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  • LM3475MFX/NOPB图
  • 深圳市恒达亿科技有限公司

     该会员已使用本站12年以上
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     该会员已使用本站7年以上
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  • 深圳市能元时代电子有限公司

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  • LM3475MF【特价现货】图
  • 齐创科技(上海北京青岛)有限公司

     该会员已使用本站14年以上
  • LM3475MF【特价现货】 现货库存
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  • LM3475MFX 现货库存
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     该会员已使用本站13年以上
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  • LM3475MF图
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  • LM3475MF
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  • 封装SOT-23-5 
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  • 深圳市恒达亿科技有限公司

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  • LM3475MM
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  • 数量5000 
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  • 深圳市恒达亿科技有限公司

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  • 数量3000 
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  • 深圳市得捷芯城科技有限公司

     该会员已使用本站11年以上
  • LM3475MF
  • 数量89 
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  • 北京耐芯威科技有限公司

     该会员已使用本站12年以上
  • LM3475MF/NOPB
  • 数量5000 
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  • 封装SOT-23-5 
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  • LM3475MFX
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  • LM3475EVAL图
  • 首天国际(深圳)科技有限公司

     该会员已使用本站16年以上
  • LM3475EVAL
  • 数量5000 
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  • 首天国际(深圳)集团有限公司

     该会员已使用本站17年以上
  • LM3475EVAL
  • 数量5000 
  • 厂家Texas Instruments 
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  • LM3475MF图
  • 深圳市华科泰电子商行

     该会员已使用本站13年以上
  • LM3475MF
  • 数量6800 
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  • 深圳市西源信息科技有限公司

     该会员已使用本站9年以上
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  • 数量8800 
  • 厂家TI/德州仪器 
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  • LM3475图
  • 北京中其伟业科技有限公司

     该会员已使用本站16年以上
  • LM3475
  • 数量3000 
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  • 北京首天国际有限公司

     该会员已使用本站16年以上
  • LM3475MM
  • 数量2280 
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  • 北京齐天芯科技有限公司

     该会员已使用本站15年以上
  • LM3475MF/NOPB
  • 数量5000 
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  • 封装SOT-23-5 
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  • 北京元坤伟业科技有限公司

     该会员已使用本站17年以上
  • LM3475EVAL
  • 数量5000 
  • 厂家National Semiconductor (TI) 
  • 封装贴/插片 
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  • 百分百原装正品,现货库存
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     该会员已使用本站15年以上
  • LM3475MF/NOPB
  • 数量5600 
  • 厂家Texas Instruments 
  • 封装SC-74A,SOT-753 
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  • 原装正品,假一罚十
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  • 北京中其伟业科技有限公司

     该会员已使用本站16年以上
  • LM3475MF NOPB
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  • 北京元坤伟业科技有限公司

     该会员已使用本站17年以上
  • LM3475EVAL
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     该会员已使用本站12年以上
  • LM3475MF
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     该会员已使用本站11年以上
  • LM3475MFX
  • 数量18800 
  • 厂家TI-德州仪器 
  • 封装SOT-23-6 
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  • LM3475MF
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产品型号LM3475的Datasheet PDF文件预览

