MAX1515ETG+ ,Low-Voltage, Internal Switch, Step-Down/DDR Regulatorfeatures dual internal♦ 1MHz Maximum Switching Frequencyn-channel MOSFET power switches for high ef ..
MAX1515ETG+T ,Low-Voltage, Internal Switch, Step-Down/DDR RegulatorApplications VCCMAX1515 V = VOUT TTNotebook DDR Memory Termination COMPLXPGOODFBActive-Termination ..
MAX1517ETJ ,TFT-LCD DC-DC Converters with Operational AmplifiersFeaturesThe MAX1516/MAX1517/MAX1518 include a high-perfor-♦ 2.6V to 5.5V Input Supply Rangemance st ..
MAX1517ETJ+ ,TFT-LCD DC-DC Converters with Operational AmplifiersFeaturesThe MAX1516/MAX1517/MAX1518 include a high-perfor-♦ 2.6V to 5.5V Input Supply Rangemance st ..
MAX1517ETJ+T ,TFT-LCD DC-DC Converters with Operational AmplifiersELECTRICAL CHARACTERISTICS(V = 3V, V = 8V, PGND = AGND = BGND = 0, I = 25µA, T = 0°C to +85°C. Typi ..
MAX1517ETJ+TG104 ,TFT-LCD DC-DC Converters with Operational AmplifiersApplicationsCONTROLLERPGNDNotebook Computer DisplaysCOMPVCPAGNDLCD Monitor PanelsMAX1518DRVPAutomot ..
MAX4163EUA ,SOT23 / Micropower / Single-Supply / Rail-to-Rail I/O Op AmpsELECTRICAL CHARACTERISTICS: +3V Operation(V =+3V, V = 0V, V = V / 2, V = V / 2, R tied to V / 2, T ..
MAX4163EUA ,SOT23 / Micropower / Single-Supply / Rail-to-Rail I/O Op AmpsGeneral Description ________
MAX4163EUA ,SOT23 / Micropower / Single-Supply / Rail-to-Rail I/O Op AmpsApplicationsMAX4162EUK -40°C to +85°C 5 SOT23-5 AABXBattery-Powered Devices Medical InstrumentsMAX4 ..
MAX4163EUA ,SOT23 / Micropower / Single-Supply / Rail-to-Rail I/O Op AmpsMAX4162/MAX4163/MAX416419-1195; Rev 0; 4/97SOT23, Micropower, Single-Supply, Rail-to-Rail I/O Op Am ..
MAX4163EUA+ ,SOT23, Micropower, Single-Supply, Rail-to-Rail I/O Op AmpsApplicationsMAX4163EUA+ -40°C to +85°C 8 µMAX — Battery-Powered Devices Medical Instruments MAX4164 ..
MAX4163EUA+T ,SOT23, Micropower, Single-Supply, Rail-to-Rail I/O Op AmpsApplicationsMAX4163EUA+ -40°C to +85°C 8 µMAX — Battery-Powered Devices Medical Instruments MAX4164 ..
MAX1515ETG+-MAX1515ETG+T
Low-Voltage, Internal Switch, Step-Down/DDR Regulator
General DescriptionThe MAX1515 constant-off-time, pulse-width-modulated
(PWM) source/sink step-down DC-DC converter is opti-
mized for use in low-voltage active-termination power
rails or chipset power supplies in notebook and sub-
notebook computers. This device features dual internal
n-channel MOSFET power switches for high efficiency
and reduced component count. External Schottky
diodes are not required. An integrated boost switch
eliminates the need for an external boost diode. The
internal 40mΩNMOS power switches easily source and
sink continuous load currents up to 3A. The MAX1515
produces an adjustable output from +0.5V to +2.7V
and achieves efficiencies as high as 95%.
The MAX1515 can be configured as a DDR regulator,
producing an output that is exactly half the memory
supply rail. The input of the power stage can be taken
from the memory supply rail itself, resulting in an effi-
cient power supply that returns the energy to the rail
from which it was sourced. The MAX1515 includes a
reference buffer that provides ±5mA of drive current.
