|
|
PDF LM2599T-12 Data sheet ( Hoja de datos )
| Número de pieza | LM2599T-12 | |
| Descripción | SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator/ with Features | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LM2599T-12 (archivo pdf) en la parte inferior de esta página. Total 31 Páginas | ||
|
No Preview Available !
April 1998
LM2599
SIMPLE SWITCHER® Power Converter 150 kHz 3A
Step-Down Voltage Regulator, with Features
General Description
The LM2599 series of regulators are monolithic integrated
circuits that provide all the active functions for a step-down
(buck) switching regulator, capable of driving a 3A load with
excellent line and load regulation. These devices are avail-
able in fixed output voltages of 3.3V, 5V, 12V, and an adjust-
able output version.
This series of switching regulators is similar to the LM2596
series, with additional supervisory and performance features
added.
Requiring a minimum number of external components, these
regulators are simple to use and include internal frequency
compensation†, improved line and load specifications,
fixed-frequency oscillator, Shutdown/Soft-start, error flag de-
lay and error flag output.
The LM2599 series operates at a switching frequency of 150
kHz thus allowing smaller sized filter components than what
would be needed with lower frequency switching regulators.
Available in a standard 7-lead TO-220 package with several
different lead bend options, and a 7-lead TO-263 Surface
mount package.
A standard series of inductors (both through hole and sur-
face mount types) are available from several different manu-
facturers optimized for use with the LM2599 series. This fea-
ture greatly simplifies the design of switch-mode power
supplies.
Other features include a guaranteed ±4% tolerance on out-
put voltage under all conditions of input voltage and output
load conditions, and ±15% on the oscillator frequency. Ex-
ternal shutdown is included, featuring typically 80 µA
standby current. Self protection features include a two stage
current limit for the output switch and an over temperature
shutdown for complete protection under fault conditions.
Features
n 3.3V, 5V, 12V, and adjustable output versions
n Adjustable version output voltage range, 1.2V to 37V
±4% max over line and load conditions
n Guaranteed 3A output current
n Available in 7-pin TO-220 and TO-263 (surface mount)
Package
n Input voltage range up to 40V
n 150 kHz fixed frequency internal oscillator
n Shutdown/Soft-start
n Out of regulation error flag
n Error output delay
n Low power standby mode, IQ typically 80 µA
n High Efficiency
n Uses readily available standard inductors
n Thermal shutdown and current limit protection
Applications
n Simple high-efficiency step-down (buck) regulator
n Efficient pre-regulator for linear regulators
n On-card switching regulators
n Positive to Negative converter
Note: † Patent Number 5,382,918.
Typical Application (Fixed Output Voltage Versions)
SIMPLE SWITCHER® and Switchers Made Simple® are registered trademarks of National Semiconductor Corporation.
© 2000 National Semiconductor Corporation DS012582
DS012582-1
www.national.com
1 page  
All Output Voltage Versions
Electrical Characteristics (Continued)
Note 10: Feedback pin removed from output and connected to 12V for the 3.3V, 5V, and the ADJ. version, and 15V for the 12V version, to force the output transistor
switch OFF.
Note 11: VIN = 40V.
Note 12: Junction to ambient thermal resistance (no external heat sink) for the package mounted TO-220 package mounted vertically, with the leads soldered to a
printed circuit board with (1 oz.) copper area of approximately 1 in2.
Note 13: Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 0.5 in2 of (1 oz.) copper area.
Note 14: Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 2.5 in2 of (1 oz.) copper area.
Note 15: Junction to ambient thermal resistance with the TO-263 package tab soldered to a double sided printed circuit board with 3 in2 of (1 oz.) copper area on
the LM2599S side of the board, and approximately 16 in2 of copper on the other side of the p-c board. See application hints in this data sheet and the thermal model
in Switchers Made Simple version 4.2.1 (or later) software.
