LTC1629/LTC1629-PG PolyPhase, High Efficiency, Synchronous Step-Down Switching Regulators FEATURES DESCRIPTIO n Dual Controller Operates from One to Twelve Phases The LTC 1629/LTC1629-PG are multiple phase, dual, n Reduces Required Input Capacitance and Power synchronous step-down current mode switching regula- Supply Induced Noise tor controllers that drive N-channel external power MOSFET n Current Mode Control Ensures Current Sharing stages in a phase-lockable fixed frequency architecture. TM n Phase-Lockable Fixed Frequency: 150kHz to 300kHz The PolyPhase controller drives its two output stages n 1.8MHz Effective Switching Frequency out of phase at frequencies up to 300kHz to minimize the n True Remote Sensing Differential Amplifier RMS ripple currents in both input and output capacitors. TM n OPTI-LOOP Compensation Reduces C The output clock signal allows expansion for up to 12 OUT n 1% Output Voltage Accuracy evenly phased controllers for systems requiring 15A to n Power Good Output Voltage Monitor (LTC1629-PG) 200A of output current. The multiple phase technique n Wide V Range: 4V to 36V Operation effectively multiplies the fundamental frequency by the IN n Very Low Dropout Operation: 99% Duty Cycle number of channels used, improving transient response n Adjustable Soft-Start Current Ramping while operating each channel at an optimum frequency for n Internal Current Foldback Plus Shutdown Timer efficiency. Thermal design is also simplified. n Overvoltage Soft-Latch Eliminates Nuisance Trips An internal differential amplifier provides true remote n Micropower Shutdown sensing of the regulated supplys positive and negative n Available in 28-Lead SSOP Package output terminals as required for high current applications. U A RUN/SS pin provides both soft-start and optional timed, APPLICATIO S short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the n Desktop Computers overcurrent latchoff is disabled. OPTI-LOOP compensa- n Internet Servers tion allows the transient response to be optimized over a n Large Memory Arrays wide range of output capacitance and ESR values. The n DC Power Distribution Systems LTC1629-PG includes a power good output pin that re- , LTC and LT are registered trademarks of Linear Technology Corporation. OPTI-LOOP and PolyPhase are trademarks of Linear Technology Corporation. places the AMPMD control pin of the LTC1629. TYPICAL APPLICATIO 10 V IN 5V TO 28V 0.1F 10F 4 35V M1 LTC1629-PG V TG1 IN CERAMIC 0.003 BOOST1 0.47F 0.1F SW1 L1 M2 RUN/SS 1H BG1 2 D1 PGND PGOOD 1000pF + SENSE1 I TH SENSE1 3.3k M3 TG2 0.003 SGND BOOST2 V 0.47F OUT 1.6V/40A SW2 L2 16k M4 1H V BG2 DIFFOUT 2 D2 EAIN INTV CC 10F + + C OUT V SENSE2 OS 16k 1000F 2 + V SENSE2 OS 4V C : T510E108K004AS L1, L2: CEPH149-IROMC M1, M3: IRF7811 OUT 1629 TA01 D1, D2: UP5840 M2, M4: IRF7809 Figure 1. High Current Dual Phase Step-Down Converter 1 + S S S S S S S S S U ULTC1629/LTC1629-PG UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW ORDER PART Input Supply Voltage (V ).........................36V to 0.3V IN RUN/SS 1 28 CLKOUT NUMBER Topside Driver Voltages (BOOST1,2).........42V to 0.3V + SENSE1 2 27 TG1 Switch Voltage (SW1, 2) .............................36V to 5 V LTC1629CG SENSE1 3 26 SW1 + + SENSE1 , SENSE2 , SENSE1 , LTC1629IG EAIN 4 25 BOOST1 SENSE2 Voltages........................ (1.1)INTV to 0.3V CC LTC1629CG-PG PLLFLTR 5 24 V IN + EAIN, V , V , EXTV , INTV , OS OS CC CC PLLIN 6 23 BG1 LTC1629IG-PG RUN/SS, AMPMD, PGOOD Voltages............7V to 0.3V PHASMD 7 22 EXTV CC Boosted Driver Voltage (BOOST-SW) ..........7V to 0.3V I 8 21 INTV CC TH PLLFLTR, PLLIN, CLKOUT, PHASMD, SGND 9 20 PGND V Voltages ................................ INTV to 0.3V V 10 19 BG2 DIFFOUT CC DIFFOUT V 11 18 BOOST2 I Voltage ................................................2.7V to 0.3V OS TH + V 12 17 SW2 Peak Output Current <1m s(TGL1,2, BG1,2)................ 5A OS SENSE2 13 16 TG2 INTV RMS Output Current................................ 50mA CC + SENSE2 14 15 AMPMD* Operating Ambient Temperature Range LTC1629C/LTC1629C-PG .......................... 0 C to 85 C G PACKAGE 28-LEAD PLASTIC SSOP LTC1629I/LTC1629I-PG ....................... 40 C to 85 C *PGOOD ON LTC1629-PG Junction Temperature (Note 2)............................. 125 C T = 125 C, q = 95 C/W JMAX JA Storage Temperature Range ................. 65 C to 150 C Consult factory for Military grade parts. Lead Temperature (Soldering, 10 sec).................. 300 C ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 15V, V = 5V unless otherwise noted. A IN RUN/SS SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Main Control Loop V Regulated Feedback Voltage (Note 3) I Voltage = 1.2V l 0.792 0.800 0.808 V EAIN TH V Maximum Current Sense Threshold V = 5V l 62 75 88 mV SENSEMAX SENSE V = 5V LTC1629 Only 65 75 85 mV SENSE1, 2 I Feedback Current (Note 3) 5 50 nA INEAIN V Output Voltage Load Regulation (Note 3) LOADREG Measured in Servo Loop I Voltage = 0.7V l 0.1 0.5 % TH Measured in Servo Loop I Voltage = 2V l 0.1 0.5 % TH V Reference Voltage Line Regulation V = 3.6V to 30V (Note 3) 0.002 0.02 %/V REFLNREG IN V Output Overvoltage Threshold Measured at V l 0.84 0.86 0.88 V OVL EAIN UVLO Undervoltage Lockout V Ramping Down 3 3.5 4 V IN g Transconductance Amplifier g I = 1.2V Sink/Source 5m A (Note 3) 3 mmho m m TH g Transconductance Amplifier Gain I = 1.2V (g xZ No Ext Load) (Note 3) 1.5 V/mV mOL TH m L I Input DC Supply Current (Note 4) Q Normal Mode EXTV Tied to V V = 5V 470 m A CC OUT OUT Shutdown V = 0V 20 40 m A RUN/SS I Soft-Start Charge Current V = 1.9V 0.5 1.2 m A RUN/SS RUN/SS V RUN/SS Pin ON Threshold V Rising 1.0 1.5 1.9 V RUN/SS RUN/SS V RUN/SS Pin Latchoff Arming V Rising from 3V 4.1 4.5 V RUN/SSLO RUN/SS I RUN/SS Discharge Current Soft Short Condition V = 0.5V V = 4.5V 0.5 2 4 m A SCL EAIN RUN/SS I Shutdown Latch Disable Current V = 0.5V 1.6 5 m A SDLDO EAIN 2 U WWW