MAX1576ETG+ ,480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera FlashELECTRICAL CHARACTERISTICS(V = 3.6V, V = V = V = 0V, ENM1 = ENM2 = ENF1 = ENF2 = IN, R = R = 6.8kΩ, ..
MAX1576ETG+T ,480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera FlashFeaturesThe MAX1576 charge pump drives up to 8 white LEDs♦ Powers Up to 8 LEDswith regulated consta ..
MAX1577ZETA+ ,1.2A White LED Regulating Charge Pump for Camera Flashes and Movie LightsApplicationsWhite LED Flashes, Strobes, and Movie LightsOrdering InformationLCD BacklightingPIN- TO ..
MAX1578ETG+ ,Complete Bias and White LED Power Supplies for Small TFT DisplaysFeatures♦ Four Regulators in One PackageThe MAX1578/MAX1579 provide four regulated outputsto meet a ..
MAX1578ETG+T ,Complete Bias and White LED Power Supplies for Small TFT DisplaysELECTRICAL CHARACTERISTICS(Circuit of Figure 3, V = 3V, CTRL = ONBIAS = IN, T = -40°C to +85°C, typ ..
MAX1579ETG+ ,Complete Bias and White LED Power Supplies for Small TFT Displaysfeatures a tem-♦ 1µA Shutdown Currentperature derating function to avoid overdriving the♦ Tiny 4mm ..
MAX4241ESA ,Single/Dual/Quad / !.8V/10A / SOT23 / Beyond-the-Rails Op AmpsApplicationsMAX4242EUA -40°C to +85°C 8 µMAX —Two-Cell Battery- Strain GaugesMAX4242ESA -40°C to +8 ..
MAX4241EUA ,Single/Dual/Quad / !.8V/10A / SOT23 / Beyond-the-Rails Op Ampsapplications.PIN- SOT PART TEMP. RANGEThe MAX4240 is offered in a space-saving 5-pin SOT23 PACKAGE ..
MAX4241EUA ,Single/Dual/Quad / !.8V/10A / SOT23 / Beyond-the-Rails Op AmpsApplicationsMAX4242EUA -40°C to +85°C 8 µMAX —Two-Cell Battery- Strain GaugesMAX4242ESA -40°C to +8 ..
MAX4241EUA ,Single/Dual/Quad / !.8V/10A / SOT23 / Beyond-the-Rails Op AmpsELECTRICAL CHARACTERISTICS — T = +25°CA(V = +1.8V to +5.5V, V = 0, V = 0, V = V / 2, R = 100kΩ tied ..
MAX4241EUA+ ,Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op AmpsELECTRICAL CHARACTERISTICS (V = +1.8V to +5.5V, V = 0, V = 0, V = V / 2, R = 100kΩ tied to V / 2, S ..
MAX4241EUA+T ,Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Ampsapplications.PART TEMP RANGEPACKAGE MARKThe MAX4240 is offered in a space-saving 5-pinSOT23 package ..
MAX1576ETG+-MAX1576ETG+T
480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera Flash
General DescriptionThe MAX1576 charge pump drives up to 8 white LEDs
with regulated constant current for uniform intensity.
The main group of LEDs (LED1–LED4) can be driven
up to 30mA per LED for backlighting. The flash group
of LEDs (LED5–LED8) are independently controlled and
can be driven up to 100mA per LED (or 400mA total).
By utilizing adaptive 1x/1.5x/2x charge-pump modes
and very-low-dropout current regulators, the MAX1576
achieves high efficiency over the full 1-cell lithium-bat-
tery voltage range. The 1MHz fixed-frequency switch-
ing allows for tiny external components, and the
regulation scheme is optimized to ensure low EMI and
low input ripple.
The MAX1576 uses two external resistors to set the
main and flash full-scale (100%) LED currents. Four
control pins are used for LED dimming by either serial
control or 2-bit logic per group. ENM1 and ENM2 set
the main LEDs to 10%, 30%, or 100% of full scale.
ENF1 and ENF2 set the flash LEDs to 20%, 40%, or
100% of full scale. In addition, connect either pair of
control pins together for single-wire, serial pulse dim-
ming control.
The MAX1576 is available in a 24-pin thin QFN, 4mm x
4mm package (0.8mm max height).