October 2004  
LM3475  
Hysteretic PFET Buck Controller  
General Description  
Features  
n Easy to use control methodology  
n 0.8V to VIN adjustable output range  
n High Efficiency (90% typical)  
The LM3475 is a hysteretic P-FET buck controller designed  
to support a wide range of high efficiency applications in a  
very small SOT23-5 package. The hysteretic control scheme  
has several advantages, including simple system design  
with no external compensation, stable operation with a wide  
range of components, and extremely fast transient re-  
sponse. Hysteretic control also provides high efficiency op-  
eration, even at light loads. The PFET architecture allows for  
low component count as well as 100% duty cycle and ultra-  
low dropout operation.  
n
0.9% ( 1.5% over temp) feedback voltage  
n 100% duty cycle capable  
n Maximum operating frequency up to 2MHz  
n Internal Soft-Start  
n Enable pin  
n SOT23-5 package  
Applications  
n TFT Monitor  
n Auto PC  
n Vehicle Security  
n Navigation Systems  
n Notebook Standby Supply  
n Battery Powered Portable Applications  
n Distributed Power Systems  
Typical Application Circuit  
20070101  
© 2004 National Semiconductor Corporation  
DS200701  
www.national.com  
Connection Diagram  
Top View  
20070102  
5 Lead Plastic SOT23-5  
NS package Number MF05A  
Package Marking and Ordering Information  
Order Number  
Package Type  
Package Marking  
Supplied As:  
LM3475MF  
SOT23-5  
S65B  
1000 units on Tape and Reel  
3000 units on Tape and Reel  
LM3475MFX  
SOT23-5  
S65B  
Pin Description  
Pin Name  
Pin Number  
Description  
FB  
1
Feedback input. Connect to a resistor divider between the output  
and GND.  
GND  
EN  
2
3
Ground.  
Enable. Pull this pin above 1.5V (typical) for normal operation.  
When EN is low, the device enters shutdown mode.  
Power supply input.  
VIN  
4
5
PGATE  
Gate drive output for the external PFET.  
www.national.com  
2
Absolute Maximum Ratings (Note 1)  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Lead Temperature  
Vapor Phase (60 sec.)  
Infared (15 sec.)  
215˚C  
220˚C  
VIN  
−0.3V to 16V  
−0.3V to 16V  
−0.3V to 5V  
−0.3V to 16V  
−65˚C to 150˚C  
440mW  
PGATE  
Operating Ratings (Note 1)  
FB  
Supply Voltage  
Operating Junction  
Temperature  
2.7V to 10V  
−40˚C to +125˚C  
EN  
Storage Temperature  
Power Dissipation (Note 2)  
ESD Susceptibilty  
Human Body Model (Note 3)  
2.5kV  
Electrical Characteristics  
Specifications in Standard type face are for TJ = 25˚C, and in bold type face apply over the full Operating Temperature  
Range (TJ = −40˚C to +125˚C). Unless otherwise specified, VIN = EN = 5.0V. Datasheet min/max specification limits are guar-  
anteed by design, test, or statistical analysis.  
Symbol  
Parameter  
Conditions  
EN = VIN (PGATE  
Open)  
Min  
170  
Typ  
Max  
320  
Unit  
IQ  
Quiescent Current  
260  
µA  
EN = 0V  
4
7
10  
VFB  
Feedback Voltage  
Feedback Voltage  
Line Regulation  
Comparator  
0.788  
0.8  
0.812  
V
%VFB/VIN  
<
<
2.7V VIN 10V  
0.01  
%/V  
<
<
VHYST  
IFB  
VthEN  
IEN  
2.7V VIN 10V  
21  
21  
50  
28  
32  
mV  
nA  
V
Hysteresis  
−40˚C to +125˚C  
FB Bias Current  
Enable Threshold  
Voltage  
600  
Increasing  
1.2  
1.5  
365  
.025  
1.8  
1
Hysteresis  
mV  
µA  
Enable Leakage  
Current  
EN = 10V  
Source  
2.8  
1.8  
ISOURCE = 100mA  
Sink  
RPGATE  
Driver Resistance  
ISink = 100mA  
Source  
VPGATE = 3.5V  
CPGATE = 1nF  
Sink  
0.475  
1.0  
IPGATE  
Driver Output Current  
Soft-Start Time  
A
VPGATE = 3.5V  
CPGATE = 1nF  
<
<
2.7V VIN 10V  
TSS  
4
ms  
ns  
V
(EN Rising)  
TONMIN  
VUVD  
Minimum On-Time  
Under Voltage  
Detection  
PGATE Open  
Measured at the FB  
Pin  
180  
0.56  
0.487  
0.613  
3
www.national.com  
Electrical Characteristics (Continued)  
Note 1: Absolute maximum ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions for which the device is intended to  
be functional, but device parameter specifications may not be guaranteed. For guaranteed specifications and test conditions, see the Electrical Characteristics.  
Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature, T  
, the junction-to-ambient thermal resistance, θ and  
JA  
J_MAX  
