MAX1779EUE+-MAX1779EUE+T Fast Delivery |IC PHOENIX CO.,LIMITED

MAX1779EUE+T ,Low-Power Triple-Output TFT LCD DC-DC ConverterApplicationsTOP VIEWTFT Active-Matrix LCD DisplaysRDY 1 16 TGNDPassive-Matrix LCD DisplaysFB 2 15 L ..
MAX1779EUE+T ,Low-Power Triple-Output TFT LCD DC-DC ConverterELECTRICAL CHARACTERISTICS(V = +3.0V, SHDN = IN, V = V = +10V, TGND = PGND = GND, C = 0.22µF, C = 2 ..
MAX177CNG ,CMOS 10-Bit A/D Converter with Track-and-HoldApplications Digital Signal Processing (DSP) Audio and Telecom Processing High Accuracy Proc ..
MAX177CNG+ ,CMOS, 10-Bit A/D Converter with Track and HoldFeatures The MAX177 is a complete CMOS sampling 10-bit 12-Bit Resolution and 10-Bit Linearity ana ..
MAX178ACNG ,Calibrated 12-Bit ADC with T/H and ReferenceELECTRICAL CHARACTERISTICS (VDD = +15V, Vcc = +5\/, Vss = -5V, REFIN = +5 OV, all specifications ..
MAX178ACNG ,Calibrated 12-Bit ADC with T/H and ReferenceFeatures . Continuous Transparent Calibration of Offset and Gain . True 12-Bit Performance w ..
MAX4614EUD+ ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesApplicationsPART TEMP. RANGE PIN-PACKAGEBattery-Operated EquipmentMAX4614CUD 0°C to +70°C 14 TSSOPA ..
MAX4614EUD+ ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesFeaturesThe MAX4614/MAX4615/MAX4616 quad, low-voltage,♦ Fast Switching Times high-speed, single-pol ..
MAX4614EUD+T ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesGeneral Description ________
MAX4615CSD ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesGeneral Description ________
MAX4615CUD ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesFeaturesThe MAX4614/MAX4615/MAX4616 quad, low-voltage,♦ Fast Switching Times high-speed, single-pol ..
MAX4615CUD+ ,Low-Voltage, High-Speed, Quad, SPST CMOS Analog SwitchesFeaturesThe MAX4614/MAX4615/MAX4616 quad, low-voltage,♦ Fast Switching Times high-speed, single-pol ..

MAX1779EUE+-MAX1779EUE+T
Low-Power Triple-Output TFT LCD DC-DC Converter
General Description
The MAX1779 triple-output DC-DC converter provides
highly efficient regulated voltages required by small
active matrix, thin-film transistor (TFT) liquid-crystal dis-
plays (LCDs). One high-power DC-DC converter and
two low-power charge pumps convert the +2.7V to
+5.5V input supply voltage into three independent out-
put voltages.
The primary high-power DC-DC converter generates a
boosted output voltage (VMAIN) up to 13V that is regu-
lated within ±1%. The low-power BiCMOS control cir-
cuitry and the low on-resistance (1Ω) of the integrated
power MOSFET allows efficiency up to 91%. The
250kHz current-mode pulse-width modulation(PWM)
architecture provides fast transient response and
allows the use of ultra-small inductors and ceramic
capacitors.
The dual charge pumps independently regulate one
positive output (VPOS) and one negative output (VNEG).
These low-power outputs use external diode and
capacitor stages (as many stages as required) to regu-
late output voltages up to +40V and down to -40V. A
proprietary regulation algorithm minimizes output rip-
ple, as well as capacitor sizes for both charge pumps.
The MAX1779 is available in the ultra-thin TSSOP pack-
age (1.1mm max height).