ApplicationsCamera Phones
LCD Backlights
LED Camera Flashes
Cell Phones and Smart Phones
PDAs, Digital Cameras, and Camcorders
FeaturesPowers Up to 8 LEDs
Up to 30mA/LED Drive for Backlight
Up to 400mA Total Drive for Flash85% Average Efficiency (PLED/ PBATT) Over Li+
Battery Discharge0.7% Typical LED Current MatchingAdaptive 1x/1.5x/2x Mode SwitchoverFlexible Brightness Control
Single-Wire, Serial Pulse Interface (5% to 100%)
2-Bit (3 Levels) Logarithmic LogicLow Input Ripple and EMILow 0.1µA Shutdown Current2.7V to 5.5V Supply Voltage RangeSoft-Start Limits Inrush CurrentOutput Overvoltage ProtectionThermal-Shutdown Protection24-Pin Thin QFN, 4mm x 4mm Package
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
Ordering Information
Typical Operating Circuit19-3326; Rev 1; 8/05
EVALUATION KIT
AVAILABLE
PARTTEMP RANGEPIN-PACKAGEMAX1576ETG-40°C to +85°C24 Thin QFN 4mm x
4mm (T2444-4)
MAX1576ETG+-40°C to +85°C24 Thin QFN 4mm x
4mm (T2444-4)
MAX1576Y
1μF1μF
4.7μF
INP
ENM1
ENM2
ENF1
ENF2
GND1
OUTC1PC1N
PGNDGND2SETFSETM
C2P
FLASHMAIN
C2N
4.7μF1μF
ON/OFF AND
CURRENT
SETTING
INPUT
2.7V TO 5.5V
OUTPUT
UP TO 480mA
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
Pin Configuration appears at end of data sheet.+ Denotes lead-free package.
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VIN= 3.6V, VGND1= VGND2= VPGND= 0V, ENM1 = ENM2 = ENF1 = ENF2 = IN, RSETM= RSETF= 6.8kΩ, 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.
INP, IN, OUT, ENM1, ENM2, ENF1,
ENF2 to GND1.......................................................-0.3V to +6.0V
SETF, SETM, LED1, LED2, LED3, LED4, LED5,
LED6, LED7, LED8 to GND1....................-0.3V to (VIN+ 0.3V)
C1N, C2N to GND1........................................-0.3V to (VIN+ 1V)
C1P, C2P to
GND1................-0.3V to Greater of (VOUT+ 1V) or (VIN+ 1V)
GND2, PGND to GND1.........................................-0.3V to +0.3V
OUT Short Circuit to GND..........................................Continuous
Continuous Power Dissipation (TA= +70°C)
24-Pin Thin QFN (derate 20.8mW/°C
above +70°C)..............................................................1666mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERCONDITIONSMINTYPMAXUNITSIN Operating Voltage2.75.5V
Undervoltage-Lockout ThresholdVIN rising or falling2.252.452.60V
Undervoltage-Lockout Hysteresis50mV
Overvoltage Protection ThresholdVOUT rising5V
1MHz switching, no load, 1.5x or 2x mode3.86.0Supply Current1x mode 10% setting, LED5–LED8 off0.3mA
Shutdown Supply CurrentENM1 = ENM2 = ENF1 = ENF2 = GND0.13µA
Soft-Start Time2ms
SET_ Bias Voltage0.604V
SET_ Leakage in ShutdownENM1 = ENM2 = ENF1 = ENF2 = GND, VSET_ = 0V or VIN0.011µA
SETM Current Range40130µA
SETF Current Range40145µA
SETM to Main LED_ Current Ratio
(ILED / ISETM)100% setting, LED1–4233A/A
SETF to Flash LED_ Current Ratio
(ILED / ISETF)100% setting, LED5–8708A/A
LED1–4-6+6LED_ Current AccuracyLED5–8-8+8%
LED_ to LED_ Current Matching (Note 2)-3.5±0.7+3.5%
LED1–LED4, RSETM = 4.64kΩ2730Maximum LED_ Sink CurrentLED5–LED8, RSETF = 4.12kΩ90100mA
LED_ Dropout Voltage(Note 3)4090mV
LED_ 1.5x and 2x Regulation
Voltage150mV
LED_ 1x to 1.5x or 1.5x to 2x
Mode Transition Threshold90100110mV
Input-Voltage-Mode Transition
Hysteresis150mV
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
Note 1:Specifications to -40°C are guaranteed by design and not production tested.
