MAX1887 ,Quick-PWM Slave Controllers for Multiphase, Step-Down Suppliesfeatures.200kHz/300kHz/550kHz (MAX1897) SwitchingSynchronized to the master’s low-side gate driver, ..
MAX1887EEE ,4.0-28 V, quick-PWM slave controller for multiphase, step-down supplieMAX1887/MAX189719-2188; Rev 1; 9/02Quick-PWM Slave Controllers for Multiphase, Step-Down Supplies
MAX1889ETE ,Triple-Output TFT LCD Power Supply with Fault ProtectionFeaturesThe MAX1889 provides the three regulated output volt- High-Performance Step-Up Regulatora ..
MAX1889ETE+ ,Triple-Output TFT LCD Power Supply with Fault ProtectionApplicationsNotebook Computer DisplaysTOP VIEWLCD Monitors 16 15 14 13Car Navigation DisplaysSHDN 1 ..
MAX1889ETE+T ,Triple-Output TFT LCD Power Supply with Fault ProtectionFeaturesThe MAX1889 provides the three regulated output volt- ♦ High-Performance Step-Up Regulatora ..
MAX188ACPP ,Low-Power, 8-Channel, Serial 12-Bit ADCsGeneral Description ________
MAX4838EXT-T ,Overvoltage Protection Controllers with Status FLAGApplicationsTypical Operating CircuitCell PhonesDigital Still CamerasPDAs and Palmtop DevicesINPUTO ..
MAX483CPA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversFeaturesThe MAX481, MAX483, MAX485, MAX487–MAX491, and' In µMAX Package: Smallest 8-Pin SOMAX1487 a ..
MAX483CPA+ ,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 ..
MAX483CSA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplicationsMAX481C/D 0°C to +70°C Dice*Industrial-Control Local Area NetworksOrdering Information ..
MAX483CSA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplications ______________Ordering InformationLow-Power RS-485 TransceiversPART TEMP. RANGE PIN-PA ..
MAX483CSA ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplications ______________Ordering InformationLow-Power RS-485 TransceiversPART TEMP. RANGE PIN-PA ..
MAX1887
Quick-PWM Slave Controllers for Multiphase, Step-Down Supplies
General DescriptionThe MAX1887/MAX1897 step-down slave controllers are
intended for low-voltage, high-current, multiphase DC-to-
DC applications. The MAX1887/MAX1897 slave con-
trollers can be combined with any of Maxim’s
Quick-PWM™ step-down controllers to form a multiphase
DC-to-DC converter. Existing Quick-PWM controllers,
such as the MAX1718, function as the master controller,
providing accurate output voltage regulation, fast tran-
sient response, and fault protection features.
Synchronized to the master’s low-side gate driver, the
MAX1887/MAX1897 include the Quick-PWM constant on-
time controller, gate drivers for a synchronous rectifier,
active current balancing, and precision current-limit cir-
cuitry.
The MAX1887/MAX1897 provide the same high effi-
ciency, ultra-low duty factor capability, and excellent
transient response as other Quick-PWM controllers. The
MAX1887/MAX1897 differentially sense the inductor
currents of both the master and the slave across cur-
rent-sense resistors. These differential inputs and the
adjustable current-limit threshold derived from an exter-
nal reference allow the slave controller to accurately
balance the inductor currents and provide precise cur-
rent-limit protection. The MAX1887/MAX1897’s dual-
purpose current-limit input also allows the slave
controller to automatically enter a low-power standby
mode when the master controller shuts down.
The MAX1887 triggers on the rising edge of the mas-
ter’s low-side gate driver, which staggers the on-times
of both master and slave, providing out-of-phase oper-
ation that can reduce the input ripple current and con-
sequently the number of input capacitors. The
MAX1897 features a selectable trigger polarity, allowing
out-of-phase or simultaneous in-phase operation.
