Programmable Synchronous DC/DC Hysteretic Controller

www.DataSheet4U.com Programmable Synchronous DC/DC Hysteretic Controller with VRM 8.5 VID Range POWER MANAGEMENT Description The SC1159 is a synchronous-buck switch-mode controller designed for use in single ended power supply applications where efficiency is the primary concern. The controller is a hysteretic type, with a user selectable hysteresis. The SC1159 is ideal for implementing DC/DC converters needed to power advanced microprocessors such as Pentium® llI and Athlon®, in both single and multiple processor configurations. Inhibit, under-voltage lockout and soft-start functions are included for controlled power-up. SC1159 features include an integrated 5 bit D/A converter, temperature compensated voltage reference, current limit comparator, over-current protection, and an adaptive deadtime circuit to prevent shoot-through of the power MOSFET during switching transitions. Power good signaling, logic compatible shutdown, and over-voltage protection are also provided. The integrated D/A converter provides programmability of output voltage from 1.050V to 1.825V in 25mV increments. The SC1159 high side driver can be configured as either a ground-referenced or as a floating bootstrap driver. The high and low side MOSFET drivers have a peak current rating of 2 amps. SC1159 Features Programmable hysteresis 5 bit DAC programmable output (1.050V-1.825V) On-chip power good and OVP functions Designed to meet latest Intel specifications Up to 95% efficiency +1% tolerance over temperature Applications Server Systems and Workstations Pentium® III Core Supplies AMD Athlon® Core Supplies Multiple Microprocessor Supplies Voltage Regulator Modules Typical Application Circuit +5V R1 * R3 * R2 1k 2 R4 1k DROOP VID0 27 U1 SC1159CSW 1 IOUT PWRGD 28 C6 0.1 INHIB 3 OCP VID1 26 R11 1k C7 0.1 R9 10k R10 1k PWRGD "POWER GOOD" "INHIBIT" 4 R5 * C1 0.1 C2 0.001 VHYST VID2 25 5 VREFB VID3 24 L1 0.5uH R6 20k 6 VSENSE VID25 23 Cin HF Cin Bulk + Vin +5V/12V 7 AGND INHIBIT 22 8 C3 0.1 +5V SOFTST IOUTLO 21 C8 0.033 _ 9 N/C LOSENSE 20 10 C4 0.01 LODRV HISENSE 19 11 LOHIB BOOTLO 18 R12 1.0 Q1 FDB6035AL 12 DRVGND HIGHDR 17 13 LOWDR BOOT 16 +12V C9 1.0 Q2 FDB7030BL R14 1.6 L2 1.0uH + Cout Bulk Cout HF 14 DRV VIN12V 15 1.05 to 1.825V C5 C10 _ R8 10k R7 * *) for the values see specific application circuit somewhere else in the datasheet Revision 3, December 2002 1 www.semtech.com SC1159 POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Parameter VIN12V BOOT to DRVGND BOOT to BOOTLO Digital Inputs AGND to DRVGND LOHIB to AGND LOSENSE to AGND IOTLO to AGND HISENSE to AGND VSENSE to AGND Continuous Power Dissipation, TA = 25 0C Continuous Power Dissipation, TC = 25 0C Operating Junction Temperature Range Lead Temperature (Soldering) 10 Sec. Storage Temperature Symbol VINMAX Maximum -0.3 to 14 -0.3 to 25 -0.3 to 15 -0.3 to 7.3 ±0.5 -0.3 to 14 -0.3 to 14 -0.3 to 14 -0.3 to 14 -0.3 to 5 Units V V V V V V V V V V W W °C °C °C PD PD TJ TL TSTG 1.2 6.25 0 to +125 300 -65 to 150 DC Electrical Characteristics Unless specified: 0 < TJ < 125°C, VIN = 12V Parameter Supply Voltage Range Supply Current (Quiescent) Symbol VIN12V