MAX1847EEE+T ,High-Efficiency, Current-Mode, Inverting PWM Controllerfeatures clock synchronization and shut-MAX1847EEE+ -40°C to +85°C 16 QSOPdown functions. The MAX18 ..
MAX1848EKA ,White LED Step-Up Converter in SOT23ApplicationsTOPCell Phones and Smart PhonesPART TEMP RANGE PIN-PACKAGEMARKPDAs, Palmtops, and Wirel ..
MAX1848EKA ,White LED Step-Up Converter in SOT23ELECTRICAL CHARACTERISTICS(V+ = 3V, V = 11V, L = 33µH, C = 1µF, C = 0.15µF, R = 5Ω , V = 1V, T = 0 ..
MAX1848EKA+T ,White LED Step-Up Converter in SOT23ELECTRICAL CHARACTERISTICS (continued)(V+ = 3V, V = 11V, L = 33µH, C = 1µF, C = 0.15µF, R = 5Ω, V = ..
MAX1848EKA-T ,White LED Step-Up Converter in SOT23ELECTRICAL CHARACTERISTICS°° °°(V+ = 3V, V = 11V, L = 33µH, C = 1µF, C = 0.15µF, R = 5Ω, V = 1V, T ..
MAX1848EKA-T ,White LED Step-Up Converter in SOT23MAX184819-2028; Rev 2; 8/05White LED Step-Up Converter in SOT23
MAX4751EUD+ ,0.9Ω, Low-Voltage, Single-Supply Quad SPST Analog Switches
MAX4753EGE+ ,0.9Ω, Low-Voltage, Single-Supply Quad SPST Analog Switches
MAX4754ETE ,+1.8 to +5.5 V, 0.5 om quad SPDT switche
MAX4754ETE+ ,0.5Ω, Quad SPDT Switches in UCSP/QFN
MAX4754ETE+T ,0.5Ω, Quad SPDT Switches in UCSP/QFN
MAX4754ETE+T ,0.5Ω, Quad SPDT Switches in UCSP/QFN
MAX1846EUB+-MAX1846EUB+T-MAX1847EEE+-MAX1847EEE+T
High-Efficiency, Current-Mode, Inverting PWM Controller
General DescriptionMAX1846/MAX1847 high-efficiency PWM inverting con-
trollers allow designers to implement compact, low-
noise, negative-output DC-DC converters for telecom
and networking applications. Both devices operate
from +3V to +16.5V input and generate -500mV to
-200V output. To minimize switching noise, both devices
feature a current-mode, constant-frequency PWM control
scheme. The operating frequency can be set from 100kHz
to 500kHz through a resistor.
The MAX1846 is available in an ultra-compact 10-pin
µMAX® package. Operation at high frequency, com-
patibility with ceramic capacitors, and inverting topol-
ogy without transformers allow for a compact design.
Compatibility with electrolytic capacitors and flexibility to
operate down to 100kHz allow users to minimize the cost
of external components. The high-current output drivers
are designed to drive a P-channel MOSFET and allow the
converter to deliver up to 30W.
The MAX1847 features clock synchronization and shut-
down functions. The MAX1847 can also be configured to
operate as an inverting flyback controller with an N-channel
MOSFET and a transformer to deliver up to 70W. The
MAX1847 is available in a 16-pin QSOP package.
Current-mode control simplifies compensation and pro-
vides good transient response. Accurate current-mode
control and over current protection are achieved through
low-side current sensing.
Applications●Cellular Base Stations●Networking Equipment●Optical Networking Equipment●SLIC Supplies●CO DSL Line Driver Supplies●Industrial Power Supplies●Servers ●VOIP Supplies
Features●90% Efficiency●+3.0V to +16.5V Input Range ●-500mV to -200V Output ●Drives High-Side P-Channel MOSFET●100kHz to 500kHz Switching Frequency●Current-Mode, PWM Control●Internal Soft-Start●Electrolytic or Ceramic Output Capacitor●The MAX1847 also offers: Synchronization to External Clock Shutdown N-Channel Inverting Flyback Option
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Pin Configurations appear at end of data sheet.+Denotes a lead(Pb)-free/RoHS-compliant package.
