LM2642MTC National Semiconductor, LM2642MTC Datasheet
LM2642MTC
Specifications of LM2642MTC
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LM2642MTC Summary of contents
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... Over-voltage protection is available for both out- puts. A UV-Delay pin is also available to allow delayed shut off time for the IC during an output under-voltage event. Block Diagram © 2003 National Semiconductor Corporation Features n Two synchronous buck regulators n 180˚ out of phase operation n 4.5V to 30V input range n Power good function monitors Ch.1 n 37µ ...
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... TOP VIEW 20046202 28-Lead TSSOP (MTC) Order Number LM2642MTC See NS Package Number MTC28 VLIN5 (Pin 7): The output of an internal 5V LDO regulator derived from VIN. It supplies the internal bias for the chip and supplies the bootstrap circuitry for gate drive. Bypass this pin to signal ground with a minimum of 4.7µ ...
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Pin Descriptions (Continued) SW2 (Pin 16): Switch-node connection for Channel 2, which is connected to the source of the top MOSFET of Channel 2. It serves as the negative supply rail for the top-side gate driver, HDRV2. HDRV2 (Pin 17): ...
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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. Voltages from the indicated pins to SGND/PGND: VIN, ILIM1, ILIM2, KS1, KS2 SW1, SW2, RSNS1, RSNS2 FB1, FB2, VDD1, VDD2 PGOOD, COMP1, COMP2, UV ...
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Electrical Characteristics Unless otherwise specified 15V, GND = PGND = 0V, VLIN5 = VDD1 = VDD2. Limits appearing in boldface type apply IN over the specified operating junction temperature range, (-20˚C to +125˚C, if not otherwise specified). Specifications ...
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... 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 100pF capacitor discharged through a 1.5kΩ resistor. ...
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FIGURE 1. Typical 2 Channel Application Circuit 7 20046203 www.national.com ...
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FIGURE 2. Typical Single Channel Application Circuit www.national.com 8 20046204 ...
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9 www.national.com ...
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Typical Performance Characteristics Softstart Waveforms ( LOAD1 LOAD2 UVP Startup Waveforms Shutdown Waveforms ( LOAD1 LOAD2 www.national.com = 0A) 20046223 20046268 = 0A) 20046222 10 Power On and PGOOD1 Waveforms ( 0A) LOAD1 ...
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Typical Performance Characteristics Ch.2 Load Transient Response 3.3V , 12V OUT IN Input Supply Current vs Temperature (Shutdown Mode V IN VLIN5 vs Temperature (Continued) 20046229 = 15V) 20046224 20046226 11 Load Transient Response Parallel Operation 1.8V , 12V OUT ...
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Typical Performance Characteristics FB Reference Voltage vs Temperature Error Amplifier Gain vs Temperature Efficiency vs Load Current Ch.2 = 2.5V, Ch.1 = Off www.national.com (Continued) Operating Frequency vs Temperature 20046266 Efficiency vs Load Current Ch.1 = 5V, Ch.2 = Off ...
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Operation Descriptions SOFT START The ON/SS1 pin has dual functionality as both channel enable and soft start control. The soft start block diagram is shown in Figure 3. The LM2642 will remain in shutdown mode while both soft start pins ...
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Operation Descriptions typical) both channels will latch off. Also, UV_DELAY will be disabled and the UV_DELAY pin will return to 0V. During UVP, both the high side and low side FET drivers will be turned off capacitor is ...
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Operation Descriptions FIGURE 7. Current Sense and Current Limit Current limit is activated when the inductor current is high enough to cause the voltage at the RSNSx pin to be lower than that of the ILIMx pin. This toggles the ...
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Component Selection Choose 60K The output voltage is limited by the maximum duty cycle as well as the minimum on time. Figure 9 shows the limits for input and output voltages. The recommended maximum out- put voltage is approximately 1V ...
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Inductor Selection The size of the output inductor can be determined from the desired output ripple voltage, Vrip, and the impedance of the output capacitors at the switching frequency. The equation to determine the minimum inductance value is as follows: ...
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MOSFET Selection (Continued) where Tj_max is the maximum allowed junction temperature in the FET, Ta_max is the maximum ambient temperature the junction-to-ambient thermal resistance of the FET, θja and TC is the temperature coefficient of the on resistance ...
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Loop Compensation (Continued) FIGURE 11. Output-Control Transfer Function The control-output corner frequencies, and thus the desired compensation corner frequencies, can be determined ap- proximately by the following equations: Since fp is determined by the output network, it will shift with ...
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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) 28-Lead TSSOP Package Order Number LM2642MTC NS Package Number MTC28 2. A critical component is any component of a life ...