|
|
PDF MP8708 Data sheet ( Hoja de datos )
| Número de pieza | MP8708 | |
| Descripción | Synchronous Step down Converter | |
| Fabricantes | MPS | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de MP8708 (archivo pdf) en la parte inferior de esta página. Total 13 Páginas | ||
|
No Preview Available !
The Future of Analog IC Technology
MP8708
High Efficiency 4A, 16V, 500kHz
Synchronous Step down Converter
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION - MELE USE ONLY
DESCRIPTION
The MP8708 is a high frequency synchronous
rectified step-down switch mode converter with
built in internal power MOSFETs. It offers a
very compact solution to achieve 4A continuous
output current over a wide input supply range
with excellent load and line regulation. The
MP8708 has synchronous mode operation for
higher efficiency over output current load range.
Current mode operation provides fast transient
response and eases loop stabilization.
Full protection features include OCP and
thermal shut down.
The MP8708 requires a minimum number of
readily available standard external components
and is available in a space saving 8-pin SOIC
package with an exposed pad.
FEATURES
• Wide 4.5V to 16V Operating Input Range
• 4A Output Current
• Low Rds(on) Internal Power MOSFETs
• Proprietary Switching Loss Reduction
Technique
• High Efficiency Synchronous Mode Operation
• Fixed 500KHz Switching Frequency
• Sync from 300KHz to 2MHz External Clock
• Internal Compensation
• Integrated Bootstrap Diode
• OCP Protection and Thermal Shutdown
• Output Adjustable from 0.805V
• Available in a Thermally Enhanced 8-pin SOIC
package
APPLICATIONS
• Notebook Systems and I/O Power
• Networking Systems
• Digital Set Top Boxes
• Personal Video Recorders
• Flat Panel Television and Monitors
• Distributed Power Systems
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
VIN
ON/OFF
1 IN
BST 4
7 VCC MP8708
5 EN/SYNC
GND
8
SW 2,3
FB 6
Rt
24.9K
Efficiency
100
VIN=5V
90
VIN=12V
R1
4.99K
VOUT 1.2V
80
70
VIN=16V
60
R2
10K
50
40
0
12345
OUTPUT CURRENT (A)
MP8708 Rev. 0.93
3/17/2009
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2009 MPS. All Rights Reserved.
1
1 page  
MP8708 – SYNCHRONOUS STEP-DOWN CONVERTER WITH INTERNAL MOSFETS
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION - MELE USE ONLY
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 12V, VOUT = 1.2V, L=1.8uH, TA = +25ºC, unless otherwise noted.
Enabled Supply Current vs.
Input Voltage
750
745
740
735
730
725
720
715
710
705 VFB=1V
700
0 5 10 15 20
INPUT VOLTAGE (V)
Vcc Regulator Line Regulation
5.5
5
4.5
4
3.5
0
5 10 15
INPUT VOLTAGE (V)
20
Peak Current vs.
Duty Cycle
7
6.8
6.6
6.4
6.2
6
5.8
5.6
5.4
5.2
5
0 10 20 30 40 50 60 70 80 90 100
DUTY CYCLE (%)
Operating Range
100
Dmax Limit
10
1 Minimum on time Limit
0.1
0
5 10 15 20
INPUT VOLTAGE (V)
Load Regulation
0.2
0.15
0.1
0.05
0
-0.05
-0.1
-0.15
-0.2
0
VVinin==1122VV
Vin=5V
Vin=16V
1234
5
OUTPUT CURRENT (A)
Line Regulation
0.2
0.15
0.1
0.05
0
-0.05
-0.1
-0.15
-0.2
0
Io=0A
Io=2A
Io=4A
5 10 15 20
INPUT VOLTAGE (V)
Case Temperature Rise vs.
Output Current
25
20
15
10
5
0
012345
OUTPUT CURRENT (A)
.
Efficiency
100
90
80
70
60
50
40
0
Vin=5V
Vin=12V
Vin=16V
12345
OUTPUT CURRENT (A)
MP8708 Rev. 0.93
3/17/2009
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2009 MPS. All Rights Reserved.
5
5 Page 
MP8708 – SYNCHRONOUS STEP-DOWN CONVERTER WITH INTERNAL MOSFETS
MPS CONFIDENTIAL AND PROPRIETARY INFORMATION - MELE USE ONLY
Selecting the Output Capacitor
The output capacitor (C2) is required to
maintain the DC output voltage. Ceramic,
tantalum, or low ESR electrolytic capacitors are
recommended. Low ESR capacitors are
preferred to keep the output voltage ripple low.
The output voltage ripple can be estimated by:
the chip to improve thermal performance
and long-term reliability.
6) Adding RC snubber circuit from IN pin to
SW pin can reduce SW spikes.
ΔVOUT
=
VOUT
fS × L
×
⎜⎜⎝⎛1
−
VOUT
VIN
⎟⎟⎠⎞ × ⎜⎜⎝⎛RESR
+
8
×
1
fS ×
C2
⎟⎟⎠⎞
Where L is the inductor value and RESR is the
equivalent series resistance (ESR) value of the
output capacitor.
In the case of ceramic capacitors, the
impedance at the switching frequency is
dominated by the capacitance. The output
voltage ripple is mainly caused by the
capacitance. For simplification, the output
voltage ripple can be estimated by:
ΔVOUT
=
8
×
VOUT
fS2 × L
×
C2
×
⎜⎜⎝⎛1 −
VOUT
VIN
⎟⎟⎠⎞
In the case of tantalum or electrolytic capacitors,
the ESR dominates the impedance at the
switching frequency. For simplification, the
output ripple can be approximated to:
Top Layer
ΔVOUT
=
VOUT
fS × L
×
⎜⎜⎝⎛1 −
VOUT
VIN
⎟⎟⎠⎞ × RESR
The characteristics of the output capacitor also
affect the stability of the regulation system. The
MP8708 can be optimized for a wide range of
capacitance and ESR values.
PCB Layout
PCB layout is very important to achieve stable
operation. Please follow these guidelines and
take Figure 4 for references.
1) Keep the connection of input ground and
GND pin as short and wide as possible.
2) Keep the connection of input capacitor and
IN pin as short and wide as possible.
3) Ensure all feedback connections are short
and direct. Place the feedback resistors
and compensation components as close to
the chip as possible.
4) Route SW away from sensitive analog
areas such as FB.
5) Connect IN, SW, and especially GND
respectively to a large copper area to cool
Bottom Layer
Figure 4—PCB Layout
MP8708 Rev. 0.93
3/17/2009
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2009 MPS. All Rights Reserved.
11
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet MP8708.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| MP8706 | Synchronous Step-down Converter | MPS |
| MP8708 | Synchronous Step down Converter | MPS |
| MP8709 | Synchronous Step-down Converter | MPS |
| 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 |