The MAX1515 uses a unique current-mode, constant-
off-time, PWM control scheme. A selectable pulse-skip-
ping mode maintains high efficiency during light-load
operation, yet still sources and sinks current on
demand. The MAX1515 can also be operated in fixed-
PWM mode for low output ripple. The programmable
constant-off-time architecture sets switching frequen-
cies up to 1MHz, which allows the user to optimize per-
formance trade-offs between efficiency, output
switching noise, component size, and cost. The
MAX1515 features an adjustable soft-start to limit surge
currents during startup and a low-power shutdown
mode to disconnect the input from the output and
reduce supply current below 1µA. The MAX1515 is
available in a 24-pin thin QFN package with an
exposed backside pad.
ApplicationsNotebook DDR Memory Termination
Active-Termination Buses
Chipset/Graphics Processor Supplies
FeaturesDual 40mΩ Internal n-Channel MOSFETsIntegrated Boost Switch+1.3V to +3.6V Input Voltage Range1% VOUTAccuracy Over Line and Load1MHz Maximum Switching FrequencyDDR Termination Regulator (DDR Mode)
Tracking Output Voltage
Source/Sink Pulse Skipping±5mA Reference BufferOutput Voltage (Non-DDR Mode)
+2.5V, +1.8V, or +1.5V Pin Selectable
+0.5V to +2.7V Adjustable1.1V ±0.75% Reference OutputAdjustable Soft-Start Inrush Current Limiting< 1µA (typ) Shutdown Supply Current< 800µA (max) Operating Supply CurrentSelectable Pulse-Skipping Operation at Light LoadsPositive and Negative Current LimitPower-Good Window ComparatorOutput Short-Circuit Protection
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Ordering InformationMAX1515
GND
VCC
COMP
PGND
REFOUT
PGOOD
VBIAS
(3.0V TO 3.6V)
VIN
(1.3V TO 3.6V)
VOUT = VTT
VREFOUT = VTTRVDDQ
(2.5V OR 1.8V)
MODE
FBSEL1
BSTVDD
SHDN
SKIP
FBSEL0
REFIN
REF
TOFF
Minimal Operating Circuit19-3507; Rev 1; 3/06
EVALUATION KIT
AVAILABLE
PARTTEMP RANGEPIN-
PACKAGEPKG CODEMAX1515ETG-40°C to +85°C24 Thin QFN
4mm x 4mmT2444-4
MAX1515ETG+-40°C to +85°C24 Thin QFN
4mm x 4mmT2444-4
Pin Configuration appears at end of data sheet.+Denotes lead-free package.
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, VIN= +3.3V, VCC= VDD= SHDN= MODE = +3.3V, VREFIN= VREF, SKIP= GND, TA
= 0°C to +85°C, unless oth-erwise noted. Typical values are at TA= +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.
