MAX1677EEE ,Compact / High-Efficiency / Dual-Output Step-Up and LCD Bias DC-DC ConverterELECTRICAL CHARACTERISTICS(V = 3.3V, C = 0.1µF, POUT = OUT, T = 0°C to +85°C, unless otherwise note ..
MAX1677EEE ,Compact / High-Efficiency / Dual-Output Step-Up and LCD Bias DC-DC ConverterApplicationsPDAs Portable PhonesHand-Held Terminals Portable InstrumentsV = 0.7V to 5.5V 3.3V MAIN ..
MAX1677EEE ,Compact / High-Efficiency / Dual-Output Step-Up and LCD Bias DC-DC ConverterFeaturesThe MAX1677 is a compact, high-efficiency, dual-out-' No External FETs Requiredput boost co ..
MAX1677EEE+ ,Compact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC ConverterELECTRICAL CHARACTERISTICS(V = 3.3V, C = 0.1µF, POUT = OUT, T = 0°C to +85°C, unless otherwise note ..
MAX1677EEE+T ,Compact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC ConverterApplicationsPDAs Portable PhonesHand-Held Terminals Portable InstrumentsV = 0.7V to 5.5V 3.3V MAIN ..
MAX1678EUA ,1-Cell to 2-Cell / Low-Noise / High-Efficiency / Step-Up DC-DC ConverterApplicationsPART TEMP. RANGE PIN-PACKAGEPagersMAX1678EUA -40°C to +85°C 8 µMAXRemote Controls Note: ..
MAX4436ESA+ ,Single-Supply, 150MHz, 16-Bit Accurate, Ultra-Low Distortion Op Amps
MAX4444ESE+T ,Ultra-High-Speed, Low-Distortion, Differential-to-Single-Ended Line Receivers with Enable
MAX4447ESE ,6500V/s / Wideband / High-Output-Current / Single- Ended-to-Differential Line Drivers with Enable
MAX4447ESE+ ,6500V/µs, Wideband, High-Output-Current, Single-Ended-to-Differential Line Drivers with Enable
MAX4450EXK+T ,Ultra-Small, Low-Cost, 210MHz, Single-Supply Op Amps with Rail-to-Rail Outputs
MAX4450EXK-T ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs
MAX1677EEE
Compact / High-Efficiency / Dual-Output Step-Up and LCD Bias DC-DC Converter
General DescriptionThe MAX1677 is a compact, high-efficiency, dual-out-
put boost converter for portable devices needing two
regulated supplies, typically for logic and liquid crystal
displays (LCDs). Operation with inputs as low as 0.7V
allows the MAX1677 to accept 1, 2, or 3-cell alkaline,
NiCd, or NiMH batteries as well as 1-cell lithium-ion bat-
teries. The device requires no external FETs and can
maintain regulation while consuming only 20µA, making
it ideal for hand-held pen-input and PDA devices oper-
ating with low-current “sleep” states.
The MAX1677’s primary regulator supplies up to
350mA at either a factory-preset 3.3V or an adjustable
2.5V to 5.5V output. On-chip synchronous rectification
provides efficiencies up to 95%. 300kHz (or externally
clocked) pulse-width-modulation (PWM) operation is
particularly suitable for applications needing low noise,
such as those with wireless features. The primary con-
verter also features pin-selectable pulse-frequency-
modulation (PFM) operation that consumes only 20µA.
A 1µA shutdown state also minimizes battery drain.
The MAX1677’s secondary step-up converter supplies up
to +28V or -28V for LCD bias, varactor tuning, or other
high-voltage, low-current functions. Other MAX1677 fea-
tures include precision reference, logic control inputs for
both regulators, and an uncommitted comparator for
low-battery detection or a reset function. The MAX1677
is supplied in Maxim’s compact 16-pin QSOP package,
which occupies no more space than a standard SO-8.
