IR3081 International Rectifier Corp., IR3081 Datasheet
IR3081
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IR3081 Summary of contents
Page 1
... ICs” which each drive and monitor a single phase of a multiphase TM converter. The XPhase to design while providing higher efficiency than conventional approaches. The IR3081 is intended for VRD or VRM/EVRD 10 applications that use external VCCVID/VTT circuits. FEATURES • 6 bit VR 10 compatible VID with 0.5% overall system accuracy • ...
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... ORDERING INFORAMATION Device IR3081MTR * IR3081M * Samples only ABSOLUTE MAXIMUM RATINGS Operating Junction Temperature……………..150 Storage Temperature Range………………….-65 ESD Rating………………………………………HBM Class 1C JEDEC standard ...
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... Applies to all VID codes and -0.3V ≤ VOSNS- ≤ 0.3V. Note 41.9kΩ ROSC Note 1 Note 1 VBIAS–VEAOUT (referenced to VBIAS) Normal operation or Fault mode V(VDRP) – V(IIN), 0.8V ≤ V(IIN) ≤ 5.5V Note 1 IR3081 o o ≤ 14V ≤ T ≤ 100 MIN TYP MAX ...
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... With FB = 0V, adjust V(SS/DEL) until EAOUT drives high Relative to Charge Voltage 1V ≤ V(OCSET) ≤ 41.9kΩ ROSC I(PWRGD) = 4mA V(PWRGD) = 5.5V 0V ≤ V(ENABLE) ≤ VCC Start – Stop -0.3V ≤ VOSNS- ≤ 0.3V, All VID Codes IR3081 MIN TYP MAX UNIT 255 300 345 kHz ...
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... Open Collector output that drives low during Softstart and any external fault condition. Connect external pull-up. 27 N/C No internal connection 28 ENABLE Enable Input. A logic low applied to this pin puts the IC into Fault mode. Page IR3081 TM during transition to a lower VID code. 10/01 /04 ...
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... IRU3086 PHASE 0.1uF IC PHASE HOT CCS PHASE FAULT CURRENT SHARE IRU3086 PHASE 0.1uF IC PHASE HOT CCS ADDITIONAL PHASES CONTROL BUS Figure 1. System Block Diagram IR3081 CIN COUT RCS RCS INPUT/OUTPUT 10/01 POWER GOOD PHASE FAULT VR HOT VOUT SENSE+ VOUT+ VOUT- VOUT SENSE- /04 ...
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... GENERATOR RAMPIN- EAIN RPHS2 PWMRMP RPWMRMP RAMP DISCHARGE SCOMP CLAMP CPWMRMP SHARE CSCOMP ADJUST ERROR AMPLIFIER + ISHARE 10K 20mV - DACIN Figure 2. PWM Block Diagram IR3081 PHASE IC PWM LATCH GATEH S PWM RESET COMPARATOR DOMINANT - R GATEL + ENABLE + BODY - BRAKING COMPARATOR X 0.91 CURRENT SENSE CSIN+ ...
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... PWM ramps are referenced to VDAC. Figure 4 depicts PWM operating waveforms under various conditions. Page 50% RAMP DUTY CYCLE SLOPE = 80mV / % DC SLOPE = 1.6mV / ns @ 200kHz SLOPE = 8.0mV / ns @ 1MHz CLK1 CLK2 CLK3 CLK4 CLK5 CLK6 CLK7 CLK8 Figure 3. 8 Phase Oscillator Waveforms IR3081 10/01 /04 ...
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... SLEW V O − MAX MIN T SLEW + BODYDIODE IR3081 DUTY CYCLE DECREASE DUE TO LOAD DECREASE (BODY BRAKING) OR FAULT (VCC UV, OCP, VID=11111X the two time constants match, the L 10/01 STEADY-STATE OPERATION /04 ...
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... PWM ramp thereby increasing its duty cycle and output current. The crossover frequency of the current share loop can be programmed with a capacitor at the SCOMP pin so that the share loop does not interact with the output voltage loop. Page Current Sense Amp CSOUT IR3081 10/01 /04 ...
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... IR3081 THEORY OF OPERATION Block Diagram The Block diagram of the IR3081 is shown in Figure 6, and specific features are discussed in the following sections. VCC - START + STOP + VCC UVLO 9.1V COMPARATOR 8.9V - ENABLE ENABLE - COMPARATOR + + VCHG IDISCHG 6uA ICHG 70uA SS/DEL VID = 11111X VID5 IROSC VID0 ...