PARTTEMP RANGEPIN-PACKAGE
MAX1846EUB-40°C to +85°C10 µMAX
MAX1846EUB+-40°C to +85°C10 µMAX
MAX1847EEE-40°C to +85°C16 QSOP
MAX1847EEE+-40°C to +85°C16 QSOP
MAX1846
MAX1847IN
COMP
FREQ
REF
GNDFB
PGND
EXT
POSITIVE
VIN
NEGATIVE
VOUT
MAX1846–MAX1847High-Efficiency, Current-Mode,
Inverting PWM Controller
Typical Operating Circuit
Ordering Information
EVALUATION KIT AVAILABLE
IN, SHDN to GND .................................................-0.3V to +20V
PGND to GND ......................................................-0.3V to +0.3VVL to PGND for VIN ≤ 5.7V ........................-0.3V to (VIN + 0.3V)
VL to PGND for VIN > 5.7V .....................................-0.3V to +6V
EXT to PGND .............................................-0.3V to (VIN + 0.3V)
REF, COMP to GND ....................................-0.3V to (VL + 0.3V)
CS, FB, FREQ, POL, SYNC to GND ......................-0.3V to +6V
Continuous Power Dissipation (TA = +70°C)10-Pin µMAX (derate 5.6mW/°C above +70°C) ..........444mW16-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 +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow)
Lead(Pb)-free...............................................................+260°CContaining lead(Pb) .....................................................+240°C
(VSHDN = VIN = +12V, SYNC = GND, PGND = GND, RFREQ = 147kΩ ±1%, CVL = 0.47µF, CREF = 0.1µF, TA = 0°C to +85°C,
unless otherwise noted.)
PARAMETERCONDITIONSMIN
TYPMAXUNITS
PWM CONTROLLEROperating Input Voltage Range3.016.5V
UVLO ThresholdVIN rising2.82.95VVIN falling2.62.74
UVLO Hysteresis60mV
FB ThresholdNo load-12012mV
FB Input CurrentVFB = -0.1V-50-650nA
Load RegulationCCOMP = 0.068µF, VOUT = -48V,
IOUT = 20mA to 200mA (Note 1)-10%
Line RegulationCCOMP = 0.068µF, VOUT = -48V,
VIN = +8V to +16.5V, IOUT = 100mA0.04%
Current-Limit Threshold85100115mV
CS Input CurrentCS = GND1020µA
Supply Current VFB = -0.1V, VIN = +3.0V to +16.5V0.751.2mA
Shutdown Supply CurrentSHDN = GND, VIN = +3.0V to +16.5V
VIN = +3.0V to +16.5V1025µA
REFERENCE AND VL REGULATORREF Output VoltageIREF = 50µA1.2361.251.264V
REF Load RegulationIREF = 0 to 500µA-2-15mV
VL Output VoltageIVL = 100µA3.854.254.65V
VL Load RegulationIVL = 0.1mA to 2.0mA-20-60mV
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
Electrical CharacteristicsStresses 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.
Absolute Maximum Ratings
Note 1: Production test correlates to operating conditions.
Note 2: Guaranteed by design and characterization.
(VSHDN = VIN = +12V, SYNC = GND, PGND = GND, RFREQ = 147kΩ ±1%, CVL = 0.47µF, CREF = 0.1µF, TA = 0°C to +85°C,
unless otherwise noted.)
