MAX1945REUI+-MAX1945REUI+T Fast Delivery |IC PHOENIX CO.,LIMITED

MAX1945REUI+T ,1MHz, 1% Accurate, 6A Internal Switch Step-Down RegulatorsELECTRICAL CHARACTERISTICS(V = V = V = V = V = 3.3V, SYNC = GND, FBSEL = High-Z, V = 0.7V, C = 0.22 ..
MAX1946ETA ,Single USB Switch with Autoreset and Fault Blanking in Tiny TDFNApplications*EP = Exposed paddle.USB Ports and USB HubsNotebook and Desktop ComputersPDAs and Palmt ..
MAX1946ETA+ ,Single USB Switch with Autoreset and Fault Blanking in Tiny TDFNfeatures to pro-♦ 2.7V to 5.5V Input Voltage Rangetect the USB port. Built-in thermal-overload prot ..
MAX1946ETA+T ,Single USB Switch with Autoreset and Fault Blanking in Tiny TDFNELECTRICAL CHARACTERISTICS(V = 5V, C = 0.1µF, C = 1µF, T = 0°C to +85°C, unless otherwise noted. Ty ..
MAX1947ETA18 ,Low Input/Output Voltage Step-Up DC-DC Converter with RESETApplications♦ Uses Only Small Ceramic CapacitorsMP3 Players, Pagers, and CD Players♦ 75ms RESET Out ..
MAX1947ETA18+ ,Low Input/Output Voltage Step-Up DC-DC Converter with Active-Low RESETApplicationsOrdering InformationMP3 Players, Pagers, and CD PlayersPKGPART TEMP RANGE PIN-PACKAGEPD ..
MAX490CPA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX148719-0122; Rev 5; 2/96Low-Power, Slew-Rate-LimitedRS-485/RS ..
MAX490CPA+ ,Low-Power, Slew-Rate-Limited RS-485/RS-422 TransceiversApplicationsguarantees a logic-high output if the input is open circuit.MAX3030E–MAX3033E: ±15kV E ..
MAX490CSA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversELECTRICAL CHARACTERISTICS(V = 5V ±5%, T = T to T , unless otherwise noted.) (Notes 1, 2)CC A MIN M ..
MAX490CSA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplications ______________Ordering InformationLow-Power RS-485 TransceiversPART TEMP. RANGE PIN-PA ..
MAX490CSA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX148719-0122; Rev 5; 2/96Low-Power, Slew-Rate-LimitedRS-485/RS ..
MAX490CSA+ ,Low-Power, Slew-Rate-Limited RS-485/RS-422 TransceiversApplicationsMAX3483E/MAX3485E/MAX3486E/MAX3488E/Low-Power RS-485 TransceiversMAX3490E/MAX3491E: +3. ..

MAX1945REUI+-MAX1945REUI+T
1MHz, 1% Accurate, 6A Internal Switch Step-Down Regulators
General Description
The MAX1945R/MAX1945S high-efficiency pulse-width
modulation (PWM) switching regulators deliver up to 6A
of output current. The devices operate from an input
supply range of 2.6V to 5.5V and provide selectable
output voltages of 1.8V, 2.5V, and adjustable output
voltages from 0.8V to 85% of the supply voltage. With
VCCat 3.3V/5V, the input voltage can be as low as
2.25V. The MAX1945R/MAX1945S are ideal for on-
board post-regulation applications. Total output voltage
error is less than ±1% over load, line, and temperature.
The MAX1945R/MAX1945S operate at a selectable
fixed frequency (500kHz or 1MHz) or can be synchro-
nized to an external clock (400kHz to 1.2MHz). The
high operating frequency minimizes the size of external
components. The high bandwidth of the internal error
amplifier provides excellent transient response. The
MAX1945R/MAX1945S have internal dual N-channel
MOSFETs to lower heat dissipation at heavy loads. Two
MAX1945R/MAX1945Ss can operate 180 degrees out-
of-phase of each other to minimize input capacitance.
The devices provide output voltage margining for
board-level testing. The MAX1945R provides a ±4%
voltage margining. The MAX1945S provides a ±9%
voltage margining.
The MAX1945R/MAX1945S are available in 28-pin
TSSOP-EP packages and are specified over the -40°C
to +85°C industrial temperature range. An evaluation kit
is available to speed designs.
