l6995 STMicroelectronics, l6995 Datasheet
l6995
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l6995 Summary of contents
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... C SS December 2002 This is preliminary information on a new product now in development. Details are subject to change without notice. INPUT-OUTPUT CONVERSION ORDERING NUMBERS: L6995D DESCRIPTION The device is a step-down controller specifically de- signed to provide extremely high efficiency conver- sion, with losses current sensing tecnique. ...
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... L6995 ABSOLUTE MAXIMUM RATINGS Symbol GND GND DR DR HGATE and BOOT, to PHASE HGATE and BOOT, to PGND V PHASE PHASE LGATE to PGND ILIM, VFB, VSENSE, NOSKIP, SHDN, PGOOD, OVP, VREF, INT, GND to GND SENSE P Power dissipation at T tot amb T Storage temperature range ...
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... CC SOFT START SECTION I Soft Start current SS SS Clamp Voltage ON TIME Ton On time duration Description through a resistor. CC Test Condition Vout=Vref Fsw=110Khz Iout=1A VFB > VREF VFB > VREF SHDN to GND SHDN to GND VREF=VSENSE OSC=250mV L6995 Min. Typ. Max. Unit 1 4.5 5.5 V 4.2 4.4 V 4.1 4 600 A 1 ...
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... L6995 ELECTRICAL CHARACTERISTICS (continued 5V 0°C to 85°C unless otherwise specified amb Symbol Parameter OFF TIME T Minimum off time OFFMIN K /T OSC OFFMIN VOLTAGE REFERENCE VREF Voltage Accuracy PWM COMPARATOR Input voltage offset I Input Bias Current FB CURRENT LIMIT AND ZERO CURRENT COMPARATOR ...
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... Figure 1. Functional & Block Diagram VCC OSC VSENSE L6995 OSC VSENSE 5/25 ...
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... L6995 1 DEVICE DESCRIPTION 1.1 Constant On Time PWM topology Figure 2. Loop block schematic diagram Vin R1 One-shot generator OSC R2 Vsense Vref + - FB R4 The device implements a Constant On Time control scheme, where the Ton is the high side MOSFET on time duration forced by the one-shot generator. The on time is directly proportional to VSENSE pin voltage and in- ...
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... DC pole in the control loop Error Offset <Vout> Vref can be connected between INT pin and INT2 is the output divider ratio given from Eq4 and F OUT is connected between INT pin and ground. C INT2 L6995 also provides an AC path INT1 Time U INT2 7/25 ...
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... Respect to a traditional PWM controller, that has an internal oscillator setting the switching frequency hys- teretic system the frequency can change with some parameters (input voltage, output current). In L6995 is im- plemented the voltage feed-forward circuit that allows constant switching frequency during steady-sate operation with the input voltage variation ...
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... In order to calculate the output volatge chargin time it should be calculated, before, the output volatrge function versus time. This function can be calculated from the inductor current function; the inductor current function can SS pin). CC Vss Soft-start active range Maximum current limit SS L6995 the NOSKIP pin. CC voltage (where the output current limit Time Time ). SS 9/25 ...
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... L6995 be supposed linear function of the time ilim t,C = --------------------------------------------------------------------------- - the output voltage is given by t,C = ------------------------ - calling V as the V final value, the output charging time can be estimated as: out out V C out -------------------------------------------------------------------------------------- - = lim ...
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... J1. Output current in excess of 20A can be reached dependently on the MOSFET type. The SW1 is used to start the device (when the supplies are already present) and to select the PFM/PWM mode 150° the system temperature is lower the 125nC. MAXLS L6995 G 11/25 ...
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... L6995 Figure 7. Demoboard Schematic Diagram C22 R6 R7 PGOOD OVP L6995 ILIM R8 C21 GNDSENSE SS C20 R12 SHDN 5V 2.2 Jumper Connection Table 1. Jumper connection with integrator Component C4 C7 INT NOINT * This component is not necessary, depends from the output ESR capacitor. See the integrator section. ...
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... DEMOBOARD LAYOUT Real dimensions: 5 7,7 cm (2,28inch X 3, 08inch) Figure 8. PCB layout: bottom side Figure 9. PCB Layout: Top side , C like in the figure 7. Note should be selected with a pole frequency N N Figure 10. Internal ground plane Figure 11. Power & signal plane L6995 13/25 ...