Note 2:LED current matching is defined as: (ILED_- IAVG) / IAVG. Matching is for LEDs within the main group (LED1–LED4) or the
flash group (LED5–LED8).
Note 3:Dropout voltage is defined as the LED_ to GND_ voltage at which current into LED_ drops 10% from the value at VLED_= 0.2V.
ELECTRICAL CHARACTERISTICS (continued)(VIN= 3.6V, VGND1= VGND2= VPGND= 0V, ENM1 = ENM2 = ENF1 = ENF2 = IN, RSETM= RSETF= 6.8kΩ, TA= -40°C to +85°C,
unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERCONDITIONSMINTYPMAXUNITSLED_ Leakage in ShutdownENM1 = ENM2 = ENF1 = ENF2 = GND0.12µA
Charge-Pump Maximum OUT
CurrentVIN ≥ 3.15V, VOUT = 3.9V480mA
1x mode, (VIN - VOUT) / IOUT2.5
1.5x mode, (1.5VIN - VOUT) / IOUT5.0Open-Loop OUT Resistance
2x mode, (2VIN - VOUT) / IOUT5.0
Switching Frequency1MHz
EN_ High VoltageVIN = 2.7V to 5.5V1.6V
EN_ Low VoltageVIN = 2.7V to 5.5V0.4V
EN_ Input CurrentVEN_ = 0V or 5.5V0.011µA
EN_ Low Shutdown Delay tSHDN
(See Figure 3)225470800µs
EN_ tLO (See Figure 3)0.5250.0µs
EN_ tHI (See Figure 3)0.5µs
Initial EN_ tHI (See Figure 3)Only required for first EN_ pulse50µs
OUT Pulldown Resistance in
ShutdownENM1 = ENM2 = ENF1 = ENF2 = GND5kΩ
Thermal-Shutdown Threshold+160°C
Thermal-Shutdown Hysteresis20°C
Typical Operating Characteristics(VIN= 3.6V, EN_ = IN, Circuit of Figure 1, RSETM= 9.09kΩ, RSETF= 4.12kΩ, TA= +25°C, unless otherwise noted.)
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
EFFICIENCY vs. Li+ BATTERY
VOLTAGE DRIVING FOUR MAIN LEDsMAX1576 toc01
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
EFFICIENCY P
LED
/ P
BATT
(%)
15mA/LED
4.5mA/LED
1.5mA/LED
EFFICIENCY vs. Li+ BATTERY
VOLTAGE DRIVING FLASH LED MODULEMAX1576 toc02
Li+ BATTERY VOLTAGE (V, TIME-WEIGHTED)
EFFICIENCY P
LED
/ P
BATT
(%)
160mA
TOTAL
80mA
TOTAL
400mA
TOTAL
BATTERY CURRENT vs. SUPPLY VOLTAGE
DRIVING FOUR MAIN LEDsMAX1576 toc03
SUPPLY VOLTAGE (V)
BATTERY CURRENT (mA)
ILED = 15mA
ILED = 4.5mA
ILED = 1.5mA
VIN FALLING
VIN RISING
BATTERY CURRENT vs. SUPPLY
VOLTAGE DRIVING FLASHMAX1576 toc04
SUPPLY VOLTAGE (V)
BATTERY CURRENT (mA)
IFLASH = 410mA
IFLASH = 168mA
IFLASH = 81mA
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE WITH FOUR MAIN LEDsMAx1576 toc05
SUPPLY VOLTAGE (V)
INPUT RIPPLE (mV
RMS
ILED = 4.5mA
ILED = 1.5mAILED = 15mA
INPUT RIPPLE VOLTAGE vs. SUPPLY
VOLTAGE WITH FLASH AND MAIN LEDsMAX1576 toc06
SUPPLY VOLTAGE (V)
INPUT RIPPLE (mV
RMS
4 MAIN LEDs AT 15mA EACH
IFLASH = 400mA
IFLASH = 80mA
IFLASH = 160mA
LED CURRENT MATCHING vs. SUPPLY
VOLTAGE WITH FOUR MAIN LEDsMAX1576 toc07
SUPPLY VOLTAGE (V)
LED CURRENT (mA)
LED CURRENT vs. AMBIENT
TEMPERATURE WITH FOUR MAIN LEDs
MAX1576 toc08
AMBEINT TEMPERATURE (°C)
TOTAL LED CURRENT (mA)3510-15
LED CURRENT vs. AMBIENT
TEMPERATURE WITH FLASH
MAx1576 toc09
AMBEINT TEMPERATURE (°C)
TOTAL LED CURRENT (mA)3510-15
-4085
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