Applications
Low-Voltage, High-Density Distributed Power
Supplies
ASIC, CPU, and DSP Core Voltages
RAM Power Supply
Base Station, Telecom, and Networking
Equipment Power Supplies
Server and Notebook Power Supplies
Features6A PWM Step-Down Regulator with 95%
Efficiency1MHz/500kHz Switching for Small External
Components0.76in2Complete 6A Regulator FootprintExternal Components’ Height <3mm±1% Output Accuracy over Load, Line, and
TemperatureOperate from 2.6V to 5.5V SupplyOperate from 2.5V Input with VCCat 3.3V/5VPreset Output Voltage of 1.8V or 2.5VAdjustable Output from 0.8V to 85% of InputVoltage Margining: ±4% (MAX1945R) or ±9%
(MAX1945S)Synchronize to External ClockSYNCOUT Provides 180-Degree Out-of-Phase
Clock OutputAll-Ceramic or Electrolytic Capacitor Designs
MAX1945R/MAX1945S
1MHz, 1% Accurate, 6A Internal Switch
Step-Down Regulators
Ordering Information
REF
COMPBST
GND
VCC
PGND
INPUT
2.6V TO 5.5V
FBSEL
CTL1
CTL2
SYNC
SYNCOUT
OUTPUT
0.8V TO
0.85 x VIN,
VOLTAGE
MARGINING
ON/OFF
SYNCHRONIZATION
CLOCK
VDD
MAX1945R
MAX1945S
180° OUT-OF-PHASE
Typical Operating Circuit
19-2640; Rev 1; 7/04
*EP = Exposed pad.
Pin Configuration appears at end of data sheet.
EVALUATION KIT
AVAILABLE
PARTTEMP RANGEPIN-PACKAGE
MAX1945REUI-40°C to +85°C28 TSSOP-EP*
MAX1945SEUI-40°C to +85°C28 TSSOP-EP*
MAX1945R/MAX1945S
1MHz, 1% Accurate, 6A Internal Switch
Step-Down Regulators
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= VCC= VCTL1= VCTL2= VDD= 3.3V, SYNC = GND, FBSEL = High-Z, VFB= 0.7V, CREF= 0.22µF, TA= 0°C to +85°C, unless
otherwise noted. Typical values are at +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.
CTL1, CTL2, IN, SYNC, VCC, VDDto GND...............-0.3V to +6V
SYNCOUT, COMP, FB, FBSEL,
REF to GND............................................-0.3V to (VCC+ 0.3V)
LX Current (Note 1).....................................................-9A to +9A
BST to LX..................................................................-0.3V to +6V
PGND to GND.......................................................-0.3V to +0.3V
Continuous Power Dissipation (TA= +85°C)
(derate 23.8mW/°C above +70°C).............................1191mW
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
IN/VCC
Input VoltageVIN2.65.5V
VIN = 3.3V1220IN Supply CurrentIINSYNC = VCC (1MHz),
no loadVIN = 5.5V48mA
VCC = 3.3V23VCC Supply CurrentICCSYNC = VCC (1MHz)VCC = 5.5V3mA
VDD = 3.3V58VDD Supply CurrentIDDSYNC = VCC (1MHz)VDD = 5.5V10mA
Total Shutdown Current from IN,
VCC, and VDDITOTALVIN = VCC = VDD = VBST - VLX = 5.5V,
CTL1 = CTL2 = GND500µA
VCC rising2.402.55VCC Undervoltage Lockout
ThresholdVUVLOWhen LX starts/stops
switchingVCC falling2.202.35V
VDD
VDD Shutdown Supply CurrentVIN = VDD = VBST = 5.5V, VLX = 5.5V or 0,
CTL1 = CTL2 = GND10µA
BST
BST Shutdown Supply CurrentIBSTVIN = VDD = VBST = 5.5V, VLX = 5.5V or 0,
CTL1 = CTL2 = GND10µA
REF
REF VoltageVREFIREF = 0, VIN = 2.6V to 5.5V1.972.002.04V
REF Shutdown ResistanceFrom REF to GND, CTL1 = CTL2 = GND10100Ω
COMP
FBSEL = High-Z305585
FBSEL = GND13.324.437.8COMP TransconductanceFrom FB to COMP,
VCOMP = 1.25V
FBSEL = VCC9.617.627.2
COMP Clamp Voltage LowVLOW_
CLAMPVIN = 2.6V to 5.5V, VFB = 0.9V0.50.81.1V
COMP Clamp Voltage HighVHIGH_
CLAMPVIN = 2.6V to 5.5V, VFB = 0.7V1.902.152.40V
COMP Shutdown ResistanceFrom COMP to GND, CTL1 = CTL2 = GND10100Ω
Note 1:LX has internal clamp diodes to PGND and IN. Applications that forward bias these diodes should take care not to exceed
the IC’s package power dissipation limits.
