Datasheet LM2698 Datasheet (National Semiconductor)

Page 1
LM2698 SIMPLE SWITCHER
®
1.35A Boost Regulator
LM2698 SIMPLE SWITCHER
March 2005

General Description

The LM2698 is a general purpose PWM boost converter. The 1.9A, 18V, 0.2ohm internal switch enables the LM2698 to provide efficient power conversion to outputs ranging from
®
The LM2698 SIMPLE SWITCHER switching frequency of either 600kHz or 1.25MHz. This pro­motes flexibility in component selection and filtering tech­niques. A shutdown pin is available to suspend the device and decrease the quiescent current to 5µA. An external compensation pin gives the user flexibility in setting fre­quency compensation, which makes possible the use of small, low ESR ceramic capacitors at the output. Switchers Made Simple and guaranteed design. The LM2698 is available in a low profile 8-lead MSOP package.
®
software is available to insure a quick, easy
features a pin selectable

Typical Application Circuit

Features

n 1.9A, 0.2, internal switch (typical) n Operating voltage as low as 2.2V n 600kHz/1.25MHz adjustable frequency operation n Switchers Made Simple n 8-Lead MSOP package
®
software

Applications

n 3.3V to 5V, 5V to 12V conversion n Distributed Power n Set-Top Boxes n DSL Modems n Diagnostic Medical Instrumentation n Boost Converters n Flyback Converters n SEPIC Converters
®
1.35A Boost Regulator
20012658
SIMPLE SWITCHER®is a registered trademark of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation DS200126 www.national.com
Page 2

Connection Diagram

LM2698
Top View
8-Lead Plastic MSOP
20012604
NS Package Number MUA08A

Ordering Information

Order Number Package Type NSC Package
Drawing
LM2698MM-ADJ MSOP-8 MUA08A 1000 Units, Tape and Reel S22B
LM2698MMX-ADJ MSOP-8 MUA08A 3500 Units, Tape and Reel S22B
Supplied As Package ID

Pin Description

Pin Name Function
1V
C
2 FB Output voltage feedback input.
3 SHDN
4 GND Analog and power ground.
5V
6V
SW
IN
7 FSLCT Switching frequency select input. V
8 NC Connect to ground.
Compensation network connection. Connected to the output of the voltage error amplifier.
Shutdown control input, active low.
Power switch input. Switch connected between SW pin and GND pin.
Analog power input.
= 1.25MHz. Ground = 600kHz.
IN
www.national.com 2
Page 3

Block Diagram

LM2698
20012603
www.national.com3
Page 4

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
LM2698
please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
V
IN
SW Voltage −0.3V V
FB Voltage −0.3V V
V
Voltage 0.965<V
C
SHDN Voltage (Note 2) −0.3V V
FSLCT (Note 2) −0.3V V
Maximum Junction Temperature
Power Dissipation (Note 3) Internally Limited
Lead Temperature 300˚C
−0.3V VIN≤ 12V
C
SHDN
FSLCT
SW
FB
<
18V
7V
1.565
7V
12V
150˚C
Vapor Phase (60 sec.) 215˚C
Infrared (15 sec.) 220˚C
ESD Susceptibility (Note 4)
Human Body Model
(Note 5) 2kV
Machine Model 200V

Operating Conditions

Operating Junction Temperature Range (Note 6) −40˚C to +125˚C
Storage Temperature −65˚C to +150˚C
Supply Voltage 2.2V to 12V
SW Voltage 0 V

