MAX1917EEE+T ,Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination SuppliesMAX191719-2335; Rev 1; 6/02Tracking, Sinking and Sourcing, Synchronous BuckController for DDR Memor ..
MAX1917EEE+T ,Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination SuppliesFeaturesThe MAX1917 provides a complete power-manage-♦ 25A Sourcing and Sinking Currentment solutio ..
MAX1917EEE-T ,Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination SuppliesELECTRICAL CHARACTERISTICS(V+ = 12V, V = V = 2.5V, C = 4.7µF, C = 1µF, C = 0.22µF, V = 0, ILIM = VL ..
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MAX191ACWG+ ,Low-Power, 12-Bit Sampling ADC with Internal Reference and Power-Downfeatures an adjustment input for MAX191ACNG 0°C to +70°C 24 Narrow Plastic DIP ±1/2trimming system ..
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. Built-InT ..
MAX487EESA ,15kV ESD-Protected / Slew-Rate-Limited / Low-Power / RS-485/RS-422 TransceiversApplicationsIndustrial-Control Local Area Networks__Selection TableRECEIVER/ QUIESCENT NUMBER OFPAR ..
MAX487EESA ,15kV ESD-Protected / Slew-Rate-Limited / Low-Power / RS-485/RS-422 Transceiversapplications. For
MAX487EESA ,15kV ESD-Protected / Slew-Rate-Limited / Low-Power / RS-485/RS-422 TransceiversApplicationsMAX481EESA -40°C to +85°C 8 SOLow-Power RS-485 TransceiversOrdering Information continu ..
MAX487EESA ,15kV ESD-Protected / Slew-Rate-Limited / Low-Power / RS-485/RS-422 TransceiversApplicationsMAX481EESA -40°C to +85°C 8 SOLow-Power RS-485 TransceiversOrdering Information continu ..
MAX487EESA+ ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversApplications:MAX491E, and MAX1487E are low-power transceivers forMAX3430: ±80V Fault-Protected, Fai ..
MAX487EESA+T ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversApplications:MAX491E, and MAX1487E are low-power transceivers forMAX3430: ±80V Fault-Protected, Fai ..
MAX1917EEE+-MAX1917EEE+T-MAX1917EEE-T
Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination Supplies
General DescriptionThe MAX1917 provides a complete power-manage-
ment solution for DDR memory. It contains a synchro-
nous buck controller and an amplifier to generate
1/2VDDRvoltage for VTT and VTTR. The VTT and VTTR
voltages are maintained within 1% of 1/2VDDR. The
controller operates in synchronous rectification mode to
ensure balanced current sourcing and sinking capabili-
ty of up to 25A. With a shutdown current of less than
5µA, the MAX1917 is the best choice for low-power
notebook applications, as well as servers and desktop
computers. An all N-FET design optimizes efficiency.
The MAX1917 can also be used for generating VDDR
and as a general-purpose step-down controller with
variable switching frequency as high as 1MHz with few
additional components.
The MAX1917 uses Maxim’s proprietary Quick-PWM™
architecture for fast transient response up to 96% effi-
ciency, and the smallest external components. Output
current monitoring is achieved without sense resistors
by monitoring the bottom FET’s drain-to-source voltage.
The current-limit threshold is programmable through an
external resistor. The MAX1917 comes in a space-sav-
ing 16-pin QSOP package.
Applications
Features25A Sourcing and Sinking CurrentAutomatically Sets VTT to 1/2VDDRVTT and VTTR Within 1% of 1/2VDDRSmallest Output Capacitors4.5V to 14V (or 28V with Resistor-Divider) Input
Voltage Range1.5V to 3.6V Input DDR Range 200kHz/300kHz/400kHz/550kHz Preset Switching
FrequenciesVariable Switching Frequency of Up to 1MHzOvercurrent Protection Without Current-Sense
ResistorInternal Soft-StartVTTR Reference Sources and Sinks Up to 25mAQuick-PWM Control for Fastest Loop ResponseUp to 96% Efficiency16-Pin QSOP Package
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
Ordering InformationMAX1917
VIN (2.5V TO 15V)
POK
VDDR
EN/HSD
POK
DDR
REF
ILIM
FSEL
GND
BST
PGND
VTT
VTTR
VOUT
VTTR
(4.5V TO 14V)
ypical Operating Circuit19-2335; Rev 1; 6/02
PARTTEMP RANGEPIN-PACKAGEMAX1917EEE-40°C to +85°C16 QSOP
EN/HSDLX
BST
PGND
VTTR
TOP VIEW
MAX1917EEE
QSOPDDR
POK
FSEL
VTT
ILIM
REF
GND
Pin ConfigurationQuick-PWM is a trademark of Maxim Integrated Products, Inc.