Electrical Characteristics (continued)
PARAMETERCONDITIONSMINTYPMAXUNITS
OSCILLATOROscillator Frequency
RFREQ = 500kΩ ±1%88100112
kHzRFREQ = 147kΩ ±1%255300345
RFREQ = 76.8kΩ ±1%500
Maximum Duty Cycle
RFREQ = 500kΩ ±1%939698RFREQ = 147kΩ ±1%858892
RFREQ = 76.8kΩ ±1%80
SYNC Input Signal Duty-Cycle
Range793%
Minimum SYNC Input Logic Low
Pulse Width50200ns
SYNC Input Rise/Fall Time(Note 2)200ns
SYNC Input Frequency Range100550kHz
DIGITAL INPUTSPOL, SYNC, SHDN Input High
Voltage2.0V
POL, SYNC, SHDN Input Low
Voltage0.45V
POL, SYNC Input CurrentPOL, SYNC = GND or VL2040µA
SHDN Input CurrentV SHDN = +5V or GND-12-40µAV SHDN = +16.5V1.56
SOFT-STARTSoft-Start Clock Cycles1024
Soft-Start Levels64
EXT OUTPUTEXT Sink/Source CurrentVIN = +5V, VEXT forced to +2.5V1A
EXT On-ResistanceEXT high or low, tested with 100mA load, VIN = +5V37.5ΩEXT high or low, tested with 100mA load, VIN = +3V512
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
(VSHDN = VIN = +12V, SYNC = GND, PGND = GND, RFREQ = 147kΩ ±1%, CVL = 0.47µF, CREF = 0.1µF, TA = -40°C to +85°C,
unless otherwise noted.) (Note 3)
PARAMETERCONDITIONSMINMAXUNITS
PWM CONTROLLEROperating Input Voltage Range3.016.5V
UVLO ThresholdVIN rising2.95VVIN falling2.6
FB ThresholdNo load-20+20mV
FB Input CurrentVFB = -0.1V-50+50nA
Load RegulationCCOMP = 0.068µF, VOUT = -48V,
IOUT= 20mA to 200mA (Note 1)-20%
Current Limit Threshold85115mV
CS Input CurrentCS = GND20µA
Supply Current VFB = -0.1V, VIN = +3.0V to +16.5V1.2mA
Shutdown Supply Current SHDN = GND, VIN = +3.0V to +16.5V25µA
REFERENCE AND VL REGULATORREF Output VoltageIREF = 50µA1.2251.275V
REF Load RegulationIREF = 0 to 500µA-15mV
VL Output VoltageIVL = 100µA3.854.65V
VL Load RegulationIVL = 0.1mA to 2.0mA-60mV
OSCILLATOROscillator FrequencyRFREQ = 500kΩ ±1%84116kHzRFREQ = 147kΩ ±1%255345
Maximum Duty CycleRFREQ = 500kΩ ±1%9398%RFREQ = 147kΩ ±1%8493
SYNC Input Signal Duty-Cycle
Range793%
Minimum SYNC Input Logic Low
Pulse Width200ns
SYNC Input Rise/Fall Time(Note 2)200ns
SYNC Input Frequency Range100550kHz
DIGITAL INPUTSPOL, SYNC, SHDN Input High
Voltage2.0V
POL, SYNC, SHDN Input Low
Voltage0.45V
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
Electrical Characteristics
(Circuit references are from Table 1 in the Main Application Circuits section, CVL = 0.47µF, CREF = 0.1°F, TA = +25°C, unless otherwise
noted.)