ApplicationsNotebook Computers
CPU Core Supply
Single-Stage (BATT to VCORE) Converters
Two-Stage (5V to VCORE) Converters
Servers/Desktop Computers
Telecom
FeaturesQuick-PWM Slave ControllerPrecise, Active Current Balance (±1.25mV )Accurate, Adjustable Current-Limit ThresholdOptimized for Low-Output Voltages (≤2V)4V to 28V Battery Input RangeFixed 300kHz (MAX1887) or Selectable
200kHz/300kHz/550kHz (MAX1897) Switching
FrequencyDrive Large Synchronous-Rectifier MOSFETs525µA (typ) ICCSupply Current20µA Standby Supply Current<1µA Shutdown (MAX1897) Supply CurrentSmall 16-Pin QSOP (MAX1887), Compact
20-Pin 5mm x 5mm QFN (MAX1897), or
20-Pin 5mm x 5mm Thin QFN (MAX1897)
MAX1887/MAX1897
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies191817168910
THIN QFN 5mm x 5mmTOP VIEW
MAX1897CM+
CM-
TON
CS-
CS+
VCC
VDD
SHDN
PGND
GND
POL
COMP
TRIGILIMLIMITV+BST
Pin Configuration19-2188; Rev 1; 9/02
Ordering Information
PARTTEMP RANGEPIN-PACKAGE
MAX1887EEE-40°C to +85°C16 QSOP
A X1 8 9 7E GP*-40°C to +85°C20 QFN 5mm ✕ 5mm
MAX1897ETP-40°C to +85°C20 Thin QFN 5mm ✕ 5mm
Typical Operating Circuit appears at end of data sheet.
Pin Configurations continued at end of data sheet.Quick-PWM is a registered trademark of Maxim Integrated
Products, Inc.
*Contact factory for availability.
MAX1887/MAX1897
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
ABSOLUTE MAXIMUM RATINGSStresses 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.
V+ to GND..............................................................-0.3V to +30V
VCC, VDDto GND (Note 3).......................................-0.3V to +6V
PGND to GND.....................................................................±0.3V
TRIG, LIMIT to GND.................................................-0.3V to +6V
SHDNto GND (MAX1897)........................................-0.3V to +6V
ILIM, CM+, CM-, CS+, CS-, COMP
to GND....................................................-0.3V to (VCC+ 0.3V)
TON, POL to GND (MAX1897)...................-0.3V to (VCC+ 0.3V)
DL to PGND................................................-0.3V to (VDD+ 0.3V)
BST to GND............................................................-0.3V to +36V
DH to LX....................................................-0.3V to (VBST+ 0.3V)
LX to BST..................................................................-6V to +0.3V
Continuous Power Dissipation (TA= +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW
20-Pin 5mm x 5mm QFN (derate 20.0mW/°C
above +70°C)..............................................................1.60W
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
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V+ = 15V, VCC= VDD= 5V, VOUT= VCOMP= 1.2V, VCM+= VCM-= VCS+= VCS-= 1.2V, SHDN= VCC
(MAX1897), TA
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
PWM CONTROLLERBattery voltage, V+4.028.0Input Voltage RangeVCC, VDD4.55.5VAX 1887 ( 300kH z) , V + = 12V , V C OM P = 1.2V 320355390
TON = GND171190209
TON = open320355390On-Time (Note 1)tONMAX1897,
V+ = 12V,
VCOMP = 1.2VTON = VCC464515566
Trigger Delay (Note 2)tTRIG75ns
SUPPLY CURRENTSQuiescent Supply Current (V+)I+Measured at V+; VILIM > 0.35V2540µA
MAX1887525800Quiescent Supply Current (VDD)
(Note 3)IDDMeasured at VDD; VILIM
