lm25088mhx-2 National Semiconductor Corporation, lm25088mhx-2 Datasheet
lm25088mhx-2
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lm25088mhx-2 Summary of contents
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... The device is available in a thermally enhanced TSSOP-16EP pin package. Simplified Application Schematic © 2008 National Semiconductor Corporation Features ■ Emulated current mode control ■ ...
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... Connection Diagrams Top View (Dither version) LM25088-1 Ordering Information Order Number LM25088MH-1 LM25088MHX-1 LM25088MH-2 LM25088MHX-2 Pin Descriptions Pin(S) Name Description 1 VIN Input supply voltage 2 EN Enable input 3 SS Soft-start 4 RAMP Ramp control signal www.national.com 30087602 Description NSC Package Drawing TSSOP-16EP, Dithering ...
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Pin(S) Name Description 5 RT/SYNC Internal oscillator frequency set input and synchronization input 6 GND Ground 7 COMP Output of the internal error amplifier 8 FB Feedback signal from the regulated output 9 OUT Output voltage connection Connect directly to ...
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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, VOUT to GND BOOT to GND SW to GND VCC to GND GND ...
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... Note 3: RAMP and COMP are output pins. As such they are not specified to have an external voltage applied. Note 4: Typical specifications represent the most likely parametric norm at 25°C operation. Note 5: For detailed information on soldering plastic MSOP packages refer to the Packaging Data Book available from National Semiconductor Corporation. Conditions ...
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Typical Performance Characteristics Typical Application Circuit Efficiency VCC VCC Frequency vs R www.national.com 30087640 30087642 RT 30087644 30087641 Shutdown Current 30087643 Frequency vs V VCC 30087645 ...
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V vs Temperature FB 30087646 Soft-Start vs Temperature 30087648 Frequency vs Temperature 30087650 Forced-Off Time vs Temperature Current-Limit vs Temperature Error Amplifier Gain/Phase 7 30087647 30087649 30087651 www.national.com ...
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Block Diagram www.national.com FIGURE 1. Block Diagram 8 30087604 ...
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Detailed Operation The LM25088 Wide Input Range Buck Controller features all the functions necessary to implement an efficient high voltage step-down converter using a minimum number of external components. The control method is based on peak current mode control utilizing ...
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Error Amplifier and PWM Comparator The internal high gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision voltage reference (1.205V). The output of the error amplifier is connected to ...
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FIGURE 3. Composition of Current Sense Signal The sample & hold DC level illustrated in Figure 3 is derived from a measurement of the re-circulating (or free-wheeling) diode current. The diode current flows through the current sense resistor connected between ...
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Where 1/f and T is the forced off-time (280 OSC SW OFF (max) ns typical, 365 ns maximum); f and T SW frequency and oscillator period, respectively. From the above equation, it can be seen that for a ...
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FIGURE 6. Conducted Emissions Measured at the Input of a LM25088 Based Buck Converter Figure 6 shows the conducted emissions on the LM25088 evaluation board input power line. It can be seen from the above picture that, the peak emissions ...
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FET when it is turned ON, if the V exceeds 1V, the comparator turns of the buck DS FET immediately. This feature will help protect the buck FET in catastrophic conditions such ...
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FIGURE 8. Current Limit Restart Timing Diagram Soft-Start The soft-start (SS) feature forces the output to rise linearly until it reaches the steady-state operating voltage set by the feedback resistors. The LM25088 will regulate the FB pin to the SS ...
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The maximum ripple current occurs at the maximum input voltage. Typically selected between 20% and 40 the full load current. Higher ripple current will result in a small- er inductor. However, it places more burden on ...
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FIGURE 10. Additional Slope Compensation for VOUT > 5V OUTPUT CAPACITORS The output capacitors smooth the inductor current ripple and provide a source of charge for load transient conditions. The output capacitor selection is primarily dictated by the following ...
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OUTPUT VOLTAGE DIVIDER R and R set the output voltage level, the ratio of these FB1 FB2 resistors can be calculated from: 1.62 kΩ was chosen for R in this design which results in a FB1 R value of 5.11 ...
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ERROR AMPLIFIER COMPENSATION and C configure the error amplifier gain COMP COMP HF characteristics to accomplish a stable voltage loop gain. One advantage of current mode control is the ability of to close the loop with only ...
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PCB BOARD LAYOUT AND THERMAL CONSIDERATIONS In a buck regulator there are two loops where currents are switched very fast. The first loop starts from the input capac- itors, through the buck MOSFET, to the inductor then out to the ...
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Bill of Materials for LM25088-1 and LM25088-2 Evaluation Boards Part Value Package C1,C2,C3,C4 2.2µF C1210 ,C5 C6,C19 0.1µF C0805 C7 1µF C0603 C8,C11 100pF C0603 C9 270pF C0603 C13 0.1µF C0603 C10 0.022µF C0603 C12 0.015µF C0603 C15 470µF 0.327x0.327x0.3 ...
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Part Value Package J1,J2,J3,J4 Terminal_Turret TP1,TP2 Slotted test point U1 PWM IC TSSOP16_EP www.national.com Manufacturer Manufacturer Part Number Description Keystone 1509 Keystone 1040 National LM25088-1/LM25088-2 24 Terminal, Turret Terminal test point slotted ECM Buck Controller ...
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Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead TSSOP-EP Package NS Package Number MXA16A 25 www.national.com ...
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