MAX1945R/MAX1945S
1MHz, 1% Accurate, 6A Internal Switch
Step-Down Regulators
ELECTRICAL CHARACTERISTICS (continued)
(VIN= VCC= VCTL1= VCTL2= VDD= 3.3V, SYNC = GND, FBSEL = High-Z, VFB= 0.7V, CREF= 0.22µF, TA= 0°C to +85°C, unless
otherwise noted. Typical values are at +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
FBSEL = GND1.7821.8001.818
FBSEL = VCC2.4752.5002.525FB Regulation Voltage
(Error Amp Only)VFBVCOMP = 1V to 2V,
VIN = 2.6V to 5.5V
FBSEL = High-Z0.7920.8000.808
Maximum Output CurrentIFB_OUTVIN = 3.3V, VOUT = 1.8V, L = 1µH6A
CTL1 = VCC,
CTL2 = VCC-1+1
CTL1 = GND,
CTL2 = VCC35
MAX1945R,
VCOMP = 1V to 2V,
VIN = 2.6V to 5.5V
CTL1 = VCC,
CTL2 = GND-5-3
CTL1 = VCC,
CTL2 = VCC-1+1
CTL1 = GND,
CTL2 = VCC810
FB Voltage Margining Output
(Error Amp Only)VMARGIN_
MAX1945S,
VCOMP = 1V to 2V,
VIN = 2.6V to 5.5V
CTL1 = VCC,
CTL2 = GND-10-8
FB Input ResistanceFB to GND, FBSEL = GND, or VFB = 1.8V,
or FBSEL = VCC, or VFB = 2.5V2550100kΩ
FB Input Bias CurrentFBSEL = High-Z, VFB = 0.7V0.010.10µA
VIN = VBST - VLX = 3.3V2643LX On-Resistance HighRON_HIGH_VIN = VBST - VLX = 2.6V3050mΩ
VIN = 3.3V2643LX On-Resistance LowRON_LOW_VIN = 2.6V3050mΩ
LX Current-Sense
TransresistanceFrom LX to COMP435465mΩ
High side8.010.412.8LX Current-Limit ThresholdDuty cycle =100%,
VIN = 2.6V/3.3V/5.5VLow side-6-4-2A
VLX = 5.5V100LX Leakage CurrentILEAK_LXVIN = 5.5V,
CTL1 = CTL2 = GNDLX = GND-100µA
SYNC = VCC0.81.01.2MHzLX Switching FrequencyfSWVIN = 2.6V/3.3VSYNC = GND400500600kHz
LX Minimum Off-TimetOFFVIN = 2.6V/3.3V155180ns
SYNC = GND90LX Maximum Duty CycleVIN = 2.6V/3.3VSYNC = VCC80%
MAX1945R/MAX1945S
1MHz, 1% Accurate, 6A Internal Switch
Step-Down Regulators
ELECTRICAL CHARACTERISTICS (continued)
(VIN= VCC= VCTL1= VCTL2= VDD= 3.3V, SYNC = GND, FBSEL = High-Z, VFB= 0.7V, CREF= 0.22µF, TA= 0°C to +85°C, unless
otherwise noted. Typical values are at +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
SYNC = GND8.810.5LX Minimum Duty CycleVIN = 2.6V/3.3VSYNC = VCC17.6%
RMS LX Output Current6A
FBSEL
FBSEL rising0.160.22
FBSEL Input Threshold 1.8V
Where 1.8V feedback
switches in and out,
VCC = 2.6V/3.3V/5.5VFBSEL falling0.080.14
FBSEL risingVCC -
VCC -
0.08FBSEL Input Threshold 2.5V
Where 2.5V feedback
switches in and out,
VCC = 2.6V/3.3V/5.5VFBSEL fallingVCC -
VCC -
FBSEL Input Current LowILOW_
FBSELFBSEL = GND-50-20µA
FBSEL Input Current HighIHIGH_
FBSELFBSEL = VCC2050µA
CTL1 /CTL2
VIL_CTL_0.40.95CTL1/CTL2 Input ThresholdVIH_CTL_VIN = 2.6V to 5.5V1.01.6V
IIL_CTL_-1+1CTL1/CTL2 Input CurrentIIH_CTL_VCTL1 or VCTL2 = 0 or 5.5V, VIN = 5.5V-1+1µA
