|
|
PDF AN908 Data sheet ( Hoja de datos )
| Número de pieza | AN908 | |
| Descripción | APPLICATION NOTE | |
| Fabricantes | ST Microelectronics | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de AN908 (archivo pdf) en la parte inferior de esta página. Total 9 Páginas | ||
|
No Preview Available !
www.DataSheet4U.com
AN908
® APPLICATION NOTE
HIGH PERFORMANCE VRM USING L4990A,
FOR Pentium Pro® PROCESSOR
by Nicola Tricomi
SYSTEM DESCRIPTION
The actual generation of Pentium Pro® microprocessors, requires a power supply with a programmable
output voltage that decreases with the increasing of the processor internal clock. At the same time
higher output currents are required and superior load transient performance has to be supplied due to
very high dI/dt requests.
The VRM (Voltage Regulator Module) proposed (Fig 1) is a step down converter based on the L4990A,
very fast current mode controller. A complete system solution is given and described. A connector with a
standard VRM pinout is used, with 4 bit for Voltage Identify system, Power Good, Enable and constant
limiting current functions are available. Output Over Voltage Protection is also available.
ELECTRICAL SPECIFICATION
Input Characteristics
Symbol
Vi
di/dt
Vbias
Parameter
Input Voltage
Slew Rate
Bias Voltage
Test Condition
Load Transient
I12 = 45mA
Min.
4.75
11.4
Typ.
5
12
Max.
5.25
0.04
14
Unit
V
A/µs
V
Output Characteristics
Symbol
Vonom
Io
η
fsw
Parameter
Test Condition
Min. Typ. Max.
Output Voltage range
By 4 bits VID
2.1 3.5
Nominal Output Voltage
2.9
Output Current
0.4 12.5
Peak Current
Pulse by pulse mode
13
Regulation
Including variation due to:
- Io = min-max
- Vo imitial set point accuracy
- Line regulation
- Output ripple and noise
- Load transient dIo/dt = 30A/µs
- Temperature
±5
Efficiency
Vo = min-max; Io = min-max
70 85 93
Output Over Voltage Protection Vo = min-max
Foldback Current
Short circuit condition
1.18 ⋅ VO
12
Switching frequency
300
Unit
V
V
A
A
%
%
A
kHz
July 1999
1/9
DataSheet4 U .com
1 page  
www.DataSheet4U.com
COMPONENT LIST
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R10a
R11
R12
R13
R14
R15
R16
R17
R18
6.8k
1.8
10k
4.7
27k
510
3.3
4.7
1k
20k
2k
2k
22k
2k
4.99k (0.1%)
2k
10k
6.2k
6.2k
AN908 APPLICATION NOTE
R19
R20
R21
R21a
R22
R23
R24
R25
R26
R27
RR1
C1-4
C5-8
C9
C10
C11
C12
C13
C14-15
3.6k
2.7k
10k
3k
3k
3.09k (0.1%)
6.19k (0.1%)
12.4k
24.9k
xx
10k (5+1)
470µF/25V HFQ Panasonic
330µF/6.3V SANYO-Oscon
33nF
680pF
150pF
220pF
47µF/50V
5.6nF
C16
C17
C18
C19
C20-22
Q1
Q2
Q3
D1
D2-5
IC1
IC2
IC3
L1
L2
L3
1µF/50V
220nF
1.2nF
1µF/50V
220nF
STP80N03L-06
BC337
BC327
STPS20L25CT
1N4148
L4990A
LM339
M74HC125
77120(6T) Magnetics
40705-TC(50T) Magnetics
T38-52(4T) Micrometals
Figure 6. PCB Layout - Xerigraphy (77.47 x 78.74mm)
DataSheet4 U .com
5/9
5 Page | ||
| Páginas | Total 9 Páginas | |
| PDF Descargar | [ Datasheet AN908.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| AN9012 | Induction Heating System Topology Review |  Fairchild |
| AN904 | MAGNETIC AMPLIFIER WITH LPR30 CONTROLLER |  STMicroelectronics |
| AN908 | APPLICATION NOTE | ST Microelectronics |
| AN90B00 | Transistor Arrays |  Panasonic 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 |