Synchronous design, enables heatsink solution. efficiency (switching s

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Synchronous design, enables heatsink solution. efficiency (switching s

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SC1182/3 combines synchronous voltage mode controller with low-dropout linear regulators providing most circuitry necessary implement three converters powering advanced microprocessors such Pentium® SC1182/3 switching section features integrated converter, pulse pulse current limiting, integrated power good signaling, logic compatible shutdown. SC1182/3 switching section operates fixed frequency 200kHz, providing optimum compromise between size, efficiency cost intended application areas. integrated converter provides programmability output voltage from 2.0V 3.5V 100mV increments 1.30V 2.05V 50mV increments with external components. SC1182/3 linear sections dropout regulators. SC1182 supplies 1.5V 2.5V nonGTL I/O, SC1183 features adjustable voltages.
Synchronous design, enables heatsink solution. efficiency (switching section). output programmability. chip power good function. Designed Intel Pentium® VRM8.1 requirements. 1.5V, 2.5V Adjustable linear section.
SC1182 SC1183
Applications
Pentium® microprocessor supplies Flexible motherboards 1.3V 3.5V microprocessor supplies Programmable triple power supplies
Typical Application Circuit
4.7uF
1500uF
0.1uF
0.1uF PWRGOOD VID0 VID1 VID2 VID3 VID4
PWRGOOD VID0 VID1 VID2 VID3 VID4 AGND LDOV GATE2 LDOS2 CSVOSENSE BSTH BSTL PGNDH PGNDL GATE1 LDOS1
1500uF
0.1uF IRLR3103N 1.00k 5mOhm VCC_CORE 1.9uH IRLR3103N 2.32k
0.1uF
SC1182/3CSW 3.3V
330uF IRLR024N 330uF 330uF
1.5V 2.5V
IRLR024N
Revision January 2001
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SC1182 SC1183
POWER MANAGEMENT Absolute Maximum Ratings
Parameter AGND PGNDL, PGNDH BSTH PGNDH, BSTL PGNDL Operating Temperature Range Junction Temperature Range Storage Temperature Range Lead Temperature (Soldering) Sec. Thermal Impedance Junction Ambient Thermal Impedance Junction Case VBOOST TSTG Symbol Maximum -0.3 -0.3 +125 +150 Units °C/W °C/W
Electrical Characteristics
Unless specified: VIN=4.75V 5.25V; AGND=PGNDH=PGNDL=0V; VOSENSE=VO; 0mV< (CS+-CS-)< 60mV; LDOV= VBOOST= 11.4V 12.6V; 25°C
Parameter Switching Section Output Voltage Supply Voltage Supply Current Load Regulation Line Regulation Minimum operating voltage Current Limit Voltage Oscillator Frequency Oscillator Duty Cycle Peak Sink/Source Current Peak Sink/Source Current Output Voltage Tempco Gain (AOL) threshold voltage source current Power good threshold voltage Dead time
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Conditions
Units
Application Circuit
Output Voltage Table ppm/oC
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5.0V 0.8A
BSTH 4.5V, BSTL 4.5V,
PGNDH PGNDL
VOSENSE
VOVP 3.0V
SC1182 SC1183
POWER MANAGEMENT Electrical Characteristics (Cont.)
Parameter Linear Sections Quiescent current Output Voltage (LDO1 SC1182) Output Voltage (LDO2 SC1182) Reference Voltage (SC1183) Feedback Bias Current (SC1183) Gain (AOL) Load Regulation Line Regulation Output Impedance VGATE 6.5V VREF LDOS GATE LDOV 2.475 1.485 1.252 2.500 1.500 1.265 2.525 1.515 1.278 Symbol Conditions Units
NOTE: This device sensitive. standard handling precautions required.
2001 Semtech Corp.
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SC1182 SC1183
POWER MANAGEMENT Configuration
VIEW
AGND GATE1 LDOS1 LDOS2 PWRGOOD CSCS+ PGNDH PGNDL GATE2 LDOV VID0 VID1 VID2 VID3 VID4 VOSENSE BSTH BSTL
Ordering Information
Part Number
Package SO-24 SO-24
Linear Voltage 1.5V/2.5V Adjustable
Temp Range 125°C 125°C
SC1182CSW.TR SC1183CSW.TR
Note: Only available tape reel packaging. reel contains 1000 devices.
