LM2679T-ADJ [NSC]
SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit; SIMPLE SWITCHER 5A降压型稳压器具有可调电流限制
| 型号： | LM2679T-ADJ |
| 厂家： | 
National Semiconductor |
| 描述： | SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit |
| 文件： | 总24页 (文件大小：358K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
March 2000
LM2679
SIMPLE SWITCHER® 5A Step-Down Voltage Regulator
with Adjustable Current Limit
General Description
Features
n Efficiency up to 92%
The LM2679 series of regulators are monolithic integrated
circuits which provide all of the active functions for a
step-down (buck) switching regulator capable of driving up to
5A loads with excellent line and load regulation characteris-
n Simple and easy to design with (using off-the-shelf
external components)
n
Resistor programmable peak current limit over a range
of 3A to 7A.
>
tics. High efficiency ( 90%) is obtained through the use of a
low ON-resistance DMOS power switch. The series consists
of fixed output voltages of 3.3V, 5V and 12V and an adjust-
able output version.
n 120 mΩ DMOS output switch
n 3.3V, 5V and 12V fixed output and adjustable (1.2V to
37V ) versions
The SIMPLE SWITCHER concept provides for a complete
design using a minimum number of external components. A
high fixed frequency oscillator (260KHz) allows the use of
physically smaller sized components. A family of standard in-
ductors for use with the LM2679 are available from several
manufacturers to greatly simplify the design process.
±
n
2%maximum output tolerance over full line and load
conditions
n Wide input voltage range: 8V to 40V
n 260 KHz fixed frequency internal oscillator
n Softstart capability
n −40 to +125˚C operating junction temperature range
Other features include the ability to reduce the input surge
current at power-ON by adding a softstart timing capacitor to
gradually turn on the regulator. The LM2679 series also has
built in thermal shutdown and resistor programmable current
limit of the power MOSFET switch to protect the device and
load circuitry under fault conditions. The output voltage is
Applications
n Simple to design, high efficiency ( 90%) step-down
switching regulators
n Efficient system pre-regulator for linear voltage
regulators
>
±
guaranteed to a 2% tolerance. The clock frequency is con-
±
trolled to within a 11% tolerance.
n Battery chargers
Typical Application
DS100847-3
SIMPLE SWITCHER® is a registered trademark of National Semiconductor Corporation.
© 2000 National Semiconductor Corporation
DS100847
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Connection Diagram and Ordering Information
TO-263 Package
Top View
DS100847-1
Order Number
LM2679S-3.3, LM2679S-5.0,
LM2679S-12 or LM2679S-ADJ
See NSC Package Number TS7B
TO-220 Package
Top View
DS100847-2
Order Number
LM2679T-3.3, LM2679T-5.0,
LM2679T-12 or LM2679T-ADJ
See NSC Package Number TA07B
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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.
Storage Temperature Range
Soldering Temperature
Wave
−65˚C to 150˚C
4 sec, 260˚C
10 sec, 240˚C
75 sec, 219˚C
Infrared
Vapor Phase
Input Supply Voltage
Softstart Pin Voltage
Switch Voltage to Ground
Boost Pin Voltage
45V
−0.1V to 6V
−1V to VIN
Operating Ratings
Supply Voltage
VSW + 8V
8V to 40V
Feedback Pin Voltage
Power Dissipation
ESD (Note 2)
−0.3V to 14V
Internally Limited
2 kV
Junction Temperature Range (TJ)
−40˚C to 125˚C
Electrical Characteristics Limits appearing in bold type face apply over the entire junction temperature
range of operation, −40˚C to 125˚C. Specifications appearing in normal type apply for TA = TJ = 25˚C. RADJ = 5.6KΩ
LM2679-3.3
Symbol
Parameter
Conditions
Typical
(Note 3)
3.3
Min
Max
Units
(Note 4)
(Note 4)
VOUT
Output Voltage
Efficiency
VIN = 8V to 40V, 100mA ≤ IOUT ≤ 5A
3.234/3.201
3.366/3.399
V
η
VIN = 12V, ILOAD = 5A
82
%
LM2679-5.0
Symbol
Parameter
Conditions
Typical
(Note 3)
5.0
Min
Max
Units
(Note 4)
(Note 4)
VOUT
Output Voltage
Efficiency
VIN = 8V to 40V, 100mA ≤ IOUT ≤ 5A
4.900/4.850
5.100/5.150
V
η
VIN = 12V, ILOAD = 5A
84
%
LM2679-12
Symbol
Parameter
Conditions
Typical
(Note 3)
12
Min
Max
Units
(Note 4)
(Note 4)
VOUT
Output Voltage
Efficiency
VIN = 15V to 40V, 100mA ≤ IOUT ≤ 5A
11.76/11.64
12.24/12.36
V
η
VIN = 24V, ILOAD = 5A
92
%
LM2679-ADJ
Symbol
Parameter
Conditions
Typ
Min
Max
Units
(Note 3)
(Note 4)
(Note 4)
VFB
Feedback
Voltage
VIN = 8V to 40V, 100mA ≤ IOUT ≤ 5A
VOUT Programmed for 5V
1.21
84
1.186/1.174
1.234/1.246
V
η
Efficiency
VIN = 12V, ILOAD = 5A
%
3
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All Output Voltage Versions
Electrical Characteristics
Limits appearing in bold type face apply over the entire junction temperature range of operation, −40˚C to 125˚C.
Specifications appearing in normal type apply for TA = TJ = 25˚C. Unless otherwise specified VIN=12V for the 3.3V, 5V and
Adjustable versions and VIN=24V for the 12V version.
