MB3817 Fujitsu Microelectronics, Inc., MB3817 Datasheet
MB3817
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MB3817 Summary of contents
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... This can be used in applications as down-conversion or down/up-conversion (Zeta method) . With fewer external components and faster operating speed, the MB3817 enables reduction in power supply unit size, making it ideal for use with internal power supplies in compact, high-performance portable devices. FEATURES • ...
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... MB3817 PIN ASSIGNMENT DTC CB1 CB2 2 (TOP VIEW (FPT-16P-M05 REF 15 CTL 14 CSCP GND OUT ...
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... CS Soft start setting capacitor connection terminal 14 CSCP Short detection setting capacitor connection terminal Power supply control terminal 15 CTL I When this terminal is High inactive state When this terminal is Low standby state Reference voltage output terminal REF MB3817 Descriptions 3 ...
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... MB3817 BLOCK DIAGRAM FB 5 Error IN Amp DTC (0.9 V) OSC PWM Comp. Soft Start SCP Comp. Comp. 1.5 V SCP 1.4 V bias 1 UVLO Latch CB1 OUT 7 8 CB2 9 OFF V CC current Q4 setting block 10 OUT (0.5 V) ...
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... FUJITSU representatives beforehand. Condition Min cm) . Condition Min. 2 CTL 150 OSC C S SCP MB3817 Rating Unit Max 440* mW 125 C Value Unit Typ. Max 1500 pF 100 k ...
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... MB3817 ELECTRICAL CHARACTERISTICS Parameter Output voltage Output temperature stability Reference Input stability section (Ref) Load stability Short circuit output current Under voltage Threshold voltage lockout protection Hysteresis width section (UVLO) Reset voltage Threshold voltage Soft start Input standby section (CS) voltage Charge current ...
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... OFF CTL CCS CTL I 9 Output “H” CC MB3817 ( Value Unit Min. Typ. Max 100 nA 200 100 0.9 60 100 dB 60 100 dB 800* kHz 1 ...
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... MB3817 TYPICAL CHARACTERISTICS Power supply current vs. power supply voltage Power supply voltage V 1.55 1.54 1.53 1.52 1.51 1.50 1.49 1.48 1.47 1.46 1.45 60 Reference voltage vs. control voltage 1.7 1.6 1.5 1.4 1 Control voltage V 8 Reference voltage vs. power supply voltage 2 1.5 1.0 0.5 0 (V) CC Reference voltage vs. ambient temperature ...
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... Timing capacitance C (Hz) Frequency stability vs. ambient temperature 500 kHz OSC (C 330 pF Ambient temperature MB3817 timing capacitance 6 (pF 6 ...
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... MB3817 (Continued) Error amp. frequency 100 k Frequency f Output current setting pin voltage vs. output current setting pin current 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Output current setting pin current I 10 Measurement circuit 225 180 135 ...
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... CSCP terminal (pin 14) is held at “L” level. Once the protection circuit has been activated, the power supply must be reset to restore operation. MB3817 (pin1) and the R (pin2) terminals possible to ...
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... MB3817 (2) Low input voltage error prevention circuit (UVLO) Power-on surges and momentary drops in power supply voltage can cause errors in control IC operation, which can destroy or damage systems. The low input voltage error protection circuit compares the supply voltage to the internal reference voltage, and sets the OUT terminal (pin 10) to “H” level in the event of a drop in supply voltage ...
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... The oscillator frequency can be set by connecting a timing capacitor (C resistor ( the RT terminal (pin2 Oscillator frequency : f OSC 1023000 f (kHz OSC C (pF Error Amp. V REF Error Amp. V REF ( the CT terminal (pin1) and a timing T MB3817 REF 13 ...
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... MB3817 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 constant. These output currents are set using the equations below. ...
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... Voltage and current waveforms on output terminal • Measuring circuit diagram CB1 7 CB 1000 pF 8 CB2 OUT U1FWJ44N 2S81121S MB3817 (5 ...
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... MB3817 METHOD OF SETTING THE SHORT DETECTION TIME The error amp. output is connected to the inverted input of the short detector comparator circuit (SCP Comp.) , where it is constantly compared to the reference voltage of approximately 1.5 V that is connected to the non- inverted input. If the switching regulator load conditions are stabilized, the short detector comparator output is at “H” level, ...
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... TREATMENT WHEN NOT USING CSCP When you do not use the timer/latch-actuated short-circuiting protection circuit, connect the CSCP terminal (pin 14) to GND. • Treatment when not using CSCP 14 CSCP MB3817 17 ...
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... MB3817 METHOD OF SETTING SOFT START TIME To protect against surge currents when the IC is turned on, a soft start setting can be made by connecting a soft start capacitor ( the CS terminal (pin 13 When the IC starts up (CTL terminal (pin 15) to “H” level, Vcc turns off and the soft start capacitor (C I which is 1 ...
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... TREATMENT WHEN NOT USING CS When not using the soft start function, the CS terminal (pin 13) should be left open. • When no soft start time is set Open 13 CS MB3817 19 ...
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... MB3817 METHOD OF SETTING THE 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 power switch-on. To prevent this problem, you may determine the voltages on the DTC terminals (pin 6) from the V (maximum ON-duty) independently for each channel as shown below ...
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... APPLICATION EXAMPLE 1. Step-down scheme MB3817 21 ...
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... MB3817 Zeta scheme 2. 22 ...
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... Flyback scheme 3. MB3817 23 ...
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... MB3817 APPLICATION 1. Equivalent series resistance and stability of smoothing capacitor The equivalent series resistance (ESR) of the smoothing capacitor in the DC/DC converter greatly affects the loop phase characteristic. A smoothing capacitor with a high ESR improves system stability because the phase is advanced into the high- frequency range of an ideal capacitor (see Fig. 34 and 35 smoothing capacitor with a low ESR reduces system stability ...
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... REF 180 C 0 180 10 k 100 180 C 0 180 10 k 100 k MB3817 vs. characteristic Condenser 220 kHz C OSC GND OS-CON kHz C OSC GND 25 ...
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... After mounting, printed circuit boards should be stored and shipped in conductive bags or containers. • Work platforms, tools, and instruments should be properly grounded. • Working personnel should be grounded with resistance of 250 between body and ground. ORDERING INFORMATION Part number MB3817PFV 26 Package 16-pin Plastic SSOP (FPT-16P-M05) ...
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... Details of "A" part "A" 0.13(.005) M 0.50±0.20 (.020±.008) 0.45/0.75 (.018/.030) MB3817 +0.20 1.25 –0.10 (Mounting height) +.008 .049 –.004 0~8° 0.10±0.10 (Stand off) (.004±.004) 0.25(.010) Dimensions in mm (inches) ...
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... MB3817 FUJITSU LIMITED All Rights Reserved. The contents of this document are subject to change without notice. Customers are advised to consult with FUJITSU sales representatives before ordering. The information and circuit diagrams in this document are presented as examples of semiconductor device applications, and are not intended to be incorporated in devices for actual use. Also, ...