SOIC)
Descriptions
Name AGND GATE1 LDOS1 LSOS2 PWRGOOD CSCS+ PGNDH PGNDL BSTL BSTH
Function Small Signal Analog Digital Ground Gate Drive Output LDO1 Sense Input LDO1 Sense Input LDO2 Input Voltage High signal setpoint +20% Open collector logic output, high within setpoint Current Sense Input (negative) Current Sense Input (positive) Power Ground High Side Switch High Side Driver Output Power Ground Side Swtch side Driver Output Supply Side Driver Supply High Side Driver Logic shuts down converter. High open normal operation. internal feedback chain Programming Input (MSB) Programming Input Programming Input Programming Input Programming Input (LSB) +12V section Gate Drive Output LDO2
VOSENSE VID4 VID3 VID2 VID1 VID0
LDOV GATE2
Note: logic level inputs outputs open collector compatible.
2001 Semtech Corp.
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SC1182 SC1183
POWER MANAGEMENT Block Diagram
CSCS+
BSTH
70mV
LEVEL SHIFT HIGH SIDE DRIVE
VID4 VID3 VID2 VID1 VID0 VOSENSE
CURRENT LIMIT
OSCILLATOR
PGNDH
SHOOT THRU CONTROL
PWRGOOD
OPEN COLLECTORS
ERROR
BSTL
SYNCHRONOUS DRIVE
LDOS1 GATE1
AGND
CONTROLLER 2.5V/ADJ. CONTROLLER 1.5V/ADJ.
PGNDL
1.265V
AGND
LDOV
GATE2
LDOS2
AGND
Setting Output Voltage.
SC1183, Output voltages must selecting appropriate resistor values. These values determined from eqution below, from table right.
VOUT 1.265 (IFB
VOUT LDO1 (LDO2) 3.45V 3.30V 3.10V 2.90V 2.80V 2.50V 1.50V
97.6 18.7
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where Feedback bias current feedback resistor Bottom feedback resistor layout diagram clarification must enough that (IFB term does cause significant error
2001 Semtech Corp.
SC1182 SC1183
POWER MANAGEMENT Output Voltage Table
Unless specified: 4.75V 5.25V; PGND VOSENSE (CS+-CS-) 60mV; 25°C
Parameter Output Voltage
Conditions Application circuit
43210 01111 01110 01101 01100 01011 01010 01001 01000 00111 00110 00101 00100 00011 00010 00001 00000 11111 11110 11101 11100 11011 11010 11001 11000 10111 10110 10101 10100 10011 10010 10001 10000
1.287 1.336 1.386 1.435 1.485 1.534 1.584 1.633 1.683 1.732 1.782 1.831 1.881 1.930 1.980 2.029 1.980 2.079 2.178 2.277 2.376 2.475 2.574 2.673 2.772 2.871 2.970 3.069 3.168 3.267 3.366 3.465
1.300 1.350 1.400 1.450 1.500 1.550 1.600 1.650 1.700 1.750 1.800 1.850 1.900 1.950 2.000 2.050 2.000 2.100 2.200 2.300 2.400 2.500 2.600 2.700 2.800 2.900 3.000 3.100 3.200 3.300 3.400 3.500
1.313 1.364 1.414 1.465 1.515 1.566 1.616 1.667 1.717 1.768 1.818 1.869 1.919 1.970 2.020 2.071 2.020 2.121 2.222 2.323 2.424 2.525 2.626 2.727 2.828 2.929 3.030 3.131 3.232 3.333 3.434 3.535
Units
2001 Semtech Corp.
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SC1182 SC1183
POWER MANAGEMENT Layout Guidelines
Careful attention layout requirements necessary successful implementation SC1182/3 controller. High currents switching 140kHz present application their effect ground plane voltage differentials must understood minimized. high power parts circuit should laid first. ground plane should used, number position ground plane interruptions should such unnecessarily compromise ground plane integrity. Isolated semi-isolated areas ground plane deliberately introduced constrain ground currents particular areas, example input capacitor bottom ground. loop formed Input Capacitor(s) (Cin), (Q1) Bottom (Q2) must kept small possible. This loop contains high current, fast transition switching. Connections should wide short possible minimize loop inductance. Minimizing this loop area will reduce EMI, lower ground injection currents, resulting electrically cleaner grounds rest system minimize source ringing, resulting more reliable gate switching signals. connection between junction output inductor should wide trace copper region. should short practical. Since this connection fast voltage transitions, keeping this connection short will minimize EMI. connection between output inductor sense resistor should wide trace copper area, there fast voltage current transitions this connection length important, however adding unnecessary impedance will reduce efficiency.