Electrical Characteristics

Specifications in standard type face are for TJ= 25˚C and those with boldface type apply over the full Operating Tempera­ture Range (T
Symbol Parameter Conditions
I
Q
V
FB
I
CL
%V
/VINFeedback Voltage Line
FB
I
B
V
IN
g
m
A
V
D
MAX
D
MIN
f
S
I
SHDN
I
L
R
DS(ON)
TH
SHDN
UVP On Threshold 1.95 2.05 2.2 V
= −40˚C to +125˚C)Unless otherwise specified. VIN=2.2V and IL= 0A, unless otherwise specified.
J
Min
(Note 6)
Typ
(Note 7)
Max
(Note 6)
Quiescent Current FB = 0V (Not Switching) 1.3 2.0 mA
V
=0V 5 10 µA
SHDN
Feedback Voltage 1.2285 1.26 1.2915 V
Switch Current Limit VIN= 2.7V (Note 8) 1.35 1.9 2.4 A
2.2V VIN≤ 12.0V 0.013 0.1 %/V
Regulation
FB Pin Bias Current
0.5 20 nA
(Note 9)
Input Voltage Range 2.2 12 V
Error Amp Transconductance I = 5µA 40 135 290 µmho
Error Amp Voltage Gain 120 V/V
Maximum Duty Cycle FSLCT = Ground 78 85 %
Minimum Duty Cycle FSLCT = Ground 15 %
FSLCT = V
IN
30
Switching Frequency FSLCT = Ground 480 600 720 kHz
Shutdown Pin Current V
FSLCT = V
SHDN
V
SHDN
IN
=V
IN
=0V −0.5 -1
1 1.25 1.5 MHz
0.01 0.1 µA
Switch Leakage Current VSW= 18V 0.01 3 µA
Switch R
DS(ON)
VIN= 2.7V, ISW= 1A 0.2 0.4
SHDN Threshold Voltage Output High 0.6 0.9 V
Output Low 0.3 0.6 V
Off Threshold 1.85 1.95 2.1 V
SW
17.5V
Units
www.national.com 4
Page 5
Electrical Characteristics (Continued)
Specifications in standard type face are for TJ= 25˚C and those with boldface type apply over the full Operating Tempera­ture Range (T
Symbol Parameter Conditions
θ
JA
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: Shutdown and voltage frequency select should not exceed V
Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, T
and the ambient temperature, T at any ambient temperature is calculated using: P temperature, and the regulator will go into thermal shutdown.
Note 4: The human body model is a 100 pF capacitor discharged through a 1.5kresistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin.
Note 5: ESD susceptibility using the human body model is 500V for V
Note 6: All limits guaranteed at room temperature (standard typeface) and at temperature extremes (bold typeface). All room temperature limits are 100% tested
or guaranteed through statistical analysis.All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Note 7: Typical numbers are at 25˚C and represent the most likely norm.
Note 8: This is the switch current limit at 0% duty cycle. The switch current limit will change as a function of duty cycle. See Typical performance Characteristics
section for I
Note 9: Bias current flows into FB pin.
Note 10: Junction to ambient thermal resistance (no external heat sink) for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit.
See "Scenario ’A’" in the Power Dissipation section.
Note 11: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately
0.0191 sq. in. of copper heat sinking. See "Scenario ’B’" in the Power Dissipation section.
Note 12: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately
0.0465 sq. in. of copper heat sinking. See "Scenario ’C’" in the Power Dissipation section.
Note 13: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately
0.2523 sq. in. of copper heat sinking. See "Scenario ’D’" in the Power Dissipation section.
Note 14: Junction to ambient thermal resistance for the MSO8 package with minimal trace widths (0.010 inches) from the pins to the circuit and approximately
0.0098 sq. in. of copper heat sinking on the top layer and 0.0760 sq. in. of copper heat sinking on the bottom layer, with three 0.020 in. vias connecting the planes. See "Scenario ’E’" in the Power Dissipation section.
= −40˚C to +125˚C)Unless otherwise specified. VIN=2.2V and IL= 0A, unless otherwise specified.
J
Min
(Note 6)
Thermal Resistance Junction to Ambient
Typ
(Note 7)
235 ˚C/W
(Note 10)
Junction to Ambient
225
(Note 11)
Junction to Ambient
220
(Note 12)
Junction to Ambient
200
(Note 13)
Junction to Ambient
195
(Note 14)
.
IN
. See the Electrical Characteristics table for the thermal resistance of various layouts. The maximum allowable power dissipation
A
vs. V
CL
IN
(MAX) = (T
D
J(MAX)−TA
.
C
)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die
(MAX), the junction-to-ambient thermal resistance, θJA,
J
Max
(Note 6)
Units
LM2698
www.national.com5
Page 6

