SC1144ABCSW

PROGRAMMABLE, HIGH PERFORMANCE MULTI-PHASE, PWM CONTROLLER Preliminary - August 24, 1999 SC1144 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION The SC1144 is a high performance, multi-phase (PWM) controller designed for high power microprocessors requiring ultra fast transient response, such as ® the Pentium ll and beyond. 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 approach greatly reduces the stress and heat on the output stage components while lowering input ripple current by as much as 80%. 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 externally initialized using a soft-start capacitor allowing the controller to “wake-up” without overshoot, thus protecting the low voltage microprocessor loads. The output drive voltage to the power MOSFETs is programmable to minimize switching losses in the drive circuitry. The floating feedback ground allows remote sense capability. The output voltage is digitally programmable by means of a 5 bit DAC. A single resistor programs the master clock frequency (8MHz max) or the controller may be synchronized using an external oscillator. The number of operating phases is programmed independently of the external clock. The parts features under-voltage lock-out with hysteresis and overcurrent protection. FEATURES • Allows use of small surface mount components • Ultra fast transient recovery time • W ide, High frequency operating range • Selectable 2, 3, 4 phase operation • Floating feedback ground for remote sensing • Precision load current sharing • Selectable internal or external clock • Soft start, Over current protection • 5-bit DAC programmable output • programmable clock, 200Khz-2Mhz per phase APPLICATIONS • High end servers and workstations • High current/Ultra-fast transient microprocessors • Voltage Regulator Modules ORDERING INFORMATION DEVICE (1) PACKAGE SO-24 TEMP. (TJ) 0 - 85°C SC1144ABCSW Note: (1) Add suffix ‘TR’ for tape and reel. BLOCK DIAGRAM PIN CONFIGURATION Top View (24-Pin SOIC) The SC1144 is patent pending Pentium is a registered trademark of Intel Corporation 1 © 1999 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 PROGRAMMABLE, HIGH PERFORMANCE MULTI-PHASE, PWM CONTROLLER Preliminary - August 24, 1999 SC1144 ABSOLUTE MAXIMUM RATINGS Parameter VCC5V to GND FBG to GND VCC12V to GND Operating Temperature Range Junction Temperature Range Storage Temperature Range Thermal Resistance Junction to Case Thermal Resistance Junction to Ambient Lead Temperature (Soldering) 10 sec Symbol Vcc5v FBG Vcc12v TA TJ TSTG θJC θJA TLEAD Limits -0.3 to + 12 ±1 -0.3 to +20 0 to +70 0 to +125 -55 to +150 25 80 300 Units V V V °C °C °C °C/W °C/W °C ELECTRICAL CHARACTERISTICS Unless otherwise noted: TA = 25°C, VCC 5V = 5V, VCC 12V = 12V, 4-Phase operation. PARAMETER Supply Voltage Range UVLO Range UVLO Hystersis UVLO Range UVLO Hystersis Supply Voltage Range Supply Current Supply Current Reference Current Pin Voltage Vid0-4 Clock Select & Divide Select Logic Threshold Vid0-4 Clock Select & Divide Select Input Bias Current Enable Pin SYMBOL VCC12V VCC5V VCC5V VCC12V VCC12V VCC5V VCC12V VCC5V VREF VINL VINH IINL IINH VINL VINH DRV0-3 Output Voltage VOL VOH DRV0-3 Source Current DRV0-3 Sink Current ISRC ISNK Isink = 1mA Isource=1ma,OUTV=Vcc12 VOUT = 2.00V VOUT = 2.00V VCC12 -1 20 40 2 .3 DRV Outputs open VOUT = 2.00V, IO = 0 Iref = 250µA Logic Low Logic High Vid0-4=0V Vid0-4=4.5V 2 -20 +50 .8 2.05 0.8 4.5 CONDITIONS MIN 10.0 TYP 12.0 3.9 50 9.0 100 5.0 12 5.5 20 40 MAX 14.0 UNITS V V mV V mV V mA mA V V V µA µA V V V V mA mA The SC1144 is patent pending 2 652 MITCHELL ROAD NEWBURY PARK CA 91320 © 1999 SEMTECH CORP. PROGRAMMABLE, HIGH PERFORMANCE MULTI-PHASE, PWM CONTROLLER Preliminary - August 24, 1999 SC1144 ELECTRICAL CHARACTERISTICS (Cont.) Unless otherwise noted: TA = 25°C, VCC5V = 5V, VCC12V = 12V, 4-Phase operation. PARAMETER Bgout Voltage Bgout Impedance External Clock Freq. Range Oscillator Frequency Accuracy Internal Clock Freq. Range Match DRV0-3 PWM Off Time Drive Voltage Range Overcurrent Comparator, Comparator, Common Mode Range OC+I/P bias Current OC-I/P bias Current Input Offset Voltage Feedback Input Impedance Maximum Duty Cycle Mimimum Duty Cycle SYMBOL VBgout RO_Bg Fext_CK FOSC Fint_CK ∆D Toff OutV OCC_CMR Output Freq. = 2MHz/Phase VO = 2.000V 5 3 Duty cycle deviation from Avg. Iref = 250µA .80 7.2 .80 -1 25 10 12 15 CONDITIONS Vid = 00000 MIN TYP 2.05 3 8.0 8.0 8.0 8.5 8.8 8.5 +1 MAX UNITS V KΩ MHz MHz MHz % % V V IB_OC+ IB_OCVOS_OCC Ri_FB Dmax Dmin Vin = 5V,Roc+