VCC, VDD, LX, SHDNto GND...................................-0.3V to +4V
MODE, IC to GND....................................................-0.3V to +4V
COMP, FB, REF, REFIN, REFOUT, PGOOD
to GND.........................................................-0.3V to (VCC+ 0.3V)
FBSEL0, FBSEL1, TOFF, SKIP, SS to GND....-0.3V to (VCC+ 0.3V)
VDDto VCC...........................................................-0.3V to + 0.3V
IN to VDD....................................................-0.3V to (VDD+ 0.3V)
PGND to GND......................................................-0.3V to +0.3V
LX to BST.................................................................-4V to +0.3V
BST to GND..........................................................-0.3V to +8.0V
LX Current (Note 1).............................................................±4.7A
REF Short Circuit to GND...........................................Continuous
REFOUT Short Circuit to GND....................................Continuous
Continuous Power Dissipation (TA= +70°C)
24-Pin Thin QFN (derate 20.8mW/°C above +70°C;
part mountedon 1in2of 1oz copper)........................1667mW
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
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
PWM CONTROLLERVIN1.33.6Input Voltage RangeVCC, VDD3.03.6V
Output Adjust RangeVOUT ≤ VIN0.52.7V
TA = +25°C
to +85°C-30+3
VFB -
VREFIN
VIN = +3.3V, ILOAD = 0,
MODE = VCCTA = 0°C to
+85°C-40+4
TA = +25°C
to +85°C2.4632.52.537FBSEL0 = VCC,
FBSEL1 = VCC,
REFIN = REFTA = 0°C to
+85°C2.4502.52.550
TA = +25°C
to +85°C1.7821.8001.827FBSEL0 = VCC,
FBSEL1 = GND,
REFIN = REFTA = 0°C to
+85°C1.7731.8001.836
TA = +25°C
to +85°C1.4771.5001.523FBSEL0=GND
FBSEL1=VCC
REFIN=REFTA = 0°C to
+85°C1.4701.5001.530
TA = +25°C
to +85°C0.4920.5000.508
Feedback Voltage Accuracy
VFB
VIN = +3.3V,
ILOAD = 0,
MODE = low
FBSEL0=GND
FBSEL1=GND
REFIN=0.5VTA = 0°C to
+85°C0.4900.5000.510
Feedback Load-Regulation ErrorVIN = +1.3V to +3.6V, ILOAD = 0 to 3A,
SKIP = VCC0.1%
Note 1:LX has clamp diodes to PGND and IN. If continuous current is applied through these diodes, thermal limits must be observed.
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VIN= +3.3V, VCC= VDD= SHDN= MODE = +3.3V, VREFIN= VREF, SKIP= GND, TA
= 0°C to +85°C, unless oth-erwise noted. Typical values are at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSink-Mode Detect ThresholdVFB -
VREFINMODE = VCC, VREFIN = +0.5V to +1.5V+18+32mV
Source-Mode Detect ThresholdVFB -
VREFINMODE = VCC, VREFIN = +0.5V to +1.5V-32-18mV
MOSFET On-ResistanceRNMOSVCC = VDD = VIN = +3.3V, ILOAD = 0.5A0.040.10Ω
Switching FrequencyfSW(Note 2)1MHz
Maximum Output CurrentIOUT(RMS)(Note 3)3.3A
ILIMIT_PVIN = +3.3V, MODE = GND or VCC,
positive or sourcing mode3.604.24.85Current-Limit Threshold
ILIMIT_NMODE = VCC, negative or sinking mode-3.0
Pulse-Skipping Current ThresholdISKIP_PVIN = +3.3V, MODE = GND or VCC, positive
or sourcing mode0.50.81.1A
IZX_PVIN = +3.3V, MODE = GND or VCC, positive
or sourcing mode200Zero Cross Current Threshold
IZX_NMODE = VCC, negative or sinking mode-350
FB Input Bias CurrentFB = 1.01 x VTARGET (Note 4)-50+50nA
RTOFF = 33.2kΩ0.2700.340.405
RTOFF = 110kΩ0.851.001.15Off-TimetOFFVFB > 0.3 x VTARGET
(Note 4)RTOFF = 499kΩ3.84.55.2