Symbol
Parameter
Conditions
Typ
Min
Max
Units
DEVICE PARAMETERS
IQ
Quiescent
Current
VFEEDBACK = 8V
4.2
6
mA
For 3.3V, 5.0V, and ADJ Versions
VFEEDBACK = 15V
For 12V Versions
VADJ
Current Limit
Adjust Voltage
1.21
6.3
1.181/1.169
5.5/5.3
1.229/1.246
7.6/8.1
V
A
ICL
IL
Current Limit
RADJ = 5.6KΩ, (Note 5)
Output
Leakage
Current
VIN = 40V, Softstart Pin = 0V
VSWITCH = 0V
VSWITCH = −1V
mA
mA
1.0
6
1.5
15
RDS(ON) Switch
On-Resistance
ISWITCH = 5A
0.12
0.14/0.225
Ω
fO
Oscillator
Measured at Switch Pin
260
225
280
kHz
Frequency
D
Duty Cycle
Maximum Duty Cycle
Minimum Duty Cycle
91
0
%
%
IBIAS
Feedback Bias
Current
VFEEDBACK = 1.3V
ADJ Version Only
85
nA
VSFST
Softstart
Threshold
Voltage
0.63
0.53
0.74
6.9
V
ISFST
Softstart Pin
Current
Softstart Pin = 0V
3.7
65
µA
θJA
Thermal
Resistance
T Package, Junction to Ambient
(Note 6)
θJA
T Package, Junction to Ambient
(Note 7)
45
θJC
θJA
T Package, Junction to Case
S Package, Junction to Ambient
(Note 8)
2
56
˚C/W
θJA
θJA
θJC
S Package, Junction to Ambient
(Note 9)
35
26
2
S Package, Junction to Ambient
(Note 10)
S Package, Junction to Case
++
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings indicate conditions under which of the device is
guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test condition, see the electrical Char-
acteristics tables.
Note 2: ESD was applied using the human-body model, a 100pF capacitor discharged through a 1.5 kΩ resistor into each pin.
Note 3: Typical values are determined with T = T = 25˚C and represent the most likely norm.
A
J
Note 4: All limits are guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are 100%
tested during production with T = T = 25˚C. All limits at temperature extremes are guaranteed via correlation using standard standard Quality Control (SQC) meth-
A
J
ods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Note 5: The peak switch current limit is determined by the following relationship: I =37,125/ R
.
ADJ
CL
1
Note 6: Junction to ambient thermal resistance (no external heat sink) for the 7 lead TO-220 package mounted vertically, with
⁄
2
inch leads in a socket, or on a PC
1
⁄2 inch leads soldered to a PC board
board with minimum copper area.
Note 7: Junction to ambient thermal resistance (no external heat sink) for the 7 lead TO-220 package mounted vertically, with
containing approximately 4 square inches of (1 oz.) copper area surrounding the leads.
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4
(Continued)
Note 8: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board area of 0.136 square inches (the same size as the
TO-263 package) of 1 oz. (0.0014 in. thick) copper.
Note 9: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board area of 0.4896 square inches (3.6 times the area of
the TO-263 package) of 1 oz. (0.0014 in. thick) copper.
Note 10: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board copper area of 1.0064 square inches (7.4 times the
area of the TO-263 package) of 1 oz. (0.0014 in. thick) copper. Additional copper area will reduce thermal resistance further. See the thermal model in Switchers Made
Simple® software.
5
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Typical Performance Characteristics
Normalized
Output Voltage
Line Regulation
Efficiency vs Input Voltage
DS100847-5
DS100847-6
DS100847-4
DS100847-7
DS100847-12
Efficiency vs ILOAD
Switch Current Limit
Operating Quiescent Current
DS100847-8
DS100847-9
Switching Frequency
Feedback Pin Bias Current
DS100847-13
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6
Block Diagram
DS100847-14
* Active Inductor Patent Number 5,514,947
†
Active Capacitor Patent Number 5,382,918
7
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Typical Performance Characteristics
Continuous Mode Switching Waveforms
VIN = 20V, VOUT = 5V, ILOAD = 5A
Discontinuous Mode Switching Waveforms
VIN = 20V, VOUT = 5V, ILOAD = 500 mA
L = 10 µH, COUT = 400 µF, COUTESR = 13 mΩ
L = 10 µH, COUT = 400 µF, COUTESR = 13 mΩ
DS100847-15
DS100847-16
A: V
Pin Voltage, 10 V/div.
A: V
Pin Voltage, 10 V/div.
SW
SW
B: Inductor Current, 2 A/div
B: Inductor Current, 1 A/div
C: Output Ripple Voltage, 20 mV/div AC-Coupled
C: Output Ripple Voltage, 20 mV/div AC-Coupled
Horizontal Time Base: 1 µs/div
Horizontal Time Base: 1 µs//iv
Load Transient Response for Continuous Mode
VIN = 20V, VOUT = 5V
L = 10 µH, COUT = 400 µF, COUTESR = 13 mΩ
Load Transient Response for Discontinuous Mode
VIN = 20V, VOUT = 5V,
L = 10 µH, COUT = 400 µF, COUTESR = 13 mΩ
DS100847-17
DS100847-18
A: Output Voltage, 100 mV//div, AC-Coupled.
B: Load Current: 500 mA to 5A Load Pulse
A: Output Voltage, 100 mV/div, AC-Coupled.
B: Load Current: 200 mA to 3A Load Pulse
Horizontal Time Base: 100 µs/div
Horizontal Time Base: 200 µs/div
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8
duction losses in the power switch to maintain high effi-
ciency. The recommended value for C Boost is 0.01µF.
Application Hints
The LM2679 provides all of the active functions required for
a step-down (buck) switching regulator. The internal power
switch is a DMOS power MOSFET to provide power supply
designs with high current capability, up to 5A, and highly ef-
ficient operation.
PIN 4 - Ground
This is the ground reference connection for all components
in the power supply. In fast-switching, high-current applica-
tions such as those implemented with the LM2679, it is rec-
ommended that a broad ground plane be used to minimize
signal coupling throughout the circuit
The LM2679 is part of the SIMPLE SWITCHER family of
power converters. A complete design uses a minimum num-
ber of external components, which have been
pre-determined from a variety of manufacturers. Using either
this data sheet or a design software program called LM267X
Made Simple (version 2.0) a complete switching power sup-
ply can be designed quickly. The software is provided free of
charge and can be downloaded from National Semiconduc-
tor’s Internet site located at http://www.national.com.
PIN 5 - Current Adjust
A key feature of the LM2679 is the ability to tailor the peak
switch current limit to a level required by a particular applica-
tion. This alleviates the need to use external components
that must be physically sized to accommodate current levels
(under shorted output conditions for example) that may be
much higher than the normal circuit operating current re-
quirements.
