MAX1765EEE ,800mA, Low-Noise, Step-Up DC-DC Converter with 500mA Linear RegulatorApplicationslimit functions to permit optimization of efficiency, exter-Wireless Handsets Personaln ..
MAX1765EEE+ ,800mA, Low-Noise, Step-Up DC-DC Converter with 500mA Linear RegulatorApplicationslimit functions to permit optimization of efficiency, exter-Wireless Handsets Personaln ..
MAX1765EUE+T ,800mA, Low-Noise, Step-Up DC-DC Converter with 500mA Linear RegulatorELECTRICAL CHARACTERISTICS(V = V = V = V = V = 3.6V, CLK/SEL = FBL = ONB = TRACK = PGND = GND, ISET ..
MAX176ACPA ,Serial-Output, 250Ksps 12-Bit ADC with T/H and RefernceELECTRICAL CHARACTERISTICS
(VDD = +5V i5%_ Vss = -11 4V to -IS75V, fCLK = 4MHE for MAX176_C/E an ..
MAX176ACPA+ ,Serial Output, 250ksps, 12-Bit ADC with Track/Hold and ReferenceGeneral Description
The MAX176 is a complete analog-to-digital converter
(ADC) that achieves a ..
MAX176ACWE ,Serial-Output, 250Ksps 12-Bit ADC with T/H and Refernce79-OO?5:hhw " 12/92
MAX4590EAE+ ,1.25Ω, Dual SPST, CMOS Analog SwitchesELECTRICAL CHARACTERISTICS–Dual Supplies(V+ = +15V, V- = -15V, V = +5V, V = +2.4V, V = +0.8V, T = T ..
MAX4590EWE ,1.25 / Dual SPST / CMOS Analog SwitchesMAX4580/MAX4590/MAX460019-1394; Rev 0; 10/981.25Ω, Dual SPST,CMOS Analog Switches
MAX4591CPE ,High-Speed / Single-Supply / Quad / SPST Analog SwitchesApplicationsMAX4591CUE 0°C to +70°C 16 TSSOPMAX4591CSE 0°C to +70°C 16 Narrow SOTest Equipment Samp ..
MAX4591CSE ,High-Speed / Single-Supply / Quad / SPST Analog SwitchesELECTRICAL CHARACTERISTICS—Single +12V Supply(V+ = +12V, V- = GND = 0, V = 5V, V = 0.8V, T = T to T ..
MAX4591EPE ,High-Speed / Single-Supply / Quad / SPST Analog SwitchesFeaturesThe MAX4591/MAX4592/MAX4593 are high-speed, Low 16Ω On-Resistanceprecision, quad, single- ..
MAX4592CPE ,High-Speed / Single-Supply / Quad / SPST Analog SwitchesELECTRICAL CHARACTERISTICS—Single +12V Supply(V+ = +12V, V- = GND = 0, V = 5V, V = 0.8V, T = T to T ..
MAX1765EEE
800mA, Low-Noise, Step-Up DC-DC Converter with 500mA Linear Regulator
General DescriptionThe MAX1765 is a high-efficiency, low-noise, step-up
DC-DC converter intended for use in battery-powered
wireless applications. This device operates at a high
1MHz fixed frequency while maintaining an exception-
ally low quiescent supply current (200µA). Its small
external components and tiny package make this
device an excellent choice for small hand-held applica-
tions that require the longest possible battery life.
The MAX1765 uses a synchronous-rectified pulse-
width-modulation (PWM) boost topology to generate
2.5V to 5.5V outputs from a wide range of input
sources, such as one to three alkaline or NiCd/NiMH
cells or a single lithium-ion (Li+) cell. Maxim's propri-
etary architecture significantly improves efficiency at
low load currents while automatically transitioning to
fixed-frequency PWM operation at medium to high load
currents to maintain excellent full-load efficiency.
Forced-PWM mode is available for applications that
require constant-frequency operation at all load cur-
rents, and the MAX1765 may also be synchronized to
an external clock to protect sensitive frequency bands
in communications equipment.
The MAX1765’s low-dropout (LDO) linear regulator and
DC-DC converter have separate shutdown control. The
linear regulator's 250mΩpass device maintains excel-
lent dropout voltage at currents up to 500mA. The
MAX1765 also features analog soft-start and current-
limit functions to permit optimization of efficiency, exter-
nal component size, and output voltage ripple.
The MAX1765 comes in a 16-pin QSOP package and a
thermally enhanced 16-pin TSSOP-EP.
____________________________FeaturesHigh-Efficiency Step-Up Converter
Up to 93% Efficiency
Adjustable Output from +2.5V to +5.5V
Up to 800mA Output
PWM Synchronous-Rectified Topology
1MHz Operating Frequency (or Sync)LDO Linear Regulator
500mA LDO Linear Regulator
2.85V Linear Regulator Output or Adjustable
(1.25V to 5V)
Low 125mV Dropout at 500mA+0.7V to +5.5V Input Range0.1µA Logic-Controlled ShutdownAdjustable Inductor Current Limit and Soft-StartThermal Shutdown1.5W, 16-Pin TSSOP-EP Package Available
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator19-1805; Rev 0; 12/00
Pin ConfigurationWireless Handsets
PCS Phones
Palmtop Computers
Personal
Communicators
Hand-Held Instruments
Portable Audio Players
Applications
Typical Operating Circuit
Ordering Information*Exposed pad
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VOUT= VPOUT= VINL= VONA= VONL= 3.6V, CLK/SEL = FBL = ONB= TRACK = PGND = GND, ISET = REF (bypassed with
0.22µF), LX = open, OUTL = open (bypassed with 4.7µF), TA
= 0°C to +85°C, unless otherwise noted. Typical values are atStresses 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.
