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MAX1677EEE+ |MAX1677EEEMAXN/a195avaiCompact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC Converter
MAX1677EEE+T |MAX1677EEETMAXIMN/a2500avaiCompact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC Converter


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: ..
MAX1678EUA ,1-Cell to 2-Cell / Low-Noise / High-Efficiency / Step-Up DC-DC ConverterELECTRICAL CHARACTERISTICS(V = V = 1.3V, I = 0, FB = GND, T = 0°C to +85°C, unless otherwise noted. ..
MAX1678EUA+T ,1 Cell to 2 Cell, Low-Noise, High-Efficiency, Step-Up DC-DC ConverterELECTRICAL CHARACTERISTICS(V = V = 1.3V, I = 0, FB = GND, T = 0°C to +85°C, unless otherwise noted. ..
MAX1678EUA+T ,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: ..
MAX1679EUA ,Single-Cell Li Battery Charger for Current-Limited SupplyELECTRICAL CHARACTERISTICS(V = V = +10V, V = +4.2V, TSEL = GND, GATE = unconnected, ADJ = unconnect ..
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
MAX4450EXK-T ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs


MAX1677EEE+-MAX1677EEE+T
Compact, High-Efficiency, Dual-Output Step-Up and LCD Bias DC-DC Converter
General Description
The 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.
Applications

PDAsPortable Phones
Hand-Held TerminalsPortable Instruments
Features
No 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 Operation
Secondary Output
Up to +28V or -28V for LCD Bias
Programmable Current Limit
0.7V to 5.5V Input Voltage Range20µA Quiescent Current1µA Shutdown CurrentLow-Battery ComparatorSmall 16-Pin QSOP Package
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter

OUTPOUT
PGND
LCDGND
LCDLX
LCDFB
GND
TOP VIEW
MAX1677
LBI
LCDON
LBO
CLK/SEL
LCDPOL
REF
QSOP

19-1403; Rev 1; 3/01
PART

MAX1677EEE-40°C to +85°C
TEMP RANGEPIN-PACKAGE

16 QSOP
EVALUATION KIT
AVAILABLE
Pin Configuration
Ordering Information
Typical Operating Circuit

MAX1677POUT
OUT
±28V
LCD
BOOST
OUTPUT
3.3V MAIN
BOOST OUTPUT
LCDFB
REF
LCDGND
GND
LCDLX
LCDON
LBI
OFF
LBO
CLK/SEL
LCDPOL
PGND
PWM
PFM
OFF
+VE OUT
-VE OUT
VIN = 0.7V to 5.5V
(UP TO MAINOUT)
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, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
GENERAL

Input Voltage RangeVIN(Note 1)0.75.5V
Minimum Startup VoltageVSTARTUPTA = +25°C, ILOAD < 1mA0.91.1V
Reference VoltageVREFIREF = 01.231.251.27V
Reference Load RegulationIREF = 0 to 50µA (Note 2)215mV
Reference Line RejectionVOUT = 2.5V to 5.5V0.25mV
Supply Current
Main DC On, LCD OffILCDOFFNo load, current into OUT2040µA
Supply Current All On,
Main DC-DC in PFM ModeIPFMNo load, current into OUT3560µA
Supply Current All On,
Main DC-DC in PWM ModeIPWMNo load, current into OUT115300µA
Supply Current in Shutdown0.35µA
MAIN BOOST DC-DC

Output VoltageVOUTFB = GND, 0 ≤ ILX ≤ 350mA,
CLK/SEL = OUT (Note 3)3.203.303.43V
FB Regulation VoltageVFB (REG)Adjustable mode, CLK/SEL = OUT (Note 3)1.2251.251.275V
FB Input CurrentIFBVFB = 1.3V0.0250nA
Output Voltage Adjustment
Range2.55.5V
Startup to Normal Mode
Transition Voltage (Note 4)VLOCKOUT2.12.4V
Line RegulationIOUT = 150mA, VIN = 2V to 3V0.6%
Load RegulationCLK/SEL = OUT, VIN = 2.4V,
ILOAD = 10mA to 200mA1%
Frequency in Startup ModefSTARTUPVOUT = 15V40300kHz
LX Leakage CurrentILX (LEAK)0.25µA
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.)
CONDITIONS