________________________Applications
TFT Active-Matrix LCD Displays
Passive-Matrix LCD Displays
PDAs
Digital-Still Cameras
Camcorders
FeaturesThree Integrated DC-DC Converters250kHz Current-Mode PWM Boost Regulator
Up to +13V Main High-Power Output
±1% Accuracy
High Efficiency (91%)Dual Charge-Pump Outputs
Up to +40V Positive Charge-Pump Output
Down to -40V Negative Charge-Pump OutputInternal Supply SequencingInternal Power MOSFETs+2.7V to +5.5V Input Supply0.1µA Shutdown Current0.5mA Quiescent CurrentInternal Soft-StartPower-Ready OutputUltra-Small External ComponentsThin TSSOP Package (1.1mm max)
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
RDYTGND
PGND
SUPP
DRVP
SUPN
DRVN
SHDN
TOP VIEW
MAX1748
MAX8726
TSSOP
INTG
REF
GND
FBP
FBN
A "+" SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES.
Pin Configuration
19-1795; Rev 1; 9/05
Ordering Information
Typical Operating Circuit appears at end of data sheet.
16 TSSOP
PIN-PACKAGETEMP RANGE
-40°C to +85°CMAX1779EUE
PART
16 TSSOP-40°C to +85°CMAX1779EUE+
+ Denotes lead-free package.
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA= 0°C to +85°C,
unless otherwise noted. Typical values are at TA= +25°C.)
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.
IN, SHDN, TGND to GND.........................................-0.3V to +6V
DRVN to GND.........................................-0.3V to (VSUPN+ 0.3V)
DRVP to GND..........................................-0.3V to (VSUPP+ 0.3V)
PGND to GND.....................................................................±0.3V
RDYto GND...........................................................-0.3V to +14V
LX, SUPP, SUPN to PGND.....................................-0.3V to +14V
INTG, REF, FB, FBN, FBP to GND...............-0.3V to (VIN+ 0.3V)
Continuous Power Dissipation (TA= +70°C)
16-Pin TSSOP (derate 9.4mW/°C above +70°C)..........755mW
Operating Temperature Range
MAX1779EUE..................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Input Supply RangeVIN2.75.5V
Input Undervoltage ThresholdVUVLOVIN rising, 40mV hysteresis (typ)2.22.42.6V
IN Quiescent Supply CurrentIINVFB = VFBP = +1.5V, VFBN = -0.2V0.51mA
SUPP Quiescent CurrentISUPPVFBP = +1.5V0.250.55mA
SUPN Quiescent CurrentISUPNVFBN = -0.1V0.250.55mA
IN Shutdown CurrentV SHDN = 0, VIN = +5V0.110μA
SUPP Shutdown CurrentV SHDN = 0, VSUPP = +13V0.110μA
SUPN Shutdown CurrentV SHDN = 0, VSUPN = +13V0.110μA
MAIN BOOST CONVERTER
Output Voltage RangeVMAINVIN13V
FB Regulation VoltageVFB1.2351.2481.261V
FB Input Bias CurrentIFBVFB = +1.25V, INTG = GND-5050nA
Operating FrequencyfOSC212250288kHz
Oscillator Maximum Duty Cycle798592%
Load RegulationIMAIN = 0 to 50mA, VMAIN = +5V0.1%
Line Regulation0.1% / V
Integrator Gm320μs
LX Switch On-ResistanceRLX(ON)ILX = 100mA1.02.0Ω
LX Leakage CurrentILXVLX = +13V0.0120μA
LX Current LimitILIM350450650mA
Maximum RMS LX Current250mA
FB Fault Trip LevelFalling edge1.071.11.14V
POSITIVE CHARGE PUMP
VSUPP Input Supply RangeVSUPP2.713V