Soft-Start PeriodTime required for output to ramp up2.93.74.5ms
tHIGH_4%+4%160Time from Nominal to Margin
HightHIGH_9%+9%360µs
tLOW_4%-4%450Time from Nominal to Margin LowtLOW_9%-9%1000µs
SYNC
SYNC Capture RangeVIN = 2.6V to 5.5V0.41.2MHz
SYNC Pulse WidthtLO, tHIVIN = 2.6V to 5.5V250ns
VIL_SYNC0.400.95SYNC Input ThresholdVIH_SYNCVIN = 2.6V to 5.5V1.01.6V
SYNC Input CurrentIIL, IIHVSYNC = 0 or 5.5V, VIN = 5.5V-1+1µA
SYNCOUT
SYNCOUT Frequency RangefSYNCOUTVCC = 2.6V to 5.5V0.41.2MHz
VOH_SYNC
OUT
VCC -
VCC -
SYNCOUT Output Voltage
VOL_SYNC
OUT
ISYNCOUT = ±1mA, VCC = 2.6V to 5.5V
0.050.40
MAX1945R/MAX1945S
1MHz, 1% Accurate, 6A Internal Switch
Step-Down Regulators
ELECTRICAL CHARACTERISTICS (continued)
(VIN= VCC= VCTL1= VCTL2= VDD= 3.3V, SYNC = GND, FBSEL = High-Z, VFB= 0.7V, CREF= 0.22µF, TA= 0°C to +85°C, unless
otherwise noted. Typical values are at +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
THERMAL SHUTDOWN
Thermal-Shutdown Hysteresis20°C
Thermal-Shutdown ThresholdWhen LX stops switching165°C
ELECTRICAL CHARACTERISTICS
(VIN= VCC= VCTL1= VCTL2= VDD= 3.3V, SYNC = GND, FBSEL = High-Z, VFB= 0.7V, CREF= 0.22µF, TA= -40°C to +85°C, unless
otherwise noted.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
IN/VCC
Input VoltageVIN2.65.5V
IN Supply CurrentIINSYNC = VCC (1MHz),
no loadVIN = 3.3V20mA
VCC Supply CurrentICCSYNC = VCC (1MHz)VCC = 3.3V4mA
VDD Supply CurrentIDDSYNC = VCC (1MHz)VDD = 3.3V8mA
Total Shutdown Current from IN,
VCC, and VDDITOTALVIN = VCC = VDD = VBST - VLX = 5.5V,
CTL1 = CTL2 = GND500µA
VCC rising2.55VCC Undervoltage Lockout
ThresholdVUVLOWhen LX starts/stops
switchingVCC falling2.20V
VDD
VDD Shutdown Supply CurrentIVDDVIN = VDD = VBST = 5.5V, VLX = 5.5V or 0,
CTL1 = CTL2 = GND10µA
BST
BST Shutdown Supply CurrentIBSTVIN = VDD = VBST = 5.5V, VLX = 5.5V or 0,
CTL1 = CTL2 = GND10µA
REF
REF VoltageVREFIREF = 0, VIN = 2.6V to 5.5V1.962.04V
REF Shutdown ResistanceFrom REF to GND, CTL1 = CTL2 = GND100Ω
COMP
FBSEL = High-Z3085
FBSEL = GND13.337.8COMP TransconductanceFrom FB to COMP,
VCOMP = 1.25V
FBSEL = VCC9.627.2
COMP Clamp Voltage LowVLOW_
CLAMPVIN = 2.6V to 5.5V, VFB = 0.9V0.51.1V
COMP Clamp Voltage HighVHIGH_
CLAMPVIN = 2.6V to 5.5V, VFB = 0.7V1.902.40V
COMP Shutdown ResistanceFrom COMP to GND, CTL1 = CTL2 = GND100Ω

Partno	Mfg	Dc	Qty	Available	Descript
MAX1945REUI+	MAXIM	N/a	50	avai	1MHz, 1% Accurate, 6A Internal Switch Step-Down Regulators
MAX1945REUI+T \|MAX1945REUIT	MAXIM	N/a	2231	avai	1MHz, 1% Accurate, 6A Internal Switch Step-Down Regulators