IR3629 International Rectifier Corp., IR3629 Datasheet

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... M IR3629/IR3629AMTRPBF 11/29/2007 IR3629/IR3629A MPbF WITH POWER GOOD OUTPUT Description The IR3629/IR3629A is a PWM controller designed for high performance synchronous Buck DC/DC applications. The IR3629/IR3629A drives DS(on) a pair of external N-MOSFETs using a fixed 600kHz (300kHz “A version”) switching frequency allowing the use of small external components. ...

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... Rating” conditions for extended periods may affect device reliability. Package Information PGood V CC LDrv PGnd HDrv V *Exposed pad on underside is connected to a copper pad through vias for 4-layer PCB board design 11/29/2007 IR3629/IR3629A MPbF OCSet 1 12 SS/ Gnd 10 3 Exposed Pad Comp ...

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... Block Diagram Fig. 2: Simplified block diagram of the IR3629/IR3629A 11/29/2007 IR3629/IR3629A MPbF 3 ...

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... Connect an external capacitor from this pin to ground to set the start up time of the output voltage. The converter can be shutdown by pulling this pin below 0.3V. 12 OCSet Current limit set point. A resistor from this pin to drain of the low side MOSFET will set the current limit threshold. 11/29/2007 IR3629/IR3629A MPbF Description 4 ...

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... IR3629, C =1.5nF LOAD IR3629A, C =1.5nF LOAD Supply ramping up Supply ramping down Supply ramping up and down Supply ramping up Supply ramping down Supply ramping up and down IR3629A IR3629 Note3 Fb=1V IR3629, Note3 IR3629A , Note3 IR3629, Fb=0.5V IR3629A, Fb=0.5V Max Units 125 C o C<T < 105 ...

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... Note2: Cold temperature performance is guaranteed via correlation using statistical quality control. Not tested in production. Note3: Guaranteed by Design but not tested in production. 9V High Side Driver (HDrv Low Side Driver (LDrv) 2V Fig. 3: Definition of Rise/Fall time and Deadband Time 11/29/2007 IR3629/IR3629A MPbF Test Condition Min SS=3V SS= 1000 SS= Note3 I ...

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... Temp[oC] Icc(static)(mA) 12.0 11.0 10.0 9.0 8.0 7.0 6.0 -40 - Temp[oC] Transconductance (gm)[mMHO] 1.5 1.4 1.4 1.3 1.3 1.2 1.2 1.1 1.1 1.0 -40 - Temp[oC] Frequency (kHz)(IR3629) 615.0 610.0 605.0 600.0 595.0 590.0 585.0 580.0 575.0 570.0 -40 - Temp[oC] 11/29/2007 IR3629/IR3629A MPbF 25.0 24.0 23.0 22.0 21.0 20.0 19.0 18.0 17.0 -40 -20 100 120 6.0 5.5 5.0 4.5 4.0 3.5 3.0 -40 -20 ...

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... During shutdown both MOSFET drivers will be turned off. Normal operation will resume by cycling the soft start pin. Pre-Bias Startup The IR3629/29A is able to start up into pre- charged output, which prevents oscillation and . 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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... Soft-Start The IR3629/29A has a programmable soft-start to control the output voltage rise and limit the inrush current during start-up. To ensure correct start-up, sequence initiates when Vcc and Vc rise above their threshold and generate the Power On Ready (POR) signal. The soft-start function operates by sourcing current to charge an external capacitor to about 3V ...

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... Fig. 9: OCset pin during normal condition Ch1: Inductor point, Ch2:Ldrv, Ch3:OCSet The value of R circuit to ensure that the over-current protection circuit activates as expected. The IR3629 current limit is designed preventing, "no blow up" circuit, and does not operate as a precision current regulator. ...

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... R ⎝ ⎠ 9 When an external resistor divider is connected to the output as shown in figure 10. V OUT IR3629A IR3624 Fb Fig. 10: Typical application of the IR3629A for programming the output voltage Equation (4) can be rewritten as: ⎛ ⎞ ∗ ⎜ ⎜ ⎟ ⎟ --( ) 5 ref 9 8 − ...

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... Inductor L Since the output capacitor has a major role in the overall performance of the converter and determines the result of transient response, selection of the capacitor is critical. The IR3629A can perform well with all types of capacitor. can rule, the capacitor must have low enough ESR to meet output ripple and load transient requirements ...

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... Power MOSFET Selection The IR3629A uses two N-Channel MOSFETs per channel. The selection criteria to meet power transfer requirements are based on maximum drain-source voltage (V ), gate-source drive DSS voltage (V ), maximum output current, On- gs resistance R , and thermal management. DS(on) The MOSFET must have a maximum operating ...

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... Feedback Compensation The IR3629A is a voltage mode controller. The control loop is a single voltage feedback path including error amplifier and error comparator. To achieve fast transient response and accurate output regulation, a compensation circuit is necessary. The goal of the compensation network is to provide a closed-loop transfer ...

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... ⎜ ⎜ ⎢ ⎝ ⎣ 4 11/29/2007 IR3629/IR3629A MPbF (16 Gain(dB) H( POLE Fig.15: Compensation network with local feedback and its asymptotic gain plot 1 As known, the transconductance amplifier has high ...

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... Type III Method ESR s/2 selected to place the pole and zeros. 11/29/2007 IR3629/IR3629A MPbF The following design rules will give a crossover frequency approximately switching frequency. The higher the band width, the potentially faster the load transient response. of the The DC gain will be large enough to provide high DC-regulation accuracy (typically -5dB to -12dB) ...

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... Use a pull up resistor (4.99K) from PGood pin to Vcc. 11/29/2007 IR3629/IR3629A MPbF Layout Consideration The layout is very important when designing high frequency switching converters. Poor layout will affect noise pickup and can cause a good design to perform with less than expected results. ...

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... Fig.16: Application circuit for IR3629A 12Vin to 1.8Vout 11/29/2007 IR3629/IR3629A MPbF 18 ...

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... However, the minimum metal to metal spacing should be ≥ 0.17mm for 2 oz. Copper (≥ 0.1mm for 1 oz. Copper and ≥ 0.23mm for 3 oz. Copper). Two 0.30mm diameter via should be placed in the center of the pad land and connected to ground to minimize the noise effect on the IC. 11/29/2007 IR3629/IR3629A MPbF 19 ...

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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. Each via in the land pad should be tented or plugged from bottom boardside with solder resist. 11/29/2007 IR3629/IR3629A MPbF 20 ...

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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. 11/29/2007 IR3629/IR3629A MPbF 21 ...

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... M) MLPD Package D E Terminal 1 Leads on 2 sides Identifier (ND- TAPE & REEL ORIENTATION 11/29/2007 IR3629/IR3629A MPbF 3x4-12Lead MILLIMETERS O L MIN NOM A 0.80 0.90 A1 0.00 0.02 A3 0.20 REF b 0.18 0.25 SEATING PLANE D2 3 4.00 BSC E 3.00 BSC E2 1. 0.30 0.40 e 0.50 PITCH Figure A VGED-4 ...

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... MLPD Package D E Terminal 1 Leads on 2 sides Identifier (ND- TAPE & REEL ORIENTATION IR WORLD HEADQUARTERS: This product has been designed and qualified for the Industrial market. 11/29/2007 IR3629/IR3629A MPbF 3x4-12Lead MILLIMETERS O L MIN NOM A 0.80 0.90 A1 ...