the ambient temperature, T . The maximum allowable power dissipation at any ambient temperature is calculated using:  
A
P
= (T  
- T )/θ . The maximum power dissipation of 0.44W is determined using T = 25˚C, θ = 225˚C/W, and T  
= 125˚C.  
J_MAX  
D_MAX  
J_MAX  
A
JA  
A
JA  
Note 3: The human body model is a 100 pF capacitor discharged through a 1.5kresistor into each pin.  
www.national.com  
4
Typical Performance Characteristics Unless specified otherwise, all curves taken at VIN = 5V,  
VOUT = 2.5V, L = 10 µH, COUT = 100 µF, ESR = 100m, and TA = 25˚C.  
Quiescent Current vs Input Voltage  
Feedback Voltage vs Temperature  
20070122  
20070123  
Hysteresis Voltage vs Input Voltage  
Hysteresis Voltage vs Temperature  
20070124  
20070125  
Efficiency vs Input Voltage  
IOUT = 2A  
Efficiency vs Load Current  
20070126  
20070127  
5
www.national.com  
Typical Performance Characteristics Unless specified otherwise, all curves taken at VIN = 5V, VOUT  
= 2.5V, L = 10 µH, COUT = 100 µF, ESR = 100m, and TA = 25˚C. (Continued)  
Start Up  
Output Ripple Voltage  
20070128  
20070129  
Load Transient Response with External Ramp  
Load Transient Response  
(Circuit from Figure 3)  
(Typical Application Circuit from Figure 5)  
20070131  
20070132  
www.national.com  
6
Block Diagram  
20070103  
Operation Description  
OVERVIEW  
The LM3475 is a buck (step-down) DC-DC controller that  
uses a hysteretic control architecture, which results in Pulse  
Frequency Modulated (PFM) regulation. The hysteretic con-  
trol scheme does not utilize an internal oscillator. Switching  
frequency depends on external components and operating  
conditions. Operating frequency decreases at light loads,  
resulting in excellent efficiency compared to PWM architec-  
tures. Because switching is directly controlled by the output  
conditions, hysteretic control provides exceptional load tran-  
sient response.  
HYSTERETIC CONTROL CIRCUIT  
The LM3475 uses a comparator-based voltage control loop.  
The voltage on the feedback pin is compared to a 0.8V  
reference with 21mV of hysteresis. When the FB input to the  
comparator falls below the reference voltage, the output of  
the comparator goes low. This results in the driver output,  
PGATE, pulling the gate of the PFET low and turning on the  
PFET.  
20070104  
FIGURE 1. Hysteretic Waveforms  
With the PFET on, the input supply charges COUT and  
supplies current to the load through the PFET and the induc-  
tor. Current through the inductor ramps up linearly, and the  
output voltage increases. As the FB voltage reaches the  
upper threshold (reference voltage plus hysteresis) the out-  
put of the comparator goes high, and the PGATE turns the  
PFET off. When the PFET turns off, the catch diode turns on,  
and the current through the inductor ramps down. As the  
output voltage falls below the reference voltage, the cycle  
repeats. The resulting output, inductor current, and switch  
node waveforms are shown in Figure 1.  
The LM3475 operates in discontinuous conduction mode at  
light load current and continuous conduction mode at heavy  
load current. In discontinuous conduction mode, current  
through the inductor starts at zero and ramps up to the peak,  
then ramps down to zero. The next cycle starts when the FB  
voltage reaches the reference voltage. Until then, the induc-  
tor current remains zero. Operating frequency is low, as are  
switching losses. In continuous conduction mode, current  
always flows through the inductor and never ramps down to  
zero.  
SOFT-START  
The LM3475 includes an internal soft-start function to protect  
components from excessive inrush current and output volt-  
age overshoot. As VIN rises above 2.7V (typical), the internal  
bias circuitry becomes active. When EN goes high, the  
7
www.national.com  
MINIMUM ON/OFF TIME  
Operation Description (Continued)  
To ensure accurate comparator switching, the LM3475 im-  
poses a blanking time after each comparator state change.  
This blanking time is 180ns typically. Immediately after the  
comparator goes high or low, it will be held in that state for  
the duration of the blanking time. This helps keep the hys-  
teretic comparator from improperly responding to switching  