PIN 1 - Switch Output
A resistor connected from pin 5 to ground establishes a cur-
rent (I(pin 5) = 1.2V / RADJ) that sets the peak current through
the power switch. The maximum switch current is fixed at a
This is the output of a power MOSFET switch connected di-
rectly to the input voltage. The switch provides energy to an
inductor, an output capacitor and the load circuitry under
control of an internal pulse-width-modulator (PWM). The
PWM controller is internally clocked by a fixed 260KHz oscil-
lator. In a standard step-down application the duty cycle
(Time ON/Time OFF) of the power switch is proportional to
the ratio of the power supply output voltage to the input volt-
age. The voltage on pin 1 switches between Vin (switch ON)
and below ground by the voltage drop of the external Schot-
tky diode (switch OFF).
level of 37,125 / RADJ
.
PIN 6 - Feedback
This is the input to a two-stage high gain amplifier, which
drives the PWM controller. It is necessary to connect pin 6 to
the actual output of the power supply to set the dc output
voltage. For the fixed output devices (3.3V, 5V and 12V out-
puts), a direct wire connection to the output is all that is re-
quired as internal gain setting resistors are provided inside
the LM2679. For the adjustable output version two external
resistors are required to set the dc output voltage. For stable
operation of the power supply it is important to prevent cou-
pling of any inductor flux to the feedback input.
PIN 2 - Input
The input voltage for the power supply is connected to pin 2.
In addition to providing energy to the load the input voltage
also provides bias for the internal circuitry of the LM2679.
For guaranteed performance the input voltage must be in the
range of 8V to 40V. For best performance of the power sup-
ply the input pin should always be bypassed with an input ca-
pacitor located close to pin 2.
PIN 7 - Softstart
A capacitor connected from pin 7 to ground allows for a slow
turn-on of the switching regulator. The capacitor sets a time
delay to gradually increase the duty cycle of the internal
power switch. This can significantly reduce the amount of
surge current required from the input supply during an abrupt
application of the input voltage. If softstart is not required this
pin should be left open circuited.
PIN 3 - C Boost
A capacitor must be connected from pin 3 to the switch out-
put, pin 1. This capacitor boosts the gate drive to the internal
MOSFET above Vin to fully turn it ON. This minimizes con-
DESIGN CONSIDERATIONS
DS100847-23
FIGURE 1. Basic circuit for fixed output voltage applications.
9
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Application Hints (Continued)
DS100847-24
FIGURE 2. Basic circuit for adjustable output voltage applications
Power supply design using the LM2679 is greatly simplified
by using recommended external components. A wide range
of inductors, capacitors and Schottky diodes from several
manufacturers have been evaluated for use in designs that
cover the full range of capabilities (input voltage, output volt-
age and load current) of the LM2679. A simple design proce-
dure using nomographs and component tables provided in
this data sheet leads to a working design with very little ef-
fort. Alternatively, the design software, LM267X Made
Simple (version 2.0), can also be used to provide instant
component selection, circuit performance calculations for
evaluation, a bill of materials component list and a circuit
schematic.
mount and through-hole devices are available. The inductors
from each of the three manufacturers have unique charac-
teristics.
Renco: ferrite stick core inductors; benefits are typically low-
est cost and can withstand ripple and transient peak currents
above the rated value. These inductors have an external
magnetic field, which may generate EMI.
Pulse Engineering: powdered iron toroid core inductors;
these also can withstand higher than rated currents and, be-
ing toroid inductors, will have low EMI.
Coilcraft: ferrite drum core inductors; these are the smallest
physical size inductors and are available only as surface
mount components. These inductors also generate EMI but
less than stick inductors.
The individual components from the various manufacturers
called out for use are still just a small sample of the vast ar-
ray of components available in the industry. While these
components are recommended, they are not exclusively the
only components for use in a design. After a close compari-
son of component specifications, equivalent devices from
other manufacturers could be substituted for use in an appli-
cation.
OUTPUT CAPACITOR
The output capacitor acts to smooth the dc output voltage
and also provides energy storage. Selection of an output ca-
pacitor, with an associated equivalent series resistance
(ESR), impacts both the amount of output ripple voltage and
stability of the control loop.
The output ripple voltage of the power supply is the product
of the capacitor ESR and the inductor ripple current. The ca-
pacitor types recommended in the tables were selected for
having low ESR ratings.
Important considerations for each external component and
an explanation of how the nomographs and selection tables
were developed follows.
INDUCTOR
In addition, both surface mount tantalum capacitors and
through-hole aluminum electrolytic capacitors are offered as
solutions.
The inductor is the key component in a switching regulator.
For efficiency the inductor stores energy during the switch
ON time and then transfers energy to the load while the
switch is OFF.
Impacting frequency stability of the overall control loop, the
output capacitance, in conjunction with the inductor, creates
a double pole inside the feedback loop. In addition the ca-
pacitance and the ESR value create a zero. These fre-
quency response effects together with the internal frequency
compensation circuitry of the LM2679 modify the gain and
phase shift of the closed loop system.
Nomographs are used to select the inductance value re-
quired for a given set of operating conditions. The nomo-
graphs assume that the circuit is operating in continuous
mode (the current flowing through the inductor never falls to
zero). The magnitude of inductance is selected to maintain a
maximum ripple current of 30% of the maximum load cur-
rent. If the ripple current exceeds this 30% limit the next
larger value is selected.
As a general rule for stable switching regulator circuits it is
desired to have the unity gain bandwidth of the circuit to be
limited to no more than one-sixth of the controller switching
frequency. With the fixed 260KHz switching frequency of the
LM2679, the output capacitor is selected to provide a unity
gain bandwidth of 40KHz maximum. Each recommended ca-
pacitor value has been chosen to achieve this result.
The inductors offered have been specifically manufactured
to provide proper operation under all operating conditions of
input and output voltage and load current. Several part types
are offered for a given amount of inductance. Both surface
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10
During the switch ON time the diode will be reversed biased
by the input voltage. The reverse voltage rating of the diode
should be at least 1.3 times greater than the maximum input
voltage.