DDR Memory Power
Supply
Processor or DSP Core
Supply
AGTL Bus Termination
Supply
Notebook Computers
Desktop Computers
Storage
Networking Systems
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(V+ = 12V, VEN/HSD= VDDR= 2.5V, CVL= 4.7µF, CVTTR= 1µF, CREF= 0.22µF, VFSEL= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise specified.)
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.
V+ to GND..............................................................-0.3V to +15V
EN/HSD to GND.....................................................-0.3V to +16V
VL to GND................................................................-0.3V to +6V
PGND to GND.......................................................-0.3V to +0.3V
VTT, DDR, POK to GND...........................................-0.3V to +6V
REF, VTTR, DL, ILIM, FSEL to GND................-0.3V to VL + 0.3V
LX to PGND............................................................-0.3V to +30V
BST to GND............................................................-0.3V to +36V
DH to LX......................................................-0.3V to VBST+ 0.3V
LX to BST..................................................................-6V to +0.3V
REF Short Circuit to GND...........................................Continuous
Continuous Power Dissipation (TA= +70°C)
16-Pin QSOP (derate up to +70°C)..............................667mW
16-Pin QSOP (derating above +70°C).....................8.3mW/°C
Operating Temperature Range
Extended.........................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering 10s.).................................+300°C
PARAMETERCONDITIONSMINTYPMAXUNITS5.514.0V+ Input Voltage RangeVL = V+4.55.5V
EN/HSD Input Voltage RangeEnabled1.515.0V
DDR Input Voltage Range03.6V
V+ Supply CurrentVTT = 2.0V0.81.2mA
DDR Supply Current115250µA
EN/HSD Supply Current510µA
VL Supply CurrentVL = V+ = 5.5V, VTT = 2.0V0.81.2mA
V+ Shutdown Supply CurrentEN/HSD = 0V35µA
DDR Shutdown Supply CurrentEN/HSD = 0V1µA
VL Shutdown Supply CurrentVL = V+ = 5.5V35µA
VL Undervoltage Lockout
ThresholdRising edge, hysteresis = 40mV4.054.254.40V
VTTVTT Input Bias CurrentVVTT = 2.5V-0.10µA
VTT Feedback Voltage Range01.8V
Overload range, VDDR = 1.8V49.55050.5VTT Feedback Voltage
AccuracyOverload range, VDDR = 3.6V49.55050.5%VDDR
REFERENCEReference Output VoltageV+ = VL = 4.5V to 5.5V, IREF = 01.982.002.02V
Reference Load RegulationV+ = VL = 5V, IREF = 0 to 50µA10mV
Reference UVLOV+ = VL = 5V1.51.61.7V
VTTRVTTR Output Voltage Range01.8V
IVTTR = -5mA to +5mA49.55050.5
IVTTR = -25mA to +25mA, VDDR = 1.8V495051VTTR Output Accuracy
IVTTR = -25mA to +25mA, VDDR = 3.6V49.55050.5
%VDDR
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
ELECTRICAL CHARACTERISTICS (continued)(V+ = 12V, VEN/HSD= VDDR= 2.5V, CVL= 4.7µF, CVTTR= 1µF, CREF= 0.22µF, VFSEL= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise specified.)
