PULSE DIMMING
(MAX8648)VEN_
20mA/div
MAX8647/48 toc17
TOTAL ILED5
5V/div
OPERATING IN 1x
MODE, ALL 6 LEDs
OPERATING
1ms/div
LINE-TRANSIENT RESPONSE
(VIN = 4.3V TO 3.8V TO 4.3V)VIN
IIN
24mA
20mA/div
200mA/div
MAX8647/48 toc18
ILED6
4.3V
3.8V
1ms/div
LINE-TRANSIENT RESPONSE WITH MODE
CHANGE (VIN = 3.8V TO 3.4V TO 3.8V)VIN
IIN
24mA
20mA/div
200mA/div
MAX8647/48 toc19
ILED6
0mA
3.8V
3.4V
Typical Operating Characteristics (continued)(VIN= 3.6V, VEN_= VIN, circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
Pin Description
PIN
MAX8647MAX8648NAMEFUNCTIONIN
Supply Voltage Input. The input voltage range is 2.7V to 5.5V. Bypass IN to GND with a
1µF ceramic capacitor as close as possible to the IC. IN is high impedance during
shutdown. Connect IN to the anodes of all the LEDs.2GNDGround. Connect GND to system ground and the input bypass capacitor as close as
possible to the IC.3C1PTransfer Capacitor 1 Positive Connection. Connect a 1µF ceramic capacitor from C1P
to C1N.4C2PTransfer Capacitor 2 Positive Connection. Connect a 1µF ceramic capacitor from C2P
to C2N.5C2NTransfer Capacitor 2 Negative Connection. Connect a 1µF ceramic capacitor from C2P
to C2N. An internal 10kΩ resistor pulls C2N to GND during shutdown.6C1NTransfer Capacitor 1 Negative Connection. Connect a 1µF ceramic capacitor from C1P
to C1N.7NEG
Charge-Pump Negative Output. Connect a 1µF ceramic capacitor from NEG to GND. In
shutdown, an internal 10kΩ resistor pulls NEG to GND. Connect the exposed paddle to
NEG directly under the IC.
8–138–13LED6–LED1
LED Current Regulators. Current flowing into LED_ is based on the internal registers.
Connect LED_ to the cathodes of the external LEDs. LED_ is high impedance during
shutdown. For the MAX8647, program any unused LED_ to off and LED_ can be
shorted to ground or left unconnected. For the MAX8648, short any unused LED_ to IN
prior to power-up to disable the corresponding current regulator.—SDAI2C Data Input. Data is read on the rising edge of SCL.—SCLI2C Clock Input. Data is read on the rising edge of SCL.—VDDLogic-Input Supply Voltage. Connect to the supply voltage driving SDA and SCL.
Bypass VDD to GND with a 0.1µF ceramic capacitor.14, 15, 16ENC, ENB, ENA
Enable and Serial-Pulse Dimming Control. ENA controls LED1, LED2, and LED3. ENB
controls LED4 and LED5. ENC controls LED6. Drive EN_ logic-high to turn on the IC
and enable the corresponding LED_ at 24mA each. Drive an individual EN_ logic-low
for greater than 4ms to turn off the corresponding-current regulators or drive all three
EN_ low to place the IC in shutdown. See the Serial-Pulse Dimming Control (MAX8648)
section.—EPExposed Paddle. Connect to NEG.
MAX8647/MAX8648
Ultra-Efficient Charge Pumps for
Six White/RGB LEDs in 3mm x 3mm Thin QFN
Detailed DescriptionThe MAX8647/MAX8648 have an inverting charge
pump and six current regulators capable of 24mA each
to drive six white LEDs or two sets of RGB LEDs. The
current regulators are matched to within ±0.4% (typ)
providing uniform white LED brightness for LCD back-
light applications. To maximize efficiency, the current
regulators operate with as little as 0.15V voltage drop.
Individual white LED current regulators conduct current
to GND or NEG to extend usable battery life. In the
case of mismatched forward voltage of white LEDs,
only the white LEDs requiring higher voltage are
switched to pull current to NEG instead of GND, further
raising efficiency and reducing battery current drain.
Current-Regulator SwitchoverWhen VINis higher than the forward voltage of the
white LED plus the 0.15V headroom of the current regu-
lator, the LED current returns through GND. If this con-
dition is satisfied for all six white LEDs, the charge
pump remains inactive. When the input voltage drops
so that the current-regulator headroom cannot be main-
tained for any of the individual white LEDs, the inverting
charge pump activates and generates a voltage on the
NEG pin that is no greater than 5V below VIN. Each cur-
rent regulator contains circuitry that detects when it is
in dropout and switches that current-regulator return
path from GND to NEG. Since this is done on an LED-
by-LED basis, the LED current is switched for only the
individual LED requiring higher voltage, thus minimizing
power consumption.
Low LED Current LevelsThe MAX8647/MAX8648 internally generate a PWM sig-
nal to obtain higher resolution at lower currents. See
Single-Wire Pulse Dimming in the Typical Operating
Characteristics section. As the ILEDsetting is below
6.4mA, the IC adjusts not only ILEDDC current, but the
duty cycle is controlled by the PWM signal. The fre-
quency of the PWM dimming signal is set at 1kHz with
a minimum duty cycle of 1/16 to avoid the LED flicking
effect to human eyes. Table 1 shows the current level
and the corresponding duty cycle.
2C Interface (MAX8647)An I2C 2-wire serial interface is provided on the
MAX8647 to control the LEDs. The serial interface
consists of a serial-data line (SDA) and a serial-clock
line (SCL). Standard I2C write-byte commands are
used. Figure 2 shows a timing diagram for the I2C pro-
tocol. The MAX8647 is a slave-only device, relying
upon a master to generate a clock signal. The master
(typically a microprocessor) initiates data transfer on
the bus and generates SCL to permit data transfer. A
master device communicates with the MAX8647 by
transmitting the proper 8-bit address (0x9A) followed
by the 8-bit control byte. Each 8-bit control byte con-
sists of a 3-bit command code and 5 bits of data (Table
1). Each transmit sequence is framed by a START (A)
condition and a STOP (L) condition (Figure 2). Each
word transmitted over the bus is 8 bits long and is
always followed by an ACKNOWLEDGE CLOCK
PULSE (K). The power-on default settings for D4 to D0
are all 0, which indicates that all LED_ are off.
Serial-Pulse Dimming Control (MAX8648)When the LEDs are enabled by driving EN_ high, the
MAX8648 ramps LED current to 24mA. Dim the LEDs
by pulsing EN_ low (1µs to 500µs pulse width). Each
pulse reduces the LED current based on the LED dim-
ming table, Table 3. After the current reaches 0.1mA,
the next pulse restores the current to 24mA. Figure 3
shows a timing diagram for EN_. ENA controls LED1,
LED2, and LED3. ENB controls LED4 and LED5. ENC
controls LED6.
If dimming control is not required, EN_ work as simple
100% brightness or off controls. Drive EN_ high to enable
the LEDs, or drive EN_ low to disable. The IC is shut-
down when all three EN_ are low for 4ms or longer.
Table 1.Internal PWM Duty Cycle vs. LED
Set Current
ILED
(mA)
DUTY CYCLE
(n/16)
ILED
(mA)
DUTY CYCLE
(n/16)1.4140.11