Extended Off-TimetOFF(EXT)VFB < 0.3 x VTARGET (Notes 2, 4)4 x
tOFFµs
Minimum On-TimetON(MIN)(Note 2)180ns
Maximum On-TimetON(MAX)511µs
SS Source CurrentISS(SRC)3.505.256.75µA
SS Sink CurrentISS(SNK)100µA
MODE = GND,
FBSEL0 = GND,
FBSEL1 = GND,
VFB = 1.01 x
VTARGET
No-Load Supply CurrentICC + IDD
+ IIN
VIN = 3.3V
(not switching) (Note 4)
MODE = VCC,
VFB = VTARGET7001200
ICC + IDD
+ IINSHDN = MODE = GND, LX = 0V or 3.3V0.220
IINSHDN = MODE = GND, LX = 0V0.220Shutdown Supply Currents
ILXSHDN = MODE = GND, LX = 3.3V0.120
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VIN= +3.3V, VCC= VDD= SHDN= MODE = +3.3V, VREFIN= VREF, SKIP= GND, TA
= 0°C to +85°C, unless oth-erwise noted. Typical values are at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
REFERENCETA = +25°C to
+85°C1.09231.1001.1077
Reference VoltageVREFVCC = +3.0V to +3.6V
TA = 0°C to
+85°C1.09071.1001.1094
Reference Load RegulationIREF = -1µA to +50µA10mV
REFIN Input Voltage RangeVREFINVCC = +3.0V to +3.6V0.51.5V
VREFIN = +0.5V to +1.5VIREFOUT = -1mA
to +1mA-10+10
REFOUT Output AccuracyVREFIN -
VREFOUT
VREFIN = +0.5V to +1.5VIREFOUT = -5mA
to +5mA -20+20
REFIN Input Bias CurrentIREFINVREFIN = 1.1V-50+50nA
FAULT DETECTIONThermal ShutdownTSHDNRising, hysteresis = 15°C+165°C
Undervoltage-Lockout ThresholdVCC(UVLO)VCC rising, 2% falling-edge hysteresis2.52.72.9V
PGOOD Trip Threshold (Lower)No load, falling edge, hysteresis = 1%-13-10-7%
PGOOD Trip Threshold (Upper)No load, rising edge, hysteresis = 1%+7+10+13%
PGOOD Propagation DelaytPGOODFB forced 2% beyond PGOOD trip
threshold10µs
PGOOD Output Low VoltageISINK = 1mA0.1V
PGOOD Leakage Current
ConditionH i g h state, for ced to 3.6V ; V C C = V D D = 3.6V 1µA
INPUTS AND OUTPUTSLogic Input High VoltageSKIP, SHDN, MODE, FBSEL0, FBSEL12.0V
Logic Input Low VoltageSKIP, SHDN, MODE, FBSEL0, FBSEL10.8V
Logic Input CurrentSKIP, SHDN, MODE, FBSEL0, FBSEL1-0.5+0.5µA
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
ELECTRICAL CHARACTERISTICS(Circuit of Figure 1, VIN= +3.3V, VCC= VDD= SHDN= MODE = +3.3V, VREFIN= VREF, SKIP= GND, TA
= -40°C to +85°C, unlessotherwise noted. Note 5)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
PWM CONTROLLERVIN1.33.6Input Voltage RangeVCC, VDD3.03.6V
Output Adjust RangeVOUT ≤ VIN0.5VCCV
VFB -
VREFINVIN = +3.3V, ILOAD = 0, MODE = VCC-5+5mV
FBSEL0 = VCC,
FBSEL1 = VCC,
REFIN = REF
FBSEL0 = VCC,
FBSEL1 = GND,
REFIN = REF
FBSEL0 = GND,
FBSEL1 = VCC,
REFIN = REF
Feedback Voltage Accuracy
VFBVIN = +3.3V, ILOAD = 0,
MODE = low
FBSEL0 = GND,
FBSEL1 = GND,
REFIN = 0.5V
Sink-Mode Detect ThresholdVFB -
VREFINMODE = VCC, VREFIN = +0.5V to +1.5V+15+35mV
Source-Mode Detect ThresholdVFB -
VREFINMODE = VCC, VREFIN = +0.5V to +1.5V-35-15mV
nFET On-ResistanceRNMOSVCC = VDD = VIN = +3.3V, ILOAD = 0.5A0.10Ω
Switching FrequencyfSW(Note 2)1MHz
Current-Limit ThresholdILIMIT_PVIN = +3.3V, MODE = GND or VCC,
positive or sourcing mode3.355.05A
Pulse-Skipping Current ThresholdISKIP_PVIN = +3.3V, MODE = GND or VCC,
positive or sourcing mode0.41.2A
RTOFF = 33.2kΩ0.2500.425
RTOFF = 110kΩ0.81.2Off-TimetOFFVFB > 0.3 x VTARGET
(Note 4)RTOFF = 499kΩ3.85.2
Maximum On-TimetON(MAX)5µs
SS Source CurrentISS(SRC)37µA
SS Sink CurrentISS(SNK)100µA
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Note 2:Guaranteed by design. Not production tested.
