SEMTECH SC1146 handbook
Contents
1. PWRGOOD Power good should be pulled up to 5V supply via a 3K 10K resistor NOTE 1 All logic inputs and outputs are open collector TTL compatible The SC1146 is patent pending O 2000 SEMTECH CORP 4 652 MITCHELL ROAD NEWBURY PARK CA 91320 ran VRM9 0 PROGRAMMABLE MULTI PHASE P SEMTECH hi6H PERFORMANCE PWMCONTROLLER 901146 Today s Results Tomorrow July 25 2000 OUTPUT VOLTAGE Unless specified O GND 1 High or Floating Veccore T4 25 C Vecsy 5V Veco 5V 4 Phase operation VDC Output Off 1 1 1 125 1 15 1 175 1 2 1 225 1 250 1 275 1 3 1 325 1 35 1 375 1 4 1 425 1 45 1 475 1 5 1 525 1 55 1 575 1 6 1 625 1 65 1 675 1 7 1 725 1 75 1 775 1 8 1 825 1 85 OOoOooo0oo0o0o0 0o0o0o0ooooocoooooloaa OOcoo0 2a a o0o000 a a o0o00o0 a a 2 o0o0o00ocozooaa 00O02 2200 200200 2002200 x0000 O 0o020 0202002002020 021000 0 1 4 1 4 1 y 1 4 4 4 4 4 1 4 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 The SC1146 is patent pending 2000 SEMTECH CORP 652 MITCHELL ROAD NEWBURY PARK CA 91320 SC1146 Pa VRM9 0 PROGRAMMABLE MULTI PHASE HIGH PERFORMANCE PWM CONTROLLER Tomorrow s Vision Today s Results SEMTECH P July 25 2000 EVALUATION BOARD SCHEMATIC INVISNOO ANIL 4HL SIJS 879 peTqestp S dAO U3T peddtys S dAO STAPSTP o3 N3dO 92u 0 L78 INIOd dIHL X9VITIOAHSAO AH2. pap o mv Mrs oy NO COW S Fs t aeo INOA OT HE9 960 sed m E dho MENU pierna y gt DUE L T4 T pos vava H inte sn 09 2 AUTE siooace_ o 8Q4 0 a e M z l E T i m Agud o RUP ar 984 PA Fe 51 o o 0 9 a 4d loo 91H ose 7 ano L Siu AQL nzz nr v LE F fado cei laine m wr 158 Hs Ser a3 w s 620 m Aornzz ni oridid Mol wn asorlos T dib TM S22 amet 820 120 gi Qd oos Fe 1 ozo i AOL naz ES AgVnoL TO chee SP yous YoinoA Le SANO 4 AN ao OPA l 5 SE t oa avaa H l 3 w E 0 6 69 L9 L A aov nea _ T stoogoe loeozaad 4v nua TE B JUN ug py L cn D a Aqua LE z z c s 129 90 vo 628 E xL t 7 AOL nzz zo L gj TL el paon i ano y E zh yox z WY 0 pue 188 ow LE F z y S zi Y EL 022 n ON 8 g a9 SS Aovnzz nigora 0 en i os L cr Ht i i seosdad 619 asorlOs VEN 30 PAS 8 6 atas mmr Se g NO 00N S E T 910 xoxo PO I 1S pio E Ni ASA t rl T TA parra esasa iy RN Mo pena H gt 19 wh 9 h 08 DAVBO ANNI nonz sioogos jocozea4 Av 0 6 69 L9 poobimd B 019 n saf Mo f a Si 3 eso zo ua E aornaz los 82d oL Aa ul atu B ul if VN ti e QNO E i Poh BE E MEE m 198 ao E Poo RE z nora neona 10 a LLL 8 poog Jamod E i sega PRBE in zant oL 10 P AAA LALO F AOL nzz LLLL n n FFFF lu ass gISS F1SS 7188 Cons il A eed id va ea za ta xot O t 89811 god buo x bi Acl The SC1146 is patent pendin
3. D CONVERTER SPECIFICATIONS Reference Application Circuit Output Accuracy Over Set Vout VID 0 4 0000 1111 Range Vocsv 5 0V Load Regulation Vo 2 000V lo 3A 20A Line Regulation Vccsy 5V Vo 2 000V Vin 4 6V Vy separated from Vccbv lo 5A Clk external POWER GOOD SIGNAL Off Leakage Current leakage Off PWRGOOD Logic High Power Good Max Sink Current Isinx max PWRGOOD lt 8V Power Good Threshold P wrgood T 1o Vout 1 300V 1 950V Voltage Tolerance P cod T Hi Vout 2 000V 3 500V Note 1 This device is ESD sensitive Use of standard ESD handling precautions is required 3 The SC1146 is patent pending 2000 SEMTECH CORP 652 MITCHELL ROAD NEWBURY PARK CA 91320 Today s Results Tomorrow s Vi ra pjsEM TECH July 25 2000 PIN DESCRIPTION Pin Name VRM9 0 PROGRAMMABLE MULTI PHASE SC1146 HIGH PERFORMANCE PWM CONTROLLER Pin Function Voc 5V Supply voltage input 5V nominal Divsel Connect to Gnd for four phase operation and to logic High for three Phase operation Clksel Clock Select Logic High selects internal clock Logic Low selects external clock Extclk External Clock Input The output frequency is determined by Clock Input Freq 4 Output freq Clock Input 4 Pull up to Vccbv to select internal clock Baer Connects to external reference resistor Sets the operating frequency of the in