N-channel0.220.5ΩP-channel0.4 1.0
LX Current LimitILX(PWM)N-channel PWM mode550670800mA
UNITSMINTYPMAXPARAMETER

ILX(PFM)N-channel PFM mode250350450
P-Channel Synchronous Rectifier
Turn-Off Current in PFM Mode4090 140mA
Internal OscillatorfCLK/SEL = OUT240300 360kHz
Oscillator Maximum Duty CycleD808590%
External Clock Frequency
Range200400kHz
ON Input ThresholdVON(LOW)
VON(HIGH)
LCDON, LCDPOL, CLK/SEL
Input Threshold
VILVOUT > 2.5V0.2VOUTVVIH0.8VOUT
LBI Falling ThresholdVLBI(TH)599614629mV
LBI Hysteresis1%
LBOOutput Low VoltageVLBO(LO)Sink current = 1mA0.1V
LBI Input Bias CurrentILBI(BIAS)50nA
LBOLeakage CurrentILBO(LEAK)VLBO= 5.5V1µA
LCDLX Voltage28V
LCDPOL connected to OUT or GND through
50kΩ150225300mA
LCDLX Switch ResistanceRLCDLXVOUT= 3.3V1.01.4Ω
LCDLX Leakage CurrentVLCDLX= 28V1µA
LCDFB Set Point Positive LCD, LCDPOL = OUT1.2251.251.275 V
Negative LCD, LCDPOL = GND-15 015mV
LCDFB Input Bias Current50nA
LCD Line RegulationILOAD= 5mA, VIN= 1.2V to 3.6V,
Figure 20.1%/V
LCD Load RegulationILOAD= 0 to 5mA, VIN= 2.4V,
Figure 20.5%
Maximum LCDLX On-TimetON LCD3.44.35.2µs
1.1V < VOUT < 5.5V0.8VOUT
0.2VOUTV
LX On-Resistance
SYMBOL

RLX(ON)N
RLX(ON)P
LCDPOL = OUT or GND300350450
LCDLX Switch Current Limit
Input Leakage CurrentON, LCDON, LCDPOL, CLK/SEL1µA
Minimum LCDLX Off-TimeOperating mode0.811.2µsStart-up mode (positive or negative)3.04.05.0
LCDFB Voltage for
Startup Mode
LCDPOL = OUT0.75VLCDPOL = GND0.5
LOGIC AND CONTROL INPUTS
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 startup 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)
LBOOutput Low VoltageVLBO(LO)Sink current = 1mA
LCDPOL = OUT or GND300450
0.1VSupply Current
Main DC On, LCD Off
Supply Current All On,
Main DC-DC in PFM ModeIPFMNo load, current into OUT60µAFB Regulation VoltageLX Leakage Current
Startup to Normal Mode Transition
Voltage (Note 4)
CONDITIONS

VLOCKOUT2.12.4V
ILX(LEAK)5
Output VoltageVOUTFB = GND, 0 ≤ILX≤350mA,
CLK/SEL = OUT (Note 3)3.173.46V
VFB(REG)Adjustable mode, CLK/SEL = OUT (Note 3)1.221.28Supply Current All On,
Main DC-DC in PWM Mode
Supply Current in Shutdown5µA
IPWMNo load, current into OUT300
ILCDOFFNo load, current into OUT40
LX Current LimitILX(PWM)N-channel PWM mode550900mA
UNITSMINMAXSYMBOLPARAMETER

ILX(PFM)N-channel PFM mode250500
Internal OscillatorfCLK/SEL = OUT240360kHz
External Clock Frequency Range200400kHz
ON Input ThresholdVON(LOW)1.1V < VOUT < 5.5V0.2VOUTVVON(HIGH)0.8VOUT
LCDON, LCDPOL, CLK/SEL
Input Threshold
VIL0.2VOUTVVIH0.8VOUT
LBI Falling ThresholdVLBI(TH)599629mV
LCD BIAS DC-DC