IINq Conditions Min 11.4 Typ 12 15 Max 13 Units V mA INH = 5V, Vin above UVLO threshold during start-up, fsw = 200 kHz, BOOTLO = 0V, C D H = C D L = 50pF INH = OV or Vin below UVLO threshold during start-up, BOOT = 13V, BOOTLO = 0V INH = 5V, VIN above UVLO threshold during start-up, fsw = 200kHz, BOOT = 13V, BOOTLO = 0V, C D H = 50pF High Side Driver Supply Current (Quiescent) IBOOTq 10 µA 5 mA  2002 Semtech Corp. 2 www.semtech.com SC1159 POWER MANAGEMENT DC Electrical Characteristics (Cont.) Unless specified: 0 < T < 125°C, VIN = 12V J Parameter Reference/Voltage Identification Reference Voltage Accuracy Symbols Conditions Min Typ Max Units VREF 11.4V < VIN12V< 12.6V, over full VID range (see Output Voltage Table) -1 1 % VID0 - VID25mV High Threshold Voltage VID0 - VID25mV Low Threshold Voltage Pow er Good Undervoltage Threshold Output Saturation Voltage Hysteresis Over Voltage Protection OVP Trip Point Hysteresis Soft Start Charge Current (1) VTH(H) VTH(L) 2.25 1 V V VTH(PWRGD) VSAT VHYS(PWRGD) IO = 5mA 82 0.5 10 88 %VREF V mV VOVP VHYS(OVP) 12 15 10 20 %VOUT mV ICHG VSS = 0.5V, resistance from VREFB pin to AGND = 20kΩ, VREFB = 1.3V Note: ICHG = (IVREFB / 5) V(SS) = 1V 10.4 13 15.6 µA Discharge Current Inhibit Comparator Start Threshold VIN 12V UVLO Start Threshold Hysteresis Hysteretic Comparator Input Offset Voltage Input Bias Current Hysteresis Accuracy Hysteresis Setting Idischg 1 mA Vstart(NH) 1 2.0 2.4 V VstartUVLO VhysUVLO 9.25 1.8 10.25 2 11.25 2.2 V V VosHYSCMP IbiasHYSCMP VHYS ACC VHYS SET VDROOP pin grounded 5 1 7 60 mV uA mV mV  2002 Semtech Corp. 3 www.semtech.com SC1159 POWER MANAGEMENT DC Electrical Characteristics (Cont.) Parameter Droop Compensation Initial Accuracy Overcurrent Protection OCP Trip Point Input Bias Current High-Side VDS Sensing Gain Initial Accuracy IOUT Source IOUT Sink Current VIOUT AC C Symbols Conditions Min Typ Max Units VDROOP ACC VDROOP = 50 mV 5 mV VOCP IbiasOCP 0.09 0.1 0.11 100 V nA 2 VHISENSE = 12V, VIOUTLO = 11.9V VIOUT = 0.5V, VHISENSE = 12V, VIOUTLO = 11.5V VIOUT =0.05V, VHISENSE = 12V, VIOUTLO = 12V VHISENSE = 11V, RIOUT = 10K Ω VHISENSE = 4.5V, RIOUT = 10k Ω VHISENSE = 3V, RIOUT = 10k Ω VHISENSE = 4.5V (Note 1) VHISENSE = 4.5V (Note 1) (Note 1) 50 65 500 40 0 0 0 2.85 1.8 80 50 3.75 2.0 1.0 6 V/V mV µA µA V V V V V Ω IsourceIOUT IsinkIOUT VIOUT(11) VIOUT Voltage Swing VIOUT(4.5V) VIOUT(3V) LOSENSE High Level Input Voltage LOSENSE Low Level Input Voltage Sample/Hold Resistance Buffered Reference VREFB Load Regulation Deadtime Circuit (1) LOHIB High Level Voltage LOHIB Low Level Input Voltage LOWDR High Level Input Voltage LOWDR Low Level Input Voltage Drive Regulator DRV Voltage Load Regulation Short Circuit Current VihLOSENSE VilLOSENSE RS/H VldregREFB 10µA < IREFB < 500µA 2 mV VihLOHIB VilLOHIB VihLOWDR VilLOWDR 2 1.0 2 1.0 V V V V VDRV VldregDRV IshortDRV 11.4 < VIN12V < 12.6V, IDRV = 50mA 1mA < IDRV < 50mA 7 100 100 9 V mV mA  2002 Semtech Corp. 4 www.semtech.com SC1159 POWER MANAGEMENT DC Electrical Characteristics (Cont.) Parameter High-Side Output Driver Peak Output Current IsrcHIGHDR IsinkHIGHDR Equivalent Output Resistance RsrcHIGHDR RsinkHIGHDR Low -Side Output Driver Peak