Typical Performance Characteristics

LM2698
Efficiency vs Load Current
= 8V, fS= 600kHz)
(V
OUT
20012667 20012666
Iqvs VIN(600 kHz, non-switching) Iqvs VIN(600 kHz, switching)
Efficiency vs Load Current
(V
= 8V, fS= 1.25MHz)
OUT
20012618
Iqvs. VIN(1.25MHz, non-switching) Iqvs VIN(1.25MHz, switching)
20012622
20012619
20012617
www.national.com 6
Page 7
Typical Performance Characteristics (Continued)
LM2698
I
q(SHDN)
vs V
IN
20012616 20012621
R
DS(ON)
vs V
IN
Switching Frequency vs VIN(600kHz) Switching Frequency vs VIN(1.25MHz)
ICLvs. Ambient Temperature
V
IN
= 3.3V, V
=8V ICLvs. V
OUT
20012620 20012623
IN
20012641 20012642
www.national.com7
Page 8

Operation

LM2698

Continuous Conduction Mode

FIGURE 1. Simplified Boost Converter Diagram
(a) First Cycle of Operation (b) Second Cycle Of Operation
The LM2698 is a current-mode, PWM boost regulator. A boost regulator steps the input voltage up to a higher output voltage. In continuous conduction mode (when the inductor current never reaches zero at steady state), the boost regu­lator operates in two cycles.
In the first cycle of operation, shown in Figure 1 (a), the transistor is closed and the diode is reverse biased. Energy is collected in the inductor and the load current is supplied by
.
C
OUT
The second cycle is shown in Figure 1 (b). During this cycle, the transistor is open and the diode is forward biased. The energy stored in the inductor is transferred to the load and output capacitor.
The ratio of these two cycles determines the output voltage. The output voltage is defined as:
where D is the duty cycle of the switch.
20012602

Inductor

www.national.com 8
20012605

FIGURE 2. (a) Inductor Current (b) Diode Current

The inductor is one of the two energy storage elements in a boost converter. Figure 2 shows how the inductor current varies during a switching cycle. The current through an inductor is quantified as:
Page 9
Operation (Continued)
If V
is constant, diL/ dt must be constant, thus the current
L(t)
in the inductor changes at a constant rate. This is the case in DC/DC converters since the voltages at the input and output can be approximated as a constant. The current through the inductor of the LM2698 boost converter is shown in Figure 2(a). The important quantities in determining a proper induc­tance value are I (the inductor current ripple). If iLis larger than I inductor current will drop to zero for a portion of the cycle and the converter will operate in discontinuous conduction mode.
is smaller than I
If i
L
above zero and the converter will operate in continuous conduction mode (CCM). All the analysis in this datasheet assumes operation in continuous conduction mode. To op­erate in CCM:
(the average inductor current) and i
L(AVG)
, the inductor current will stay
L(AVG)
>
I
L(AVG)
i
L
L(AVG)
, the
LM2698

