ir3831 International Rectifier Corp., ir3831 Datasheet
ir3831
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ir3831 Summary of contents
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... DDR memory applications. IR3831 is configured to generate termination voltage (VTT) for DDR memory applications. IR3831 offers programmability of start up time, switching frequency and current limit while operating in wide input and output voltage range. The switching frequency is programmable from 250kHz to 1 ...
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... PACKAGE DESIGNATOR M M 02/20/ Boot Gnd 14 Enable COMP Gnd Rt PACKAGE PIN COUNT DESCRIPTION IR3831MTRPbF 15 IR3831MTR1PbF 15 IR3831MPbF o C and - PGnd θ θ PCB - PGood OCSet PARTS PER REEL ...
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... Block Diagram Fig. 2. Simplified block diagram of the IR3831 02/20/09 IR3831MPbF 3 ...
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... Switch node. This pin is connected to the output inductor Input voltage connection pin. IN Supply voltage for high side driver. Connect a 0.1uF capacitor from this 13 Boot pin to SW. 14 Enable Enable pin to turn on and off the device. 15 Gnd Signal ground for internal reference and control circuitry. 02/20/09 IR3831MPbF Description 4 ...
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... Tj SS=0V, No Switching, Enable low SS=3V, Vcc=5V, Fs=500kHz CC(Dyn) Enable high Vcc Rising Trip Level Vcc Falling Trip Level Supply ramping up and down Supply ramping up Supply ramping down Supply ramping up and down Enable=3.3V IR3831MPbF Max 16 5.5 5.5 0.90*Vin 8 1650 125 <5.5V, Vp=0.6V, V =12V Min ...
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... Note4 Note4 Fs=250kHz 92 Vfb-Vp -5 Vp=0. 0.40 8 Note4 7 Note4 20 Note4 100 Vcc=4.5V 3.4 Note4 0 Source 14 2.7 Fs=250kHz 20.8 Fs=500kHz 43 Fs=1500kHz 136 Note4 -10 I(Boot)=30mA 180 IR3831MPbF <5.5V, Vp=0.6V, V =12V, in TYP MAX Units 0.7 0.775 V 250 275 500 550 kHz 1500 1650 1.8 Vp-p 0 130 200 % μA +1 0.85 12 ...
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... Note3: Cold temperature performance is guaranteed via correlation using statistical quality control. Not tested in production. Note4: Guaranteed by Design but not tested in production. 02/20/ Test Condition Note4 Note4 Fb Rising Relative to charge voltage, SS rising Note4 I =-5mA PGood SW=0V, Enable=0V SW=0V,Enable=high,SS=3V,Vp=0V, Note4 IR3831MPbF <5.5V, Vp=0.6V, V =12V Min TYP MAX 140 20 470 515 560 2 2.1 2.3 260 300 340 ...
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... IR3831MPbF C - 125 C) F =500 kHz Icc(Dyn) - 100 Te m p[oC] ISS - 100 IOCSET (500k 100 [oC] ...
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... Typical Efficiency and Power Loss Curves Vin=12V, Vo=0.75V, Io=1A- 8A, Vcc=5V, Fs=400kHz Room Temperature, No Air Flow 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0 02/20/ Iout (A) 0.75V out Iout (A) 0.75V out IR3831MPbF ...
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... Typical Efficiency and Power Loss Curves Vin=5V, Vo=0.75V, Io=1A- 8A, Vcc=5V, Fs=400kHz Room Temperature, No Air Flow 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 02/20/ Iout (A) 0.75V out Iout (A) 0.75V out IR3831MPbF ...
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... MOSFETs using Fig. 3a. Normal Start up, Device turns on when the Bus voltage reaches 10.2V Figure 3b. shows the recommended start-up sequence for the non-tracking operation of IR3831, when Enable is used as a logic input. Fig. 3b. Recommended startup sequence, IR3831MPbF . This is desirable particularly in exceeds the desired output voltage level. ...
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... Figure 3c. shows the recommended startup sequence for tracking operation of IR3831 with Enable used as logic input. Fig. 3c. Recommended startup sequence, Sequenced operation Pre-Bias Startup IR3831 is able to start up into pre-charged output, which prevents disturbances of the output voltage. The output starts in asynchronous fashion and keeps the synchronous MOSFET off until the first gate signal for control MOSFET is generated ...
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... Shutdown The IR3831 can be shutdown by pulling the Enable pin below its 1 V threshold. This will tri- state both, the high side driver as well as the low side driver. Alternatively, the output shutdown by pulling the soft-start pin below 0.3V. In shutdown by this method, the high side driver is turned off, and the low side driver is turned on ...
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... Thermal Shutdown Temperature sensing is provided inside IR3831. The trip threshold is typically set to 140 trip threshold is exceeded, thermal shutdown turns off both MOSFETs and discharges the soft start capacitor. Automatic restart is initiated when the sensed temperature drops within the operating range. o There hysteresis in the thermal shutdown threshold ...