4. Gate Drives firing 90 out of phase Vour 7 1 0V lg 10A Vcc2212V Asynchronous operation ERROR AMPLIFIER At the heart of the controller is an ultra fast transcon ductance error amplifier Since the output inductor val ues can be selected to be a minimum usually less than a micro Henry the delays due to inductor ramp time are minimized during transient load recovery The higher frequency of operation also allows use of much smaller capacitance on the output This means that the dc dc converter output capacitors hold time is less The error amplifier must therefore respond extremely fast Recover the Fort after a transient The SC1146 error amplifier recovers to its normal duty cycle after applica tion of a full load transient within 2 usec maximum largely dependant on supply quality and usually within tusec This minimizes undershoot and overshoot during application of a transient 8 652 MITCHELL ROAD NEWBURY PARK CA 91320 Today s Results Tomorrow s Vision P SEMTEC July 25 2000 ERROR AMPLIFIER CONT VRM9 0 PROGRAMMABLE MULTI PHASE HIGH PERFORMANCE PWM CONTROLLER Tek Run 2MS s Sample MERK bees T 1 TN eim ons TV M Spe yA ao b 23 Jun 1998 15 20 37 Fig 3 Transient response Top trace Current sense 8A div 30A usec Bottom trace Voyr Tek BE Single Seq 100M5 s B EF Edge Slope ues Coupling Slope Level Mode DC X 8
5. Generator IPOWERGOOD VID1 GND VID2 I LI ENABLE VIDS t z SH FBG VIDA t BGour OC 1 DO FB Y PWM Generator Error Amp OC 1 1 1 COMP 24 Pin SOIC Reference The SC1146 is patent pending 2000 SEMTECH CORP Pentium is a registered trademark of Intel Corporation 652 MITCHELL ROAD NEWBURY PARK CA 91320 Today s Results Tomorrow s Vi ra pjsEM TECH July 25 2000 ABSOLUTE MAXIMUM RATINGS Parameter VRM9 0 PROGRAMMABLE MULTI PHASE HIGH PERFORMANCE PWM CONTROLLER SC1146 Limits Vccsy to GND 0 3 to 12 FBG to GND 1 Voce to GND 0 3 to 20 Operating Temperature Range 0 to 70 Junction Temperature Range 0 to 125 Storage Temperature Range 55 to 150 Thermal Resistance Junction to Case 25 Thermal Resistance Junction to Ambient 80 Lead Temperature Soldering 10 sec ELECTRICAL CHARACTERISTICS Unless otherwise noted T 25 C Voc 4 5V Veco 5V 4 Phase operation PARAMETER SYMBOL CONDITIONS Supply Voltage Range Voce UVLO Range Vccsv UVLO Hystersis Vecsv Supply Volt
6. patent pending O 2000 SEMTECH CORP 652 MITCHELL ROAD NEWBURY PARK CA 91320
7. 00mv Normal me Source Type Edge ch2 Holdoff 5 545 Fig 4 Transient response Top trace Gate Drive Bottom trace Transient current 16A div 30A usec The error amplifier has two inverting inputs one for the High Range VID4 set to logic high and one input for the Low Range The effective gain of the error ampli fier stays constant in both ranges keeping the loop gain constant regardless of output voltage range The SC1146 is patent pending O 2000 SEMTECH CORP SC1146 BANDGAP REFERENCE SOFT START The precision internal bandgap reference provides a stable temperature compensated 2 05 V reference for the error amplifier s non inverting input the DAC per for the VID digital to analog converter the under voltage lock out circuitry as well as the reference for the Bias generator current sources The error amplifiers non inverting input is connected to the bandgap reference through a 3Kohm resistor which is also externally con nected to a soft start capacitor via the BGoyy pin Upon application of power the non inverting input of the er ror amplifier is held low for a short time set by the RC product of the soft start capacitor and 3Kohm allowing for the decoder and PWM controller to settle This pre vents any harmful output voltage overshoots upon start up or after a converter shut down as a result of over current or the enable pin pulled low The non inverting input then ramps up according to
