lm5037mtx National Semiconductor Corporation, lm5037mtx Datasheet
lm5037mtx
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lm5037mtx Summary of contents
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... MHz capable os- cillator with synchronization capability, precision reference and thermal shutdown. Simplified Push-Pull Power Converter © 2008 National Semiconductor Corporation Features ■ High voltage (100V) start-up regulator ■ ...
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... Connection Diagram Ordering Information Order Number LM5037MT LM5037MTX www.national.com 30069402 Top View 16-Lead TSSOP Package Package Type NSC Package Drawing TSSOP-16 MTC16 2 Supplied As 92 Units per Rail 2500 Units on Tape and Reel ...
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Pin Descriptions PIN NAME DESCRIPTION 1 RAMP Pulse width modulator ramp 2 UVLO Line under-voltage lockout 3 COMP Input to the pulse width modulator 4 FB Feedback 5 RT2 Oscillator dead-time control 6 AGND Analog ground 7 RT1 Oscillator maximum ...
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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. VIN to GND VCC, OUTA, OUTB to GND CS to GND UVLO, FB, RT2, RT1, RAMP, SS, REF to ...
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Symbol Parameter Soft-Stop Current Sink Oscillator (RT1 and RT2 Pins) DT Dead-Time F Frequency 1 (at OUTA, half SW1 oscillator frequency) F Frequency 2 (at OUTA, half SW2 oscillator frequency) DC level Input Sync threshold PWM Controller (Comp Pin) Delay ...
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Typical Performance Characteristics Typical Application Circuit Efficiency Start-Up Regulator Current (UVLO = REF REF www.national.com V VCC 30069450 30069404 Feedback Amplifier Gain/Phase 30069406 6 and REF VIN 30069403 VCC VCC ...
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Oscillator Frequency vs RT1 30069408 V vs Temperature FB 30069411 Dead-Time vs Temperature 30069413 Dead-Time vs RT2 Oscillator Frequency vs Temperature Soft-Start and Restart Current vs Temperature 7 30069410 30069412 30069414 www.national.com ...
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Block Diagram www.national.com FIGURE 1. Simplified Block Diagram 8 30069418 ...
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Functional Description The LM5037 PWM controller contains all the features neces- sary to implement double-ended power converter topologies such as push-pull, half-bridge and full-bridge. The unique ar- chitecture allows the modulator to be configured for either voltage-mode or current-mode control. ...
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When designing with a current sense resistor, all the noise sensitive, low power ground con- nections should be connected together near the AGND pin, and a single connection should be made to the power ground ...
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SOFT-START The soft-start circuit allows the regulator to gradually reach a steady state operating point, thereby reducing start-up stress- es and current surges. When bias is supplied to the LM5037, the SS pin capacitor is discharged by an internal MOSFET. ...
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CURRENT MODE The LM5037 can be configured for current mode control by injecting a signal representative of primary current into the RAMP pin. One way to achieve this is shown in Figure 5. Filter components R and C are used ...
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FIGURE 5. Current Mode Configuration with Slope Compensation FIGURE 6. Timing Diagram for Current Mode Configuration 13 30069422 30069423 www.national.com ...
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OSCILLATOR The LM5037 oscillator frequency and the maximum duty cy- cle are set by two external resistors connected between the RT1 and RT2 pins to AGND. The minimum dead-time be- tween OUTA and OUTB pulses is proportional to the RT2 ...
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During thermal shutdown, the soft-start capacitor is fully discharged and the controller follows a normal start-up sequence after the junc- tion temperature falls to the operating level (140°C). Application Information The following information is intended ...
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CURRENT MODE CONTROL USING THE LM5037 The LM5037 can be configured in current mode control by applying the primary current signal into the RAMP pin. One way to achieve this is shown in Figure 9, which depicts a sim- plified ...
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OSC current sense resistor ( mΩ, slope compensation will suffice. The slope compensation "volts" that re- sults from the above expression ...
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FIGURE 13. Current Sense Using Current Sense Resistor (R1) UVLO DIVIDER SELECTION A dedicated comparator connected to the UVLO pin detects an input under-voltage condition. When the UVLO pin voltage is below 0.45V, the LM5037 controller low ...
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For example, if the LM5037 enabled when V reaches 33V, and disabled when V decreases to 30V, R1 PWR should be 113 kΩ, and R2 should be 4.42 kΩ. The voltage at the UVLO pin should not ...
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In the case of continuous cycle-by-cycle current limit detec- tion at the CS pin, the time required for C hiccup mode threshold is: For example 0.01 µF the time t1 is approximately RES 2.0 ms. The cool ...
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21 www.national.com ...
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Physical Dimensions www.national.com inches (millimeters) unless otherwise noted 16-Lead TSSOP Package NS Package Number MTC16 22 ...
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Notes 23 www.national.com ...
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... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...