LM2640MTC-ADJ National Semiconductor, LM2640MTC-ADJ Datasheet
LM2640MTC-ADJ
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LM2640MTC-ADJ Summary of contents
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... Output overvoltage shutdown protection n Programmable soft-start (each controller linear regulator output n Precision 2.5V reference output n 28-pin TSSOP Applications n Notebook and subnotebook computers n Wireless data terminals n Battery-powered instruments 28-Lead TSSOP (MTC) DS100148-1 Top View Order Number LM2640MTC-ADJ See NS Package Number MTC28 December 1998 www.national.com ...
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Pin Description (Refer to Typical Application Circuits) Pin # Name 1 CSH2 The sense point for the positive side of the voltage across the current sense resistor (R13) placed in series with output # 2. The regulated output voltage appearing ...
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Typical Application Circuits 3 www.national.com ...
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Typical Application Circuits www.national.com (Continued) 4 ...
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... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. IN, SW1, and SW2 FB1 and FB2 SD, ON/OFF1, ON/OFF2, −0 2NDFB/FPWM, SYNC, REF, SS1, SS2, COMP1, COMP2 and CSL1 LIN CSH1, CSH2, and CSL2 ...
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Electrical Characteristics Typicals and limits appearing in regular type apply for T tion temperature range for operation +125˚C. Unless otherwise specified under the Parameter or Conditions columns 10V, and ON/OFF1 ...
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... The LM2640 actively limits its junction temperature to about 150˚C. Note 4: For detailed information on soldering plastic small-outline packages, refer to the Packaging Databook available from National Semiconductor Corporation. Note 5: For testing purposes, ESD was applied using the human-body model, a 100 pF capacitor discharged through a 1.5 k Note 6: A typical is the center of characterization data taken with T Note 7: All limits are guaranteed ...
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Electrical Characteristics Note 8: Both controllers are ON but not switching. Currents entering the IC at IN, CSL1, CSH1, CSL2, and CSH2 are measured. Those entering at CSL1 and CSH1 are multiplied by 0.50 to emulate the effect of a ...
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Block Diagram FIGURE 3. LM2640 Block Diagram 9 DS100148-2 www.national.com ...
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Typical Performance Characteristics Efficiency vs Load Current DS100148-14 Efficiency vs Load Current DS100148-17 Efficiency vs Load Current DS100148-20 Efficiency vs Load Current DS100148-23 www.national.com Efficiency vs Load Current DS100148-15 Efficiency vs Load Current DS100148-18 Efficiency vs Load Current DS100148-21 Efficiency ...
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Typical Performance Characteristics REF Output Voltage DS100148-26 Normalized Error Amplifier Offset vs Junction Temperature DS100148-29 Normalized Oscillator Frequency vs. Junction Temperature DS100148-32 Theory of Operation Basic Operation of the Current-Mode Controller The output voltage is held at a constant value ...
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Theory of Operation (Continued) inductor current ramps up, causing a voltage drop across the sense resistor, and this voltage is amplified by the current sense amplifier. The voltage signal from the current sense amplifier is applied to the input of ...
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Application Information (Continued) It must be understood that the maximum allowable current of 50mA must include the current drawn by the gate drive cir- cuitry. This means that the maximum current available for use at the LIN pin is 50 ...
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Application Information As can be seen in the approximation for Q quency for f (HF) occurs at the maximum value lowest frequency for f (HF) is about 1.8V). 4.5V and V OUT As noted ...
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Application Information (Continued) R13 = µH = 0.825 gain = 55 dB The values of compensation components will be: C10 = 2200 pF, R11 = 8.2k, and C12 will not be used. ...
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Design Procedure (Continued important to understand that all inductors are not created equal, as the method of specifying inductance varies widely. It must also be noted that the inductance of every inductor decreases with current. The core material, ...
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Design Procedure (Continued) cifically designed for switching applications. Capacitors such as these with good high frequency ( 100 kHz) specifications are not cheap. Aluminum electrolytic capacitors should generally not be used in switching regulator applications where the ambient temperature goes ...
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Design Procedure (Continued) The physical placement of the Schottky diode must be as close as possible to the FET, since any parasitic (lead) in- ductance in series with the Schottky will slow its turn-ON and cause current to flow through ...
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... National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. 28-Lead TSSOP (MTC) Order Number LM2640MTC-ADJ NS Package Number MTC28 2. A critical component is any component of a life support ...