Application Hints (Continued)
In some cases multiple capacitors are required either to re-
duce the ESR of the output capacitor, to minimize output
ripple (a ripple voltage of 1% of Vout or less is the assumed
performance condition), or to increase the output capaci-
tance to reduce the closed loop unity gain bandwidth (to less
than 40KHz). When parallel combinations of capacitors are
required it has been assumed that each capacitor is the ex-
act same part type.
BOOST CAPACITOR
The boost capacitor creates a voltage used to overdrive the
gate of the internal power MOSFET. This improves efficiency
by minimizing the on resistance of the switch and associated
power loss. For all applications it is recommended to use a
0.01µF/50V ceramic capacitor.
The RMS current and working voltage (WV) ratings of the
output capacitor are also important considerations. In a typi-
cal step-down switching regulator, the inductor ripple current
(set to be no more than 30% of the maximum load current by
the inductor selection) is the current that flows through the
output capacitor. The capacitor RMS current rating must be
greater than this ripple current. The voltage rating of the out-
put capacitor should be greater than 1.3 times the maximum
output voltage of the power supply. If operation of the system
at elevated temperatures is required, the capacitor voltage
rating may be de-rated to less than the nominal room tem-
perature rating. Careful inspection of the manufacturer’s
specification for de-rating of working voltage with tempera-
ture is important.
R
ADJ, ADJUSTABLE CURRENT LIMIT
A key feature of the LM2679 is the ability to control the peak
switch current. Without this feature the peak switch current
would be internally set to 7A or higher to accommodate 5A
load current designs. This requires that both the inductor
(which could saturate with excessively high currents) and the
catch diode be able to safely handle up to 7A which would be
conducted under load fault conditions.
If an application only requires a load current of 3A or 4A the
peak switch current can be set to a limit just over the maxi-
mum load current with the addition of a single programming
resistor. This allows the use of less powerful and more cost
effective inductors and diodes.
The peak switch current is equal to a factor of 37,125 divided
by RADJ. A resistance of 5.6KΩ sets the current limit to typi-
cally 6.3A and an RADJ of 8.25KΩ reduces the maximum cur-
rent to approximately 4.4A. For predictable control of the cur-
rent limit it is recommended to keep the peak switch current
greater than 3A. For lower current applications a 3A switch-
ing regulator with adjustable current limit, the LM2673, is
available.
INPUT CAPACITOR
Fast changing currents in high current switching regulators
place a significant dynamic load on the unregulated power
source. An input capacitor helps to provide additional current
to the power supply as well as smooth out input voltage
variations.
Like the output capacitor, the key specifications for the input
capacitor are RMS current rating and working voltage. The
RMS current flowing through the input capacitor is equal to
one-half of the maximum dc load current so the capacitor
should be rated to handle this. Paralleling multiple capacitors
proportionally increases the current rating of the total capaci-
tance. The voltage rating should also be selected to be 1.3
times the maximum input voltage. Depending on the unregu-
lated input power source, under light load conditions the
maximum input voltage could be significantly higher than
normal operation and should be considered when selecting
an input capacitor.
When the power switch reaches the current limit threshold it
is immediately turned OFF and the internal switching fre-
quency is reduced. This extends the OFF time of the switch
to prevent a steady state high current condition. As the
switch current falls below the current limit threshold, the
switch will turn back ON. If a load fault continues, the switch
will again exceed the threshold and switch back OFF. This
will result in a low duty cycle pulsing of the power switch to
minimize the overall fault condition power dissipation.
Css SOFTSTART CAPACITOR
This optional capacitor controls the rate at which the LM2679
starts up at power on. The capacitor is charged linearly by an
internal current source. This voltage ramp gradually in-
creases the duty cycle of the power switch until it reaches
the normal operating duty cycle defined primarily by the ratio
of the output voltage to the input voltage. The softstart
turn-on time is programmable by the selection of Css.
The input capacitor should be placed very close to the input
pin of the LM2679. Due to relative high current operation
with fast transient changes, the series inductance of input
connecting wires or PCB traces can create ringing signals at
the input terminal which could possibly propagate to the out-
put or other parts of the circuitry. It may be necessary in
some designs to add a small valued (0.1µF to 0.47µF) ce-
ramic type capacitor in parallel with the input capacitor to
prevent or minimize any ringing.
The formula for selecting a softstart capacitor is:
CATCH DIODE
When the power switch in the LM2679 turns OFF, the current
through the inductor continues to flow. The path for this cur-
rent is through the diode connected between the switch out-
put and ground. This forward biased diode clamps the switch
output to a voltage less than ground. This negative voltage
must be greater than −1V so a low voltage drop (particularly
at high current levels) Schottky diode is recommended. Total
efficiency of the entire power supply is significantly impacted
by the power lost in the output catch diode. The average cur-
rent through the catch diode is dependent on the switch duty
cycle (D) and is equal to the load current times (1-D). Use of
a diode rated for much higher current than is required by the
actual application helps to minimize the voltage drop and
power loss in the diode.
Where:
ISST = Softstart Current, 3.7µA typical
tSS = Softstart time, from design requirements
VSST = Softstart Threshold Voltage, 0.63V typical
VOUT = Output Voltage, from design requirements
VSCHOTTKY = Schottky Diode Voltage Drop, typically 0.5V
VIN = Maximum Input Voltage, from design requirements
If this feature is not desired, leave the Softstart pin (pin 7)
open circuited
SIMPLE DESIGN PROCEDURE
11
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Step 4: Use Table 3 to determine an output capacitor. With a
3.3V output and a 15µH inductor there are four through-hole
output capacitor solutions with the number of same type ca-
pacitors to be paralleled and an identifying capacitor code
given. Table 2 provides the actual capacitor characteristics.
Any of the following choices will work in the circuit:
Application Hints (Continued)
Using the nomographs and tables in this data sheet (or use
the available design software at http://www.national.com) a
complete step-down regulator can be designed in a few
simple steps.
