Fairchild RC4391 Data Handbook
Summary
Discover comprehensive technical specifications for the RC4391 semiconductor component. This resource provides detailed electrical characteristics, absolute maximum ratings, and operational guidelines, covering everything from pin assignments to performance under varying voltage and temperature ranges. Essential for electronics engineers and hardware designers, this manual ensures precise integration of the device into complex power management or timing circuit applications.
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Page Summary Contents For Fairchild RC4391 Data Handbook
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PRODUCT SPECIFICATION RC4391 Pin Assignments Pin Descriptions Pin LBR VFB Number Pin Function Description LBD VREF Low Battery Resistor (LBR) Low Battery Detector (LBD) CX +VS Timing Capacitor (CX) GN...
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RC4391 PRODUCT SPECIFICATION Electrical Characteristics (VS = +6.0V, over the full operating temperature range unless otherwise noted) Symbol Parameters Condition Min Typ Max Units +VS Supply Voltage ...
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PRODUCT SPECIFICATION RC4391 Electrical Characteristics (VS = +6.0V, TA = +25°C unless otherwise noted) Symbol Parameters Condition Min Typ Max Units ISY Supply Voltage VS = +4.0V, m A No External Loa...
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RC4391 PRODUCT SPECIFICATION Typical Performance Characteristics 6.5 6.0 5.5 5.0 4.5 4.0 3.5 +VS (V) TA (¡C) (k z) Figure 1. Oscillator Frequency vs. Supply Voltage Figure 2. Oscillator Frequency vs. ...
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PRODUCT SPECIFICATION RC4391 Principles of Operation reference. Because CF is initially discharged a positive voltage is applied to the comparator, and the output of the The basic switching inverter c...
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RC4391 PRODUCT SPECIFICATION (Internal) SC +V (Internal) +V - 0.7V OUT Max 0 m A MAX +V - V SW Ground LX -V - V OUT Figure 9. Inverting Regulator Waveforms This feedback system will vary the duration ...
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PRODUCT SPECIFICATION RC4391 When power is first applied, the output filter capacitor is dis- inductor current (waveform E) to build up to a higher peak charged so the ground lead potential starts at ...
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RC4391 PRODUCT SPECIFICATION (Internal) OSC (Internal) BEQ1 OUT BAT BAT MAX +V - V SW OUT LX Figure 12. Step-Down Regulator Waveforms The oscillator creates a squarewave using a method similar 2. Find...
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PRODUCT SPECIFICATION RC4391 Step-Down Design Procedure Compensation 1. Select an operating frequency. When large values (> 50 k W) are used for the voltage setting resistors (R1 and R2 of Figure 8...
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RC4391 PRODUCT SPECIFICATION Device Shutdown The following external power transistor circuits may demand some adjustment to resistor values to satisfy various power The entire device may be shut down ...
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PRODUCT SPECIFICATION RC4391 TIP116 MBR140P -VOUT VREFFBV +V Lx R3 CF 4.7K Lx Cx GND Figure 9. Inverting High Power Application equations and suggestions for the circuits of Figures 14 and The thresho...
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RC4391 PRODUCT SPECIFICATION VREFFBV +V Lx MBR030 Cx GND +VOUT Note: A minimum load ³1m A must be connected. Figure 16. Step-Down Medium Power Application MBR140P TIP116 VBAT 5K CX 470 p F CF 470µF (+...
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LB LB PRODUCT SPECIFICATION RC4391 Simplified Schematic Diagram
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RC4391 PRODUCT SPECIFICATION Troubleshooting Chart Symptom Possible Problems Draws excessive supply current on star-up. Inductance value too low. Output frequency (FO) too low. Combination of low resi...
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PRODUCT SPECIFICATION RC4391 Pot Core Inductor Design Electrical Circuit Magentic Circuit North South Flux 65-3464-07 Figure 20. Electricity vs. Magnetism au ss Electricity Versus Magnetism the point ...
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RC4391 PRODUCT SPECIFICATION 3. Pot cores can be easily air-gapped. The length of the Use of the Design Aid Graph gap is simply adjusted using different washer 1. From the application requirement, det...
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PRODUCT SPECIFICATION RC4391 If the actual number of turns is significantly less than the Where: number from the table then the wire size can be increased to use up the leftover winding area and reduc...
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RC4391 PRODUCT SPECIFICATION Mechanical Dimensions 8-Lead Ceramic DIP Package Notes: Inches Millimeters Symbol Notes 1. Index area: a notch or a pin one identification mark shall be located Min. Max. ...
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PRODUCT SPECIFICATION RC4391 Mechanical Dimensions (continued) 8-Lead Plastic DIP Package Notes: Inches Millimeters Symbol Notes 1. Dimensioning and tolerancing per ANSI Y14.5M-1982. Min. Max. Min. Ma...
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RC4391 PRODUCT SPECIFICATION Mechanical Dimensions (continued) 8-Lead SOIC Package Notes: Inches Millimeters Symbol Notes 1. Dimensioning and tolerancing per ANSI Y14.5M-1982. Min. Max. Min. Max. 2. &...
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PRODUCT SPECIFICATION RC4391 Ordering Information Part Number Package Operating Temperature Range RC4391N 8 Lead Plastic DIP 0˚C to +70°C RC4391M 8 Lead Plastic SOIC 0˚C to +70°C RV4391N 8 Lead Plasti...
Manual Details
| Brand | Fairchild |
|---|---|
| Pages | 22 |
| File Size | 153.56 KB |
| Published | June 05, 2026 |
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Frequently Asked Questions
Which RC4391 variant should I use if my system runs between -55°C and +125°C?
You must use the RM4391D, as it is rated for an operating temperature range of -55˚C to +125˚C.
What voltage consideration should I remember when using this chip in an inverting application?
The maximum allowable supply voltage (+V) will be reduced by the value of the negative output voltage (VOUT), unless an external power transistor is utilized.
How does the device monitor battery levels during operation?
It uses two dedicated pins: Pin 1 (LBR) monitors the Low Battery Resistor, and Pin 2 (LBD) detects the specific low battery condition.
What is the peak switch current I should be aware of when designing the circuit?
The absolute maximum switching current (I) allowed by the chip is 375 mA MAX.