MAX847EEI ,1-Cell / Step-Up Two-Way Pager System ICELECTRICAL CHARACTERISTICS(OUT = 3.0V, BATT = 1.2V, NICD = 3.6V, T = -40°C to +85°C, unless otherwi ..
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MAX848ESE ,1-Cell to 3-Cell / High-Power / Low-Noise / Step-Up DC-DC ConvertersFeaturesThe MAX848/MAX849 boost converters set a new stan- ' Up to 95% Efficiencydard of high effic ..
MAX848ESE+ ,1-Cell-to-3-Cell, High-Power, Low-Noise, Step-Up DC-DC ConvertersELECTRICAL CHARACTERISTICS(V = 3.6V, GND = PGND = CLK/SEL = ON1 = ON2 = AINSEL = AIN1 = AIN2 = FB = ..
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MAX848ESE-T ,1-Cell-to-3-Cell, High-Power, Low-Noise, Step-Up DC-DC ConvertersFeaturesThe MAX848/MAX849 boost converters set a new stan- ♦ Up to 95% Efficiencydard of high effic ..
MB81C81A-35 ,CMOS 256K-BIT HIGH-SPEED SRAMMay 1990 00
Edition1.0 FUJITSU
M38 1 C8 1A-25/-35
CMOS 256K-BI T HIGH-SPEED SRAM
256K Words ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMFUJITSU SEMICONDUCTORADVANCED INFO. AE0.1EDATA SHEETMEMORYCMOS4 · 512 K · 32 BITSYNCHRONOUS DYNAMIC ..
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MB81N643289-60FN ,8 x 256K x 32 bit double data rate FCRAMapplications where large memory density and high effective bandwidth arerequired and where a simple ..
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MAX847EEI
1-Cell / Step-Up Two-Way Pager System IC
________________General DescriptionThe MAX847 is a complete power-supply and monitor-
ing system for two-way pagers or other low-power digi-
tal communications devices. It requires few external
components. Included on-chip are:A 1-cell input, 80mA output, synchronous-rectified
boost DC-DC regulator with a digitally controlled
+1.8V to +4.9V output Three low-noise linear-regulator outputsThree DAC-controlled comparators for software-
driven 3-channel A/D conversionSPI™-compatible serial interfaceReset and low-battery (LBO) warning outputsCharger for NiCd, NiMH, lithium battery, or storage
capacitor for RF PA power or system backupTwo 1.8W(typical) serial-controlled open-drain
MOSFET switches
An evaluation kit for the MAX847 (MAX847EVKIT) is
available to aid in design and prototyping.
Pin Configuration appears at end of data sheet.
____________________________Features80mA Output from 1 Cell at 90% Efficiency13µA Idle Mode™(coast) CurrentSelectable Low-Noise PWM or Low-Current
OperationPWM Operating Frequency Synchronized to
Seven Times an External Clock SourceOperates at 270kHz with No External ClockAutomatic Backup-Battery Switchover
________________________ApplicationsTwo-Way Pagers
GPS Receivers
1-Cell Powered Hand-Held Equipment
MAX847
1-Cell, Step-Up
Two-Way Pager System IC
____________________________________________________Typical Operating CircuitIdle Mode is a trademark of Maxim Integrated Products. SPI is a trademark of Motorola, Inc.
MAX847
1-Cell, Step-Up
Two-Way Pager System IC
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(OUT = 3.0V, BATT = 1.2V, NICD = 3.6V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
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.
BATT, OUT, NICD, LBO, RSO to AGND...................-0.3V to +6V
REG1, OFS, REG2, REF, R2IN to AGND...-0.3V to (OUT + 0.3V)
SCL, SDO, SDI, CS, SYNC, FILT, DR2IN,
CH0, LBI, RSIN, RUN to AGND...................-0.3V to (REG1 + 0.3V)
REG3.......................................................-0.3V to (REG2 + 0.3V)
DR1, DR2 to DRGND...............................-0.3V to (BATT + 0.3V)
PGND, DRGND to AGND......................................-0.3V to +0.3V
LX1 to PGND.............................................-0.3V to (OUT + 0.3V)
Continuous Power Dissipation (TA= +70°C)
28-Pin QSOP (derate 8mW/°C above +70°C).............640mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +165°C
Lead Temperature (soldering, 10sec).............................+300°C
MAX847
1-Cell, Step-Up
Two-Way Pager System IC
ELECTRICAL CHARACTERISTICS (continued)(OUT = 3.0V, BATT = 1.2V, NICD = 3.6V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
MAX847
1-Cell, Step-Up
Two-Way Pager System IC
ELECTRICAL CHARACTERISTICS (continued)(OUT = 3.0V, BATT = 1.2V, NICD = 3.6V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
MAX847
1-Cell, Step-Up
Two-Way Pager System IC
ELECTRICAL CHARACTERISTICS (continued)(OUT = 3.0V, BATT = 1.2V, NICD = 3.6V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
Note 1:Specifications to -40°C are guaranteed by design, not production tested.