LED CURRENT vs. RSETMMAX1576 toc10
RSETM (kΩ)
LED CURRENT (mA)
100% BRIGHTNESS SETTING
LED CURRENT vs. RSETFMAX1576 toc11
RSETF (kΩ)
LED CURRENT (mA)
100% BRIGHTNESS SETTING
OPERATING WAVEFORMS (1x MODE)MAX1576 toc12
400ns/div
VOUT50mV/div
AC-COUPLED
VIN20mV/div
AC-COUPLED
4 MAIN LEDs AT 20mA EACH
OPERATING WAVEFORMS (1.5x MODE)MAX1576 toc13
400ns/div
VOUT
VOUT
50mV/div
AC-COUPLED
VIN
VIN
20mV/div
AC-COUPLED
4 MAIN LEDs AT 20mA EACH
OPERATING WAVEFORMS (2x MODE)MAX1576 toc14
400ns/div
VOUTVOUT
50mV/div
AC-COUPLED
VIN
VIN
20mV/div
AC-COUPLED
4 MAIN LEDs AT 20mA EACH
FLASH AT 400mA
FLASH RESPONSEMAX1576 toc15
400μs/div
VEN1F
VEN2F
5V/div
500mA/div
500mA/div
500mV/div
AC-COUPLED
IIN
IOUT
VOUT
4 MAIN LEDs AT 20mA EACH. 400mA FLASH
Typical Operating Characteristics (continued)(VIN= 3.6V, EN_ = IN, Circuit of Figure 1, RSETM= 9.09kΩ, RSETF= 4.12kΩ, TA= +25°C, unless otherwise noted.)
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
Pin Description
PINNAMEFUNCTIONOUTOutput. Bypass to ground with a 4.7µF ceramic capacitor. Connect to the anodes of all the LEDs. OUT is
internally pulled to ground through a 5kΩ resistor during shutdown.ENM1ENM2Enable and Brightness Control for LED1–LED4 (Backlight). See Table 1 and Figure 3.ENF1ENF2Enable and Brightness Control for LED5–LED8 (Flash). See Table 2 and Figure 3.LED8LED7LED6LED5
Flash LED_ Cathode Connection and Charge-Pump Feedback. Current flowing into LED_ is based on the
ENF_ logic levels and RSETF. The charge pump regulates the lowest LED_ voltage to 0.15V. Grounding any
LED_ forces OUT to operate at approximately 5V. Connect LED_ to IN if this LED is not populated.GND2GND1
Ground. Connect GND_ to system ground and the ground side of the input bypass capacitor as close to the
IC as possible.LED4LED3LED2LED1
Main LED_ Cathode Connection and Charge-Pump Feedback. Current flowing into LED_ is based on the
ENM_ logic levels and RSETM. The charge-pump regulates the lowest LED_ voltage to 0.15V. Grounding any
LED_ forces OUT to operate at approximately 5V. Connect LED_ to IN if this LED is not populated.SETM
Bias Current Set Input for LED1–LED4. The current flowing out of SETM sets the maximum (100%) bias
current into each LED. SETM is internally biased to 0.604V. Connect a resistor (RSETM) from SETM to ground
to set the main LED current, RSETM = (233 x 0.604) / ILED(MAX). SETM is high impedance during shutdown.SETF
Bias Current Set Input for LED5–LED8. The current flowing out of SETF sets the maximum (100%) bias
current into each LED. SETF is internally biased to 0.604V. Connect a resistor (RSETF) from SETF to ground
to set the flash LED current, RSETF = (708 x 0.604) / ILED(MAX). SETF is high impedance during shutdown.
Typical Operating Characteristics (continued)(VIN= 3.6V, EN_ = IN, Circuit of Figure 1, RSETM= 9.09kΩ, RSETF= 4.12kΩ, TA= +25°C, unless otherwise noted.)