Note 3:Not tested; guaranteed by layout. Maximum output current may be limited by thermal capability to a lower value.
Note 4:VTARGETis the set output voltage determined by VREFIN, FBSEL0, and FBSEL1.
Note 5:Specifications to -40°C are guaranteed by design, not production tested.
ELECTRICAL CHARACTERISTICS (continued)(Circuit of Figure 1, VIN= +3.3V, VCC= VDD= SHDN= MODE = +3.3V, VREFIN= VREF, SKIP= GND, TA
= -40°C to +85°C, unlessotherwise noted. Note 5)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSMODE = GND,
FBSEL0 =
FBSEL1 = GND,
VFB = 1.01 x
VTARGET
No-Load Supply CurrentICC + IDD
+ IIN
VIN = 3.3V
(Note 4)
MODE = VCC
VFB = VTARGET1300
ICC + IDD
+ IINSHDN = MODE = GND, LX = 0V or 3.3V20
IINSHDN = MODE = GND, LX = 0V20Shutdown Supply Currents
ILXSHDN = MODE = GND, LX = 3.3V20
REFERENCEReference VoltageVREFVCC = +3.0V to +3.6V1.0861.114V
Reference Load RegulationIREF = -1µA to +50µA12mV
REFIN Input Voltage RangeVREFINV C C = + 3.0V to + 3.6V , V C C > V RE F IN + 1.35V 0.51.5V
VREFIN = +0.5V to +1.5VIREFOUT = -1mA
to +1mA-15+15
REFOUT Output AccuracyVREFIN -
VREFOUT
VREFIN = +0.5V to +1.5VIREFOUT = -5mA
to +5mA-25+25
FAULT DETECTIONUndervoltage-Lockout ThresholdVCC(UVLO)VCC rising, 2% falling-edge hysteresis2.402.95V
PGOOD Trip Threshold (Lower)No load, falling edge, hysteresis = 1%-13-7%
PGOOD Trip Threshold (Upper)No load, rising edge, hysteresis = 1%+7+13%
INPUTS AND OUTPUTSLogic Input High VoltageSKIP, SHDN, MODE, FBSEL0, FBSEL12.0V
Logic Input Low VoltageSKIP, SHDN, MODE, FBSEL0, FBSEL10.8V
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
1.25V OUTPUT EFFICIENCY
vs. LOAD CURRENTMAX1515 toc01
LOAD CURRENT (A)
EFFICIENCY (%)0.10.01
SINK, SKIP
SOURCE,
PWMSINK, PWM
SOURCE, SKIP
VIN = 2.5V
VOUT = 1.25V
RTOFF = 110kΩ
1.25V OUTPUT EFFICIENCY
vs. LOAD CURRENTMAX1515 toc02
LOAD CURRENT (A)
EFFICIENCY (%)0.10.01
SINK, SKIP
SOURCE,
PWMSINK, PWM
SOURCE, SKIP
VIN = 2.5V
VOUT = 1.25V
RTOFF = 220kΩ
1.25V OUTPUT VOLTAGE
vs. LOAD CURRENTMAX1515 toc03
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)2-2-101
SINK, SKIP
SOURCE, PWM
SINK, PWM
SOURCE, SKIP
VIN = 2.5V
VOUT = 1.25V
RTOFF = 110kΩ
0.9V OUTPUT EFFICIENCY
vs. LOAD CURRENTMAX1515 toc04
LOAD CURRENT (A)
EFFICIENCY (%)0.10.01
SINK, SKIP
SOURCE,
PWM
SINK, PWM
SOURCE, SKIP
VIN = 1.8V
VOUT = 0.9V
RTOFF = 110kΩ
0.9V OUTPUT EFFICIENCY
vs. LOAD CURRENTMAX1515 toc05
LOAD CURRENT (A)
EFFICIENCY (%)0.10.01
SINK, SKIP
SOURCE,
PWM
SINK, PWM
SOURCE, SKIP
VIN = 1.8V
VOUT = 0.9V
RTOFF = 220kΩ
0.9V OUTPUT VOLTAGE
vs. LOAD CURRENTMAX1515 toc06
LOAD CURRENT (A)
OUTPUT VOLTAGE (V)2-2-101
SINK, SKIP
SOURCE, PWMSINK, PWM
SOURCE, SKIP
VIN = 1.8V
VOUT = 0.9V
RTOFF = 110kΩ
SWITCHING FREQUENCY
vs. LOAD CURRENTMAX1515 toc07
LOAD CURRENT (A)
SWITCHING FREQUENCY (kHz)210-1-2
PWM MODE
SKIP MODE
VIN = 2.5V
VOUT = 1.25V
Typical Operating Characteristics(MAX1515 Circuit of Figure1, VIN = 2.5V, VDD= VCC= SHDN= MODE = 3.3V, TA = +25°C, unless otherwise noted.)