PARAMETERCONDITIONSMINTYPMAXUNITSThermal Shutdown Rising temperature, typical hysteresis = 15°C +160 °C
SOFT-STARTILIM Ramp Period Ramps the ILIM trip threshold from 20% to 100%
in 20% increments 1.7 ms
OSCILLATORFSEL = VL 200
FSEL = unconnected300
FSEL = REF400 Oscillator Frequency
FSEL = GND550
kHzFSEL = VL 2.18 2.5 2.83
FSEL not connected1.451.671.89
FSEL = REF 1.09 1.25 1.41 On Time (Note 1)
FSEL = GND0.820.911.00Minimum Off Time (Note 1) 350 400 ns
CURRENT LIMITLX to PGND, ILIM = VL90100110
LX to PGND, RILIM = 100kΩ405060Current-Limit Threshold
(Positive Direction)LX to PGND, RILIM = 400kΩ170200230
Current-Limit Threshold
(Negative Direction)
LX to PGND, ILIM = VL, with percentage of positive
current-limit threshold-90-110-130%
ILIM Input Current5µA
VL REGULATOROutput Voltage5.5V < V+ < 14V
1mA < IVL < 35mA4.85.05.2V
Line Regulation5.5V < V+ < 14V, IVL = 10mA0.2%
RMS Output Current35mA
Bypass CapacitorESR < 100mΩ2.2µF
DRIVERDH Gate-Driver On-ResistanceVBST - VLX = 5V1.42.5Ω
DL Gate-Driver On-Resistance
(Source)DL high state1.63Ω
DL Gate-Driver On-Resistance
(Sink)DL low state0.751.25Ω
DL rising32Dead TimeDL falling30ns
FSEL LOGICLogic Input Current-33µA
Logic GND Level0.5V
Logic REF LevelFSEL = VREF1.652.35V
Logic Float LevelFSEL floating3.153.85V
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
ELECTRICAL CHARACTERISTICS (continued)(V+ = 12V, VEN/HSD= VDDR= 2.5V, CVL= 4.7µF, CVTTR= 1µF, CREF= 0.22µF, VFSEL= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for TA
= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise specified.)
PARAMETERCONDITIONSMINTYPMAXUNITSLogic VL LevelFSEL = VLVL - 0.4V
EN/HSD LOGICEN/HSD Shutdown CurrentMax IEN/HSD for VEN/HSD = 0.8V0.53.0µA
Logic HighVL = V+ = 4.5V to 5.5V, 100mV hysteresis1.45V
Logic LowVL = V+ = 4.5V to 5.5V0.8V
POWER-OK OUTPUTUpper VTT Threshold110112114%VDDR/
Lower VTT Threshold868890%VDDR/
Upper VTTR Threshold110112114%VDDR/
Lower VTTR Threshold868890%VDDR/
POK Output Low LevelISINK = 2mA0.4V
POK Output High LeakageVPOK = 5.5V5µA
ELECTRICAL CHARACTERISTICS(V+ = 12V, VEN/HSD= VDDR= 2.5V, CVL= 4.7µF, CVTTR= 1µF, CREF= 0.22µF, VFSEL= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for TA
= -40°C to +85°C, unless otherwise specified.) (Note 2)
PARAMETERCONDITIONSMINTYPMAXUNITS5.514.0VV+ Input Voltage RangeVL = V+4.55.5V
EN/HSD Input Voltage RangeEnabled1.515.0V
DDR Input Voltage Range03.6V
V+ Supply CurrentVTT = 2.0V1.2mA
DDR Supply Current250µA
EN/HSD Supply CurrentVEN/HSD = 2.5V10µA
VL Supply CurrentVL = V+ = 5.5V1.2mA
V+ Shutdown Supply CurrentEN/HSD = 0V5µA
DDR Shutdown Supply CurrentEN/HSD = 0V1µA
VL Shutdown Supply CurrentVL = V+ = 5.5V5µA
VL Undervoltage Lockout
ThresholdRising edge, hysteresis = 40mV4.054.40V
VTTVTT Input Bias CurrentVVTT = 2.5V-0.150µA
VTT Feedback Voltage Range01.8V
Overload range, VDDR = 1.8V49.550.5VTT Feedback Voltage
AccuracyOverload range, VDDR = 3.6V49.550.5%VDDR
REFERENCEReference Output VoltageV+ = VL = 4.5V to 5.5V, IREF = 01.982.02V
Reference Load RegulationV+ = VL = 5V, IREF = 0 to 50µA10mV
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