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... L6995 Table 3. PCB Layout guidelines Goal Low radiation and low magnetic coupling with the adjacent circuitry. Don’t penalty the efficiency. Ensure high accuracy in the current sense system. Reduce the noise effect on IC. Table 4. Component list The component list is shared in two sections: the first for the general-purpose component, the second for power ...
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... C34Y5U1E106Z TOKIN C3225Y5V1E106Z TDK Dimension ECJ4XF1E106Z PANASONIC TMK325F106ZH TAIYO YUDEN ETQP6F0R6BFA PANASONIC A959ASR60N TOKO DXM1306-R60-T COEV CEP12D38H0R6 SUMIDA STMicroelectronics STMicroelectronics STMicroelectronics STMicroelectronics = 1.25V 270kHz with an input voltage around V OUT SW L6995 Notes N.M. 25V Input capacitor Notes Q3 N.M. Q3 N.M. Q4 N.M. 25V Linear regulator = 20V with IN 15/25 ...
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... L6995 3 STEP BY STEP DESIGN V = 20V V = 1.25V I = 20A F IN OUT OUT In this design it is considered a low profile demoboard great attention is given to the components height. 3.1 Input capacitor. A pulsed current (with zero average value) flows through the input capacitor of a buck converter. The AC com- ...
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... ESR (ESR OUT is this power loss (few percent of the rated output power), the required (typically, = 510 °C for these low-voltage classes) and T the ON as STS25NH3LL. ON L6995 ) should be OUT must be greater than VIN DSS MAX , the higher is the gate ON moves G with a 17/25 ...
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... The device output voltage is adjustable by connecting a voltage divider from output to VSENSE pin. Minimum output voltage 0.9V. Once output divider and frequency divider have been designed as to ob- OUT REF tain the required output voltage and switching frequency, the following equation gives the smallest input voltage, which allows L6995 to regulate (which corresponds -------------- ----------------------------- - – ...
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... [A] V in= ut=1 .25V 20K C7,C13 R4 OSC BOOT C4 D1 HGATE Q1 PHASE Q2 LGATE R1 D2 L6995 PGND U1 GND NOSKIP VSENSE GNDSENSE NOINT INT INT VFB C1 VREF NOINT TP3 Cn C5 L6995 20,0 24,0 Vcc J1 VIin GNDin L1 VOUT R3 C14,C15 R2 GNDOUT C3 INT Rn 19/25 ...
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... L6995 3.11 DEMOBOARD LAYOUT Real dimensions: 4 2.7 cm (1.85inch X1.063inch) Figure 14. Top side components placement Figure 15. Bottom side Jumpers distribution Table 5. Component list Part name Value RESISTOR R1, R5, R9, R10 33k R2 10k R3 10k R4 21k R6 470k 120k CAPACITOR C1 330pF C2 N.M. C3 N.M. C4 100nF 10nF ...
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... PANASONIC DO3316P-272HC COILCRAFT ETQP6H2R2GF PANASONIC DQ7545 COEV STMicroelectronics STMicroelectronics = 1.8V 250kHz with an input voltage around V OUT ut=1 . 0Khz PFM L6995 Notes Double mos in sigle package 3 = 20V and 6,0 21/25 ...
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... L6995 4 TYPICAL OPERATING CHARACTERISTICS The measurements refer to the part list in table 4. V Figure 19. Soft Start with no load. Ch1-> Inductor current Ch2-> Output voltage Figure 20. Soft Start with 20A load. Ch1-> Inductor current Ch2-> Output voltage Ch3-> Soft Start voltage 22/25 = 20V V = 1.25V F ...
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... Khz] 350 300 250 200 P SK/P FM 150 P WM 100 Figure 26. Switching Frequency Vs Input Voltage 150 100 10 L6995 20 25 PFM 0 23/25 ...
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... L6995 mm DIM. MIN. TYP. MAX. MIN. A 1.20 A1 0.050 0.150 0.002 A2 0.800 1.000 1.050 0.031 b 0.190 0.300 0.007 c 0.090 0.200 0.004 D (1) 6.400 6.500 6.600 0.252 E 6.200 6.400 6.600 0.244 E1 (1) 4.300 4.400 4.500 0.170 e 0.650 L 0.450 0.600 0.750 0.018 L1 1.000 k 0˚ (min.) 8˚ (max.) aaa 0 ...
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