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
ELECTRICAL CHARACTERISTICS (continued)
(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA= 0°C to +85°C,
unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETER SYMBOLCONDITIONSMINTYPMAXUNITS
Operating Frequency0.5 ×
fOSCHz
FBP Regulation VoltageVFBP1.201.251.30V
FBP Input Bias CurrentIFBPVFBP = +1.5V-5050nA
DRVP PCH On-Resistance310Ω
VFBP = +1.200V1.55ΩDRVP NCH On-ResistanceVFBP = +1.300V20kΩ
FBP Power-Ready Trip LevelRising edge1.091.131.16V
FBP Fault Trip LevelFalling edge1.11V
Maximum RMS DRVP Current0.1A
NEGATIVE CHARGE PUMP
VSUPN Input Supply RangeVSUPN2.713V
Operating Frequency0.5 ×
fOSCHz
FBN Regulation VoltageVFBN-50050mV
FBN Input Bias CurrentIFBNVFBN = -0.05V-5050nA
DRVN PCH On-Resistance310Ω
VFBN = +0.050V1.55ΩDRVN NCH On-ResistanceVFBN = -0.050V20kΩ
FBN Power-Ready Trip LevelFalling edge80120165mV
FBN Fault Trip LevelRising edge140mV
Maximum RMS DRVN Current0.1A
REFERENCE
Reference VoltageVREF-2µA < IREF < 50µA1.2311.251.269V
Reference Undervoltage
ThresholdVREF rising0.91.051.2V
LOGIC SIGNALS
SHDN Input Low Voltage0.25V hysteresis (typ)0.9V
SHDN Input High Voltage2.1V
SHDN Input CurrentI SHDN0.011μA
RDY Output Low VoltageISINK = 2mA0.250.5V
RDY Output High VoltageV RDY = +13V0.011μA
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
PARAMETERSYMBOLCONDITIONSMINMAXUNITS
Input Supply RangeVIN2.75.5V
Input Undervoltage ThresholdVUVLOVIN rising, 40mV hysteresis (typ)2.22.6V
IN Quiescent Supply CurrentIINVFB = VFBP = +1.5V, VFBN = -0.2V1mA
SUPP Quiescent CurrentISUPPVFBP = +1.5V0.55mA
SUPN Quiescent CurrentISUPNVFBN = -0.1V0.55mA
IN Shutdown CurrentV SHDN = 0, VIN = +5V10μA
SUPP Shutdown CurrentV SHDN = 0, VSUPP = +13V10μA
SUPN Shutdown CurrentV SHDN = 0, VSUPN = +13V10μA
MAIN BOOST CONVERTER
Output Voltage RangeVMAINVIN13V
FB Regulation VoltageVFB1.2251.271V
FB Input Bias CurrentIFBVFB = +1.25V, INTG = GND-5050nA
Operating FrequencyfOSC195305kHz
Oscillator Maximum Duty Cycle7992%
LX Switch On-ResistanceRLX(ON)ILX = 100mA2.0Ω
LX Leakage CurrentILXVLX = +13V20µA
LX Current LimitILIM350700mA
FB Fault Trip LevelFalling edge1.071.14V
POSITIVE CHARGE PUMP
SUPP Input Supply RangeVSUPP2.713V
FBP Regulation VoltageVFBP1.201.30V
FBP Input Bias CurrentIFBPVFBP = +1.5V-5050nA
DRVP PCH On-Resistance10Ω
VFBP = +1.200V5ΩDRVP NCH On-ResistanceVFBP = +1.300V20kΩ
FBP Power-Ready Trip LevelRising edge1.091.16V
NEGATIVE CHARGE PUMP
SUPN Input Supply RangeVSUPN2.713V
FBN Regulation VoltageVFBN-5050mV
FBN Input Bias CurrentIFBNVFBN = -0.05V-5050nA
DRVN PCH On-Resistance10Ω
VFBN = +0.050V5ΩDRVN NCH On-ResistanceVFBN = -0.050V20kΩ
FBN Power-Ready Trip LevelFalling edge80165mV
REFERENCE
Reference VoltageVREF-2µA < IREF < 50µA1.2231.269V
Reference UndervoltageVREF rising0.91.2V
ELECTRICAL CHARACTERISTICS
(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA= -40°C to +85°C,
unless otherwise noted.) (Note 1)
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
