ir3821 International Rectifier Corp., ir3821 Datasheet
ir3821
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ir3821 Summary of contents
Page 1
... The onboard switching controller and MOSFETs make the IR3821 a space-efficient solution, providing accurate power delivery for low output voltage applications. The IR3821 operates from a single 4.5V to 14V input supply and generates an output voltage adjustable from 0.6V to 0.75*Vin at loads up to 7A. A versatile regulator offering programmability of startup time, power good threshold and current limit, the IR3821’ ...
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... V IN PGnd AGnd Vsns FB COMP AGnd AGnd SS OCSet Fig. 2: Package outline (Top view) PACKAGE PIN COUNT DESCRIPTION IR3821MTRPbF 15 IR3821MTR1PbF 15 PD-60331 IR3821MPbF o C θ θ PCB - PGood V CC PARTS PER REEL 4000 750 ...
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... Block Diagram Fig. 3. Simplified block diagram of the IR3821. 11/04/08 PD-60331 IR3821MPbF 3 ...
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... This pin powers the high side driver and must be connected to a voltage C higher than input voltage. A minimum of 0.1uF high frequency capacitor must be connected from this pin to the power ground (PGnd). 15 AGnd Signal ground for internal reference and control circuitry. Pins 4, 5 and 15 need to be connected together on system board. 11/04/08 IR3821MPbF Description PD-60331 4 ...
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... V =1.8V, Io=0A o SS=3V, V =24V =12V =1.8V, Io=0A o Supply ramping up Supply ramping down Supply ramping up and down Supply ramping up Supply ramping down Supply ramping up and down PD-60331 IR3821MPbF Max Units 125 =12V, 0 C<T (Ic)< 105 Min TYP ...
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... Note3: Guaranteed by Design but not tested in production. 11/04/08 Test Condition Min 540 Note3 Note3 Fb=0V 75 SS=3V SS= 1000 SS=0V 15 Vsns Ramping Down 0. =4mA PGood 0 15 Note3 , Note3 Hiccup SS Note3 Note3 PD-60331 IR3821MPbF TYP MAX Units 600 660 kHz 1. -0.1 -0 μ μmho 1300 1600 μ 0.25 V 0.38 0. 0.25 ...
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... Temp[oC] 11/04/08 7.0 6.0 5.0 4.0 3.0 2.0 80 100 120 -40 -20 22.0 21.0 20.0 19.0 18.0 17.0 16.0 15.0 14.0 13.0 80 100 120 -40 -20 27.0 25.0 23.0 21.0 19.0 17.0 15.0 80 100 120 -40 -20 26.0 25.0 24.0 23.0 22.0 21.0 20.0 19.0 18.0 17.0 16.0 15.0 -40 -20 80 100 120 PD-60331 IR3821MPbF 125 C) Ic(static 100 120 Temp[oC] Ic(dynamic 100 120 Temp[oC] Iss 100 120 Temp[oC] Iocset 100 120 Temp[oC] 7 ...
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... There hysteresis in the thermal shutdown threshold. 11/04/08 mode PWM Pre-Bias Startup The IR3821 is able to start up into pre-charged output, which 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 IR3821 has 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, Ch3:OCSet --( 3 ) The value of R circuit to ensure that the over-current protection circuit activates as expected. The IR3821 current limit is designed primarily as disaster preventing, and doesn't operate as a precision current regulator. PD-60331 IR3821MPbF Deadtime Blanking time ...
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... R ⎝ ⎠ 9 When an external resistor divider is connected to the output as shown in figure 10. V OUT IR3624 IR3821 Fb Fig. 10: Typical application of the IR3821 for programming the output voltage Equation (4) can be rewritten as: ⎛ ⎞ V ⎜ ⎜ ⎟ ⎟ = ∗ --( ) 5 ref − ...
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... The ) overall performance of the converter and determine the result of transient response, selection of the capacitor is critical. The IR3821 can perform well with all types of capacitors. can rule the capacitor must have low enough ESR to meet output ripple and load transient requirements, yet have high enough ESR to satisfy stability requirements ...
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... Feedback Compensation The IR3821 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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... R R Cross over frequency is expressed as ⎤ ⎞ ⎟ ⎟ ⎥ ⎠ ⎦ PD-60331 IR3821MPbF OUT E Comp 9 V REF Frequency (current source) ...
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... Ω Select : π ref * ref PD-60331 IR3821MPbF ( ) 1 for Θ max = and F 0 ≥ OSC , KΩ , check ...
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... This helps to reduce the EMI radiated by the power traces due to the high switching currents through them. Place the input capacitor directly to the Vin pin of IR3821. To reduce the ESR replace the single input capacitor with two parallel units. The feedback part of the system should be kept 14.25mΩ ...
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... Typical Application for IR3821 Fig.16: Typical Application circuit for 12V to 1. using ceramic output capacitors 11/04/08 12V to 1. PD-60331 IR3821MPbF 17 ...
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... The 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. 11/04/08 PD-60331 IR3821MPbF 18 ...
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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. 11/04/08 PD-60331 IR3821MPbF 19 ...
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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. 11/04/08 PD-60331 IR3821MPbF 20 ...
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... This product has been designed and qualified for the Consumer market. 11/04/08 233 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. 10/07 PD-60331 IR3821MPbF TAC Fax: (310) 252-7903 21 ...