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... The IR3081 can accept changes in the VID code while operating and vary the DAC voltage accordingly. The sink/source capability of the VDAC buffer amplifier is programmed by the same external resistor that sets the oscillator frequency. The slew rate of the voltage at the VDAC pin can be adjusted by an external capacitor between VDAC pin and the VOSNS- pin ...
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... Table 1. Voltage Identification (VID) is selected to program the desired amount of fixed offset voltage below the FB . When the load current increases, the adaptive DRP IR3081 VID3 VID2 VID1 VID0 VID5 ...
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... Amplifier Phase IC VDRP - IIN ISHARE ISHARE ISHARE ISHARE + VDAC Figure 8. Adaptive voltage positioning Control IC Error Amplifier VDAC + EAOUT - RFB FB IFB RFB2 RDRP AVP Amplifier VDRP - IIN IIN + IR3081 Current Sense Amplifier CSIN+ + CSIN- - 10k Current Sense Amplifier CSIN+ + CSIN- - 10k Vo Rt 10/01 /04 ...
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... If SS/DEL pin is pulled below 0.9V, the converter can be disabled. Under Voltage Lockout (UVLO) The UVLO function monitors the IR3081’s VCC supply pin and ensures that IR3081 has a high enough voltage to power the internal circuit. The IR3081’s UVLO is set higher than the minimum operating voltage of compatible Phase ICs thus providing UVLO protection for them as well ...
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... VDAC voltage from the VDRP voltage. System Reference Voltage (VBIAS) The IR3081 supplies a 6.8V/5mA precision reference voltage from the VBIAS pin. The oscillator ramp amplitude tracks the VBIAS voltage, which should be used to program the Phase IC trip points to minimize phase delay errors. ...
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... VID0 EAOUT CONTROL VID1 4 VID1 FB IC VID2 5 VID2 VDRP VID3 6 VID3 IIN VID4 7 VID4 OCSET ROCSET ROSC Figure 11. IR3081/IR3086 Six-Phase VRM/EVRD 10 Converter Page VGATE QGATE RBIASIN 20k DGATE RGATE 1 RMPIN+ 2 IR3086 RMPIN- PHASE 3 HOTSET IC 4 VRHOT 5 ISHARE CFB RBBFB RFB1 ...
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... DESIGN PROCEDURES - IR3081 AND IR3086 CHIPSET IR3081 EXTERNAL COMPONENTS Oscillator Resistor Rosc The oscillator of IR3081 generates a triangle waveform to synchronize the phase ICs, and the switching frequency of the each phase converter equals the oscillator frequency, which is set by the external resistor R the curve in Figure 13. ...
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... R is the required output impedance of the converter the current flowing out of FB pin as shown in Figure 14, but also affected by the and total input offset voltage of current sense amplifiers. R DRP IR3081 is the source current of VDAC pin as SOURCE (7) (8) (9) and room temperature L_MAX ...
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... SW PWMRMP IN DAC and Resistors R and R CS+ CS+ . Pre-select the capacitor C L CS- is determined by the ratio of the bias current from the non-inverting CS value is needed. CS+ IR3081 (15) (16) and R respectively FB DRP . PWMRMP should be connected to the input of the RAMP (17) − − DAC ...
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... HOTSET PHASEx1 , PHASEx1 ∗ − PHASEx BIAS HOTSET PHASEx 1 ∗ − BIAS PHASEx ∗ R PHASEx 1 − PHASEx IR3081 (ºC) of phase IC. Determine J (20) (21) (22) R and R PHASE1, PHASE2 PHASE3 and R and connect HOTSET pin PHASEx2, (23) (24) 10/01 /04 ...
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... PHASEx 1 − BIAS HOTSET DRP CCP1 VO+ CCP RFB1 - VDRP EAOUT EAOUT + (b) Type III compensation Figure 12. Voltage loop compensation network and C CP IR3081 PHASEx PHASEx2 (25) (26) and C removed. DRP CCP1 RFB RCP CCP CFB FB - EAOUT EAOUT VDAC RDRP + CDRP from Equations (27) and (28), where L ...
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... FB R DRP and C from Equations (34) and (35 ∗ ∗ ∗ ∗ PWMRMP V O ∗ DRP IR3081 (27) (28) is the equivalent resistance of inductor DCR. LE (29) (30) (31) (32) (33) (34) (35) and capacitor C are not needed. Choose DRP (36) 10/01 and FB /04 ...