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... V. 02/20/09 Maximum Duty Ratio Considerations A fixed off-time of 200 ns maximum is specified for the IR3831. This provides an upper limit on the operating duty ratio at any given switching frequency clear, that higher the switching frequency, the lower is the maximum duty ratio at which the IR3831 can operate. To allow some ...
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... R9 from Fb to ground. For the calculated value of R8 see feedback compensation section Fig. 10. Typical application of the IR3831 for 1 R Further, the tracking reference Vp may be itself 2 derived from some master reference by means of a resistive divider as shown in Fig. 9. This is common in active bus termination circuits such = 1 ...
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... For the buck converter, the inductor value for the desired determined using the following relation Where: If Δi ≈ 35%(I .......... ....(12) calculated to be 0.63μH. Select L=0.6 μH. The MPL104-0R6 from Delta provides a compact, low profile inductor suitable for this application. IR3831MPbF .......... .......... .......... .. (13 and D = 0.0625, the I = 1.94 A RMS ...
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... The IR3831 can perform well with all types of capacitors rule, the capacitor must have low enough ESR to meet output ripple and load transient requirements. The goal for this design is to meet the voltage ripple requirement in the smallest possible capacitor size ...
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... III compensation network. The typically used compensation network for voltage-mode controller is shown in figure 14. Again, the transfer function is given by replacing Z .......... ....... (21) the transfer function can be expressed as IR3831MPbF = Zero Frequency of the Output Capacitor = % .......... .......... .......... 0 75 π ...
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... These result to ESR location of the F s/2 Select crossover frequency: F Since F place the pole and zeros. IR3831MPbF Compensator Compensator ESR ESR o o Type Type Type II Type <F <F <F < ...
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... PGood pin, when the output voltage is not in regulation, to less than Select : C 560 pF 3 mA. A typical value used is 4.7kΩ. = Ω , Select : R 210 10 Ω IR3831MPbF ) from the SW pin OCSET R has a positive temperature DS(on) ∗ OCSet OCSet = = I .......... L ( critical ) R ...
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... R3 1 1.47k C3 1 560pF C4 1 22000pF R8 1 6.65K R10 1 210 C7 1 2200pF U1 1 IR3831 02/20/09 Description Manufacturer SMD Elecrolytic, Fsize, 25V, 20% Panasonic 1206, 16V, X7R, 20% Panasonic - ECG 11.5x10x4mm, 20%, 1.7mOhm Delta 0805, 6.3V, X5R, 20% Panasonic- ECG Thick Film, 0603,1/10 W,1% Rohm Thick Film, 0603,1/10W,1% ...
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... Fig. 18: Inductor node at 8A, sourcing current, Ch :SW Fig. 20: Output Voltage Ripple, 8A, sourcing current 02/20/09 Fig. 17: Start up with Prebias Fig. 19: Inductor node at -3A, sinking out Fig. 21: Short (Hiccup) Recovery out IR3831MPbF Load :SS 1 out 2 DDQ, 3 current ...
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... TYPICAL OPERATING WAVEFORMS Vin=12V, Vcc=5V, Vo=0.75V, Room Temperature, No Air Flow Fig. 22: Tracking 8A, sourcing current out 3 DDQ Ch :PGood 4 Fig. 24: Transient Response, 1A/us -0.5A to +0.5A load , out 02/20/09 Fig. 23: Tracking -3A load, sinking current IR3831MPbF : out :PGood 3 DDQ 4 24 ...
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... TYPICAL OPERATING WAVEFORMS Vin=12V, Vcc=5V, Vo=0.75V, Io=+8A, Room Temperature, No Air Flow Fig.25: Bode Plot at 8A load (sourcing current) shows a bandwidth of 43kHz and phase margin of 02/20/09 IR3831MPbF 63 degrees 25 ...
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... The inductor, output capacitors and the IR3831 should be as close to each other as possible. This helps to reduce the EMI radiated by the power traces due to the high switching currents through them. Place the input capacitor directly at the Vin pin of IR3831. ...
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... Single point connection between AGND & PGND, should be close to the SupIRBuck, kept away from noise sources. Fig. 26c. IR3831 layout considerations – Mid Layer 1 Fig. 26d. IR3831 layout considerations – Mid Layer 2 02/20/09 IR3831MPbF PGnd Power Vin Ground Plane AGnd Use separate traces ...
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... Pad lands (the 4 big pads other than the 11 IC pins) length and width should be equal to maximum part pad length and width. However, the minimum metal to metal spacing should be no less than 0.17mm for 2 oz. Copper; no less than 0.1mm for 1 oz. Copper and no less than 0.23mm for 3 oz. Copper. 02/20/09 IR3831MPbF 28 ...
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... 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. 02/20/09 IR3831MPbF 29 ...
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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. 02/20/09 IR3831MPbF 30 ...
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... This product has been designed and qualified for the Consumer market 02/20/09 BOTTOM VIEW 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 Visit us at www.irf.com for sales contact information Data and specifications subject to change without notice. 01/09 IR3831MPbF TAC Fax: (310) 252-7903 31 ...