ELECTRICAL CHARACTERISTICS (continued)(V+ = 12V, VEN/HSD= VDDR= 2.5V, CVL= 4.7µF, CVTTR= 1µF, CREF= 0.22µF, VFSEL= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for TA
= -40°C to +85°C, unless otherwise specified.) (Note 2)
PARAMETERCONDITIONSMINTYPMAXUNITSReference UVLOV+ = VL = 5V1.51.7V
VTTRVTTR Output Voltage Range01.8V
IVTTR = -5mA to +5mA49.550.5
IVTTR = -25mA to +25mA, VDDR = 1.8V4951VTTR Output Accuracy
IVTTR = -25mA to +25mA, VDDR = 3.6V49.550.5
%VDDR
OSCILLATORFSEL = VL2.182.83
FSEL not connected1.451.89
FSEL = REF1.091.41 On Time (Note 1)
FSEL = GND0.821.00Minimum Off Time (Note 1) 400 ns
CURRENT LIMITLX to PGND, ILIM = VL85110
LX to PGND, RILIM = 100kΩ3560Current-Limit Threshold
(Positive Direction)
LX to PGND, RILIM = 400kΩ160230
Current-Limit Threshold
(Negative Direction)
LX to PGND, ILIM = VL, with percentage of positive
current-limit threshold-90-130%
VL REGULATOROutput Voltage 5.5V < V+ < 14V; 1mA < IVL < 35mA 4.8 5.2 VRMS Output Current 35 mABypass Capacitor ESR < 100mΩ 2.2 µF
FSEL LOGICLogic Input Current3µA
Logic GND Level0.5V
Logic REF LevelFSEL = VREF1.652.35V
Logic Float LevelFSEL floating3.153.85V
Logic VL LevelFSEL = VLVL - 0.4V
EN/HSD LOGICEN/HSD Shutdown CurrentIEN/HSD for VEN/HSD = 0.8V0.53.0µA
Logic HighVL = V+ = 4.5V to 5.5V, 100mV hysteresis1.45V
Logic LowVL = V+ = 4.5V to 5.5V0.8V
POWER-OK OUTPUTUpper VTT Threshold110114%VDDR
Lower VTT Threshold8690%VDDR
Note 1:On Time and Off Time specifications are measured from 50% point to 50% point at the DH pin with LX forced to 0V, BST
forced to 5V, and a 250pF capacitor connected from DH to LX. Actual in-circuit times may differ due to MOSFET switching
speeds.
Note 2:Specifications to -40°C are guaranteed by design and are not production tested.
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
ELECTRICAL CHARACTERISTICS (continued)(V+ = 12V, VEN/HSD= VDDR= 2.5V, CVL= 4.7µF, CVTTR= 1µF, CREF= 0.22µF, VFSEL= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for TA
= -40°C to +85°C, unless otherwise specified.) (Note 2)
PARAMETERCONDITIONSMINTYPMAXUNITSUpper VTTR Threshold110114%VDDR
Lower VTTR Threshold8690%VDDR
POK Output Low LevelISINK = 2mA0.4V
POK Output High LeakageVPOK = 5.5V5µA
EFFICIENCY vs. LOAD CURRENT
AT 1.25V OUTPUT
MAX1917 toc01
LOAD CURRENT (A)
EFFICIENCY (%)70
VIN = 5V
VIN = 2V
VIN = 2.5V
CIRCUIT OF FIGURE 3
EFFICIENCY vs. LOAD CURRENT
AT 0.9V OUTPUT
MAX1917 toc02
LOAD CURRENT (A)
EFFICIENCY (%)84
VIN = 5V
VIN = 2.5V
CIRCUIT OF FIGURE 3
EFFICIENCY vs. LOAD CURRENT
AT 1.25V OUTPUT
MAX1917 toc03
LOAD CURRENT (A)
EFFICIENCY (%)40
VIN = 12V
VIN = 2.5V
CIRCUIT OF FIGURE 4
VIN = 5V
EFFICIENCY vs. LOAD CURRENT
AT 0.9V OUTPUT
MAX1917 toc04
EFFICIENCY (%)65
CIRCUIT OF FIGURE 4
VIN = 5V
VIN = 2.5V
FREQUENCY vs. LOAD CURRENT
AT 1.25V OUTPUT
MAX1917 toc05
FREQUENCY (kHz)
VIN = 12V
CIRCUIT OF FIGURE 3
VIN = 5V
VIN = 2.5V
FREQUENCY vs. LOAD CURRENT
AT 0.9V OUTPUT
MAX1917 toc06
FREQUENCY (kHz)
CIRCUIT OF FIGURE 3
VIN = 5V
VIN = 2.5V
Typical Operating Characteristics(V+ = 12V, VOUT= 1.25V, TA= +25°C, unless otherwise noted.)