0.1uF 0.1uF
AGND GATE1 LDOS1 LDOS2 PWRGOOD CSCS+ PGNDH PGNDL GATE2 LDOV VID0 VID1 VID2 VID3 VID4 VOSENSE BSTH BSTL
Cout 1.00k 5mOhm Vout 2.32k
SC1182
3.3V Cout Lin1
Lin1
Heavy lines indicate high current paths.
SC1182, RA1, RA2, required. LDOS1 connects Lin1, LDOS2 connects Lin2
Lin2
Cout Lin2
Layout Diagram SC1182/3
2001 Semtech Corp.
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SC1182 SC1183
POWER MANAGEMENT Layout Guidelines
Output Capacitor(s) (Cout) should located close load possible, fast transient load currents supplied Cout only, connections between Cout load must short, wide copper areas minimize inductance resistance. SC1182/3 best placed over quiet ground plane area, avoid pulse currents Cin, loop flowing this area. PGNDH PGNDL should returned ground plane close package. AGND should connected ground side (one output capacitor(s). this possible, AGND connected ground path between Output Capacitor(s) Cin, loop. Under circumstances should AGND returned ground inside Cin, loop. SC1182/3 should supplied from supply through resistor, should decoupled directly AGND 0.1µF ceramic capacitor, trace lengths should short possible. Current Sense resistor divider across should form small loop possible, traces running back SC1182/3 should parallel close each other. 0.1µF capacitor should mounted close pins possible. Ideally, grounds sections should returned ground side (one output capacitor(s).
Vout
Currents various parts power section
2001 Semtech Corp. www.semtech.com
SC1182 SC1183
POWER MANAGEMENT Layout Guidelines
COMPONENT SELECTION SWITCHING SECTION OUTPUT CAPACITORS Selection begins with most critical component. Because fast transient load current requirements modern microprocessor core supplies, output capacitors must supply transient load current requirements until current output inductor ramps level. Output capacitor therefore most important criteria. maximum simply calculated from:
Where Maximum transient voltage excursion Transient current step
calculated maximum inductor value assumes 100% duty cycle, some allowance must made. Choosing inductor value calculated maximum will guarantee that inductor current will ramp fast enough reduce voltage dropped across faster rate than capacitor sags, hence ensuring good recovery from transient with additional excursions. must also concerned with ripple current output inductor general rule thumb been allow maximum output current ripple current. Note that most output voltage ripple produced inductor ripple current flowing output capacitor ESR. Ripple current calculated from:
ILRIPPLE fOSC
example, meet 100mV transient limit with load step, output capacitor must less than 10m. meet this kind level, there three available capacitor technologies.
Each Cap. Technology (µF) 1500 Qty. Rqd. (µF) 2000 7500 Total
Ripple current allowance will define minimum permitted inductor value. POWER FETS FETs chosen based several criteria with probably most important being power dissipation power handling capability. power dissipation combination conduction losses, switching losses bottom body diode recovery losses. Conduction losses simply calculated
PCOND RDS(on)
Tantalum OS-CON Aluminum
choice which simply cost/performance issue, with Aluminum being cheapest, taking most space. INDUCTOR Having decided suitable type value output capacitor, maximum allowable value inductor calculated. large inductor will produce slow current ramp rate will cause output capacitor supply more transient load current longer leading output voltage below excursion calculated above. maximum inductor value calculated from:
where duty cycle
Switching losses estimated assuming switching time, assume 100ns then:
more generally,
fOSC
Body diode recovery losses more difficult estimate, first approximation, reasonable assume that stored charge bottom body diode will moved through starts turn resulting power dissipation will
fOSC
where lesser (VIN
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first order approximation, convenient only con9 www.semtech.com
SC1182 SC1183
POWER MANAGEMENT Layout Guidelines
sider conduction losses determine suitability. 2.8V 14.2A requirement, typical losses would Using 1.5X Room temp RDS(ON) allow temperature rise.
type IRL34025 IRL2203 4410 RDS(on) 10.5 1.69 1.19 2.26 S0-8
position, power dissipation will approximately halved temperature rise reduced factor INPUT CAPACITORS since ripple current input capacitors high output current, suitable capacitors must chosen accordingly. Also, during fast load transients, there restrictions input di/dt. These restrictions require useable energy storage within converter circuitry, either extra output capacitance more usually, additional input capacitors. Choosing input capacitors will help maximize ripple rating given size.