noise spikes (See Reducing Switching Noise) and ESL  
spikes (See Output Capacitor Selection) at the output.  
device enters soft-start. During soft-start, the reference volt-  
age is ramped up to the nominal value of 0.8V in approxi-  
mately 4ms. Duty cycle and output voltage will increase as  
the reference voltage is ramped up.  
UNDER VOLTAGE DETECTION  
When the output voltage falls below 70% (typical) of the  
normal voltage, as measured at the FB pin, the device turns  
off PFET and restarts a new soft-start cycle. In short circuit,  
the PFET is always on, and the converter is effectively a  
resistor divider from input to output to ground. Whether the  
part restarts depends on the power path resistance and the  
short circuit resistance. This feature should not be consid-  
ered as overcurrent protection or output short circuit protec-  
tion.  
At very low or very high duty cycle operation, maximum  
frequency will be limited by the blanking time. The maximum  
operating frequency can be determined by the following  
equations:  
FMAX = D / tonmin  
FMAX = (1-D) / toffmin  
Where D is the duty cycle, defined as VOUT/VIN, and tonmin  
and toffmin is the sum of the blanking time, the propagation  
delay time and the PFET delay time (see Figure 1).  
PGATE  
During switching, the PGATE pin swings from VIN (off) to  
ground (on). As input voltage increases, the time it takes to  
slew the gate of the PFET on and off also increases. Also, as  
the PFET gate voltage approaches VIN, the PGATE current  
driving capability decreases. This can cause a significant  
additional delay in turning the switch off when using a PFET  
with a low threshold voltage. These two effects will increase  
power dissipation and reduce efficiency. Therefore, a PFET  
with relatively high threshold voltage and low gate capaci-  
tance is recommended.  
ENABLE PIN (EN)  
The LM3475 provides a shutdown function via the EN pin to  
disable the device. The device is active when the EN pin is  
pulled above 1.5V (typ) and in shutdown mode when EN is  
below 1.135V (typ). In shutdown mode, total quiescent cur-  
rent is less than 10µA. The EN pin can be directly connected  
to VIN for always-on operation.  
www.national.com  
8
Design Information  
SETTING OUTPUT VOLTAGE  
Where delay is the sum of the LM3475 propagation delay  
time and the PFET delay time. The propagation delay is  
90ns typically.  
The output voltage is programmed using a resistor divider  
between VOUT and GND as shown in Figure 2. The feedback  
resistors can be calculated as follows:  
Minimum output ripple voltage can be determined using the  
following equation:  
VOUT_PP = VHYST ( R1 + R2 ) / R2  
USING A FEED-FORWARD CAPACITOR  
The operating frequency and output ripple voltage can also  
be significantly influenced using a speed up capacitor, Cff, as  
shown in Figure 2. Cff is connected in parallel with the high  
side feedback resistor, R1. The output ripple causes a cur-  
rent to be sourced or sunk through this capacitor. This cur-  
rent is essentially a square wave. Since the input to the  
feedback pin (FB) is a high impedance node, the bulk of the  
current flows through R2. This superimposes a square wave  
ripple voltage on the FB node. The end result is a reduction  
in output ripple and an increase in operating frequency.  
When adding Cff, calculate the formula above with α= 1. The  
value of Cff depends on the desired operating frequency and  
the value of R2. A good starting point is 1nF ceramic at  
100kHz decreasing linearly with increased operating fre-  
quency. Also note that as the output voltage is programmed  
below 1.6V, the effect of Cff will decrease significantly.  
Where Vfb is 0.8V typically.  
The feedback resistor ratio, α = (R1+R2) / R2, will also be  
used below to calculate output ripple and operating fre-  
quency.  
INDUCTOR SELECTION  
The most important parameters for the inductor are the  
inductance and the current rating. The LM3475 operates  
over a wide frequency range and can use a wide range of  
inductance values. Minimum inductance can be calculated  
using the following equation:  
20070115  
Where D is the duty cycle, defined as VOUT/VIN, and I is the  