8. L INS LZA NV 92H epou Hhutaes aemod SWISVNS OMI JHI SNIIVHVdSS AH GWTIOHINOO A LLOSHIG 44 NWO S SOPTOS HHL JO SZWHHIl PPLTOS HLIM YAHLIDOL QXTIGVSIG ANY Q3T8VNS HUY S G PIOS TIY TdWe ONIWNSdW D Ag gza 80 128 0 as q NASN3 x seyd J zg ied ZUNZx 228 MZ 8 b914 ccu Aq 398 berg Scd ES asorios T T ji o 950 Spo or 094 qos Hy m an AD eH yasasa 4 L Sao dl ni Ero rey i 10 r8 nono E oa avaa H i See quib 159 0 6 60 9 100 L i nua ad E No 4 0 a Adu Z Y zn sroogos jocozeas Ley RES M p 02d ny 9pL10S zzy 900001 F E 8 as E OL fos elu 8lH 6 9 n 8a 80 c org ni Js aH E F l 001 dal A dwog 00 WAY t TA g EJ 8 a 869 Dy 990719
9. O O se11481 0 0 VRM9 0 PROGRAMMABLE MULTI PHASE HIGH PERFORMANCE PWM CONTROLLER 2006 Today s Results Tomorrow s Vision ptem July 25 2000 DESCRIPTION The SC1146 is the latest high performance multi phase PWM controller designed for high power mi croprocessors requiring ultra fast transient response The SC1146 is programmable for the voltage range required by the latest Microprocessors Utilizing a novel and unique design the controller distributes the output load across up to four converter channels by digitally phase shifting the PWM outputs This ap proach greatly reduces the stress and heat on the out put stage components while lowering input ripple cur rent by as much as 8096 Accurate current sharing among the four phases is achieved by precision design techniques and trimming of critical elements The high speed transconductance error amplifier is ex ternally initialized using a soft start capacitor allowing the controller to wake up without overshoot thus pro tecting the low voltage microprocessor loads The out put drive voltage to the power MOSFETs is pro grammable to minimize switching losses in the drive circuitry The output voltage is digitally programmable by means of a 5 bit DAC new codes A single resistor programs the master clock frequency 8MHz max or the clock can be supplied by an external source where exact fre quency control is desired The number of operating phases is prog
10. R26 open R27 R28 R29 R30 51 1 4W 1206 10K gl g fa al A A MW OA R31 R32 R34 R35 R36 R37 TBD used at light load contact factory S1 Vout Clk switch C amp K 800 cal swch U1 U3 U4 U5 SC1405B SC1405TS Semtech 805 498 211 1 ge U2 C1146CSW Semtech 805 498 21 11 U6 LM358 Unless otherwise noted all resistors are 1 10W 5 0805 and all capacitors are 20 50v 0805 The SC1146 is patent pending 2000 SEMTECH CORP any 7 652 MITCHELL ROAD NEWBURY PARK CA 91320 Today s Results Tomorrow s Vision P SEMTEC July 25 2000 THEORY OF OPERATION FUNCTIONAL DESCRIPTION The SC1146 is a programmable high performance multi phase controller designed for the most demand ing DC DC converter applications in which transient response space input ripple current and component form factor and cost are paramount The SC1146 is configured to operate with external MOSFET drivers such as the SC1405 in high efficiency synchronous applications See Evaluation Board Schematic The SC1146 based dc dc converter consists of four buck converter controllers integrated and synchro nized The high clock frequency allows for smaller in ductor values and miniature surface mount low induc tance output capacitors Since each stage has 1 4 the output current the conduction losses in each stage is reduced by a factor of 1 16 Precision active trimm
11. age Range Supply Current DRV Outputs open Supply Current Vour 2 00V Io 0 Reference Current Pin Voltage lref 250u4A VIDO 4 Clock Select amp Divide Select Logic Threshold Logic Low Logic High VIDO 4 Clock Select amp Divide Select Input Bias Current Vid0 4 OV Vid0 4 4 5V Enable Pin Maximum Duty Cycle FB 0V DRVO 3 Output Voltage la IMA lsource 1mA PWRGOOD Voy DRVO 3 Source Current Vour 2 00V DRVO 3 Sink Current The SC1146 is patent pending O 2000 SEMTECH CORP Vour 2 00V 652 MITCHELL ROAD NEWBURY PARK CA 91320 ran VRM9 0 PROGRAMMABLE MULTI PHASE P SEMTECH hi6H PERFORMANCE pwm CONTROLLER 901146 Today s Results Tomorrow July 25 2000 ELECTRICAL CHARACTERISTICS Cont Unless otherwise noted T 25 C Vecsv 5V Veco 5V 4 Phase operation PARAMETER SYMBOL CONDITIONS Bgout Voltage Vegout Vid 00000 Bgout Impedance Ro Bg External Clock Freq Range Fes ck Oscillator Frequency lref 2504A Internal Clock Freq Range Match DRVO 3 Duty cycle Avg 50 PWM Off Time Overcurrent Comparator OCC_CMR Comparator Common Mode Range OC I P bias Current IB_OC Vin 5V OC I P bias Current IB_OC Vin 5V Input Offset Voltage VOS_OCC Vin 5V Feedback Input Impedance Ri_FB Vo 2 00V Duty Cycle Range
