LM5642XMTX/NOPB National Semiconductor, LM5642XMTX/NOPB Datasheet
LM5642XMTX/NOPB
Specifications of LM5642XMTX/NOPB
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LM5642XMTX/NOPB Summary of contents
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... Over-voltage protection is available for both outputs. A UV- Delay pin is also available to allow delayed shut off time for the IC during an output under-voltage event. Typical Application Circuit © 2010 National Semiconductor Corporation LM5642/LM5642X Features ■ Two synchronous buck regulators ■ ...
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Connection Diagrams Top View Ordering Information Order Number Package Type LM5642MH 28-Lead eTSSOP LM5642MHX LM5642MTC 28-Lead TSSOP LM5642MTCX LM5642XMT LM5642XMTX Pin Descriptions KS1 (Pin 1): The positive (+) Kelvin sense for the internal current sense amplifier of Channel 1. Use ...
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Adding a capacitor to this pin pro- vides a soft-start feature that minimizes inrush current and output voltage overshoot. ON/SS2 (Pin 10): Channel 2 enable pin. See the description for Pin 9, ON/SS1. May be ...
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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 SYNC, COMP1, COMP2, UV Delay − ...
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Symbol Parameter V V Overvoltage OVP OUT Shutdown Latch Threshold S SW1, SW2 ON-Resistance V wx_R Gate Drive I CBOOTx Leakage Current V CBOOT I HDRVx and LDRVx Source SC_DRV Current I HDRVx Sink Current sk_HDRV I LDRVx Sink Current ...
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... TSSOP package above. A thermal shutdown will occur if the temperature exceeds the maximum junction temperature of the device. 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 1.5 kΩ resistor. ...
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FIGURE 1. Typical 2 Channel Application Circuit 7 20060103 www.national.com ...
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FIGURE 2. Typical Single Channel Application Circuit 8 20060104 ...
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9 www.national.com ...
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Typical Performance Characteristics Softstart Waveforms (No-Load Both Channels) Over-Current and UVP Shutdown (VIN = 24V, Io2 = 0A) Ch.1 Load Transient Response (VIN = 24V, Vo1 = 1.8V) www.national.com UVP Startup Waveform (VIN = 24V) 20060123 20060120 Ch.2 Load Transient ...
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Ch. 2 Load Transient Response (VIN = 36V, Vo2 = 3.3V) 20060128 Input Supply Current vs Temperature (Shutdown Mode V = 28V) IN 20060124 VLIN5 vs Temperature 20060126 Ch.1 Load Transient Response (VIN = 36V, Vo1 = 1.8V) Input Supply ...
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FB Reference Voltage vs Temperature Error Amplifier Tranconductance Gain vs Temperature Efficiency vs Load Current Ch.2 = 3.3V, Ch.1 = Off www.national.com Operating Frequency vs Temperature 20060166 Efficiency vs Load Current Using Resistor Sense Ch.1 = 1.8V, Ch.2 = Off ...
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Efficiency vs Load Current Using Vds Sense Ch.2 = 3.3V, Ch.1 = Off 13 20060173 www.national.com ...
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Operating Descriptions SOFT START The ON/SS1 pin has dual functionality as both channel enable and soft start control. Referring to the soft start block diagram is shown in Figure 3, the LM5642 will remain in shutdown mode while both soft ...
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OVER VOLTAGE PROTECTION (OVP) If the output voltage on either channel rises above 113% of nominal, over voltage protection activates. Both channels will latch off. When the OVP latch is set, the high side FET driver, HDRVx, is immediately turned ...
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SWITCHING NOISE REDUCTION Power MOSFETs are very fast switching devices. In syn- chronous rectifier converters, the rapid increase of drain cur- rent in the top FET coupled with parasitic inductance will ...
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To ensure accurate current sensing using V cial attention in board layout is required. The KSx and RSNSx pins require separate traces to form a Kelvin connection at ...
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Where Vfb = 1.238V. Although increasing the value of R1 and R2 will increase efficiency, this will also decrease accuracy. Therefore, a maximum value is recommended for R2 in order to keep the output within .3% of Vnom. This maximum ...
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Maximum ESR criterion can be used when the associated capacitance is high enough, otherwise more capacitors than the number determined by this criterion should be used in parallel. MINIMUM CAPACITANCE CALCULATION In a switch mode power supply, the minimum output ...
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The input RMS current in this case is given by: Where, again, I1 and I2 are the maximum load currents of channel 1 and 2, and D1 and D2 are the duty cycles. This ...
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Loop Compensation The general purpose of loop compensation is to meet static and dynamic performance requirements while maintaining stability. Loop gain is what is usually checked to determine small-signal performance. Loop gain is equal to the product of control-output transfer ...
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A second zero can also be added with a resistor in series with Cc2. If used, this zero should be placed at fn, where the con- trol to output gain rolls off at -40dB/dec. Generally, fn will be well below ...
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Bill Of Materials for Figure 1 24V to 1.8, 3.3V LM5642 ID Part Number U1 LM5642 Q1, Q4 Si4850EY Q2, Q5 Si4840DY D3 BAS40-06 L1 RLF12560T-4R2N100 L2 RLF12545T-100M5R1 C1 C3216X7R1H105K C3, C4, C14, VJ1206Y101KXXAT C15 C27 C2012X5R1C105K C6, C16 C5750X5R1H106M ...
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Bill of Materials for Figure 2 30V to 1.8V, 20A LM5642 ID Part Number U1 LM5642 Q1, Q4 Si4850EY Q2, Q3, Q5, Q6 Si4470DY D3 BAS40-06 L1,L2 RLF12560T-2R7N110 C1 C3216X7R1H105K C10, C24, C27 C2012X5R1C105K C6, C16, C28, C5750X5R1H106M C30 C9, ...
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Bill Of Materials Based on Figure Part Number U1 LM5642X Q1, Q4 Si4850EY Q2, Q5 Si4840DY D3 BA54A L1, L2 RLF12545T-4R2N100 C1 C3216X7R1H105K C3, C4, C14, VJ1206Y101KXXAT C15 C27 C2012X5R1C105K C6, C28 C5750X7R1H106M C9, C23 C4532X7R0J107M C2, ...
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Bill Of Materials Based on Figure Part Number U1 LM5642X Q1, Q4 Si4850EY Q2, Q5 Si4840DY D3 BA54A L1, L2 RLF12545T-5R6N6R1 C1 C3216X7R1H105K C3, C4, C14, VJ1206Y101KXXAT C15 C27 C2012X5R1C105K C6, C28 C5750X7R1H106M C9, C23 C4532X7R0J107M C2, ...
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Physical Dimensions inches (millimeters) unless otherwise noted 28-Lead TSSOP Package Order Number LM5642MTC, LM5642XMT NS Package Number MTC28 28-Lead eTSSOP Package Order Number LM5642MH, LM5642XMH NS Package Number MXA28A 27 www.national.com ...
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