Step 1: Define the power supply operating conditions:
Required output voltage
2 x 220µF/10V Sanyo OS-CON (code C5)
2 x 820µF/16V Sanyo MV-GX (code C5)
1 x 3900µF/10V Nichicon PL (code C7)
2 x 560µF/35V Panasonic HFQ (code C5)
Maximum DC input voltage
Maximum output load current
Step 2: Set the output voltage by selecting a fixed output
LM2679 (3.3V, 5V or 12V applications) or determine the re-
quired feedback resistors for use with the adjustable
LM2679−ADJ
Step 5: Use Table 4 to select an input capacitor. With 3.3V
output and 15µH there are three through-hole solutions.
These capacitors provide a sufficient voltage rating and an
rms current rating greater than 2A (1/2 Iload max). Again us-
ing Table 2 for specific component characteristics the follow-
ing choices are suitable:
Step 3: Determine the inductor required by using one of the
four nomographs, Figure 3 through Figure 6. Table 1 pro-
vides a specific manufacturer and part number for the induc-
tor.
2 x 680µF/63V Sanyo MV-GX (code C13)
1 x 1200µF/63V Nichicon PL (code C25)
1 x 1500µF/63V Panasonic HFQ (code C16)
Step 4: Using Table 3 (fixed output voltage) or Table 6 (ad-
justable output voltage), determine the output capacitance
required for stable operation. Table 2 provides the specific
capacitor type from the manufacturer of choice.
Step 6: From Table 5 a 5A or more Schottky diode must be
selected. For through-hole components only 40V rated di-
odes are indicated and 4 part types are suitable:
Step 5: Determine an input capacitor from Table 4 for fixed
output voltage applications. Use Table 2 to find the specific
capacitor type. For adjustable output circuits select a capaci-
tor from Table 2 with a sufficient working voltage (WV) rating
greater than Vin max, and an rms current rating greater than
one-half the maximum load current (2 or more capacitors in
parallel may be required).
1N5825
MBR745
80SQ045
6TQ045
Step 7: A 0.01µF capacitor will be used for Cboost. For the
50mS softstart delay the following parameters are to be
used:
Step 6: Select a diode from Table 5. The current rating of the
diode must be greater than I load max and the Reverse Volt-
age rating must be greater than Vin max.
I
SST: 3.7µA
SS: 50mS
t
Step 7: Include a 0.01µF/50V capacitor for Cboost in the de-
sign and then determine the value of a softstart capacitor if
desired.
V
V
V
V
SST: 0.63V
OUT: 3.3V
SCHOTTKY: 0.5V
IN: 16V
Step 8: Define a value for RADJ to set the peak switch cur-
rent limit to be at least 20% greater than Iout max to allow for
±
at least 30% inductor ripple current ( 15% of Iout). For de-
Using Vin max ensures that the softstart delay time will be at
least the desired 50mS.
signs that must operate over the full temperature range the
switch current limit should be set to at least 50% greater than
Iout max (1.5 x Iout max).
Using the formula for Css a value of 0.148µF is determined
to be required. Use of a standard value 0.22µF capacitor will
produce more than sufficient softstart delay.
FIXED OUTPUT VOLTAGE DESIGN EXAMPLE
A system logic power supply bus of 3.3V is to be generated
from a wall adapter which provides an unregulated DC volt-
age of 13V to 16V. The maximum load current is 4A. A soft-
start delay time of 50mS is desired. Through-hole compo-
nents are preferred.
Step 8: Determine a value for RADJ to provide a peak switch
current limit of at least 4A plus 50% or 6A.
Step 1: Operating conditions are:
Vout = 3.3V
Use a value of 6.2KΩ.
ADJUSTABLE OUTPUT DESIGN EXAMPLE
Vin max = 16V
In this example it is desired to convert the voltage from a two
battery automotive power supply (voltage range of 20V to
28V, typical in large truck applications) to the 14.8VDC alter-
nator supply typically used to power electronic equipment
from single battery 12V vehicle systems. The load current re-
quired is 3.5A maximum. It is also desired to implement the
power supply with all surface mount components. Softstart is
not required.
Iload max = 4A
Step 2: Select an LM2679T-3.3. The output voltage will have
a tolerance of
±
±
2% at room temperature and 3% over the full operating
temperature range.
Step 3: Use the nomograph for the 3.3V device ,Figure 3.
The intersection of the 16V horizontal line (Vin max) and the
4A vertical line (Iload max) indicates that L46, a 15µH induc-
tor, is required.
Step 1: Operating conditions are:
Vout = 14.8V
Vin max = 28V
From Table 1, L46 in a through-hole component is available
from Renco with part number RL-1283-15-43.
Iload max = 3.5A
www.national.com
12
Step 5: An input capacitor for this example will require at
least a 35V WV rating with an rms current rating of 1.75A
(1/2 Iout max). From Table 2 it can be seen that C12, a
33µF/35V capacitor from Sprague, has the highest
voltage/current rating of the surface mount components and
that two of these capacitor in parallel will be adquate.
Application Hints (Continued)
Step 2: Select an LM2679S-ADJ. To set the output voltage
to 14.9V two resistors need to be chosen (R1 and R2 in Fig-
ure 2). For the adjustable device the output voltage is set by
the following relationship:
Step 6: From Table 5 a 5A or more Schottky diode must be
selected. For surface mount diodes with a margin of safety
on the voltage rating one of two diodes can be used:
MBRD1545CT
Where VFB is the feedback voltage of typically 1.21V.
6TQ045S
A recommended value to use for R1 is 1K. In this example
then R2 is determined to be:
Step 7: A 0.01µF capacitor will be used for Cboost.
The softstart pin will be left open circuited.
Step 8: Determine a value for RADJ to provide a peak switch
current limit of at least 3.5A plus 50% or 5.25A.
R2 = 11.23KΩ
The closest standard 1% tolerance value to use is 11.3KΩ
This will set the nominal output voltage to 14.88V which is
within 0.5% of the target value.
Use a value of 7.15KΩ.
Step 3: To use the nomograph for the adjustable device, Fig-
ure 6, requires
a
calculation of the inductor
Volt•microsecond constant (E•T expressed in V•µS) from
the following formula:
where VSAT is the voltage drop across the internal power
switch which is Rds(ON) times Iload. In this example this would
be typically 0.12Ω x 3.5A or 0.42V and VD is the voltage drop
across the forward bisased Schottky diode, typically 0.5V.
