MB3785APFV Fujitsu, MB3785APFV Datasheet
MB3785APFV
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MB3785APFV Summary of contents
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... FUJITSU SEMICONDUCTOR DATA SHEET ASSP BIPOLAR Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities MB3785A DESCRIPTION The MB3785A is a PWM-based 4-channel switching regulator controller featuring high-precision, high-frequency capabilities. All of the four channels of circuits allow their outputs to be set in three modes: step-down, step-up, and inverted ...
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MB3785A (Continued) • Output circuit - The drive output for PNP transistors is the totem-pole type allowing the on-current and off-current values to be set independently. • Adjustable dead time over the entire duty ratio range • Built-in standby and ...
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PIN DESCRIPTION Pin No. Symbol I/O 1 Ca1 — CH1 output transistor OFF-current setting pin. Insert a capacitor between the Ca1 and the Cb1 pins, then set the output transistor OFF-current. 48 Cb1 — 7 +IN1(E) I CH1 error amp ...
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MB3785A (Continued) Pin No. Symbol I/O 33 DTC4 I CH4 38 VE4 I 39 OUT4 O 14 OSC — OSC — OUT 16 R — — — ...
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BLOCK DIAGRAM CH 1 Error Amp 1 + +IN1 (E) 7 – –IN1 (E) 6 FB1 5 V Comparator 1 REF + DTC Comparator 1 – –IN1 (C) 8 DTC1 Error Amp 2 +IN2 ( ...
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MB3785A FUNCTIONAL DESCRIPTION 1. Switching Regulator Function (1) Reference voltage circuit The reference voltage circuit generates a temperature-compensated reference voltage ( 2.50 V) using the voltage supplied from the power supply terminal (pin 18). This voltage is used as the ...
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Channel Control Function The MB3785A allows the four channels of power supply circuits to be controlled independently. Set the voltage levels on the CTL1 (pin 20), CTL2 (pin 21), and CTL3 (pin 22) terminals to turn the circuit of ...
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MB3785A ABSOLUTE MAXIMUM RAGINGS (See WARNING) Parameter Symbol Power supply voltage V Control input voltage V Power dissipation P Operating ambient T temperature Storage temperature The packages are mounted on the epoxy board (4 cm WARNING: Permanent ...
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ELECTRICAL CHARACTERISTICS Parameter Reference voltage Rate of changed in output voltage vs. Temperature Input stability Load stability Sort-circuit output current Threshold voltage Hysteresis width Reset voltage ( Input threshold voltage Input bias current Input voltage range Input offset ...
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MB3785A (Continued) Parameter Input offset voltage Input bias current Common mode input voltage range Voltage gain Frequency bandwidth Input threshold voltage Input bias current Latch mode source current Latch input voltage Input threshold voltage Input bias current Latch mode source ...
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TYPICAL CHARACTERISTIC CURVES 1. Supply current vs. Supply voltage CTL1 CTL1 Supply voltage V ( Reference voltage and Output ...
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MB3785A (Continued) 7. Triangular wave maximum amplitude voltage vs. Timing capacitance 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1 Timing capacitance C 9. Triangular wave cycle vs. Timing capacitance 100 50 10 ...
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Gain vs. Frequency and Phase vs. Frequency –20 – 100 K Frequency f (Hz) [Measuring Circuit] 2.5 V 2.5 V 240 k 4.7 k 4.7 k – ...
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MB3785A METHODS OF SETTING THE OUTPUT VOLTAGE 1. Method of Connecting Channels 1 and 2: When Output Voltage (V V REF Method of Connecting Channels 1 and 2: When Output Voltage (V V REF ...
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Method of Connecting Channels 3 and 4: When Output Voltage (V V REF Method of Connecting Channels 3 and 4: When Output Voltage (V V REF OUT REF ...
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MB3785A METHOD OF SETTING THE OUTPUT CURRENT The output circuit is comprised of a totem-pole configuration. Its output current waveform is such that the ON-current value is set by constant current and the OFF-current value is set by a time ...
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METHOD OF SETTING TIME CONSTANT FOR TIMER/LATCH-ACTUATED SHORT- CIRCUTING PROTECTION CIRCUIT Figure 5 schematically shows the protection latch circuit. The outputs from the output-shorting detection comparators are respectively connected to the inverted inputs of the SCP comparator. ...
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MB3785A TREATMENT WHEN NOT USING SCP When you do not use the timer/latch-actuated short-circuiting protection circuit, connect the SCP terminal (pin 23) to GND with the shortest distance possible. Also, connect the comparator’s input terminal for each channel to the ...
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METHOD OF SETTING THE TRIANGULAR-WAVE OSCILLATOR CIRCUIT 1. When Not Using Ceramic Resonator Connect the OSC terminal (pin 14) to GND and leave the OSC IN to set the oscillation frequency with only C Figure 7. When Not Using Ceramic ...
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MB3785A <Precautions> When the oscillation rise time at power switch-on is compared between a ceramic and a crystal resonator known that the crystal resonator is about 10 to 100 times slower to rise than the ceramic resonator. Therefore, ...
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METHOD OF SETTING THE DEAD TIME AND SOFT START 1. Dead Time When the device is set for step-up inverted output based on the flyback method, the output transistor is fixed to a full-on state (ON-duty = 100 %) at ...
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MB3785A Figure 11. When Using DTC to Set Dead Time DTC3 (DTC4) Vdt R 2 <Precautions> When you use a ceramic resonator, pay attention when setting the dead time because the triangular-wave amplitude is determined by ...
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It is also possible to set soft start simultaneously with the dead time by configuring the DTC terminals as shown below. Figure 15. Setting Dead Time and Soft Start for CH1 and CH2 19 V REF Cdt R 1 DTC1 ...
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MB3785A EQUIVALENT SERIES RESISTOR AND STABILITY OF SMOOTHING CAPACITOR The equivalent series resistance (ESR smoothing capacitor in a DC/DC converter greatly affects the phase characteristics of the loop depending on its value. System stability is improved by ESR ...
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Data) The phase margin is halved by changing the smoothing capacitor from an aluminum electrolytic capacitor (R 1 small-ESR semiconductor electrolytic capacitor (OS – CON; R Figure 20. DC/DC Converter AV- Characteristic Measuring Circuit FB Figure ...
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MB3785A EXAMPLE OF APPLICATION CIRCUIT +IN 7 4.7 k – 150 k 5 4.7 k RFB DTC +IN 12 4.7 k –IN 11 ...
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... Ground the workbenches, tools, and measuring equipment to earth. • Make sure that operators wear wrist straps or other appropriate fittings grounded to earth via a resistance of 250 ohms placed in series between the human body and earth. ORDERING INFORMATION Part number MB3785APFV Package 48-pin plastic LQFP (FPT-48P-M05) MB3785A ...
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... MB3785A PACKAGE DIMENSION 48-pin Plastic LQFP (FPT-48P-M05) 9.00±0.20(.354±.008)SQ 7.00±0.10(.276±.004) INDEX 48 1 LEAD No. 0.50±0.08 (.0197±.0031) 0.10(.004) 1995 FUJITSU LIMITED F48013S-2C +0.20 1.50 0.10 (MOUNTING HEIGHT) +.008 .059 .004 25 24 5.50 8.00 (.217) (.315) REF NOM Details of "A" part ...
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... FUJITSU sales representatives before such use. The company will not be responsible for damages arising from such use without prior approval ...