Output Current IsrcLOWDR IsinkLOWDR Equivalent Output Resistance RsrcLOWDR RsinkLOWDR duty cycle < 2%, tpw < 100us, TJ = 125°C VDRV = 6.5V, VLOWDR = 1.5V (src), or VLOWDR = 5V (sink) TJ = 125°C VDRV = 6.5V, VLOWDR = 6V TJ = 125°C VDRV = 6.5V, VLOWDR = 0.5V 2 A duty cycle < 2%, tpw < 100us, TJ = 125°C VBOOT - VBOOTLO = 6.5V, VHIGHDR = 1.5V (src), or VHIGHDR = 5V (sink) TJ = 125°C VBOOT - VBOOTLO = 6.5V, VHIGHDR = 6V TJ = 125°C VBOOT - VBOOTLO = 6.5V, VHIGHDR = 0.5V 45 Ω 5 2 A Symbol Conditions Min Typ Max Units 45 Ω 5 AC Electrical Characteristics (Note 1) Parameter Hysteretic Comparators Propagation Delay Time from VSENSE to HIGHDR or LOWDR (excluding deadtime) Output Drivers HIGHDR rise/fall time LOWDR rise/falltime Overcurrent Protection Comparator Propagation Delay Time Deglitch Time (Includes comparator propagation delay time) tOVPROP tOVDGL 2 1 5 µs µs trHIGHDR trHIGHDR trLOWDR tfLOWDR CI = 9nF, VBOOT = 6.5v, VBOOTLO = grounded, TJ =125°C CI = 9nF, VDRV = 6.5V, TJ =125°C 60 60 ns ns tHCPROP 10mV overdrive, 1.3V ≤ Vref ≤ 1.8V 150 250 ns Symbol Conditions Min Typ Max Units  2002 Semtech Corp. 5 www.semtech.com SC1159 POWER MANAGEMENT AC Electrical Characteristics (Cont.) (Note 1) Parameter Overvoltage Protection Comparator Propagation Delay Time Deglitch Time (Includes comparator protection delay time) High-Side Vds Sensing Response Time tVDSRESP VHISENSE = 12V, VIOUTLO pulsed from 12V to 11.9V, 100ns rise and fall times VHISENSE = 4.5V, VIOUTLO pulsed from 4.5V to 4.4V, 100ns rise and fall times VHISENSE = 3V, VIOUTLO pulsed from 3.0V to 2.9V, 100ns rise and fall times Short Circuit Protection Rising Edge Delay Sample/Hold Switch turn-on/turn-off Delay Pow er Good Comparator Propagation Delay Softstart Comparator Propagation Delay Deadtime Driver Non-overlap Time LODRV Propagation Delay TLODRVDLY 400 ns tNOL CLOWDR = 9nF, 10% threshold on LOWDR 30 100 ns tSLST overdrive = 10mV 560 900 ns tPWRGD 1 µs tVDSRED tSWXDLY LOSENSE grounded 3V < VHISENSE < 11V VLOSENSE = VHISENSE 300 30 2 µs tOVPROP tOVDGL 1 1 3 µs µs Symbols Conditions Min Typ Max Units 3 µs 3 µs 500 100 ns ns Note: (1) Guaranteed, but not tested. (2) This device is ESD sensitive. Use of standard ESD handling precautions is required.  2002 Semtech Corp. 6 www.semtech.com SC1159 POWER MANAGEMENT Test Circuit Timing Diagram Simplified Block Diagram  2002 Semtech Corp. 7 www.semtech.com SC1159 POWER MANAGEMENT Pin Configuration Top View Ordering Information Device (1) P ackag e SO-28 Temp Range (TJ) 0° to 125°C SC1159SWTR SC1159EVB Evaluation Board Note: (1) Only available in tape and reel packaging. A reel contains 1000 devices. (28-Pin SOIC) Pin Descriptions Pin # 1 Pin Name IOUT DROOP 2 3 4 5 6 7 8 9 10 11 12 13 OCP VHYST VREFB VSENSE AGND SOFTST NC LODRV LOHIB DRVGND LOWDR Pin Function Current Out. The output voltage on this pin is proportional to the load current as measured across the high side MOSFET, and is approximately equal to 2 x RDS(ON) x ILOAD. Droop Voltage. This pin is used to set the amount of output voltage set-point droop as a function of load current. The voltage is set by a resistor divider between IOUT and AGND. Over Current Protection. This pin is us