> 0.35VMAX1897<15µA
Quiescent Supply Current (VCC)
(MAX1897, Note 3)ICCMeasured at VCC; VILIM > 0.35V525800µA
Standby Supply Current (V+)Measured at V+; ILIM = GND<15µA
MAX18872040Standby Supply Current (VDD)
(Note 3)
Measured at VDD; ILIM
= GNDMAX1897<15µA
Standby Supply Current (VCC)
(MAX1897, Note 3)Measured at VCC; ILIM = GND2040µA
Shutdown Supply Current (V+)
(MAX1897)
Measured at V+; VCC = VDD = 0 or 5V,
SHDN = GND<15µA
Shutdown Supply Current (VDD)
(MAX1897, Note 3)Measured at VDD; SHDN = GND<15µA
Shutdown Supply Current (VCC)
(MAX1897, Note 3)Measured at VCC; SHDN = GND<15µA
MAX1887/MAX1897
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, V+ = 15V, VCC= VDD= 5V, VOUT= VCOMP= 1.2V, VCM+= VCM-= VCS+= VCS-= 1.2V, SHDN= VCC
(MAX1897), TA
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
CURRENT SENSINGOn-Time Adjustment Range0.42 < VCOMP < 2.8V, VOUT ≥ 0.7V-40+40%
COMP Output CurrentICOMPSink and source30µA
MAX1887-1.25+1.25
Current-Balance Offset
(VCM+ - VCM-) -
(VCS+ - VCS-), ICOMP =
0, -100mV ≤ (VCM+ -
VCM-) ≤ +100mVMAX1897-1.25+1.25
Current-Balance
Transconductance(VCM+ - VCM-) - (VCS+ - VCS-) = ±25mV1.2mS
Current-Sense, Common-Mode
RangeCM+, CM-, CS+, CS--0.2+2.0V
Current-Sense Input CurrentCM+, CM-, CS+, CS--1+1µA
VILIM = 0.5V47.550.052.5Positive Current-Limit ThresholdVC_LIMVCM+ - VCM- and
VCS+ - VCS-VILIM = 1V97.5100.0102.5mV
VILIM = 0.5V-80-75-70Negative Current-Limit
ThresholdVCS+ - VCS-VILIM = 1V-160-150-140mV
ILIM Standby Threshold Voltage0.20.3V
ILIM Input Current-100+100nA
LIMIT Propagation DelaytLIMITFalling edge, 3mV over trip threshold1.5µs
LIMIT Output Low VoltageVOL(LIMIT)ISINK = 1mA0.1V
LIMIT Leakage CurrentILIMITLIMIT forced to 5.5V< 0.011.00µA
FAULT PROTECTIONVCC/VDD Undervoltage Lockout
Threshold (Note 3)
Rising edge, hysteresis = 20mV, switching
disabled below this level3.453.85V
Thermal Shutdown ThresholdRising, hysteresis = 15°C (typ)160°C
GATE DRIVERSMAX18871.03.5DH Gate-Driver On-Resistance
(Note 4)RON ( D H ) VBST - VLX forced to 5VMAX18971.04.5Ω
MAX18871.03.5High state (pullup)MAX18971.04.5
MAX18870.41.0
DL Gate-Driver On-Resistance
(Note 4)RON(DL)
Low state (pulldown)MAX18970.42.0
DH Gate-Driver Source/Sink
CurrentIDHDH forced to 2.5V, VBST - VLX forced to 5V1.3A
DL Gate-Driver Sink CurrentIDLDL forced to 2.5V4.0A
DL Gate-Driver Source CurrentIDLDL forced to 2.5V1.3A
DL rising35Dead TimeDH rising26ns
MAX1887/MAX1897
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V+ = 15V, VCC= VDD= 5V, VOUT= VCOMP= 1.2V, VCM+= VCM-= VCS+= VCS-= 1.2V, SHDN= VCC
(MAX1897), TA
= -40°C to +85°C, unless otherwise noted.) (Note 5)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
PWM CONTROLLERAX 1887 ( 300kH z) , V + = 12V , V C OM P = 1.2V 320390
TON = GND (550kHz)171209
TON = open (300kHz)320390On Time (Note 3)tONMAX1897,
V+ = 12V,
VCOMP = 1.2VTON = VCC (200kHz)464566
SUPPLY CURRENTSQuiescent Supply Current (V+)I+Measured at V+; VILIM > 0.35V40µA
MAX1887800Quiescent Supply Current (VDD)
(Note 3)IDDMeasured at VDD;
VILIM > 0.35VMAX18975µA
Quiescent Supply Current (VCC)
(MAX1897, Note 3)ICCMeasured at VCC; VILIM > 0.35V800µA
Standby Supply Current (V+)Measured at V+; ILIM = GND5µA
MAX188740Standby Supply Current (VDD)
(Note 3)
Measured at VDD;
ILIM = GNDMAX18975µA