ONA, ONB, ONL, TRACK, OUT, INL to GND..............-0.3V, +6V
PGND to GND.....................................................................±0.3V
LX to GND...............................................-0.3V to (POUT + 0.3V)
OUTL to GND..............................................-0.3V to (INL + 0.3V)
CLK/SEL, REF, FB, FBL, ISET, POUT
to GND...................................................-0.3V to (OUT + 0.3V)
OUTL Short Circuit.....................................................Continuous
Continuous Power Dissipation (TA = +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW
16-Pin TSSOP-EP (derate 19mW/°C above +70°C)....1500mW
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
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
ELECTRICAL CHARACTERISTICS (continued)(VOUT= VPOUT= VINL= VONA= VONL= 3.6V, CLK/SEL = FBL = ONB= TRACK = PGND = GND, ISET = REF (bypassed with
0.22µF), LX = open, OUTL = open (bypassed with 4.7µF), TA
= 0°C to +85°C, unless otherwise noted. Typical values are at= +25°C.)
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
ELECTRICAL CHARACTERISTICS (continued)(VOUT= VPOUT= VINL= VONA= VONL= 3.6V, CLK/SEL = FBL = ONB= TRACK = PGND = GND, ISET = REF (bypassed with
0.22µF), LX = open, OUTL = open (bypassed with 4.7µF),
TA= 0°C to +85°C, unless otherwise noted. Typical values are at
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
ELECTRICAL CHARACTERISTICS
(VOUT= VPOUT= VINL= VONA= VONL= 3.6V, CLK/SEL = FBL = ONB= TRACK = PGND = GND, ISET = REF (bypassed with
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
ELECTRICAL CHARACTERISTICS (continued)
(VOUT= VPOUT= VINL= VONA= VONL= 3.6V, CLK/SEL = FBL = ONB= TRACK = PGND = GND, ISET = REF (bypassed with
Note 1:Operating voltage. Since the regulator is bootstrapped to the output, once started it will operate down to 0.7V input.
Note 2:The device is in startup mode when VOUTis below this value (see Low-Voltage Startup Oscillatorsection). Do not apply full
load current.
Note 3:Supply current into the OUT and POUT pins. This current correlates directly to the actual battery-supply current, but is
reduced in value according to the step-up ratio and efficiency.
Note 4:Minimum recommended ISET voltage in normal mode is 0.625V.
Note 5:ONA, ONB, ONL have hysteresis of approximately 0.15 ✕VOUT.
Note 6:Specifications to -40°C are guaranteed by design and not production tested.
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
MAX1765
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
Typical Operating Characteristics (continued)
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
Typical Operating Characteristics (continued)
MAX1765
Detailed Description
The MAX1765 is a highly efficient, low-noise power
supply for portable RF hand-held instruments. This
boost power supply combines an LDO linear regulator,
a low-noise, high-power, step-up switching regulator,
an N-channel power MOSFET, a P-channel synchro-
nous rectifier, shutdown control, and a precision volt-
age reference in a single 16-pin QSOP or a thermally
enhanced TSSOP-EP (Figure 1).
The switching DC-DC converter boosts a 1-cell to 3-cell
NiMH/NiCd or a single Li+ battery input to an
adjustable output voltage between 2.5V and 5.5V. The
MAX1765 guarantees startup with voltages as low as
1.1V and will remain operational down to 0.7V (Figure
2). The internal LDO regulator provides linear postregu-
lation for noise-sensitive circuitry, or it can be used as a
separate voltage output adjustable from 1.25V up to
POUT.
The MAX1765 is optimized for use in cellular phones
and other applications requiring low noise during full-
power operation, as well as low quiescent current for
maximum battery life during standby and shutdown.
The device automatically transitions to a low-quiescent-
current pulse-skipping control scheme during light
loads that reduces the quiescent power consumption to
360µW. The supply current of the device can be further
reduced to 1µA when the device is shut down. Figure 2
shows a typical application of the MAX1765 in normal
mode.
The switching regulator supports two low-noise modes:
fixed-frequency PWM for low noise in all load condi-
tions, and synchronization of the internal oscillator to an
external clock driving the CLK input. In TRACK mode,
the DC and linear regulator work together to maintain
excellent PSRR without excessive efficiency loss.
Additional MAX1765 features include synchronous rec-
tification for high efficiency and increased battery life,
dual boost shutdown controls for µP or a pushbutton
momentary switch, and a separate shutdown control for
the linear regulator.
Step-Up Converter
During DC-DC converter operation, the internal N-chan-
nel MOSFET turns on for the first part of each cycle,
allowing current to ramp up in the inductor and store
energy in a magnetic field. During the second part of
each cycle, the MOSFET turns off and inductor current
flows through the synchronous rectifier to the output filter
capacitor and the load. As the energy stored in the
inductor is depleted, the current ramps down and the
synchronous rectifier turns off. The CLK/SEL pin deter-
mines whether a pulse-skipping or PWM control method
is used at light loads (Table 1).
Normal Operation
Pulling CLK/SEL low selects the MAX1765’s normal
operating mode. In this mode, the device operates in
PWM when driving medium to heavy loads and auto-
matically switches to SKIP mode if the load requires
800mA, Low-Noise, Step-Up DC-DC Converter
with 500mA Linear Regulator