12. g 652 MITCHELL ROAD NEWBURY PARK CA 91320 2000 SEMTECH CORP Today s Results tomorrow s Vision P SEMTEC July 25 2000 BILL OF MATERIAL Reference Value VRM9 0 PROGRAMMABLE MULTI PHASE SC1146 HIGH PERFORMANCE PWM CONTROLLER Manufacturer C2 C4 C11 C19 C20 C28 C29 C37 039 1u 10V X7R AVX 818 883 7606 C3 10uF 6 3V Al Elec Murata C5 C12 C14 C17 C18 C21 C22 C26 C27 22u 10V Murata 512 250 5082 PN GRM235Y5V226Z010 C6 C7 C15 C24 C32 1uF 16V Murata Al Elec C8 330uF 16V Nichicon C16 C25 C33 10u 16V Murata C40 01u Murata C42 022 any C45 C49 01 Murata X7R C46 001 Murata C50 C51 C52 C53 1nF any C54 1000uF Murata Al Elec 0 p l D1 D2 D3 D4 D5 D7 D9 D11 SS12 1A SS32 3A General Instruments General Instruments J1 INPUT L1 L2 L3 L4 6uh 12A Falco 305 662 7276 PN 702508 Q1 Q4 Q7 Q10 IR7811 Int Rectifier Q3 Q6 Q9 Q12 IR3101D2 Alter FDB7030BL Int Rectifier Fairchild Semiconductors R1 10 Dale any R2 R10 C13 R14 R17 C23 R33 C34 C43 0 any R4 R12 R16 R23 1 5 or zero any R5 R6 R7 R38 10K any R8 R9 R1 1 R13 22 any R18 SEL any R19 100 any R20 2 2k any R22 15k R24 300k R25 R40 R41 R42 R43 2 2
13. ing ensures 196 matching of duty cycles among phases thus ensuring the heat and component stress is shared equally The SC1146 may also be configured in asyn chronous mode by using buffer transistors VRM9 0 PROGRAMMABLE MULTI PHASE HIGH PERFORMANCE PWM CONTROLLER SC1146 ables the PWM controller sequentially A resistor from Rage pin to FBG programs the frequency and ramp time Clock Freq 8 2K Rref 8Mhz The ramps are then compared to the error amplifier out put at the high speed PWM comparator inputs The con troller outputs are buffered versions of the comparator outputs Tek Run Sere TI Sample Ly 1 i JA 920uW A 135ns 320uV 440MV 21 Sep 1998 16 59 04 ib a a der M 250ns Chi X BEP ZOUmvAW Fig 1 Voy Ripple Voy 1 0V lour 30A DECODER BIAS GENERATOR PWM CONTROLLER The 8 MHz clock is divided down to 2 MHz for four phase operation by the clock decoder The start of the output pulses are time shifted 90 degrees by the de coder with respect to each other The Bias Generator generates the ramps to each phase by a precision trimmed current source and on chip capacitors The decoder which is synchronized to the bias generator via the master clock phase shifts the ramps and en The SC1146 is patent pending O 2000 SEMTECH CORP Tek Run 5 00GS s Sampie NL 6 8 V 23 Jun 1998 13 00 35 VAT i M 200ns Chi Y VOS Fig 2 The four
14. rammed independently of the external clock The parts features under voltage lock out with hysteresis and over current protection PIN CONFIGURATION TEL 805 498 2111 FAX 805 498 3804 WEB http www semtech com FEATURES e Allows use of small surface mount components e Ultra fast transient recovery time e Dramatic reduction of input ripple current and out put ripple voltage e 5 bit programmable DAC for the latest lower output voltage Microprocessors e Wide High frequency operating range Selectable 2 3 4 phase operation 5 Volt only operation eliminates the need for 12V supply e Precision load current sharing 1 PWM match Selectable internal or external clock e Soft start UVLO Over current protection APPLICATIONS e High end servers and workstations e High current Ultra fast transient microprocessors ORDERING INFORMATION DEVICE PACKAGE TEMP T SC1146CSW TR SO 24 0 85 C Note 1 Only available in tape and reel packaging A reel contains 1000 devices BLOCK DIAGRAM PWM Top View Clock Select Generator E PWRGOOD PWM Generator o DRVS Oscil ator Bias Generator Clksel t Ti DRV1 I Vcc2 Extelk t RREF VIDO 1 r3 DRVO I3 DRV2 PWM