allowable inductor ripple current.  
FIGURE 2. Hysteretic Window  
Maximum allowable inductor ripple current should be calcu-  
lated as a function of output current (IOUT) as shown below:  
Imax = IOUT x 0.3  
The inductor must also be rated to handle the peak current  
(IPK) and RMS current given by:  
SETTING OPERATING FREQUENCY AND OUTPUT  
RIPPLE  
Although hysteretic control is a simple control scheme, the  
operating frequency and other performance characteristics  
depend on external conditions and components. If the induc-  
tance, output capacitance, ESR, VIN, or Cff is changed, there  
will be a change in the operating frequency and possibly  
output ripple. Therefore, care must be taken to select com-  
ponents which will provide the desired operating range. The  
best approach is to determine what operating frequency is  
desirable in the application and then begin with the selection  
of the inductor and output capacitor ESR. The design pro-  
cess usually involves a few iterations to select appropriate  
standard values that will result in the desired frequency and  
ripple.  
IPK = (IOUT + I/2) x 1.1  
The inductance value and the resulting ripple is one of the  
key parameters controlling operating frequency.  
OUTPUT CAPACITOR SELECTION  
Once the desired operating frequency and inductance value  
are selected, ESR must be selected based on the equation  
in the Setting Operating Frequency and Output Ripple. This  
process may involve a few iterations to select standard ESR  
and inductance values.  
Without the feedforward capacitor (Cff), the operating fre-  
quency (F) can be approximately calculated using the for-  
mula:  
In general, the ESR of the output capacitor and the inductor  
ripple current create the output ripple of the regulator. How-  
ever, the comparator hysteresis sets the first order value of  
this ripple. Therefore, as ESR and ripple current vary, oper-  
ating frequency must also vary to keep the output ripple  
9
www.national.com  
Capacitors with high ESL (equivalent series inductance) val-  
ues should not be used. As shown in Figure 1, the output  
ripple voltage contains a small step at both the high and low  
peaks. This step is caused by and is directly proportional to  
the output capacitor’s ESL. A large ESL, such as in an  
electrolytic capacitor, can create a step large enough to  
cause abnormal switching behavior.  
Design Information (Continued)  
voltage regulated. The hysteretic control topology is well  
suited to using ceramic output capacitors. However, ceramic  
capacitors have a very low ESR, resulting in a 90˚ phase  
shift of the output voltage ripple. This results in low operating  
frequency and increased output ripple. To fix this problem a  
low value resistor could be added in series with the ceramic  
output capacitor. Although counter intuitive, this combination  
of a ceramic capacitor and external series resistance provide  
highly accurate control over the output voltage ripple. An-  
other method is to add an external ramp at the FB pin as  
shown in Figure 3. By proper selection of R1 and C2, the FB  
pin sees faster voltage change than the output ripple can  
cause. As a result, the switching frequency is higher while  
the output ripple becomes lower. The switching frequency is  
approximately:  
INPUT CAPACITOR SELECTION  
A bypass capacitor is required between VIN and ground. It  
must be placed near the source of the external PFET. The  
input capacitor prevents large voltage transients at the input  
and provides the instantaneous current when the PFET turns  
on. The important parameters for the input capacitor are the  
voltage rating and the RMS current rating. Follow the manu-  
facturer’s recommended voltage de-rating. RMS current and  
power dissipation (PD) can be calculated with the equations  
below:  
Other types of capacitor, such as Sanyo POSCAP, OS-CON,  
and Nichicon ’NA’ series are also recommended and may be  
used without additional series resistance. For all practical  
purposes, any type of output capacitor may be used with  
proper circuit verification.  
20070120  
FIGURE 3. External Ramp  
DIODE SELECTION  
P-CHANNEL MOSFET SELECTION  