Current Limit

The current limit in the LM2698 is referenced to the peak switch current. The peak currents in the switch of a boost converter will always be higher than the average current supplied to the load. To determine the maximum average output current that the LM2698 can supply, use:
I
OUT(MAX)
Where ICLis the switch current limit (see Electrical Chara­teristics table and Typical Performance Curves). Hence, as
increases, the maximum current that can be supplied to
V
IN
the load increases, as shown in Figure 3.
L
=(ICL− iL)*(1−D) = (ICL− iL)*VIN/V
OUT
Choose the minimum I CCM operation. A common choice is to set i
.
I
L(AVG)
to determine the minimum L for
OUT
L
to 30% of
The inductance value will also affect the stability of the converter. Because the LM2698 utilizes current mode con­trol, the inductor value must be carefully chosen. See the COMPENSATION section for recommended inductance val­ues.
Choosing an appropriate core size for the inductor involves calculating the average and peak currents expected through the inductor. In a boost converter,
and I
L(Peak)=IL(AVG)
+ iL,
where
A core size with ratings higher than these values should be chosen. If the core is not properly rated, saturation will dramatically reduce overall efficiency.
20012673

FIGURE 3. Maximum Output Current vs Input Voltage

Diode

The diode in a boost converter such as the LM2698 acts as a switch to the output. During the first cycle, when the transistor is closed, the diode is reverse biased and current is blocked; the load current is supplied by the output capaci­tor. In the second cycle, the transistor is open and the diode is forward biased; the load current is supplied by the induc­tor.
Observation of the boost converter circuit shows that the average current through the diode is the average load cur­rent, and the peak current through the diode is the peak current through the inductor. The diode should be rated to handle more than its peak current. To improve efficiency, a low forward drop Schottky diode is recommended.

Input Capacitor

Due to the presence of an inductor at the input of a boost converter, the input current waveform is continuous and triangular. The inductor ensures that the input capacitor sees fairly low ripple currents. However, as the inductor gets smaller, the input ripple increases. The rms current in the input capacitor is given by:
The input capacitor should be capable of handling the rms current. Although the input capacitor is not so critical in boost applications, a 10 µF or higher value, good quality capacitor prevents any impedance interactions with the input supply.
www.national.com9
Page 10
Operation (Continued)
A 0.1µF or 1µF ceramic bypass capacitor is also recom-
LM2698
mended on the V be connected very close to pin 6 to effectively filter high frequency noise. When operating at 1.25 MHz switching frequency, a minimum bypass capacitance of 0.22 µF is recommended.

Output Capacitor

The output capacitor in a boost converter provides all the output current when the switch is closed and the inductor is charging. As a result, it sees very large ripple currents. The output capacitor should be capable of handling the maxi­mum RMS current. The RMS current in the output capacitor is:
where,
and
The ESR and ESL of the output capacitor directly control the output ripple. Use capacitors with low ESR and ESL at the output for high efficiency and low ripple voltage. Surface mount tantalums, surface mount polymer electrolytic, and polymer tantalum, Sanyo OS-CON, or multi-layer ceramic capacitors are recommended at the output.
pin (pin 6) of the IC. This capacitor must
IN
D=(V
OUT-VIN
)/V
OUT

Compensation

This section presents a step-by-step procedure to design the compensation network at pin 1 (V
) of the LM2698. These
c
design methods will produce a conservative and stable con­trol loop.
There is a minimum inductance requirement in any current mode converter. This is a function of V
, duty cycle, and
OUT
switching frequency, among other things. The graphs below plot the recommended inductance range vs. duty cycle for
= 12V. The two lines represent the upper and lower
V
OUT
bounds of the recommended inductance range. The simpli­fied compensation procedure that follows assumes that the inductance never drops below the Q = 5 line. Figure 4 plots the equation:
(1)
where,
= 0.15,
R
DSON
*
Se = 0.072
fS, and Q = 0.5 and 5 Use Q = 5 to calculate the minimum inductance recom-
mended for a stable design. Choosing an inductor between the Q = 0.5 and Q = 5 values provides a good tradeoff between size and stability. Note that as V 5V, R Characteristics section (R case R
increases, as shown in the Typical Performance
DS(ON)
DS(ON)
should be used when choosing the induc-
vs.VINcurve). The worst
DS(ON)
drops less than
IN
tance. To view plots for different Vout, multiply the Y axis by a factor of V
/12, or plot Equation (1) for the respective
OUT
output voltage.
20012654

FIGURE 4. Minimum Inductance Requirements for (a) fS= 600kHz and (b) fS= 1.25MHz

www.national.com 10
20012653
Page 11
Operation (Continued)
The goal of the compensation network is to provide the best static and dynamic performance while insuring stability over line and load variations. The relationship of stability and
LM2698
performance can be best analyzed by plotting the magnitude and phase of the open loop frequency response in the form of a bode plot. A typical bode plot of the LM2698 open loop frequency response is shown in Figure 5.