LCDLX Switch Current LimitLCDPOL connected to OUT or GND
through 50kΩ150300mA
LCDFB Set PointPositive LCD, LCDPOL = OUT1.221.28V
-20+20Negative LCD, LCDPOL = GNDmV
GENERAL
MAIN
LCD BIAS DC-DC
LOGIC
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter

EFFICIENCY vs. LOAD CURRENT
(VOUT = 3.3V)
MAX1677-01
LOAD CURRENT (mA)
EFFICIENCY (%)
PWM MODE
C = 2.4V
D = 1.2V
PFM MODE
A = VIN = 2.4V
B = VIN = 1.2VB
EFFICIENCY vs. LOAD CURRENT
(VOUT = 5V)
MAX1677-02
LOAD CURRENT (mA)
EFFICIENCY (%)
PWM MODEA: VIN = 3.6V
B: VIN = 2.4V
C: VIN = 1.2V
PFM MODE
D: VIN = 3.6VE: VIN = 2.4V
F: VIN = 1.2V
MAXIMUM LOAD CURRENT
vs. BATTERY INPUT VOLTAGE
(PWM MODE)
MAX1677-03
INPUT VOLTAGE (V)
LOAD CURENT (mA)
VOUT = 3.3V
VOUT = 5V
EFFICIENCY vs. LOAD CURRENT
(LCD VOUT = 12V)
MAX1677-04
LOAD CURRENT (mA)
EFFICIENCY (%)
CIRCUIT OF FIGURE 2A: VIN = 3.6V
B: VIN = 2.4V
C: VIN = 1.2V
EFFICIENCY vs. LOAD CURRENT
(LCD VOUT = 20V)
MAX1677-05
LOAD CURRENT (mA)
EFFICIENCY (%)
CIRCUIT OF FIGURE 2
A: VIN = 3.6V
B: VIN = 2.4VC: VIN = 1.2V
REFERENCE VOLTAGE
vs. REFERENCE CURRENT
MAX1677-06
REFERENCE CURRENT (μA)
REFERENCE VOLTAGE (V)
Typical Operating Characteristics

(Circuits of Figures 2 and 3, TA = +25°C, unless otherwise noted.)
LOAD CURRENT
vs. STARTUP VOLTAGE
MAX1677-07
START-UP VOLTAGE (V)
LOAD CURRENT (mA)
PWM
PFM
VOUT = 3.3V
TESTED WITH
RESISTIVE LOAD
NO-LOAD SUPPLY CURRENT vs.
INPUT VOLTAGE (LCD OFF)
MAX1677-08
INPUT VOTAGE (V)
SUPPLY CURRENT (mA)
VOUT = 3.3V
PFM MODE
LCD OFF
NO-LOAD SUPPLY CURRENT vs.
INPUT VOLTAGE (LCD ON)
MAX1677-09
INPUT VOLTAGE (V)
SUPPLY CURRENT (mA)
VOUT = 3.3V
PFM MODE
VLCD = -20V
MAX1677
Compact, High-Efficiency, Dual-Output
Step-Up and LCD Bias DC-DC Converter

10mV/
div
VLX
ILX
VRIPPLE
200mA/
div
100mV/
div
5μs/div
LCD SWITCHING WAVEFORMS

MAX1677-13
LDCLX CURRENT LIMIT = 350mA,
2.4VIN, +12VOUT, 10mA LOAD
10mV/
div
VLX
ILX
VRIPPLE
200mA/
div
100mV/
div
2μs/div
LCD SWITCHING WAVEFORMS
(50kΩ FROM LCDPOL TO OUT)

MAX1677-14
LCDLX CURRENT LIMIT = 225mA,
50mV/
div
IOUT
VRIPPLE
200mA/
div
2ms/div
MAIN BOOST CONVERTER
LOAD TRANSIENT

MAX1677-15
VIN = 2.4V, VOUT = 3.3V
2V/
div
VLX
ILX
VRIPPLE
100mA/
div
50mV/
div
1μs/div
MAIN BOOST CONVERTER SWITCHING
WAVEFORMS (PWM MODE)