Typical Performance Characteristics (Circuit of Figure 1)
Normalized
Output Voltage
Line Regulation
Efficiency
Switch Saturation
Voltage
DS012582-2
DS012582-3
Switch Current Limit
Dropout Voltage
DS012582-4
Operating
Quiescent Current
DS012582-5
Shutdown
Quiescent Current
DS012582-6
DS012582-7
Minimum Operating
Supply Voltage
DS012582-8
DS012582-9
5
DS012582-10
www.national.com
5 Page 
LM2599 Series Buck Regulator Design Procedure (Fixed Output) (Continued)
PROCEDURE (Fixed Output Voltage Version)
3. Catch Diode Selection (D1)
A. The catch diode current rating must be at least 1.3 times
greater than the maximum load current. Also, if the power
supply design must withstand a continuous output short, the
diode should have a current rating equal to the maximum
current limit of the LM2599. The most stressful condition for
this diode is an overload or shorted output condition.
B. The reverse voltage rating of the diode should be at least
1.25 times the maximum input voltage.
C. This diode must be fast (short reverse recovery time) and
must be located close to the LM2599 using short leads and
short printed circuit traces. Because of their fast switching
speed and low forward voltage drop, Schottky diodes provide
the best performance and efficiency, and should be the first
choice, especially in low output voltage applications.
Ultra-fast recovery, or High-Efficiency rectifiers also provide
good results. Ultra-fast recovery diodes typically have re-
verse recovery times of 50 ns or less. Rectifiers such as the
IN5400 series are much too slow and should not be used.
4. Input Capacitor (CIN)
A low ESR aluminum or tantalum bypass capacitor is needed
between the input pin and ground to prevent large voltage
transients from appearing at the input. In addition, the RMS
current rating of the input capacitor should be selected to be
at least 1⁄2 the DC load current. The capacitor manufacturers
data sheet must be checked to assure that this current rating
is not exceeded. The curve shown in Figure 15 shows typical
RMS current ratings for several different aluminum electro-
lytic capacitor values.
This capacitor should be located close to the IC using short
leads and the voltage rating should be approximately 1.5
times the maximum input voltage.
If solid tantalum input capacitors are used, it is recomended
that they be surge current tested by the manufacturer.
Use caution when using ceramic capacitors for input bypass-
ing, because it may cause severe ringing at the VIN pin.
For additional information, see section on input capaci-
tors in Application Information section.
EXAMPLE (Fixed Output Voltage Version)
3. Catch Diode Selection (D1)
A. Refer to the table shown in Figure 11. In this example, a
5A, 20V, 1N5823 Schottky diode will provide the best perfor-
mance, and will not be overstressed even for a shorted out-
put.
4. Input Capacitor (CIN)
The important parameters for the Input capacitor are the in-
put voltage rating and the RMS current rating. With a nominal
input voltage of 12V, an aluminum electrolytic capacitor with
a voltage rating greater than 18V (1.5 x VIN) would be
needed. The next higher capacitor voltage rating is 25V.
The RMS current rating requirement for the input capacitor in
a buck regulator is approximately 1⁄2 the DC load current. In
this example, with a 3A load, a capacitor with a RMS current
rating of at least 1.5A is needed. The curves shown in Figure
15 can be used to select an appropriate input capacitor.
From the curves, locate the 35V line and note which capaci-
tor values have RMS current ratings greater than 1.5A. A
680 µF, 35V capacitor could be used.
For a through hole design, a 680 µF/35V electrolytic capaci-
tor (Panasonic HFQ series or Nichicon PL series or equiva-
lent) would be adequate. other types or other manufacturers
capacitors can be used provided the RMS ripple current rat-
ings are adequate.
For surface mount designs, solid tantalum capacitors are
recommended. The TPS series available from AVX, and the
593D series from Sprague are both surge current tested.
11 www.national.com
11 Page | ||
| Páginas | Total 31 Páginas | |
| PDF Descargar | [ Datasheet LM2599T-12.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LM2599T-12 | SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator/ with Features | National Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |