MAX1748EUE ,Triple-Output TFT LCD DC-DC ConverterELECTRICAL CHARACTERISTICS(V = +3.0V, SHDN = IN, V = V = 10V, TGND = PGND = GND, C = 0.22µF, C = 47 ..
MAX1748EUE+ ,Triple-Output TFT-LCD DC-DC ConvertersELECTRICAL CHARACTERISTICS(V = +3.0V, SHDN = IN, V = V = 10V, TGND = PGND = GND, C = 0.22µF, C = 47 ..
MAX1748EUE+ ,Triple-Output TFT-LCD DC-DC ConvertersMAX1748/MAX872619-3430; Rev 0; 10/04Triple-Output TFT-LCD DC-DC Converters
MAX1748EUE+T ,Triple-Output TFT-LCD DC-DC ConvertersFeaturesThe MAX1748/MAX8726 triple-output DC-DC converters♦ Three Integrated DC-DC Convertersin a l ..
MAX17491GTA+ ,Single-Phase Synchronous MOSFET DriverApplicationsNotebooks/Desktops/ServersTypical Operating CircuitCPU Core Power SuppliesMultiphase St ..
MAX17491GTA+T ,Single-Phase Synchronous MOSFET DriverFeaturesThe MAX17491 is a single-phase synchronous nonin-♦ Single-Phase Synchronous MOSFET Driverve ..
MAX4581EEE+ ,Low-Voltage, CMOS Analog Multiplexers/SwitchesApplications♦ Low Distortion: < 0.02% (600) ΩBattery-Operated Equipment♦ Low Crosstalk: < -96dB (50 ..
MAX4581EPE ,Low-Voltage, CMOS Analog Multiplexers/SwitchesGeneral Description ________
MAX4581ESE ,Low-Voltage, CMOS Analog Multiplexers/SwitchesApplications♦ +2V to +12V Single-Supply OperationBattery-Operated Equipment±2V to ±6V Dual-Supply O ..
MAX4581ESE ,Low-Voltage, CMOS Analog Multiplexers/SwitchesApplications♦ +2V to +12V Single-Supply OperationBattery-Operated Equipment±2V to ±6V Dual-Supply O ..
MAX4581ESE ,Low-Voltage, CMOS Analog Multiplexers/SwitchesFeaturesThe MAX4581/MAX4582/MAX4583 are low-voltage, ♦ Pin Compatible with Industry-Standard CMOS a ..
MAX4581ESE+ ,Low-Voltage, CMOS Analog Multiplexers/SwitchesELECTRICAL CHARACTERISTICS—Dual Supplies(V = 4.5V to 5.5V, V = -4.5V to -5.5V, V = 2.4V, V = 0.8V, ..
MAX1748EUE
Triple-Output TFT LCD DC-DC Converter
General DescriptionThe MAX1748 triple-output DC-DC converter in a low-
profile TSSOP package provides the regulated voltages
required by active matrix, thin-film transistor (TFT) liquid
crystal displays (LCDs). One high-power DC-DC con-
verter and two low-power charge pumps convert the
+3.3V to +5V input supply voltage into three independent
output 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 (0.35Ω) of the
integrated power MOSFET allows efficiency up to 93%.
The 1MHz current-mode 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 MAX1748 is available in the ultra-thin TSSOP pack-
age (1.1mm max height).
________________________ApplicationsTFT Active Matrix LCD Displays
Passive Matrix LCD Displays
PDAs
Digital Still Cameras
Camcorders
FeaturesThree Integrated DC-DC Converters1MHz Current-Mode PWM Boost Regulator
Up to +13V Main High-Power Output
±1% Accuracy
High Efficiency (93%)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 Current0.6mA Quiescent CurrentInternal Soft-StartPower-Ready OutputUltra-Small External ComponentsThin TSSOP Package (1.1mm max)
MAX1748riple-Output TFT LCD DC-DC Converter
Pin Configuration19-1740; Rev 0; 6/00
Ordering Information
Typical Operating Circuit appears at end of data sheet.
MAX1748
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= 470pF, TA
= 0°C to +85°C, unlessStresses 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.....................................................................±0.3VRDYto 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
MAX1748EUE.................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX1748riple-Output TFT LCD DC-DC Converter
ELECTRICAL CHARACTERISTICS (continued)(VIN= +3.0V, SHDN= IN, VSUPP= VSUPN= 10V, TGND = PGND = GND, CREF= 0.22µF, CINTG= 470pF, TA
= 0°C to +85°C, unless
MAX1748
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= 470pF, TA
= -40°C to +85°C,
MAX1748riple-Output TFT LCD DC-DC Converter
MAIN OUTPUT VOLTAGE
vs. LOAD CURRENTMAX1748 toc01
IMAIN (mA)
MAIN
(V)
MAIN STEP-UP CONVERTER
EFFICIENCY vs. LOAD CURRENT
(BOOST ONLY)
MAX1748toc02
IMAIN (mA)
EFFICIENCY (%)
MAIN STEP-UP CONVERTER
EFFICIENCY vs. LOAD CURRENT
(BOOST ONLY)
MAX1748toc03
IMAIN (mA)
EFFICIENCY (%)10050150200250400300350
EFFICIENCY vs. LOAD CURRENT
(BOOST CONVERTER AND CHARGE PUMPS)MAX1748toc04
EFFICIENCY (%)
NEGATIVE CHARGE-PUMP EFFICIENCY
vs. LOAD CURRENT
MAX1748toc06
INEG (mA)
EFFICIENCY (%)
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= 470pF, TA
= -40°C to +85°C,
Note 1:Specifications from 0°C to -40°C are guaranteed by design, not production tested.
MAX1748
Triple-Output TFT LCD DC-DC Converter
Typical Operating Characteristics (continued)(Circuit of Figure 5, VIN= 3.3V, TA= +25°C, unless otherwise noted.)
MAX1748riple-Output TFT LCD DC-DC Converter
Typical Operating Characteristics (continued)(Circuit of Figure 5, VIN= 3.3V, TA= +25°C, unless otherwise noted.)
Pin Description
MAX1748
Triple-Output TFT LCD DC-DC Converter
Detailed DescriptionThe MAX1748 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 MAX1748 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 ConverterThe MAX1748 main step-up converter switches at a
constant 1MHz 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 sum of the
voltage-error, slope-compensation, and current-feed-
back signals trips the multi-input comparator and
resets 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 RegulatorThe MAX1748 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 MAX1748 contains internal P-channel and N-channel
MOSFETs to control the power transfer. The internal
MOSFETs switch at a constant 500kHz (0.5 ✕fOSC).
Negative Charge PumpDuring 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 PumpDuring 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
(VC3+ VSUPP), charge flows from C3 to C4 until the
diode (D3) turns off.
Soft-StartFor the main boost regulator, soft-start allows a gradual
increase of the internal current-limit level during startup
to reduce input surge currents. The MAX1748 divides
Pin Description (continued)