FIGURE 5. Bode plot of the LM2698 Frequency Response using the Typical Application Circuit

Poles are marked with an ’X’, and zeros are marked with a ’O’. The bolded ’O’ labeled ’f
’ is a right-half plane zero.
RHP
Right half plane zeros act like normal zeros to the magnitude (+20dB/decade slope influence) and like poles to the phase (−90˚ shift). Three curves are shown. The powerstage curve is the frequency response of the powerstage, which includes the switch, diode, inductor, output capacitor, and load. The compensator curve is the frequency response of the com­pensator, which is the error amp combined with the compen­sation network. T is the product of the powerstage and the compensator and is the complete open loop frequency re­sponse. The power stage response is fixed by line and load constraints, while the compensator is set by the external compensation network at pin 1. The compensator can be designed in a few simple steps as follows.
Quick Compensator Design
Calculate:
where,
where R Choose C
Choose
OUT
C1
20012657
= 875k = 4.7nF
Where,
www.national.com11
Page 12
Operation (Continued)
LM2698
If the output capacitor is of high ESR (0.1or higher), it may be necessary to use C 1/(2πC used. Choose C
where R
ESR) (Hz) is lower than fS/2 (Hz), CC2should be
OUT
(R
OUT
such that:
C2
C+ROUT
= output impedance of the error amp (875 k).
Improving Transient Response Time
The above compensator design provides a loop gain with high phase margin for a large stability margin. The transient response time of this loop is limited by the lower mid­frequency gain necessary to achieve a high phase margin. If it is desired to increase the transient response time, C be decreased. Decreasing C increasingly shorter transient response times, however the loop phase margin will become progressively lower as C decreased. When optimizing the loop gain for transient re­sponse time, it is recommended to keep the phase margin above 40˚.
. A rule of thumb is that if
C2
)(C
ESR) / (RCR
OUT
by 2x, 4x, and 6x will yield
C1
OUT
) (F)
Additional Comments on the Open Loop Frequency Re­sponse
The procedure used here to pick the compensation network will provide a good starting point. In most cases, these values will be sufficient for a stable design. It is always recommended to check the design in a real test setup. This is easy to do with the aid of a dynamic load. Set the high and low load values to your system requirements and switch between the two at about 1kHz. View the output voltage with an oscilloscope using AC coupling, and zoom in enough to see the waveform react to the load change. Use the follow­ing table to determine if your design is stable. Remember to use worst case conditions (V
IN(MIN),ROUT(MIN),ROUT(MAX)
).
Response Conclusion What to
Change
Underdamped, weak attenuation
Underdamped,
Nearing instability Make C
larger
Stable Nothing
C1
strong attenuation
Critically damped Stable Nothing
may
C1
is
C1
Overdamped Stable Nothing

Application Information

FIGURE 6. 3.3V to 10V Boost Converter

www.national.com 12
20012668
Page 13
Application Information (Continued)

1.25MHz Boost Converter

Figure 6 shows the LM2698 boosting 3.3V to 10V at 300mA. As discussed in the COMPENSATION section, the R of the internal FET in the LM2698 raises as the input voltage drops below 5V (see Typical Performance Characteristics). The minimum input voltage for this application is 2.5V, at
DS(ON)
which point the R
is approximately 200m. Substitut-
DS(ON)
ing these values in for Equation (1), it is found that either a 10 µH (1.25MHz operation) or a 22 µH (600kHz operation) is necessary for a stable design. The circuit is operated at
1.25MHz to allow for a smaller inductance. From the Com­pensator Design equations, R
is calculated to be 18.6k,
C
and a 20kresistor is used.
LM2698