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Typical Operating Characteristics (continued)(MAX1515 Circuit of Figure1, VIN = 2.5V, VDD= VCC= SHDN= MODE = 3.3V, TA = +25°C, unless otherwise noted.)
REF VOLTAGE
vs. REF LOAD CURRENTMAX1515 toc08
REF LOAD CURRENT (μA)
REF VOLTAGE ERROR (V)602040
REFOUT VOLTAGE REGULATION
vs. LOAD CURRENT
MAX1515 toc09
REFOUT LOAD CURRENT (mA)
REFOUT VOLTAGE (V)50-5-10
TOFF TIME
vs. TOFF RESISTOR
MAX1515 toc10
TOFF RESISTOR (kΩ)
TOFF (
PEAK CURRENT LIMIT
vs. SS VOLTAGE
MAX1515 toc11
SS VOLTAGE (V)
PEAK CURRENT LIMIT (A)
VIN = 2.5V
VOUT = 1.25V
RTOFF = 110kΩ
STARTUP AND SHUTDOWN WAVEFORM
(HEAVY LOAD)MAX1515 toc12
500μs/div
3.3V
1.25V
A: PGOOD, 5V/div
B: SS, 2V/div
C: SHDN, 5V/div
D: INDUCTOR CURRENT, 1A/div
E: OUTPUT VOLTAGE, 1V/div
SKIP = GND, RLOAD = 10Ω
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Typical Operating Characteristics (continued)(MAX1515 Circuit of Figure1, VIN = 2.5V, VDD= VCC= SHDN= MODE = 3.3V, TA = +25°C, unless otherwise noted.)
STARTUP AND SHUTDOWN WAVEFORM
(LIGHT LOAD)MAX1515 toc13
1ms/div
3.3V
1.25V
A: PGOOD, 5V/div
B: SS, 2V/div
C: SHDN, 5V/div
D: INDUCTOR CURRENT, 1A/div
E: OUTPUT VOLTAGE, 1V/div
SKIP = GND, RLOAD = 100Ω
DDR-MODE LOAD TRANSIENTMAX1515 toc14
20μs/div
2.5V
1.25V
A: LX, 2V/div
B: LOAD CONTROL,
5V/div
C: INDUCTOR CURRENT, 2A/div
D: OUTPUT VOLTAGE, 50mV/div
SKIP = GND
DDR-MODE LOAD TRANSIENTMAX1515 toc15
20μs/div
2.5V
-2A
1.25V
A: LX, 2V/div
B: LOAD CONTROL,
5V/div
C: INDUCTOR CURRENT, 2A/div
D: OUTPUT VOLTAGE, 50mV/div
SKIP = GND
DDR-MODE LOAD TRANSIENTMAX1515 toc16
20μs/div
2.5V
-2A
1.25V
A: LX, 2V/div
B: LOAD CONTROL,
5V/div
C: INDUCTOR CURRENT, 2A/div
D: OUTPUT VOLTAGE, 50mV/div
SKIP = GND
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Typical Operating Characteristics (continued)(MAX1515 Circuit of Figure1, VIN = 2.5V, VDD= VCC= SHDN= MODE = 3.3V, TA = +25°C, unless otherwise noted.)