MAX1677-10
2.4VIN, 3.3VOUT,
200mA IOUT
2V/
div
VLX
ILX
VRIPPLE
100mA/
div
20mV/
div
2μs/div
MAIN BOOST CONVERTER SWITCHING
WAVEFORMS (PFM MODE)

MAX1677-11
1.2VIN, 3.3VOUT,
20mA IOUT
2V/
div
VLX
ILX
VRIPPLE
100mA/
div
50mV/
div
10μs/div
MAIN BOOST CONVERTER SWITCHING
WAVEFORMS (PFM MODE, 50mA OUTPUT)

MAX1677-12
PFM, 1.2VIN,
3.3VOUT, 50mA IOUT
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

1V/
div
VOUT
VIN
50mV/
div
5ms/div
MAIN BOOST CONVERTER
LINE TRANSIENT

MAX1677-16
VIN = 2V TO 3V, VOUT = 3.3V,
ILOAD = 150mA
1V/
div
VLCD
VIN
50mV/
div
5ms/div
LCD LINE TRANSIENT
(VLCD = +12V)

MAX1677-17
VIN = 2V TO 3V, VLCD = +12V,
IOUT = 5mA
1V/
div
VOUT
1V/
div
500μs/div
MAIN BOOST CONVERTER
STARTUP DELAY

MAX1677-19
VIN = 2.4V, VOUT = 3.3V,
ILOAD = 10mA
Typical Operating Characteristics (continued)

(Circuits of Figures 2 and 3, TA= +25°C, unless otherwise noted.)
2V/
div
VLCD
LCDON
10V/
div
10ms/div
LCD STARTUP DELAY

MAX1677-20
VIN = 2.4V, VLCD = -20V,
1V/
div
VLCD
VIN
50mV/
div
5ms/div
LCD LINE TRANSIENT
(VLCD = -20V)

MAX1677-18
VIN = 2V TO 3V, VLCD = -20V,
IOUT = 5mA
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.
NAMEFUNCTION
OUTOutput Sense Input. The device is powered from OUT. Bypass to GND with a 0.1µF ceramic capacitor.
Connect OUT to POUT through a 10Ωseries resistor.FBDual Mode™ Main Boost Feedback Input. Connect to GND for 3.3V output. Connect a voltage-divider from
OUT to FB to adjust the output in the 2.5V to 5.5V range (Figure 5).
PIN
LBILow-Battery-Comparator Input. Threshold is 614mV. Set the low-battery trip-point with an external voltage
divider (Figure 7).LBOOpen-Drain, Low-Battery Output. LBOis low when LBI is below 614mV, otherwise it remains high.
Sync Clock and PWM Select Input.
CLK/SEL = low: low-power, low-quiescent-current PFM mode.
CLK/SEL = high: low-noise, high-power PWM mode at 300kHz.
CLK/SEL = driven with external clock of 200kHz to 400kHz, synchronized PWM high-power mode.CLK/SELLCDFBLCD Feedback Input. Threshold is 1.25V for positive with LCDPOL high, and 0 for negative with
LCDPOL low.GNDGroundREF1.25V Reference Output. Bypass with 0.1µF. LCDPOLLCD Polarity Select Input. Sets LCD boost converter polarity and peak current output (Table 2).LCDONLCD Enable Input. Drive high to turn on LCD boost converter. Main DC-DC must also be on. ONI.C. Enable Input. Drive high to enable the MAX1677.LCDLXLCD Boost 28V Switch DrainLCDGNDSource of the Internal N-Channel DMOS LCD Boost-Converter SwitchPGNDSource of the Internal N-Channel Main Boost-Converter SwitchLXMain Output Boost Internal Switch DrainPOUTBoost DC-DC Converter Power Output. Source of internal P-channel MOSFET main boost-converter
synchronous rectifier.
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