Note 3: Parameters to -40°C are guaranteed by design and characterization.(VSHDN = VIN = +12V, SYNC = GND, PGND = GND, RFREQ = 147kΩ ±1%, CVL = 0.47µF, CREF = 0.1µF, TA = -40°C to +85°C,
unless otherwise noted.) (Note 3)
PARAMETERCONDITIONSMINMAXUNITSPOL, SYNC Input CurrentPOL, SYNC = GND or VL40µA
SHDN Input CurrentV SHDN = +5V or GND-120µAV SHDN = +16.5V6
EXT OUTPUTEXT On-ResistanceEXT high or low, IEXT = 100mA, VIN = +5V7.5ΩEXT high or low, IEXT = 100mA, VIN = +3V12
REFERENCE VOLTAGE
vs. TEMPERATURE
MAX1846/7 toc06
REF
(V)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1846/7 toc05
IIN
(mA)
VFB = -0.1V
OUTPUT VOLTAGE LOAD REGULATION
MAX1846/7 toc04
OUTPUT VOLTAGE (V)
APPLICATION CIRCUIT B VIN = 5V100010010
EFFICIENCY vs. LOAD CURRENTMAX1846/7 toc03
LOAD CURRENT (mA)
EFFICIENCY (%
VIN = 12V
VIN = 16.5V
APPLICATION CIRCUIT CVOUT = -48V
110100100010,000
EFFICIENCY vs. LOAD CURRENTMAX1846/7 toc02
LOAD CURRENT (mA)
EFFICIENCY (%
VIN = 5V
VIN = 3.3V
VOUT = -12VAPPLICATION CIRCUIT B
VIN = 3V
110100100010,000
EFFICIENCY vs. LOAD CURRENTMAX1846/7 toc01
LOAD CURRENT (mA)
EFFICIENCY (%
VIN = 5V
VIN = 16.5V
VOUT = -5VAPPLICATION CIRCUIT A
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
Typical Operating Characteristics
Electrical Characteristics (continued)
(Circuit references are from Table 1 in the Main Application Circuits section, CVL = 0.47µF, CREF = 0.1°F, TA = +25°C, unless otherwise
noted.)
Typical Operating Characteristics (continued)5V/div
1A/div
5V/div
VOUT
EXITING SHUTDOWNMAX1846/7 toc15
APPLICATION CIRCUIT B
1ms/div
SHDN
160200040006000800010,000
EXT RISE/FALL TIME
vs. CAPACITANCEMAX1846/7 toc14
CAPACITANCE (pF)
TIME (ns)
RISE TIME
FALL TIME
VIN = 12V
SWITCHING FREQUENCY
vs. TEMPERATUREMAX1846/7 toc13
FREQUENCY (kHz
TEMPERATURE (C)
RFREQ = 147k 1%
SWITCHING FREQUENCY
vs. RFREQ
MAX1846/7 toc12
RFREQ (k)
fOSC
(kHz)
OPERATING CURRENT
vs. TEMPERATURE
MAX1846/7 toc11
TEMPERATURE (C)
OPERATING CURRENT (mA)
A: VIN = 3V, VOUT = -12V
B: VIN = 5V, VOUT = -5V
C: VIN = 16.5V, VOUT = -5V
APPLICATION CIRCUIT A
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATUREMAX1846/7 toc10
SHUTDOWN SUPPLY CURRENT (A)
TEMPERATURE (C)
VIN = 10V
VIN = 16.5V
VIN = 3V
VL LOAD REGULATION
MAX1846/7 toc09
IVL (mA)
VL (V)
VL VOLTAGE
vs. TEMPERATURE
MAX1846/7 toc08
TEMPERATURE (C)
VL (V)
IVL = 0
REFERENCE LOAD REGULATION
MAX1846/7 toc07
IREF (A)
REF
(V)
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
(Circuit references are from Table 1 in the Main Application Circuits section, CVL = 0.47µF, CREF = 0.1°F, TA = +25°C, unless otherwise
noted.)