The catch diode provides the current path to the load during  
the PFET off time. Therefore, the current rating of the diode  
must be higher than the average current through the diode,  
which be calculated as shown:  
The PFET switch should be selected based on the maximum  
Drain-Source voltage (VDS), Drain current rating (ID), maxi-  
mum Gate-Source voltage (VGS), on resistance (RDSON),  
and Gate capacitance. The voltage across the PFET when it  
is turned off is equal to the sum of the input voltage and the  
diode forward voltage. The VDS must be selected to provide  
some margin beyond the sum of the input voltage and Vd.  
ID_AVE = IOUT x (1 − D)  
The peak voltage across the catch diode is approximately  
equal to the input voltage. Therefore, the diode’s peak re-  
verse voltage rating should be greater than 1.3 times the  
input voltage.  
Since the current flowing through the PFET is equal to the  
current through the inductor, ID must be rated higher than the  
maximum IPK. During switching, PGATE swings the PFET’s  
gate from VIN to ground. Therefore, A PFET must be se-  
lected with a maximum VGS larger than VIN. To insure that  
the PFET turns on completely and quickly, refer to the  
PGATE section.  
A Schottky diode is recommended, since a low forward  
voltage drop will improve efficiency.  
For high temperature applications, diode leakage current  
may become significant and require a higher reverse voltage  
rating to achieve acceptable performance.  
www.national.com  
10  
resistor in series with PGATE. However, this resistor will  
increase the switching losses in the PFET and will lower  
efficiency. Therefore it should be kept as small as possible  
and only used when necessary. Another method to reduce  
switching noise (other than good PCB layout, see Layout  
section) is to use a small RC filter or snubber. The snubber  
should be placed in parallel with the catch diode, connected  
close to the drain of the PFET, as shown in Figure 4. Again,  
the snubber should be kept as small as possible to limit its  
impact on system efficiency. A typical range is a 10-100Ω  
resistor and a 470pF to 2.2nF ceramic capacitor.  
Design Information (Continued)  
The power loss in the PFET consists of switching losses and  
conducting losses. Although switching losses are difficult to  
precisely calculate, the equation below can be used to esti-  
mate total power dissipation. Increasing RDSON will increase  
power losses and degrade efficiency. Note that switching  
losses will also increase with lower gate threshold voltages.  
PDswitch = RDSONx (IOUT)2x D + F x IOUTx VINx (ton + toff)/2  
where:  
ton = FET turn on time  
toff = FET turn off time  
A value of 10ns to 50ns is typical for ton and toff. Note that  
the RDSON has a positive temperature coefficient. At 100˚C,  
the RDSON may be as much as 150% higher than the value  
at 25˚C.  
The Gate capacitance of the PFET has a direct impact on  
both PFET transition time and the power dissipation in the  
LM3475. Most of the power dissipated in the LM3475 is used  
to drive the PFET switch. This power can be calculated as  
follows:  
The amount of average gate driver current required during  
switching (IG) is:  
IG = Qg x F  
And the total power dissipated in the device is:  
IqVIN + IGVIN  
20070105  
Where Iq is typically 260µA as shown in the Electrical Char-  
acteristics table. As gate capacitance increases, operating  
frequency may need to be reduced, or additional heat sink-  
ing may be required to lower the power dissipation in the  
device.  
FIGURE 4. PGATE Resistor and Snubber  
Layout  
PC board layout is very important in all switching regulator  
designs. Poor layout can cause EMI problems, excess  
switching noise and poor operation.  
In general, keeping the gate capacitance below 2000pF is  
recommended to keep transition times (switching losses),  
and power losses low.  
As shown in Figure 6 and Figure 7, place the ground of the  
input capacitor as close as possible to the anode of the  
diode. This path also carries a large AC current. The switch  
node, the node connecting the diode cathode, inductor, and  
PFET drain, should be kept as small as possible. This node  
is one of the main sources for radiated EMI.  
