LM2641MTC-ADJ National Semiconductor, LM2641MTC-ADJ Datasheet
LM2641MTC-ADJ
Specifications of LM2641MTC-ADJ
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LM2641MTC-ADJ Summary of contents
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... 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) DS100949-1 Top View Order Number LM2641MTC-ADJ See NS Package Number MTC28 DS100949 January 2000 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, 2NDFB/FPWM, SYNC, REF, SS1, SS2, COMP1, COMP2 and CSL1 LIN CSH1, CSH2, and CSL2 (Note ...
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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 LM2641 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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Block Diagram www.national.com FIGURE 3. LM2641 Block Diagram 8 DS100949-2 ...
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Typical Performance Charateristics Efficiency vs Load Current DS100949-14 Efficiency vs Load Current DS100949-17 Efficiency vs Load Current DS100949-20 Ref Output Voltage DS100949-23 Efficiency vs Load Current DS100949-15 Efficiency vs Load Current DS100949-18 Efficiency vs Load Current DS100949-21 Ref Output Voltage ...
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Typical Performance Charateristics Normalized Error Amplifier Voltage vs Junction Temperature DS100949-26 Shutdown Quiescent Current And Standby Quiescent Current vs Supply Voltage DS100949-29 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) losses. The load current value where the transition from fixed-frequency to pulse-skipping operation occurs is the point where the inductor current goes low enough to cause the voltage measured across the current sense resistor (R4 or ...
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Application Information SYNC Pin The basic operating frequency of 300kHz can be increased 400kHz by using the SYNC pin and an external CMOS or TTL clock. The synchronizing pulses must have a minimum pulse width of 200 ...
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Application Information FIGURE 4. Typical Compensation Network The components shown will add poles and zeros to the loop gain as given by the following equations: C10 adds a pole whose frequency is given by: (C10 ...
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Application Information FIGURE 6. Calculated Gain Plot for 3.3V/4A Application Looking at the plot, it can be seen that the unity-gain cross- over frequency f is expected to be about 25kHz. Using this c value, the phase margin at the ...
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Design Procedure (Continued) The data sheet for the inductor must be reviewed carefully to verify that the selected component will have the desired in- ductance at the frequency and current for the application. Current Rating This specification may be the ...
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Design Procedure (Continued also recommended that a 0.1µF ceramic capacitor be placed from V to ground for high frequency bypassing, lo- IN cated as close as possible to the V IN OUTPUT CAPACITORS The output capacitor(s) are critical ...
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Design Procedure (Continued) POWER MOSFETs Two N-channel logic-level MOSFETs are required for each output. The voltage rating should be at least 1.2 times the maximum input voltage. Maximizing efficiency for a design requires selecting the right FET. The ON-resistance of ...
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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. inches (millimeters) unless otherwise noted 28-Lead TSSOP (MTC) Order Number LM2641MTC-ADJ NS Package Number MTC28 2. A critical component is any component of a life ...