MAIN OUTPUT VOLTAGE vs. LOAD CURRENT
(L = 10μH, 5V OUTPUT)
MAX1779-01
IMAIN (mA)
MAIN
(V)
VIN = +3.0V
VIN = +4.2V
FIGURE 6
MAIN STEP-UP CONVERTER EFFICIENCY
vs. LOAD CURRENT
(L = 10μH, 5V OUTPUT)
MAX1779-02
IMAIN (mA)
EFFICIENCY (%)
VIN = +3.0V
VIN = +4.2V
FIGURE 6
MAIN OUTPUT VOLTAGE vs. LOAD CURRENT
(L = 33μH, 5V OUTPUT)
MAX1779-03
IMAIN (mA)
MAIN
(V)VIN = +4.2V
VIN = +3.0V
FIGURE 5
MAIN STEP-UP CONVERTER EFFICIENCY
vs. LOAD CURRENT
(L = 33μH, 5V OUTPUT)
MAX1779-04
IMAIN (mA)
EFFICIENCY (%)
VIN = +4.2V
VIN = +3.0V
FIGURE 59.96
MAIN OUTPUT VOLTAGE vs. LOAD CURRENT
(L = 33μH, 10V OUTPUT)
MAX1779-05
IMAIN (mA)
MAIN
(V)
VIN = +3.3V
VIN = +5.0V
FIGURE 550
MAIN STEP-UP CONVERTER EFFICIENCY
vs. LOAD CURRENT
(L = 33μH, 10V OUTPUT)
MAX1779-06
IMAIN (mA)
EFFICIENCY (%)
VIN = +5.5V
VIN = +3.3V
FIGURE 5
Typical Operating Characteristics
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (continued)
(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= +10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 2200pF, TA= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINMAXUNITS
LOGIC SIGNALS
SHDN Input Low Voltage0.25V hysteresis (typ)0.9V
SHDN Input High Voltage2.1V
SHDN Input CurrentI SHDN1μA
RDY Output Low VoltageISINK = 2mA0.5V
RDY Output High LeakageV RDY = +13V1μA
Note 1:Specifications to -40°C are guaranteed by design, not production tested.
4.0μs/div
RIPPLE WAVEFORMS
MAX1779-14
A. VMAIN = 5V, IMAIN = 100mA, 10mV/div
B. VNEG = -8V, INEG = 1mA, 5mV/div
C. VPOS = 12V, IPOS = 1mA, 5mV/div, FIGURE 5
12V
-8V
100μs/div
LOAD TRANSIENT
(L = 10μH, 500μs PULSE)
MAX1779-15
A. VMAIN = 5V, 50mV/div
B. VMAIN = 5mA to 50mA, 25mA/div
FIGURE 6
5.0V
4.9V
5.1V
50mA
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Typical Operating Characteristics (continued)
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
POSITIVE CHARGE-PUMP OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX1779-10
IPOS (mA)
POS
(V)VSUPP = +7V
VSUPP = +6VVSUPP = +5V
POSITIVE CHARGE-PUMP EFFICIENCY
vs. LOAD CURRENT
MAX1779-11
IPOS (mA)
POS
(V)
VSUPP = +5V
VSUPP = +6V
VSUPP = +7V
VPOS = +12V
SWITCHING FREQUENCY
vs. INPUT VOLTAGE
MAX1779-12
INPUT VOLTAGE (V)
SWITCHING FREQUENCY (kHz)
REFERENCE VOLTAGE
vs. REFERENCE LOAD CURRENT
MAX1779-13
IREF (μA)
REF
(V)
EFFICIENCY vs. LOAD CURRENT
(BOOST CONVERTER AND CHARGE PUMPS)
MAX1779-07
IMAIN (mA)
EFFICIENCY (%)
VMAIN = +5V
TWO-STAGE
CHARGE PUMPS
VMAIN = +10V
SINGLE-STAGE
CHARGE PUMPS
VNEG = -8V, INEG = 1mA
VPOS = +12V, IPOS = 1mA-8.08
NEGATIVE CHARGE-PUMP OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX1779-08
INEG (mA)
NEG
(V)
VSUPN = +5V
VSUPN = +6V
VSUPN = +7V
NEGATIVE CHARGE-PUMP EFFICIENCY
vs. LOAD CURRENT
MAX1779-09
INEG (mA)
EFFICIENCY (%)5101520
VSUPN = +5V
VNEG = -8V
VSUPN = +6V
VSUPN = +7V
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
100μs/div
LOAD TRANSIENT WITHOUT INTEGRATOR
(L = 10μH, 500μs PULSE)
MAX1779-16
A. VMAIN = 5V, 50mV/div
B. VMAIN = 5mA to 50mA, 25mA/div