DDR-MODE LOAD TRANSIENTMAX1515 toc17
20μs/div
2.5V
-2A
1.25V
A: LX, 2V/div
B: LOAD CONTROL,
5V/div
C: INDUCTOR CURRENT, 2A/div
D: OUTPUT VOLTAGE, 50mV/div
SKIP = GND
DDR-MODE LOAD TRANSIENTMAX1515 toc18
20μs/div
2.5V
-2A
1.25V
A: LX, 2V/div
B: LOAD CONTROL,
5V/div
C: INDUCTOR CURRENT, 2A/div
D: OUTPUT VOLTAGE, 50mV/div
SKIP = GND
REFIN TRANSITIONMAX1515 toc19
50μs/div
3.3V
1.5V
1.0V
1.5V
1.0V
-2A
A: PGOOD, 5V/div
B: REFIN, 0.5V/div
C: OUTPUT VOLTAGE, 0.5V/div
D: INDUCTOR CURRENT, 2A/div
SKIP = GND
REFOUT LOAD TRANSIENTMAX1515 toc20
10μs/div
+10mA
-10mA
1.25V
1.26V
1.24V
A: REFOUT LOAD, 20mA/divB: REFOUT VOLTAGE, 10mV/div
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Pin Description
PINNAMEFUNCTION1, 2PGNDPower Ground. Internal connection to the source of the internal synchronous-rectifier switch. Connect
both PGND pins together.ICInternally Connected Pin. Connect to PGND.
4VDD
Supply Input for the Low-Side Gate Drive and REFOUT Buffer. Connect to the system supply voltage,
+3.0V to +3.6V. Bypass to PGND with a 1µF (min) ceramic capacitor. VDD supplies power to the
drivers and the REFOUT buffer.REFOUTREFIN Buffered Output. REFOUT provides a buffered output voltage of REFIN when MODE = VCC.
Bypass to GND with a 0.47µF ceramic capacitor. REFOUT is disabled when MODE = GND.SSSoft-Start. Connect a capacitor from SS to GND to limit the inrush current during startup.PGOOD
Power-Good Open-Drain Output. PGOOD is low when the output voltage is more than 10% above or
below the normal regulation point. PGOOD is high impedance when the output is in regulation.
PGOOD is low in shutdown.TOFFOff-Time Select Input. Connect a resistor from TOFF to GND to adjust the off-time.
9FB
Feedback Input.
In DDR mode (MODE = VCC), FB regulates to the voltage at REFIN.
In non-DDR mode (MODE = GND), connect directly to the output for preset voltage operation or to a
resistive voltage-divider for adjustable-mode operation.COMPIntegrator Compensation. Connect a 470pF capacitor from COMP to VCC for integrator
compensation.VCCAnalog Supply Input. Connect to the system supply voltage, +3.0V to +3.6V, with a series 10Ω
resistor. Bypass to GND with a 1µF (min) ceramic capacitor.GNDAnalog Ground. Connect exposed backside pad to GND.REF+1.1V Reference Voltage Output. Bypass to GND with a 1.0µF bypass capacitor. Can supply 50µA
for external loads. Reference turns off in shutdown.REFINExternal Reference Input. In DDR mode (MODE = VCC), REFIN sets the voltage that FB regulates to.
In non-DDR mode (MODE = GND), connect REFIN to REF.SHDN
Shutdown Control. Low disables the switching regulator. SHDN and MODE select the operational
mode of the MAX1515.