15. ternal clock and the ramp time for the PWM Reference voltage at this pin is 2 05V Trimmed to set 250pA at 8MHz VIDO Programming Input LSB VID1 Programming Input VID2 Programming Input VID3 Programming Input VIDA Programming Input MSB OC Over current comparator Non Inverting input OC Over current comparator Inverting input COMP Compensation Pin Compensation is acheived by connecting a capacitor in series with a resistor between this pin and FBG A 300K ohm resistor must also be directly connected between this pin and FBG FB Feedback input connected to supply output BGour Bandgap Reference Output Output resistance 3Kohm Must be bypassed with 4 7nF 100nF capacitor to FBG This capacitor programs the soft start time FBG Feedback Ground This pin must be connected to return side of output caps This pin is not internally connected to GND ENABLE Connects to 5V to ENABLE Connect to GND to disable entire device GND Ground Pin DRV2 Phase 2 output output voltage range 3V Veca 1V DRVO Phase 0 output output voltage range 3V Veca 1V VCC2 Supply voltage for the DRVO 3 may be connected to 5V or 12V supply There is no Undervoltage Lockout on this pin DRV1 Phase 1 output output voltage range 3V Veca 1V DRV3 Phase 3 output output voltage range 3V Voc 1V
16. the RC time constant allowing gradual rise of output voltage OVER CURRENT COMPARATOR The SC1146 has an internal over current comparator designed to sense current in the input supply path The comparator inputs have a high common voltage range thus allowing operation under all possible volt age current combinations The output of the compara tor pulls the BG oy soft start pin low thus disabling the error amplifier and causing the PWM outputs to enter minimum duty cycle mode regulating the output at a minimum voltage A current sense trace may be used as the current sense resistor This will utilize the trace as input filter inductor thus preventing conducted emissions to input supply For details of programming the overcurrent comparator refer to SC1144 EVB user manual SC1146 Special features The SC1146 is a special version of the original SC1144 4 phase PWM controller with the latest VRM9 0 VID codes which allow programming lower output voltages required by the latest Microprocessors Also a 12V supply is no longer required The Voc and PWRGOOD pins can be connected to Vcc5v This eases the connection to 5V only MOSFET drivers such as the SC1405 The DRVs will swing to Vcc5v eliminating the need for 12V to 5V level shifting There is no Under Voltage Lockout on Voc 9 652 MITCHELL ROAD NEWBURY PARK CA 91320 ran VRM9 0 PROGRAMMABLE MULTI PHASE P SEMTECH hi6H PERFORMANCE PWMCONTROLLER 901146 Today s Res
17. ults Tomorrow July 25 2000 An evaluation board is available which may be ordered directly from the factory SC1146 1405EVB is a DC DC converter utilizing the SC1146 four phase controller in a high current synchronous application The evaluation board is intended as a guideline for board design layout and to assess key performance parameters such as tran sient response thermal stress management and input and output ripple considerations The SC1146EVB includes a DIP switch for mode voltage selection as well as qualified selection of components for the SC1146 operation The SC1144EVB user manual contains useful general applications information applicable to SC1146 and may be accessed from our website at www semtech com K DIMENSIONS Y ig INCHES MM MIN MAX L 5985 6141 b y 2914 2992 7 JETAIL A OUTLINE DRAWING SO 24 E 394 1 419 050 BSC 015 020 004 0 118 0926 1043 2 010 029 0091 0125 o 8 r 016 050 JEDEC MS 013AD Ii A EH EE EH LIS S F XI IC IG rmioico iuw PE M X 45 le cm SEE DETAIL A B17104B DIMENSIONS A AND B DO NOT INCLUDE MOLD PROTUSIONS CONTROLLING DIMENSION MILLIMETERS ECNO00 1215 10 The SC1146 is
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SEMTECH SC1146 handbook