Typical Operating Characteristics (continued)500mA/div
200mV/div
ILOAD
VOUT
LOAD-TRANSIENT RESPONSEMAX1846/7 toc20
APPLICATION CIRCUIT C
400s/div
ILOAD = 4mA to 100mA1A/div
500mV/div
ILOAD
VOUT
LOAD-TRANSIENT RESPONSEMAX1846/7 toc19
APPLICATION CIRCUIT B
2ms/div
ILOAD = 10mA to 400mA
1A/div
10V/div
100mV/divVOUT
LIGHT-LOAD SWITCHING
WAVEFORMMAX1846/7 toc18
APPLICATION CIRCUIT B
1s/div
ILOAD = 50mA
1A/div
10V/div
100mV/divVOUT
HEAVY-LOAD SWITCHING
WAVEFORMMAX1846/7 toc17
APPLICATION CIRCUIT B
1s/div
ILOAD = 600mA
5V/div
1A/div
5V/div
VOUT
ENTERING SHUTDOWNMAX1846/7 toc16
APPLICATION CIRCUIT B
1ms/div
SHDN
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
PINNAMEFUNCTIONMAX1846MAX18471POL
Sets polarity of the EXT pin. Connect POL to GND to set EXT for use with an external
PMOS high-side FET. Connect POL to VL to set EXT for use with an external NMOS low-
side FET in transformer-based applications.2VLVL Low-Dropout Regulator. Connect 0.47µF ceramic capacitor from VL to GND.3FREQ
Oscillator Frequency Set Input. Connect a resistor (RFREQ) from FREQ to GND to set the
internal oscillator frequency from 100kHz (RFREQ = 500kW) to 500kHz (RFREQ = 76.8kW).
RFREQ is still required if an external clock is used at SYNC. See Setting the Operating
Frequency section.4COMPCompensation Node for Error Amp/Integrator. Connect a series resistor/capacitor network
from COMP to GND for loop compensation. See Design Procedure.5REF1.25V Reference Output. REF can source up to 500µA. Bypass with a 0.1µF ceramic
capacitor from REF to GND.6FBFeedback Input. Connect FB to the center of a resistor-divider connected between the
output and REF. The FB threshold is 0.7, 9N.C.No Connection8SHDNShutdown Control. Drive SHDN low to turn off the DC-DC controller. Drive high or connect
to IN for normal operation.10, 11GNDAnalog Ground. Connect to PGND.12PGNDNegative Rail for EXT Driver and Negative Current-Sense Input. Connect to GND.13CSPositive Current-Sense Input. Connect a current-sense resistor (RCS) between CS and
PGND.14EXTExternal MOSFET Gate-Driver Output. EXT swings from IN to PGND.15INPower-Supply Input16SYNC
Operating Frequency Synchronization Control. Drive SYNC low or connect to GND to set
the internal oscillator frequency with RFREQ. Drive SYNC with a logic-level clock input
signal to externally set the converter’s operating frequency. DC-DC conversion cycles
initiate on the rising edge of the input clock signal. Note that when driving SYNC with an
external signal, RFREQ must still be connected to FREQ.
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
Pin Description
MAX1847
REFFB
GND
EXT
PGND
FREQ
COMPIN
0.22μF
150kΩ
0.1μF
10.0kΩ
95.3kΩ
0.02Ω
10μH
DO5022P-103
CMSH5-40
47μF
16V
FDS6375
3 x 22μF
10V
POL
SYNC
SHDN
10kΩ
47μF
16V
22kΩ
10, 11
7, 9N.C.
VIN
+3V to +5.5V
0.47μFVOUT
-12V AT 400mA
SANYO
16TPB47M
1200pF
220pF
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
Typical Application Circuit
MAX1846
MAX1847
STARTUP
CIRCUITRY
CONTROL
CIRCUITRY
REGULATOR
OSCILLATOR
REFERENCE
SLOPE
COMP
UNDER-
VOLTAGE
LOCK OUT
SOFT-START
MAX1847 ONLY
MAX1847 ONLY
POL
FREQ
COMP
REF
SYNC
SHDN
ERROR
AMPLIFIER
CURRENT-
SENSE
AMPLIFIER
GND
ERROR
COMPARATOR
EXT DRIVER
EXT
PGND
PGND
X3.3
MAX1846–MAX1847High-Eficiency, Current-Mode, Inverting PWM Controller
Functional Diagram