SHDN MODE Description
LowLowStep-down regulator and REFOUT OFF
LowHighStep-down regulator OFF, REFOUT active
HighLowStep-down regulator ON, non-DDR mode, REFOUT OFF
HighHighStep-down regulator ON, DDR mode, REFOUT activeMODE
Mode-Select Pin. Mode sets the regulator into DDR mode or non-DDR operation mode, and controls
the REFOUT buffer. When MODE = VCC, MAX1515 is set in DDR mode and REFOUT is active. When
MODE = GND, MAX1515 is set in non-DDR mode and REFOUT is disabled. See the Modes of
Operation (MODE) section.FBSEL0Used with FBSEL1 to set the output voltage of the step-down regulator when MODE = GND.
Connect to GND if MODE = VCC.
MAX1515
Low-Voltage, Internal Switch,
Step-Down/DDR Regulator
Standard Application CircuitThe MAX1515 standard application circuit (Figure 1)
generates a tracking output voltage and a reference
buffer output required for DDR termination regulators.
See Table 1 for component selections. Table 2 lists the
component manufacturers.
Detailed DescriptionThe MAX1515 synchronous, current-mode, constant
off-time, PWM DC-DC converter steps down an input
voltage (VIN) from +1.3V to +3.6V to an output voltage
from +0.5V to +2.7V. The MAX1515 output delivers up
to 3A of continuous current. Internal 40mΩNMOS
power switches improve efficiency, reduce component
count, and eliminate the need for a boost diode or any
external Schottky diodes (Figure 2).
Pin Description (continued)
PINNAMEFUNCTIONFBSEL1Used with FBSEL0 to set the output voltage of the step-down regulator when MODE = GND.
Connect to GND if MODE = VCC.SKIPPulse-Skipping Control Input. Connect to VCC for low-noise, forced-PWM mode. Connect to GND to
enable automatic pulse-skipping operation.BSTBoost Flying-Capacitor Connection. Connect an external 0.01µF capacitor as shown in the standard
application circuit (Figure 1).
21, 22LXInductor Switched Node. LX is the connection for the source of the high-side NMOS power switch
and drain of the low-side NMOS synchronous-rectifier switch. Connect both LX pins together.
23, 24INPower Input. Supply voltage input for the switching regulator. Connect to a +1.3V to +3.6V supply
voltage. Connect both IN pins together.
Table 1. Component Selection for Standard Applications
COMPONENT±2A AT 1.25VOUT
DDR MODE (MODE = VCC)
±2A AT 0.9VOUT
DDR MODE (MODE = VCC)Input Voltage (VIN)2.3V to 2.7V1.6V to 2.0V
Output Voltage (VOUT)1.25V0.9V
CIN, Input Capacitor33µF, 6.3V, ceramic
TDK C3225XR0J336V
33µF, 6.3V, ceramic
TDK C3225XR0J336V
Switching Frequency (fSW)250kHz500kHz250kHz500kHz
L, Inductor2.5µH, 4.5A, Sumida
CDRH8D28-2R5
1.2µH, 6.8A, Sumida
CDR7D28MN-1R2
2.5µH, 4.5A, Sumida
CDRH8D28-2R5
1.2µH, 6.8A, Sumida
CDR7D28MN-1R2
COUT, Output Capacitor
330µF, 18mΩ
Sanyo 2R5TPE330MI
POSCAP
220µF, 18mΩ
Sanyo 2R5TPE220MI
POSCAP
330µF, 18mΩ
Sanyo 2R5TPE330MI
POSCAP
220µF, 18mΩ
Sanyo 2R5TPE220MI
POSCAP
RTOFF221kΩ, 1%110kΩ, 1%221kΩ, 1%110kΩ, 1%
Table 2. Component Suppliers
SUPPLIERWEBSITECoilcraftwww.coilcraft.com
Coiltronicswww.coiltronics.com
Kemetwww.kemet.com
Panasonicwww.panasonic.com
Sanyowww.sanyo.com
Sumidawww.sumida.com
Taiyo Yudenwww.t-yuden.com
TDKwww.component.tdk.com
TOKOwww.tokoam.com