SINGLE-WIRE DIMMING RESPONSEMAX1576 toc16
2ms/div
VEN1M,
VEN2M
5V/div
2V/div
50mA/divIOUT
VOUT
LINE-TRANSIENT RESPONSEMAX1576 toc17
40μs/div
1V/div
50mA/div
1V/div
AC-COUPLED
VIN
VOUT
IOUT
MAX1576
480mA White LED 1x/1.5x/2x Charge Pump for
Backlighting and Camera Flash
Detailed DescriptionThe MAX1576 charge pump drives up to four white
LEDs in the main display for backlighting and up to four
white LEDs for flash with regulated constant current for
uniform intensity. By utilizing adaptive 1x/1.5x/2x
charge-pump modes and very-low-dropout current reg-
ulators, it achieves high efficiency over the 1-cell lithi-
um-battery input voltage range. 1MHz fixed-frequency
switching allows for tiny external components and low
input ripple.
1x to 1.5x SwitchoverWhen VINis higher than VOUT, the MAX1576 operates
in 1x mode and VOUTis pulled up to VIN. The internal
current regulators regulate the LED current. As VIN
drops, VLED_eventually falls below the switchover
threshold of 100mV and the MAX1576 starts switching
in 1.5x mode. When the input voltage rises above VOUT
by approximately 50mV, the MAX1576 switches back to
1x mode.
1.5x to 2x SwitchoverWhen VINis less than VOUTbut greater than two-thirds
VOUT, the MAX1576 operates in 1.5x mode. The inter-
nal current regulators regulate the LED current. As VIN
drops, VLED_ eventually falls below the switchover
threshold of 100mV, and the MAX1576 starts switching
in 2x mode. When the input voltage rises above two-
thirds VOUTby approximately 50mV, the MAX1576
switches back to 1.5x mode.
Soft-StartThe MAX1576 includes soft-start circuitry to limit inrush
current at turn-on. Once the input voltage is applied,
the output capacitor is charged directly from the input
with a ramped current source (with no charge-pump
action) until the output voltage approaches the input
voltage. Once this occurs, the charge pump deter-
mines if 1x, 1.5x, or 2x mode is required. In the case of
1x mode, the soft-start is terminated and normal opera-
tion begins. In the case of 1.5x or 2x mode, soft-start
operates until the lowest of LED1–LED4 reaches regu-
lation. If the output is shorted to ground or is pulled less
than 1.25V, the output current is limited by soft-start.
True Shutdown™ ModeWhen ENM1, ENM2, ENF1, and ENF2 are simultaneously
held low, the MAX1576 is shut down after a 0.5ms shut-
down delay and the input is isolated from the output. OUT
is internally pulled to GND with 5kΩduring shutdown.
Thermal ShutdownThe MAX1576 includes a thermal-limit circuit that shuts
down the IC at approximately +160°C. Turn-on occurs
after the IC cools by approximately 20°C.
Applications Information
Setting the Main Output CurrentSETM controls LED1–LED4 bias current. Current flow-
ing into LED1, LED2, LED3, and LED4 is a multiple of
the current flowing out of SETM.
ILED1= ILED2= ILED3= ILED4= K x (0.604V / RSETM)True Shutdown is a trademark of Maxim Integrated Products, Inc.
Pin Description (continued)
PINNAMEFUNCTIONINSupply Voltage Input. Bypass to ground with a 1µF ceramic capacitor. The input voltage range is 2.7V to
5.5V. IN is high impedance during shutdown.PGNDPower Ground. Connect PGND to system ground. PGND is used for charge-pump switching currents.C1NTransfer Capacitor 1 Negative Connection. Connect to a 1µF ceramic capacitor between C1P and C1N.
C1N is internally shorted to IN during shutdown.C2NTransfer Capacitor 2 Negative Connection. Connect to a 1µF ceramic capacitor between C2P and C2N.
C2N is internally shorted to IN during shutdown.INPSupply Voltage Input. Bypass to PGND with a 4.7µF ceramic capacitor. The input voltage range is 2.7V to
5.5V. INP is high impedance during shutdown.C2PTransfer Capacitor 2 Positive Connection. Connect a 1µF ceramic capacitor from C2P to C2N. During
shutdown, if OUT > IN, C2P is shorted to OUT, and if OUT < IN, C2P is shorted to IN.C1PTransfer Capacitor 1 Positive Connection. Connect a 1µF ceramic capacitor from C1P to C1N. During
shutdown, if OUT > IN, C1P is shorted to OUT, and if OUT < IN, C1P is shorted to IN.
—EPExposed Paddle. Connect the exposed paddle to ground. Connect PGND, GND1, and GND2 to the
exposed paddle directly under the IC.