REDUCING SWITCHING NOISE  
Although the LM3475 employs internal noise suppression  
circuitry, external noise may continue to be excessive. There  
are several methods available to reduce noise and EMI.  
MOSFETs are very fast switching devices. The fast increase  
in PFET current coupled with parasitic trace inductance can  
create unwanted noise spikes at both the switch node and at  
VIN. Switching noise will increase with load current and input  
voltage. This noise can also propagate through the ground  
plane, sometimes causing unpredictable device perfor-  
mance. Slowing the rise and fall times of the PFET can be  
very effective in reducing this noise. Referring to Figure 4,  
the PFET can be slowed down by placing a small (1-10)  
The feedback pin is a high impedance node and is therefore  
sensitive to noise. Be sure to keep all feedback traces away  
from the inductor and the switch node, which are sources of  
noise. Also, the resistor divider should be placed close to the  
FB pin. The gate pin of the external PFET should be located  
close to the PGATE pin.  
Using a large, continuous ground plane is also recom-  
mended, particularly in higher current applications.  
11  
www.national.com  
Layout (Continued)  
20070101  
FIGURE 5.  
Bill of Materials  
Designator  
Description  
10µF, 16V, X5R  
100µF, 6V, Ta  
1nF, 25V, X7R  
Schottky, 20V, 2A  
10µH, 3.1A  
Part Number  
Vendor  
TAIYO YUDEN  
AVX  
CIN  
EMK325BJ106MN  
TPSY107M006R0100  
VJ1206Y102KXXA  
CMSH2-20L  
COUT  
CFF  
Vishay  
D1  
Central Semiconductor  
Sumida  
L1  
CDRH103R100  
Si2343  
Q1  
30V, 2.5A  
Vishay  
RFB2  
RFB1  
1k, 0805, 1%  
2.15k, 0805, 1%  
CRW08051001F  
CRCW08052151F  
Vishay  
Vishay  
20070106  
FIGURE 6. Top Layer (Standard Board)  
(2:1 Scale)  
www.national.com  
12  
Layout (Continued)  
20070107  
FIGURE 7. Top Layer (with External Ramp)  
(2:1 Scale)  
20070130  
FIGURE 8. Bottom Layer  
(2:1 Scale)  
13  
www.national.com  
Physical Dimensions inches (millimeters) unless otherwise noted  
5 Lead Plastic SOT23-5  
NS package Number MF05A  
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.  
For the most current product information visit us at www.national.com.  
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NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS  
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR  
CORPORATION. As used herein:  
1. Life support devices or systems are devices or systems  
which, (a) are intended for surgical implant into the body, or  
(b) support or sustain life, and whose failure to perform when  
properly used in accordance with instructions for use  
provided in the labeling, can be reasonably expected to result  
in a significant injury to the user.  
2. A critical component is any component of a life support  
device or system whose failure to perform can be reasonably  
expected to cause the failure of the life support device or  
system, or to affect its safety or effectiveness.  
BANNED SUBSTANCE COMPLIANCE  
National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship  
Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned  
Substances’’ as defined in CSP-9-111S2.  
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配单直通车
LM3475MF产品参数
型号:LM3475MF
Brand Name:Texas Instruments
是否无铅: 含铅
是否Rohs认证: 不符合
生命周期:Obsolete
IHS 制造商:TEXAS INSTRUMENTS INC
零件包装代码:SOT-23
包装说明:LSSOP, TSOP5/6,.11,37
针数:5
Reach Compliance Code:not_compliant
ECCN代码:EAR99
HTS代码:8542.39.00.01
Factory Lead Time:1 week
风险等级:5.27
Samacsys Description:Sync. Sw. Controller 3V:6V,LM3475MF
模拟集成电路 - 其他类型:SWITCHING REGULATOR
控制模式:CURRENT-MODE
控制技术:HYSTERETIC CURRENT MODE
最大输入电压:10 V
最小输入电压:2.7 V
标称输入电压:5 V
JESD-30 代码:R-PDSO-G5
JESD-609代码:e0
长度:2.9 mm
湿度敏感等级:1
功能数量:1
端子数量:5
最高工作温度:125 °C
最低工作温度:-40 °C
最大输出电流:1 A
封装主体材料:PLASTIC/EPOXY
封装代码:LSSOP
封装等效代码:TSOP5/6,.11,37
封装形状:RECTANGULAR
封装形式:SMALL OUTLINE, LOW PROFILE, SHRINK PITCH
峰值回流温度(摄氏度):260
认证状态:Not Qualified
座面最大高度:1.45 mm
子类别:Switching Regulator or Controllers
表面贴装:YES
切换器配置:BOOST
最大切换频率:2000 kHz
温度等级:AUTOMOTIVE
端子面层:Tin/Lead (Sn/Pb)
端子形式:GULL WING
端子节距:0.95 mm
端子位置:DUAL
处于峰值回流温度下的最长时间:NOT SPECIFIED
宽度:1.6 mm
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