INTG = REF, FIGURE 6
5.0V
4.9V
50mA
10μs/div
LOAD TRANSIENT WITHOUT INTEGRATOR
(L = 10μH, 5μs PULSE)
MAX1779-17
A. VMAIN = 5V, 100mV/div
B. IL, 200mA/div
C. IMAIN = 10mA to 100mA, 100mA/div
INTG = REF, FIGURE 6
5.0V
400mA
100mA
200mA
Typical Operating Characteristics (continued)
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
100μs/div
LOAD TRANSIENT
(L = 33μH, 500μs PULSE)
MAX1779-18
A. VMAIN = 5V, 50mV/div
B. IMAIN = 10mA to 100mA, 50mA/div
FIGURE 5
5.1V
4.9V
100mA
100μs/div
LOAD TRANSIENT WITHOUT INTEGRATOR
(L = 33μH, 500μs PULSE)
MAX1779-19
A. VMAIN = 5V, 50mV/div
B. IMAIN = 10mA to 100mA, 50mA/div
INTG = REF, FIGURE 5
5.1V
4.9V
100mA
5.0V
10μs/div
LOAD TRANSIENT
(L = 33μH, 5μs PULSE)
MAX1779-20
A. VMAIN = 5V, 50mV/div
B. IMAIN = 20mA to 200mA, 100mA/div
FIGURE 5
5.1V
4.9V
200mA
5.0V
200μs/div
STARTUP WAVEFORM
(L = 10μH)
MAX1779-21
A. VSHDN = 0 to 2V, 2V/div
B. VMAIN = 5V, 1V/div
C. IL, 500 mA/div
FIGURE 6, RMAIN = 100Ω
500mA
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Pin Description
PINNAMEFUNCTIONRDYActive-Low Open-Drain Output. Indicates all outputs are ready. The on-resistance is 125Ω (typ).
2FBMain Boost Regulator Feedback Input. Regulates to 1.25V nominal. Connect feedback resistive
divider to analog ground (GND).INTGMain Boost Integrator Output. If used, connect 2200pF to analog ground (GND). To disable
integrator, connect to REF.
4INSupply Input. +2.7V to +5.5V input range. Bypass with a 0.1μF capacitor between IN and GND, as
close to the pins as possible.GNDAnalog Ground. Connect to power ground (PGND) underneath the IC.REFInternal Reference Bypass Terminal. Connect a 0.22μF capacitor from this terminal to analog ground
(GND). External load capability to 50μA.FBPPositive Charge-Pump Regulator Feedback Input. Regulates to 1.25V nominal. Connect feedback
resistive divider to analog ground (GND).FBNNegative Charge-Pump Regulator Feedback Input. Regulates to 0V nominal.SHDNActive-Low Logic-Level Shutdown Input. Connect SHDN to IN for normal operation.
Typical Operating Characteristics (continued)
(Circuit of Figure 5, VIN= +3.3V, TA= +25°C, unless otherwise noted.)
4ms/div
POWER-UP SEQUENCING
MAX1779-23
A. VSHDN = 0 to 2V, 2V/div
B. VMAIN = 5V, RMAIN = 50Ω, 2.5V/div
C. VNEG = -8V, RNEG = 8kΩ, 10V/div
D. VPOS = +12V, RPOS = 12kΩ, 10V/div
10V
-10V
200μs/div
STARTUP WAVEFORM
(L = 33μH)
MAX1779-22
A. VSHDN = 0 to 2V, 2V/div
B. VMAIN = 5V, 1V/div
C. IL, 500mA/div
RMAIN = 50Ω
500mA
MAX1779
Low-Power Triple-Output TFT LCD DC-DC
Converter
Detailed Description
The MAX1779 is a highly efficient triple-output power
supply for TFT LCD applications. The device contains
one high-power step-up converter and two low-power
charge pumps. The primary boost converter uses an
internal N-channel MOSFET to provide maximum effi-
ciency and to minimize the number of external compo-
nents. The output voltage of the main boost converter
(VMAIN) can be set from VINto 13V with external resistors.