Note 2:This is not a tested parameter, since the IC is powered from OUT, not BATT. The only limitation in the BATT range is the
inability to generate more than 5 times, or less than 1.15 times the BATT voltage at OUT. This is due to PWM controller
duty-cycle limitations in Run Mode.
Note 3:Minimum start-up voltage is tested by determining when the LX pins can draw at least 50mA for 1µs (min) at a 50kHz (min)
repetition rate. This guarantees that the IC will deliver at least 200µA at the OUT pin.
Note 4:This supply current is drawn from the OUT pin. Current drain from the battery depends on voltages at BATT and OUT and
on the DC-to-DC converter’s efficiency.
Note 5:Current into BATT pin in addition to the supply current at OUT. This current is roughly constant from Coast to Run Mode.
Note 6:Current into NICD pin when NICD isn’t being charged and isn’t regulating OUT.
Note 7:Current into NICD pin when NICD is regulating OUT. Doesn’t include current drawn from OUT by the rest of the circuit.
Measured by setting the OUT regulation point to 2.8V and holding OUT at 3.0V.
Note 8:Current into NICD pin when BATT and OUT are both at 0V. This test guarantees that NICD won’t draw significant current
when the main battery is removed and backup is not activated.
Note 9:Serial-interface timing specifications are not tested and are provided for design guidance only. Serial-interface functionali-
ty is tested by clocking data in at 5MHz with a 50% duty-cycle clock and checking for proper operation. With OUT set
below 2.5V, the serial-interface clock frequency should be reduced to 1MHz to ensure proper operation.
Note 10:This specification is not directly tested but is guaranteed by correlation to LX on-resistance and current-limit tests.
Note 11:Measured by using the internal feedback network and Coast-Mode error comparator to regulate OUT. Doesn’t include
ripple voltage due to inductor currents.
Note 12:Measured by using the internal feedback network and Run-Mode error comparator to regulate OUT. Doesn’t include ripple
voltage due to inductor currents.
Note 13:Uses the OUT measurement techniques described for the OUT Error, Coast Mode, and OUT Error Run Mode specifications.
Note 14:PLL acquisition characteristics depend on the impedance at the FILT pin. The specification is not tested and is provided
for design guidance only.
Note 15:The limits in this specification are not guaranteed and are provided for design guidance only.
__________________________________________Typical Operating Characteristics(Circuit of Figure 2, TA= +25°C, unless otherwise noted.)
MAX847
1-Cell, Step-Up
Two-Way Pager System ICypical Operating Characteristics (continued)(Circuit of Figure 2, TA= +25°C, unless otherwise noted.)
MAX847
1-Cell, Step-Up
Two-Way Pager System IC
______________________________________________________________Pin Description
MAX847
1-Cell, Step-Up
Two-Way Pager System ICFigure 1. Functional Diagram
______________Detailed DescriptionThe MAX847 contains several functional blocks that
simplify the integration of power-supply and monitoring
functions within a 1-cell powered system. They are
described in the following subsections.
Voltage RegulatorsRegulator outputs include the following:OUT: Main switch-mode boost outputREG1: 1.5Wswitch and output voltage clamp. Switches
REG1 to OUT and clamps REG1 at 3.3V when OUT
is set to 3.4V or more.REG2: Linear-regulated, 24mA low-noise output that
regulates so that VOUT- VREG2is a set difference
voltage (10µA •ROFS). Output peak-to-peak ripple is
typically 2mV with a 10µF bypass capacitor at REG2.
REG2 clamps output at 3.3V.REG3: Low-noise, 1V linear regulator that supplies
2mA.
Main DC-DC Boost Converter (OUT)OUT is the main DC-DC converter’s output. It supplies
current from the internal synchronous-rectified boost reg-
ulator and needs no external FETs or voltage-setting
resistors. The output voltage (VOUT) is adjusted from
1.8V to 4.9V in 100mV steps (Tables 2 and 6) by internal
DAC control using a serial-data command. OUT can
supply up to 80mA, less the current supplied to the other
regulators (REG1, REG2, and REG3).
OUT can also be put into a low-current, pulse-skipping
Coast Mode (13µA typical quiescent current) by reset-
ting the RUN/COAST serial input bit and holding the
RUNpin at 0V. OUT supplies up to 40mA in Coast
Mode. Typically, when changing from Run to Coast
Mode, a lower OUT voltage is also set (Table 5) to fur-
ther reduce system operating current. The extent of this
reduction depends on the minimum operating voltage
of the system components when they are in standby or
sleep states.
MAX847
1-Cell, Step-Up
Two-Way Pager System ICFigure 2. Standard Application Circuit