ApplicationsPDAsPortable Phones
Hand-Held TerminalsPortable Instruments
FeaturesNo External FETs RequiredMain Output
Up to 350mA for Logic Supply
Fixed 3.3V or Adjustable (2.5V to 5.5V)
Synchronous Rectification for High Efficiency
(up to 95%)
300kHz (200kHz to 400kHz Synchronizable)
Fixed-Frequency PWM OperationSecondary Output
Up to +28V or -28V for LCD Bias
Programmable Current Limit0.7V to 5.5V Input Voltage Range20µA Quiescent Current1µA Shutdown CurrentLow-Battery ComparatorSmall 16-Pin QSOP Package
MAX1677
Step-Up and LCD Bias DC-DC Converter
Pin Configuration
Ordering Information
Typical Operating Circuit
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VOUT= 3.3V, CREF= 0.1µF, POUT = OUT, 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.
OUT, LCDON, ON, POUT, LBI, LBO,
LX to GND.............................................................-0.3V to +6V
CLK/SEL, LCDPOL, REF, LCDFB,
FB to GND.............................................-0.3V to (VOUT+ 0.3V)
LCDLX to GND.......................................................-0.3V to +30V
PGND, LCDGND to GND......................................-0.3V to +0.3V
POUT to OUT.........................................................-0.3V to +0.3V
Continuous Power Dissipation (TA= +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)...........696mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
ELECTRICAL CHARACTERISTICS (continued)(VOUT= 3.3V, CREF= 0.1µF, POUT = OUT, TA
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
Note 1:The MAX1677 operates in bootstrap mode (operates from the output voltage). Once started, it will operate down to 0.7V
input. If VINexceeds the set VOUT, VOUTwill follow one diode drop below VIN.
Note 2:CREF= 0.22µF for applications where IREF > 10µA.
Note 3:In low-power mode (CLK/SEL = GND), the output voltage regulates 1% higher than in low-noise mode (CLK/SEL = OUT or
synchronized).
Note 4:The device is in a start-up mode when VOUTis below this value.
Note 5:Specifications to -40°C are guaranteed by design and not production tested.
ELECTRICAL CHARACTERISTICS(VOUT= 3.3V, CREF= 0.1µF, POUT = OUT, TA
= -40°C to +85°C, unless otherwise noted. ) (Note 5)
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
Typical Operating Characteristics
(Circuits of Figures 2 and 3, TA = +25°C, unless otherwise noted.)
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
Typical Operating Characteristics (continued)
(Circuits of Figures 2 and 3, TA= +25°C, unless otherwise noted.)
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
Typical Operating Characteristics (continued)
(Circuits of Figures 2 and 3, TA= +25°C, unless otherwise noted.)
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter
Pin Description
Dual Mode is a trademark of Maxim Integrated Products.
_______________Detailed Description
The MAX1677 is a highly efficient dual-output power
supply for battery-powered devices. On-chip are two
complete step-up DC-DC converters to power main
logic and bias an LCD (Figure 1). The main boost con-
verter (MBC) has on-chip P-channel and N-channel
MOSFETs that provide synchronous-rectified voltage
conversion for maximum efficiency at loads up to
300mA. See Table 1 for available output current with
typical battery configurations. The output voltage of the
MBC is factory-preset to 3.3V, or can be set from 2.5V
to 5.5V with external resistors (dual-mode operation).
Either fixed-frequency PWM or low-operating-current
PFM operation can be selected for the MBC using the
CLK/SEL input (Table 2).
The LCD boost converter (LCD) includes an internal N-
channel DMOS switch to generate positive or negative
voltages up to ±28V. The polarity of the LCD output is
set by LCDPOL input (Table 3). Figure 2 shows the
MAX1677 configured for a positive LCD output voltage
with a 3.3V main output. Figure 3 shows the MAX1677
configured for a negative LCD output. LCDPOL also
allows the current limit of LCDLX to be reduced from
350mA to 225mA to allow minimum-size inductors in
low-current LCD applications (typically for LCD loads
<10mA).
Also included in the MAX1677 are a precision 1.25V
reference that sources up to 50µA, logic shutdown con-
trol for the MBC and LCD (the MBC must be on for the
LCD to operate), and a low-battery comparator.