FIGURE 7. 3.3V SEPIC Converter

3.3V SEPIC

The LM2698 can be used to implement a SEPIC technology. The advantages of the SEPIC topology are that it can step up or step down an input voltage, and it has low input current ripple.
The conversion ratio for the SEPIC is :
where
D’ = 1−D
Solving for D yeilds:
To avoid subharmonic oscillations, it is recommended that inductors L1 and L2 be the same inductance. Currents con­ducted by the inductors are:
20012631
I
1=IOUT(VOUT/VIN
1=VIN
D/(2*L1*fs)
i I
2=IOUT
)
i1=VIND/(2*L2*fs) The switch sees a maximum current of I
1+I2
+ i1+ i2.If
L1 = L2 = L, the maximum switch current is given by:
I
OUT
(1+V
OUT/VIN
)+VIND/(L*fs)
The maximum load current is limited by this relationship to the switch current.
The polarity of C
will change between each cycle, so a
SEPIC
ceramic capacitor should be used here. A high quality, low ESR capacitor will directly improve efficiency because all the load current passes through C
should be chosen using the same relationship as in the
C
IN
boost converter (see the C
IN
.
SEPIC
section). CINmust be able to
provide the necessary RMS current.
www.national.com13
Page 14
Application Information (Continued)
LM2698

FIGURE 8. Level-Shifted SEPIC Converter

Level-Shifted SEPIC

The circuit shown in Figure 8 is similar to the SEPIC shown in Figure 7, except that it is level shifted to provide a negative output voltage. This is achieved by connecting the ground of the LM2698 to the output. The circuit analysis for the level­shifted SEPIC is the same as the SEPIC. The voltage at the input of the LM2698 will need to be clamped if the absolute value of the output voltage plus the input voltage exceeds 12V, the absolute maximum rating for the V
pin. The sim-
IN
plest way to do this is with a zener diode, as shown in Figure
8. Likewise, if the FSLCT pin is pulled high to operate at 1.25 MHz, its voltage must not exceed 12V. To prevent any high frequency noise from entering the LM2698’s internal cir­cuitry, a high frequency bypass capacitor must be placed as close to pin 6 as possible. A good choice for this capacitor is a 0.1µF ceramic capacitor.

Layout Consideration

Power Dissipation

The output power of the LM2698 is limited by its maximum power dissipation. The maximum power dissipation is deter­mined by the formula
=(T
P
D
jmax-TA
where T (125˚C), T
is the maximum specified junction temperature
jmax
is the ambient temperature, and θJAis the ther-
A
mal resistance of the package. θ
)/θ
JA
is dependant on the
JA
layout of the board as shown below.
20012643
20012611
20012612
www.national.com 14
Page 15
Application Information (Continued)
20012613
LM2698
20012615
20012614
www.national.com15
Page 16

Physical Dimensions inches (millimeters)

unless otherwise noted
1.35A Boost Regulator
®
8-Lead Plastic MSOP
NS Package Number MUA08A
LM2698 SIMPLE SWITCHER
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.
LIFE SUPPORT POLICY
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.
BANNED SUBSTANCE COMPLIANCE
National Semiconductor manufactures products and uses packing materials that 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.
National Semiconductor Americas Customer Support Center
Email: new.feedback@nsc.com Tel: 1-800-272-9959
www.national.com
National Semiconductor Europe Customer Support Center
Fax: +49 (0) 180-530 85 86
Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790
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.
National Semiconductor Asia Pacific Customer Support Center
Email: ap.support@nsc.com
National Semiconductor Japan Customer Support Center
Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560
Loading...