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination SuppliesFREQUENCY vs. INPUT VOLTAGE
MAX1917 toc07
INPUT VOLTAGE (V)
FREQUENCY (kHz)
CIRCUIT OF FIGURE 3
IOUT = 7A
IOUT = 0.1A
FREQUENCY vs. TEMPERATURE
MAX1917 toc08
TEMPERATURE (°C)
FREQUENCY (kHz)
CIRCUIT OF FIGURE 3
ILOAD = 3.5A
SHUTDOWN CURRENT
vs. INPUT VOLTAGE
MAX1917 toc09
INPUT VOLTAGE (V)
SHUTDOWN CURRENT (
CIRCUIT OF FIGURE 6
SHUTDOWN CURRENT
vs. INPUT VOLTAGE
MAX1917 toc10
INPUT VOLTAGE (V)
SHUTDOWN CURRENT (mA)
CIRCUIT OF FIGURE 31.22
LOAD REGULATION WITHOUT
DROOP RESISTOR
MAX1917 toc11
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)
VDDR = 2.5V
VIN = 5V
VIN = 12V
VIN = 2.5V
LOAD REGULATION WITH
DROOP RESISTOR
MAX1917 toc12
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)
VDDR = 2.5V
VIN = 12V
VIN = 5V
VIN = 2.5V
MAX1917 toc13
IOUT
5A/div
VVTT
50mV/div
20μs/div
TRANSIENT LOAD RESPONSE
WITHOUT DROOP RESISTORCIRCUIT OF FIGURE 3
MAX1917 toc14
IOUT
5A/div
VVTT
50mV/div
20μs/div
TRANSIENT LOAD RESPONSE
WITH DROOP RESISTORCIRCUIT OF FIGURE 3
MAX1917 toc15
VOUT
1V/div
VPOK
5V/div
VDDR
2.5V
VEN/HSD
10V/div
400μs/div
POWER-UP WITH VDDR TRACKING
Typical Operating Characteristics (continued)(V+ = 12V, VOUT= 1.25V, TA= +25°C, unless otherwise noted.)
Pin Description
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
CURRENT LIMIT vs. TEMPERATUREMAX1917 toc16
TEMPERATURE (°C)
CURRENT LIMIT (A)6020400-20
RILIM = 402kΩ
RILIM = 200kΩ
MAX1917 toc17
VIN (V)
INDUCTOR CURRENT (A)119753
INDUCTOR PEAK AND VALLEY CURRENT
vs. INPUT VOLTAGE AT CURRENT LIMIT
IPEAK
IVALLEY
CIRCUIT OF FIGURE 3
RILIM = 400kΩ
ypical Operating Characteristics (continued)(V+ = 12V, VOUT= 1.25V, TA= +25°C, unless otherwise noted.)
PINNAMEFUNCTIONEN/HSDEnable/High-Side Drain. Connect to the high-side N-FET drain for normal operation. Leave unconnected or
connect to GND for low-power shutdown.DDRDDR Reference Input. An applied voltage at DDR sets VVTT and VVTTR to 1/2VDDR. DDR voltage range is
from 0 to 3.6V.POKPower-OK Output. POK is an open-drain output and is logic high when both VTT and VTTR are within 12%
of regulation. POK is pulled low in shutdown.VTTVTT Feedback Input. Connect to VTT output.ILIMCurrent-Limit Threshold Adjustment. Connect a resistor from ILIM to GND to set the current-limit threshold,
or connect ILIM to VL for default setting. See the Setting the Current Limit section.FSELFrequency Select. Selects the switching frequency of the MAX1917. See Table 1 for configuration of FSEL.REFReference Bypass. Connect a 0.22µF or larger capacitor from REF to GND.GNDGroundVTTRVTTR Reference Output. Connect a 1µF or larger capacitor from VTTR to GND. VTTR is capable of
sourcing and sinking up to 25mA.V+Input Supply Voltage. Supply input for the VL regulator and the VTTR regulator. Bypass with a 0.22µF or
larger capacitor.VLInternal Regulator Output. Connect a 2.2µF or larger capacitor from VL to GND. VL can be connected to
V+ if the operating range is 4.5V to 5.5V.DLLow-Side MOSFET Gate Drive. Connect to the gate of the low-side N-channel MOSFET.PGNDPower GroundBSTBootstrapped Supply to Drive High-Side N-Channel MOSFET. Connect a 0.47µF or larger capacitor from
BST to LX.DHHigh-Side MOSFET Gate Drive. Connect to the high-side N-channel MOSFET gate.LXInductor Switching Node
MAX1917racking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
Functional DiagramON TIME
COMPUTE
VTTFSEL
POK
DDR
EN/HSD
VTTR
GND
REF
VTT
PGND
BST
ILIM
1-SHOT
TRIGQ
TON
1-SHOT
5μA
TRIGQ
REF
REF
MAX1917