BOTTOM Bottom losses almost entirely conduction. body diode forced into conduction beginning bottom switch conduction period, when turns off, there very little voltage across resulting switching losses. Conduction losses determined
PCOND RDS(
example above: type IRL34025 IRL2203 Si4410 RDS(on) 10.5 1.33 0.93 1.77 Package D2Pak D2Pak S0-8
Each package types characteristic thermal impedance, TO-220 package, thermal impedance mostly determined heatsink used. surface mount packages double sided FR4, printed circuit board material, thermal impedances 40oC/W D2PAK 80oC/W SO-8 readily achievable. corresponding temperature rise detailed below:
Temperature rise (oC) type IRL34025 IRL2203 4410 67.6 47.6 180.8 Bottom 53.2 37.2 141.6
apparent that single SO-8 Si4410 adequate this application, using parallel pairs each
2001 Semtech Corp. www.semtech.com
SC1182 SC1183
POWER MANAGEMENT Typical Characteristics
Typical Efficiency Vo=3.5V
Typical Efficiency Vo=2.8V
Efficiency
Efficiency 3.5V 3.5V Sync 3.5V Sync
2.8V 2.8V Sync 2.8V Sync
Typical Efficiency Vo=2.5V
Typical Efficiency Vo=2.0V
Efficiency
Efficiency
2.5V 2.5V Sync 2.5V Sync
2.0V 2.0V Sync 2.0V Sync
(Amps)
Typical Ripple, Vo=2.8V, Io=10A
Transient Response Vo=2.8V, Io=300mA
2001 Semtech Corp.
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2001 Semtech Corp.
VOUT
4.7uF
0.1uF
POWER MANAGEMENT Typical Application Circuit
1500uF
1500uF
CSVO SENSE
EMPTY
PWRGOOD VID0
0.1uF 1.9uH IRLR3103N 5mOhm
VID1 VID2 VID3 VID4 PGNDH PGNDL GATE1 LDOS1 AGND LDOV GATE2 LDOS2 BSTL BSTH
IRLR3103N 1.00k 2.32k 0.1uF
PWRGOOD
VID0
43210 01111 01110 01101 01100 01011 01010 01001 01000 00111 00110 00101 00100 00011 00010 00001 00000 2.10 2.20 2.30 2.40 2.50 2.60 2.70 2.80 2.90 3.00 3.10 3.20 3.30 3.40 3.50
43210 1.30 11111 1.35 11110 1.40 11101 1.45 11100 1.50 11011 1.55 11010 1.60 11001 1.65 11000 1.70 10111 1.75 10110 1.80 10101 1.85 10100 1.90 10011 1.95 10010 2.00 10001 2.05 10000
VID1 SC1182CS
VID2
VCC_CORE 0.1uF
VID3
2.5V
VID4
1500uF 1500uF 1500uF 1500uF
SCOP
3.3V
IRLR024N 330uF 330uF 330uF 330uF
1.5V
330uF
Schematic SC1182 (fixed output voltages) SC1183, output voltage setting resistor. Layout Diagram "Setting Output Voltage" section details
IRLR024N
330uF
SC1182 SC1183
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SC1182 SC1183
POWER MANAGEMENT Materials List
Item Qty. C11, C12, C14, C15, C16, Value 0.1uF 1500uF 330uF 4.7uF 1.9uH IRLR3103N IRLR024N EMPTY 1.00k 2.32k 5mOhm DIP-6 SC1182CS OAR-1 Series Turns 16AWG MICROMETALS T50-52D core Sanyo MV-GX equiv. Notes
2001 Semtech Corp.
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SC1182 SC1183
POWER MANAGEMENT Outline Drawing
Contact Information
Semtech Corporation Power Management Products Division Mitchell Rd., Newbury Park, 91320 Phone: (805)498-2111 (805)498-3804
2001 Semtech Corp.
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Synchronous design, enables heatsink solution. efficiency (switching s

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