Standby Supply Current (VCC)
(MAX1897, Note 3)Measured at VCC; ILIM = GND40µA
Shutdown Supply Current (V+)
(MAX1897)
Measured at V+; VCC = VDD = 0 or 5V,
SHDN = GND5µA
Shutdown Supply Current (VDD)
(MAX1897, Note 3)Measured at VDD; SHDN = GND5µA
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, V+ = 15V, VCC= VDD= 5V, VOUT= VCOMP= 1.2V, VCM+= VCM-= VCS+= VCS-= 1.2V, SHDN= VCC
(MAX1897), TA
= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
LOGICLogic Input High Voltage
(MAX1897)VIHSHDN, POL; VCC = 4.5V to 5.5V2.4V
Logic Input Low Voltage
(MAX1897)VILSHDN, POL; VCC = 4.5V to 5.5V0.8V
High3.0TRIG Logic LevelsVTRIG350mV hysteresisLow1.2V
Logic high (VCC; 200kHz operation)VCC - 0.4
Open (300kHz operation)1.53.1TON Logic Levels (MAX1897)VTON
Logic low (GND; 550kHz operation)0.5
TRIG-1+1
SHDN (MAX1897)-1+1
POL (MAX1897)-2+1Logic Input Current
TON = GND or VDD (MAX1897)-2+3
MAX1887/MAX1897
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, V+ = 15V, VCC= VDD= 5V, VOUT= VCOMP= 1.2V, VCM+= VCM-= VCS+= VCS-= 1.2V, SHDN= VCC
(MAX1897), TA
= -40°C to +85°C, unless otherwise noted.) (Note 5)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSShutdown Supply Current (VCC)
(MAX1897, Note 3)Measured at VCC; SHDN = GND5µA
CURRENT SENSINGOn-Time Adjustment Range0.42 < VCOMP < 2.8V, VOUT ≥ 0.7V-40+40%
COMP Output CurrentICOMPSink and source30µA
MAX1887-2.0+2.0
Current-Balance Offset
(VCM+ - VCM-) -
(VCS+ - VCS-), ICOMP = 0,
-100mV ≤ (VCM+ - VCM-)≤ +100mVMAX1897-2.0+2.0
Current-Sense, Common-Mode
RangeCM+, CM-, CS+, CS--0.2+2.0V
VILIM = 0.5V47.552.5Positive Current-Limit ThresholdVC_LIMVCM+ - VCM- and
VCS+ - VCS-VILIM = 1V97.5102.5mV
VILIM = 0.5V-80-70Negative Current-Limit
ThresholdVCS+ - VCS-VILIM = 1V-160-140mV
ILIM Standby Threshold Voltage0.20.3V
FAULT PROTECTIONVCC/VDD Undervoltage Lockout
Threshold (Note 3)
Rising edge, hysteresis = 20mV, switching
disabled below this level3.453.85V
GATE DRIVERSMAX18873.5DH Gate-Driver On-Resistance
(Note 4)RON ( D H ) VBST - VLX forced toMAX18974.5Ω
MAX18873.5High state (pullup)MAX18974.5
MAX18871.0
DL Gate-Driver On-Resistance
(Note 4)RON(DL)
Low state (pulldown)MAX18972.0
LOGICHigh3.0TRIG Logic LevelsVTRIG350mV hysteresisLow1.2V
Logic high (VCC; 200kHz operation)VCC - 0.4
Open (300kHz operation)1.53.1TON Logic Levels (MAX1897)VTON
Logic low (GND; 550kHz operation)0.5
Note 1:On-time and off-time specifications are measured from 50% point to 50% point at the DH pin with LX = PGND, VBST= 5V, and a
500pF capacitor from DH to LX to simulate external MOSFET gate capacitance. Actual in-circuit times may be different due to
MOSFET switching speeds.
Note 2:The trigger delay time, tTRIG, is measured from the time the TRIG pin transitions to time when the DL pin goes low.
Note 3:The 20-pin MAX1897 has a separate analog PWM supply voltage input (VCC) and gate-driver supply input (VDD). For the 16-pin
MAX1887 device, the analog PWM supply voltage input and the gate-driver supply voltage input are internally connected and
named VDD.
Note 4:Production testing limitations due to package handling require relaxed maximum on-resistance specifications for the MAX1897’s
QFN package. The MAX1887 and MAX1897 contain the same die, and the QFN package imposes no additional resistance in-
circuit.