The switching frequency of 260KHz is the nominal value to
use to estimate the ON time of the switch during which en-
ergy is stored in the inductor.
For this example E•T is found to be:
Using Figure 6, the intersection of 27V•µS horizontally and
the 3.5A vertical line (Iload max) indicates that L48 , a 47µH
inductor, or L49, a 33µH inductor could be used. Either in-
ductor will be suitable, but for this example selecting the
larger inductance will result in lower ripple current.
From Table 1, L48 in a surface mount component is available
from Pulse Engineering with part number P0848.
Step 4: Use Table 6 to determine an output capacitor. With a
14.8V output the 12.5 to 15V row is used and with a 47µH in-
ductor there are three surface mount output capacitor solu-
tions. Table 2 provides the actual capacitor characteristics
based on the C Code number. Any of the following choices
can be used:
1 x 33µF/20V AVX TPS (code C6)
1 x 47µF/20V Sprague 594 (code C8)
1 x 47µF/20V Kemet T495 (code C8)
Important Note: When using the adjustable device in low
voltage applications (less than 3V output), if the nomograph,
Figure 6, selects an inductance of 22µH or less, Table 6 does
not provide an output capacitor solution. With these condi-
tions the number of output capacitors required for stable op-
eration becomes impractical. It is recommended to use ei-
ther a 33µH or 47µH inductor and the output capacitors from
Table 6.
13
www.national.com
Application Hints (Continued)
INDUCTOR VALUE SELECTION GUIDES (For Continuous Mode Operation)
DS100847-19
DS100847-20
FIGURE 3. LM2679-3.3
FIGURE 4. LM2679-5.0
DS100847-22
DS100847-21
FIGURE 6. LM2679-ADJ
FIGURE 5. LM2679-12
www.national.com
14
Application Hints (Continued)
Table 1. Inductor Manufacturer Part Numbers
Renco
Pulse Engineering
Coilcraft
Inductor
Reference
Number
Inductance Current
Through Hole
Surface
Mount
Through
Hole
Surface
Mount
Surface Mount
(µH)
(A)
L23
L24
L25
L29
L30
L31
L32
L33
L34
L38
L39
L40
L41
L44
L45
L46
L47
L48
L49
33
22
15
100
68
47
33
22
15
68
47
33
22
68
10
15
10
47
33
1.35
1.65
2.00
1.41
1.71
2.06
2.46
3.02
3.65
2.97
3.57
4.26
5.22
3.45
4.47
5.60
5.66
5.61
5.61
RL-5471-7
RL-1283-22-43
RL-1283-15-43
RL-5471-4
RL1500-33
RL1500-22
RL1500-15
PE-53823 PE-53823S DO3316-333
PE-53824 PE-53824S DO3316-223
PE-53825 PE-53825S DO3316-153
RL-6050-100 PE-53829 PE-53829S DO5022P-104
RL-5471-5
RL6050-68
PE-53830 PE-53830S DO5022P-683
PE-53831 PE-53831S DO5022P-473
PE-53932 PE-53932S DO5022P-333
PE-53933 PE-53933S DO5022P-223
PE-53934 PE-53934S DO5022P-153
RL-5471-6
RL6050-47
RL-5471-7
RL6050-33
RL-1283-22-43
RL-1283-15-43
RL-5472-2
RL6050-22
—
—
—
—
—
—
—
—
—
—
—
PE-54038 PE-54038S
PE-54039 PE-54039S
PE-54040 PE-54040S
PE-54041 P0841
—
RL-5472-3
—
RL-1283-33-43
RL-1283-22-43
RL-5473-3
—
—
PE-54044
—
P0845
P0846
P0847
P0848
P0849
—
RL-1283-10-43
RL-1283-15-43
RL-1283-10-43
RL-1282-47-43
RL-1282-33-43
—
—
—
—
—
DO5022P-103HC
DO5022P-153HC
DO5022P-103HC
—
—
Inductor Manufacturer Contact Numbers
Coilcraft
Phone (800) 322-2645
FAX (708) 639-1469
Phone +44 1236 730 595
FAX +44 1236 730 627
Phone (619) 674-8100
FAX (619) 674-8262
Phone +353 93 24 107
FAX +353 93 24 459
Phone (800) 645-5828
FAX (516) 586-5562
Coilcraft, Europe
Pulse Engineering
Pulse Engineering,
Europe
Renco Electronics
15
www.national.com
Application Hints (Continued)
Table 2. Input and Output Capacitor Codes
Surface Mount
Capacitor
AVX TPS Series
Sprague 594D Series
Kemet T495 Series
Reference
Code
C
WV
(V)
6.3
10
10
16
16
20
20
25
35
35
Irms
C
(µF)
120
220
68
WV
(V)
6.3
6.3
10
10
16
16
16
20
25
25
35
35
50
Irms
(A)
C
WV
(V)
6.3
6.3
6.3
10
10
10
20
20
20
35
35
50
Irms
(A)
(µF)
330
100
220
47
(A)
(µF)
100
220
330
100
150
220
33
C1
C2
1.15
1.1
1.1
0.82
1.1
1.4
C3
1.15
0.89
1.15
0.77
0.94
0.77
0.63
0.66
1.05
1.35
1
1.1
C4
150
47
1.1
C5
100
33
1.1
C6
100
180
47
1.3
1.1
C7
68
1.95
1.15
1.05
1.6
0.78
0.94
0.94
0.63
0.63
0.66
C8
22
47
C9
10
33
68
C10
C11
C12
C13
22
68
10
15
0.75
1
22
33
4.7
15
0.9
www.national.com
16
Application Hints (Continued)
Table 2. Input and Output Capacitor Codes (continued)