The dual charge pumps independently regulate a posi-
tive output (VPOS) and a negative output (VNEG). These
low-power outputs use external diode and capacitor
stages (as many stages as required) to regulate output
voltages up to +40V and down to -40V. A proprietary
regulation algorithm minimizes output ripple as well as
capacitor sizes for both charge pumps.
Also included in the MAX1779 are a precision 1.25V
reference that sources up to 50µA, logic shutdown,
soft-start, power-up sequencing, fault detection, and an
active-low open-drain ready output.
Main Boost Converter
The MAX1779 main step-up converter switches at a
constant 250kHz internal oscillator frequency to allow
the use of small inductors and output capacitors. The
MOSFET switch pulse width is modulated to control the
power transferred on each switching cycle and to regu-
late the output voltage.
During PWM operation, the internal clock’s rising edge
sets a flip-flop, which turns on the N-channel MOSFET
(Figure 1). The switch turns off when the voltage-error,
slope-compensation, and current-feedback signals trip
the comparators and reset the flip-flop. The switch
remains off for the rest of the clock cycle. Changes in
the output voltage error signal shift the switch current
trip level, consequently modulating the MOSFET duty
cycle.
Dual Charge-Pump Regulator
The MAX1779 contains two individual low-power charge
pumps. One charge pump inverts the supply voltage
(SUPN) and provides a regulated negative output voltage.
The second charge pump doubles the supply voltage
(SUPP) and provides a regulated positive output voltage.
The MAX1779 contains internal P-channel and N-channel
MOSFETs to control the power transfer. The internal
MOSFETs switch at a constant 125kHz (0.5 ✕fOSC).
Negative Charge Pump
During the first half-cycle, the P-channel MOSFET turns
on and the flying capacitor C5 charges to VSUPNminus
a diode drop (Figure 2). During the second half-cycle,
the P-channel MOSFET turns off, and the N-channel
MOSFET turns on, level shifting C5. This connects C5 in
parallel with the reservoir capacitor C6. If the voltage
across C6 minus a diode drop is lower than the voltage
across C5, charge flows from C5 to C6 until the diode
(D5) turns off. The amount of charge transferred to the
output is controlled by the variable N-channel on-resis-
tance.
Positive Charge Pump
During the first half-cycle, the N-channel MOSFET turns
on and charges the flying capacitor C3 (Figure 3). This
initial charge is controlled by the variable N-channel
on-resistance. During the second half-cycle, the N-
channel MOSFET turns off and the P-channel MOSFET
turns on, level shifting C3 by VSUPPvolts. This connects
C3 in parallel with the reservoir capacitor C4. If the volt-
age across C4 plus a diode drop (VPOS+ VDIODE) is
smaller than the level-shifted flying capacitor voltage
Pin Description (continued)
PINNAMEFUNCTIONDRVNNegative Charge-Pump Driver Output. Output high level is VSUPN, and low level is PGND.SUPNNegative Charge-Pump Driver Supply Voltage. Bypass to PGND with a 0.1μF capacitor.DRVPPositive Charge-Pump Driver Output. Output high level is VSUPP, and low level is PGND.SUPPPositive Charge-Pump Driver Supply Voltage. Bypass to PGND with a 0.1μF capacitor.PGNDPower Ground. Connect to GND underneath the IC.LXMain Boost Regulator Power MOSFET N-Channel Drain. Connect output diode and output capacitor
as close to PGND as possible.TGNDMust be connected to ground.

Partno	Mfg	Dc	Qty	Available	Descript
MAX1779EUE+ \|MAX1779EUE	MAX	N/a	193	avai	Low-Power Triple-Output TFT LCD DC-DC Converter
MAX1779EUE+	MAXIM	N/a	580	avai	Low-Power Triple-Output TFT LCD DC-DC Converter
MAX1779EUE+T \|MAX1779EUET	MAXIM	N/a	68612	avai	Low-Power Triple-Output TFT LCD DC-DC Converter
MAX1779EUE+T	MAX	N/a	19	avai	Low-Power Triple-Output TFT LCD DC-DC Converter