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... and determine the C C), SCOMP π ROOM LE CI π 6 ∗ ∗ PWMRMP SW PWMRMP − − DAC I DAC IR3081 (37) (38) (39) (40) (41) ) based on the (42) ( 43) 10/01 /04 ...
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... Switching Frequency: f =400 kHz SW Output Inductors: L=220 nH, R =0.47 mΩ L Output Capacitors: AL-Polymer, C=560uF, R IR3081 EXTERNAL COMPONENTS Oscillator Resistor Rosc Once the switching frequency is chosen, R frequency of 400kHz per phase, choose R Soft Start Capacitor C and Resistor R SS/DEL Because faster over-current protection is required, the soft start capacitor used ...
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... R 3 ∗ TOFST − 3 ∗ ∗ Ω − 3 ∗ IR3081 VDAC =30.1kΩ) is 76uA. Calculate the OSC − 6 ∗ − = Ω 100 − 6 ∗ − 101 41uA with OCSET 3 ∗ ...
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... RA PHASE4 PHASE5 = PHASE31 PHASE41 PHASE51 . 0 628 3 ∗ = Ω − 628 =3.24kΩ, P PHASE42 PHASE52 IR3081 , and calculate the PWMRMP )] =16.2kΩ PWMRMP CS- , CS- PHASE1 =0.637 starting from down- PHASE6 = R =10kΩ, PHASE61 =7.87kΩ, R =17.4kΩ PHASE62 10/01 =0.628, /04 ...
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... O CI − π − 4 π − ∗ ∗ 105 * . IR3081 . CP − 6 ∗ ∗ ∗ ∗ ( 560 365 Ω − − 560 * =68nF CP and calculate ...
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... Switching Frequency: f =800 kHz SW Output Inductors: L=100 nH, R =0.5 mΩ L Output Capacitors: Ceramic, C=22uF, R IR3081 EXTERNAL COMPONENTS Oscillator Resistor Rosc Once the switching frequency is chosen, R switching frequency of 800kHz per phase, choose R Soft Start Capacitor C and Resistor R SS/DEL Because faster over-current protection is required, the soft start capacitor used ...
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... O = − − 3 ∗ Ω 576 − 3 ∗ IR3081 VDAC =13.3kΩ) is 170uA. Calculate the OSC − 6 ∗ − = Ω 100 − 6 ∗ − 101 90uA with OCSET 3 ∗ 800 ...
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... PHASE23 =4.42kΩ PHASE53 =6.49kΩ PHASE63 IR3081 , and calculate the PWMRMP )] Ω CS- , CS- R and R PHASEx1, PHASEx2 PHASEx3 =0.597 starting from down- PHASE6 Ω 10/01 =0.665, PHASE1 ...
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... CI =3.5kHz CI IR3081 3 ∗ Ω 887 = 146 kHz − − 6 ∗ ∗ ∗ 162 * . ...
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... − 3 π 3500 * 22 − 4 π − ∗ ∗ 105 * . 3500 IR3081 011 . − − − 105 * . 105 10/ ...
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... Control bus signals, VDAC, RMPOUT, IIN, VBIAS, and especially EAOUT, should not cross over the fast transition nodes. Page OCSET VDAC VDAC VCC SS/DEL IR3081 and R . Avoid using any via for the CC/DEL 10/01 /04 ...
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... Copper (≥ 0.1mm for 1 oz. Copper and ≥ 0.23mm for 3 oz. Copper) • A single 0.30mm diameter via shall be placed in the center of the pad land and connected to ground to minimize the noise effect on the IC. Page IR3081 10/01 /04 ...
Page 36
... Ensure that the solder resist in-between the lead lands and the pad land is ≥ 0.15mm due to the high aspect ratio of the solder resist strip separating the lead lands from the pad land. • The single via in the land pad should be tented with solder resist 0.4mm diameter, or 0.1mm larger than the diameter of the via. Page IR3081 10/ 01/04 ...
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... The maximum length and width of the land pad stencil aperture should be equal to the solder resist opening minus an annular 0.2mm pull back to decrease the incidence of shorting the center land to the lead lands when the part is pushed into the solder paste. Page IR3081 10/ 01/04 ...
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... ROSC (K Ohm) IR3081 100 100 ISINK ISOURCE FB, BBFB, OCSET Bias Current VDAC Sink Current VDAC Source Current 10/ 01/04 ...
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... IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 www.irf.com Page C/W, θ JA Data and specifications subject to change without notice. This product has been designed and qualified for the Consumer market. Qualification Standards can be found on IR’s Web site. IR3081 C/W JC TAC Fax: (310) 252-7903 10/01 /04 ...