Through Hole
Capacitor
Reference
Code
Sanyo OS-CON SA
Series
Sanyo MV-GX Series
Nichicon PL Series
Panasonic HFQ Series
C (µF)
WV
(V)
6.3
6.3
6.3
10
Irms
C
WV
(V)
6.3
16
16
16
16
16
35
35
35
35
63
63
63
63
Irms
(A)
C
WV
(V)
10
10
10
10
10
10
10
10
16
16
16
16
16
16
25
35
35
35
50
50
50
63
63
63
63
Irms
(A)
C
WV
(V)
35
35
35
35
35
35
35
35
50
50
50
50
50
50
63
63
Irms
(A)
(A)
1
(µF)
1000
270
470
560
820
1000
150
470
680
1000
220
470
680
1000
(µF)
680
(µF)
82
C1
C2
47
150
330
100
220
33
0.8
0.8
0.4
1.95
2.45
1.87
2.36
0.96
1.92
2.28
2.25
2.09
0.6
820
0.98
1.06
1.28
1.71
2.18
2.36
2.68
0.41
0.55
0.77
1.02
1.22
1.88
0.63
0.79
1.43
2.68
0.82
1.04
1.3
120
220
330
560
820
1000
2200
56
0.44
0.76
1.01
1.4
C3
0.75
0.95
1.25
1.3
1000
1200
2200
3300
3900
6800
180
C4
C5
10
C6
16
1.62
1.73
2.8
C7
100
150
100
47
16
0.65
1.3
C8
16
C9
20
1.4
0.36
0.5
C10
C11
C12
C13
C14
C15
C16
C17
C18
C19
C20
C21
C22
C23
C24
C25
25
1.7
270
100
220
470
560
1200
330
1500
0.76
1.2
470
0.92
1.44
1.68
2.22
1.42
2.51
680
1.5
820
1.75
1800
220
220
560
2200
150
220
330
100
0.75
1.62
2.22
2.51
390
820
1200
Capacitor Manufacturer Contact Numbers
Nichicon
Panasonic
AVX
Phone
(847) 843-7500
(847) 843-2798
(714) 373-7857
(714) 373-7102
(845) 448-9411
(845) 448-1943
(207) 324-4140
(207) 324-7223
(619) 661-6322
(619) 661-1055
(864) 963-6300
(864) 963-6521
FAX
Phone
FAX
Phone
FAX
Sprague/Vishay
Sanyo
Phone
FAX
Phone
FAX
Kemet
Phone
FAX
17
www.national.com
Application Hints (Continued)
Table 3. Output Capacitors for Fixed Output Voltage Application
Surface Mount
Output
Inductance
(µH)
AVX TPS Series
Sprague 594D
Series
Voltage
(V)
Kemet T495 Series
No.
5
C Code
C1
No.
5
C Code
No.
5
C Code
C2
10
15
22
33
10
15
22
33
47
10
15
22
33
47
68
100
C1
C1
C7
C7
C6
C7
C7
C3
C7
C6
C7
C6
C7
C6
C5
C5
4
C1
4
4
C3
3.3
3
C2
2
3
C4
1
C1
2
3
C4
4
C2
4
4
C4
3
C3
2
3
C5
5
3
C2
2
3
C4
2
C2
2
2
C4
2
C2
1
2
C4
4
C5
3
5
C9
3
C5
2
4
C9
2
C5
2
3
C8
12
2
C5
1
3
C8
2
C4
1
2
C8
1
C5
1
2
C7
1
C4
1
1
C8
Through Hole
Output
Voltage
(V)
Inductance Sanyo OS-CON SA
Sanyo MV-GX
Series
Panasonic HFQ
Series
Nichicon PL Series
(µH)
Series
C Code
No.
2
No.
2
C Code
No.
1
C Code
C8
No.
2
C Code
C6
10
15
22
33
10
15
22
33
47
10
15
22
33
47
68
100
C5
C5
C5
C5
C4
C5
C5
C4
C4
C7
C8
C7
C7
C7
C6
C6
C6
C5
2
2
1
C7
2
C5
3.3
1
1
C10
C10
C5
1
C5
1
C7
1
1
1
C5
1
C7
2
2
1
C6
2
C5
1
1
C10
C9
1
C5
1
C7
5
1
1
1
C5
1
C5
1
1
C5
1
C4
1
C4
1
1
C4
1
C2
2
C4
2
1
C10
C6
1
C14
C17
C13
C12
C11
C10
C9
2
C4
1
1
1
1
C5
1
1
C5
1
1
C5
12
1
1
C4
1
1
C4
1
1
C3
1
1
C3
1
1
C2
1
1
C3
1
1
C2
1
1
C1
No. represents the number of identical capacitor types to be connected in parallel
C Code indicates the Capacitor Reference number in Table 2 for identifying the specific component from the manufacturer.
www.national.com
18
Application Hints (Continued)
Table 4. Input Capacitors for Fixed Output Voltage Application
(Assumes worst case maximum input voltage and load current for a given inductance value)
Surface Mount
Output
Voltage
(V)
Inductance
(µH)
AVX TPS Series
Sprague 594D
Series
Kemet T495 Series
No.
3
*
C Code
No.
2
C Code
No.
3
C Code
C9
10
15
22
33
10
15
22
33
47
10
15
22
33
47
68
100
C7
*
C10
C13
C13
C13
C6
3
4
C12
C12
C12
C9
3.3
*
*
2
3
*
*
2
3
3
4
*
C4
C9
*
2
3
3
C12
C13
C13
C13
C10
C10
C12
C13
C13
C13
C13
4
C10
C12
C12
C12
C10
C10
C10
C12
C12
C12
C12
5
3
4
*
*
2
3
*
*
1
2
4
4
4
*
C9
C8
C9
*
2
4
2
4
3
4
12
3
4
*
*
2
3
*
*
2
2
*
*
1
2
Through Hole
Output
Voltage
(V)
Inductance Sanyo OS-CON SA
Sanyo MV-GX
Series
Panasonic HFQ
Series
Nichicon PL Series
(µH)
Series
C Code
No.
2
*
No.
2
C Code
No.
1
C Code
C18
C25
C24
C24
C25
C25
C25
C23
C19
C18
C18
C18
C24
C23
C21
C22
No.
1
C Code
C8
10
15
22
33
10
15
22
33
47
10
15
22
33
47
68
100
C9
C8
C13
C14
C14
C8
*
2
1
1
C16
C16
C16
C8
3.3
*
*
*
1
1
1
*
1
1
1
2
*
C7
*
2
1
1
2
C8
1
1
C8
*
*
5
2
C13
C14
C12
C8
1
1
C16
C13
C11
C8
*
*
1
1
1
*
*
1
1
1
2
2
*
C10
C10
*
2
1
1
2
C8
1
1
C8
2
C8
1
1
C8
*
*
12
2
C12
C14
C13
C11
1
1
C14
C13
C15
C11
*
*
1
1
1
*
*
1
1
1
*
*
1
1
1
*
Check voltage rating of capacitors to be greater than application input voltage.
