LTC1629-6 PolyPhase, Synchronous Step-Down Switching Regulator FEATURES DESCRIPTIO TM n Reduces Required Input Capacitance and Power The LTC 1629-6 is a PolyPhase synchronous stepdown Supply Induced Noise current mode switching regulator controller with 0.6V n True Remote Sensing Differential Amplifier reference that drives N-channel external power MOSFET n 0.6V, 1% Voltage Reference Accuracy stages in a phase-lockable fixed frequency architecture. n PolyPhase Controller Operates from Two to Twelve The PolyPhase controller drives its two output stages out Phases of phase at frequencies up to 300kHz to minimize the RMS n Current Mode Control Ensures Current Sharing ripple currents in both input and output capacitors. The n Phase-Lockable Fixed Frequency: 150kHz to 300kHz output clock signal allows expansion for up to 12 evenly n 1.8MHz Effective Switching Frequency Capability phased controllers for systems requiring 15A to 200A of n OPTI-LOOP Compensation Reduces C output current. The multiple phase technique effectively OUT n Power Good Output Voltage Monitor multiplies the fundamental frequency by the number n Wide V Range: 4V to 36V Operation of channels used, improving transient response while IN n Very Low Dropout Operation: 99% Duty Cycle operating each channel at an optimum frequency for n Adjustable Soft-Start Current Ramping efficiency. Thermal design is also simplified. n Internal Current Foldback Plus Shutdown Timer An internal differential amplifier provides true remote n Overvoltage Soft-Latch Eliminates Nuisance Trips sensing of the regulated supplys positive and negative n Micropower Shutdown output terminals as required for high current applications. n Available in 28-Lead SSOP Package A RUN/SS pin provides both soft-start and optional timed, U short-circuit shutdown. Current foldback limits MOSFET APPLICATIO S 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 LTC1629-6 includes a power good output pin that , LTC and LT are registered trademarks of Linear Technology Corporation. indicates when the output voltage is inside the 10% OPTI-LOOP is a registered trademark of Linear Technology Corporation. PolyPhase is a trademark of Linear Technology Corporation. tolerance window. TYPICAL APPLICATIO 10 V IN 5V TO 15V 0.1F 10F 6 35V M1 LTC1629-6 V TG1 IN CERAMIC 0.002 BOOST1 0.47F 0.1F L1 SW1 M2 RUN/SS 1H BG1 2 D1 PGOOD PGND 3300pF + SENSE1 I TH SENSE1 1.5k CLKOUT M3 TG2 0.002 SGND BOOST2 V 0.47F OUT 0.7V/40A SW2 L2 10k M4 1H V BG2 DIFFOUT 2 D2 EAIN INTV CC 10F CER + + C OUT V SENSE2 OS X5R 60.4k 270F 4 + V SENSE2 OS 2V C : T510E108K004AS L1, L2: CEPH149-IROMC-H M1, M3: Si7840DP OUT 1629 TA01 D1, D2: UPS840 M2, M4: Si7440DP Figure 1. High Current Dual Phase Step-Down Converter 16296f 1 S S S S S S S S S U ULTC1629-6 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) ORDER PART Input Supply Voltage (V ).........................36V to 0.3V IN TOP VIEW NUMBER Topside Driver Voltages (BOOST1,2).........42V to 0.3V RUN/SS 1 28 CLKOUT Switch Voltage (SW1, 2) .............................36V to 5 V + SENSE1 2 27 TG1 LTC1629EG-6 + + SENSE1 , SENSE2 , SENSE1 , SENSE1 3 26 SW1 SENSE2 Voltages........................ (1.1)INTV to 0.3V CC EAIN 4 25 BOOST1 + EAIN, V , V , EXTV , INTV , PLLFLTR 5 24 V OS OS CC CC IN RUN/SS, PGOOD Voltages ...........................7V to 0.3V PLLIN 6 23 BG1 PHASMD 7 22 EXTV Boosted Driver Voltage (BOOST-SW) ..........7V to 0.3V CC I 8 21 INTV CC PLLFLTR, PLLIN, CLKOUT, PHASMD, TH SGND 9 20 PGND V Voltages ................................ INTV to 0.3V DIFFOUT CC V 10 19 BG2 DIFFOUT I Voltage ................................................2.7V to 0.3V TH V 11 18 BOOST2 OS Peak Output Current <1m s(TGL1,2, BG1,2)................ 5A + V 12 17 SW2 OS INTV RMS Output Current................................ 50mA CC SENSE2 13 16 TG2 Operating Ambient Temperature Range + SENSE2 14 15 PGOOD LTC1629EG-6 (Note 6) ......................... 40 C to 85 C G PACKAGE Junction Temperature (Note 2)............................. 125 C 28-LEAD PLASTIC SSOP Storage Temperature Range ................. 65 C to 150 C T = 125 C, q = 95 C/W JMAX JA Lead Temperature (Soldering, 10 sec).................. 300 C Consult LTC Marketing for parts specified with wider operating temperature ranges. 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 0.594 0.600 0.606 V EAIN TH V Maximum Current Sense Threshold V = 5V l 62 75 88 mV SENSEMAX SENSE 65 75 85 mV 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 0.64 0.66 0.68 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 16296f 2 U WWW