No. represents the number of identical capacitor types to be connected in parallel
C Code indicates the Capacitor Reference number in Table 2 for identifying the specific component from the manufacturer.
19
www.national.com
Application Hints (Continued)
Table 5. Schottky Diode Selection Table
Reverse
Voltage
(V)
Surface Mount
Through Hole
3A
5A or More
3A
5A or
More
20V
30V
40V
SK32
1N5820
SR302
SK33
MBRD835L
1N5821
31DQ03
1N5822
MBR340
31DQ04
SR403
30WQ03F
SK34
MBRD1545CT
6TQ045S
1N5825
MBR745
80SQ045
6TQ045
30BQ040
30WQ04F
MBRS340
MBRD340
SK35
50V or
More
MBR350
31DQ05
SR305
30WQ05F
Diode Manufacturer Contact Numbers
International Rectifier
Phone
(310) 322-3331
(310) 322-3332
(800) 521-6274
(602) 244-6609
(516) 847-3000
FAX
Motorola
Phone
FAX
General
Phone
Semiconductor
FAX
(516) 847-3236
(805) 446-4800
(805) 446-4850
Diodes, Inc.
Phone
FAX
www.national.com
20
Application Hints (Continued)
Table 6. Output Capacitors for Adjustable Output Voltage Applications
Surface Mount
Output Voltage Inductance
AVX TPS Series
Sprague 594D
Series
Kemet T495 Series
(V)
(µH)
No.
7
5
4
3
4
3
2
3
2
2
1
3
2
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
C Code
C1
C1
C1
C1
C1
C1
C1
C2
C2
C2
C2
C2
C2
C3
C2
C5
C5
C5
C4
C5
C5
C5
C5
C6
C6
C6
C6
C8
C8
C8
C8
C9
C10
C9
C9
No.
6
4
3
2
3
2
2
3
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
4
3
2
1
1
1
C Code
No.
7
5
4
3
4
3
2
3
2
2
1
3
2
1
1
2
2
1
1
2
2
1
1
1
1
1
1
2
2
2
1
2
1
1
1
8
5
4
3
2
2
C Code
C3
*
*
*
*
33
47
33
47
C2
C2
1.21 to 2.50
2.5 to 3.75
C3
C2
C3
C2
C3
22
33
47
22
33
47
68
22
33
47
68
33
47
68
100
33
47
68
100
33
47
68
100
33
47
68
100
33
47
68
100
10
15
22
33
47
68
C2
C3
3.75 to 5
5 to 6.25
C2
C3
C2
C3
C3
C4
C3
C4
C3
C4
C3
C4
C4
C4
C3
C4
6.25 to 7.5
7.5 to 10
10 to 12.5
12.5 to 15
15 to 20
C4
C6
C3
C4
C6
C8
C6
C8
C6
C8
C5
C8
C6
C8
C6
C8
C6
C8
C6
C8
C8
C8
C8
C8
C8
C8
C8
C8
C10
C9
C10
C10
C10
C10
C11
C11
C11
C11
C12
C12
C12
C12
C12
C12
C9
C9
C11
C12
C12
C12
C13
C13
C13
C13
C13
C13
20 to 30
No Values Available
30 to 37
21
www.national.com
Application Hints (Continued)
Table 6. Output Capacitors for Adjustable Output Voltage Applications
(continued)
Through Hole
Output Voltage Inductance Sanyo OS-CON SA
Sanyo MV-GX
Series
Panasonic HFQ
Series
Nichicon PL Series
(V)
(µH)
Series
C Code
No.
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
No.
5
4
3
2
3
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
C Code
No.
5
3
3
2
3
2
1
2
2
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
C Code
C3
No.
3
2
2
1
2
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
C Code
C
*
*
*
*
33
47
33
47
C3
C2
C3
C2
C3
C2
C2
C5
C4
C4
C4
C5
C4
C4
C4
C7
C7
C7
C7
C7
C7
C7
C7
C9
C9
C9
C9
C10
C10
C10
C10
C1
C1
1.21 to 2.50
2.5 to 3.75
C3
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C5
C2
C2
C5
C5
C2
C2
C2
C2
C2
C2
C2
C2
C2
C2
C2
C2
C2
C2
C10
C11
C10
C10
C10
C10
C1
C1
C1
C3
22
33
47
22
33
47
68
22
33
47
68
33
47
68
100
33
47
68
100
33
47
68
100
33
47
68
100
33
47
68
100
10
15
22
33
47
68
C1
C1
3.75 to 5
5 to 6.25
C1
C1
C1
C3
C6
C3
C6
C1
C6
C3
C6
C1
C6
C1
C6
C3
6.25 to 7.5
7.5 to 10
10 to 12.5
12.5 to 15
15 to 20
C6
C1
C2
C1
C6
C14
C14
C14
C14
C14
C14
C9
C6
C2
C2
C6
C2
C2
C2
C9
C10
C10
C10
C10
C7
C15
C15
C15
C15
C15
C15
C15
C15
C16
C16
C16
C16
C20
C20
C20
C20
C20
C20
C7
C7
C7
C7
No Values
C7
20 to 30
Available
C7
C7
C12
C11
C11
C11
C11
C11
No Values
Available
30 to 37
* Set to a higher value for a practical design solution. See Applications Hints section
No. represents the number of identical capacitor types to be connected in parallel
C Code indicates the Capacitor Reference number in Table 2 for identifying the specific component from the manufacturer.
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22
Physical Dimensions inches (millimeters) unless otherwise noted
TO-263 Surface Mount Power Package
Order Number LM2679S-3.3, LM2679S-5.0,
LM2679S-12 or LM2679S-ADJ
NS Package Number TS7B
23
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
TO-220 Power Package
Order Number LM2679T-3.3, LM2679T-5.0,
LM2679T-12 or LM2679T-ADJ
NS Package Number TA07B
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