- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384634 > LXV16VB102M (National Semiconductor Corporation) Non-synchronous Step-down Controller for Pentium Microprocessors PDF資料下載
參數(shù)資料
| 型號(hào)： | LXV16VB102M |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Non-synchronous Step-down Controller for Pentium Microprocessors |
| 中文描述： | 非同步降壓控制器，用于奔騰微處理器 |
| 文件頁(yè)數(shù)： | 5/8頁(yè) |
| 文件大?。?/td> | 157K |
| 代理商： | LXV16VB102M |
Application Hints
GENERAL
This is a cost effective non-synchronous buck solution for
powering Pentium and similar microprocessors (AMD’s K5,
Motorola’s PowerPC, etc.) that draws large current at a low
voltage. Fairly high efficiency of 86% or better at 10A load
can be achieved by properly selecting the components.
PIN FUNCTIONS
+V
—This is the positive input supply for the controller to
work. A suitable input bypass capacitor must be present at
this pin to minimize voltage transients and to supply the cur-
rent needed to drive the external MOSFET.
Ground
—Circuit ground.
Output
—Sources pulsed current up to 1.4A maximum to
drive external MOSFET. To minimize turn-on delay of the ex-
ternal MOSFET, copper trace between this pin and the gate
of the MOSFET should be kept as short as possible.
Feedback
—Senses the regulator output voltage so that a
feedback control loop is achieved. A resistor divider can be
used to choose the desired output voltage.
ON/OFF
—Allows the controller to be shut down by a logic
level signal. If the shutdown feature is not needed, the pin
can be either grounded or left open, both of which enable the
controller.
COMPONENTS SELECTION
Input Filter
Depending on the system requirement, an inductor may or
may not be necessary. When there is no explicit input di/dt
limitation, the filter can be composed of capacitors only. The
inductor plays an important role in limiting the input di/dt so
that the input power rail appears a quiet supply for other
loads. It also limits the inrush current during power on. The
best inductance value is too complicated to calculate but can
be easily determined by experiment. For a typical Pentium
motherboard application, 2μH is recommended. The bulk ca-
pacitors in the input filter should be of low ESR type or oth-
erwise the input di/dt requirement may not be met.Alow cost
low ESR electrolytic capacitor manufactured by United
Chemicon, LXV16VB102M, is recommended here.
Bill of Material
Output Filter
The output filter plays an extremely important role in meeting
the load transient requirement. From the viewpoint of load
transient response, it is desirable to have a low inductance
and a high output capacitance. However, too low an induc-
tance causes huge ripple current through the MOSFETs
which translates into lower efficiency. Also too big a bank of
output capacitors may not be economical in terms of both
cost of the regulator and motherboard real estate. It may
also require a larger input capacitor bank to stay within input
di/dt specification. The output voltage ripple is determined by
the amount of ripple current in the inductor and the ESR of
the output capacitor bank. For the typical situation where
Pentium processor is the load, a 2.5μH inductor and a bank
of three 1500μF electrolytic capacitors are recommended.
Sanyo’s
ultra
low-ESR
6MV1500GX, is recommended.
electrolytic
capacitor,
the
MOSFET Selection
It is desirable to have the on-resistance of the MOSFET as
low as possible so that its conduction loss is minimized and
high efficiency can be maintained. A good idea is to use two
low-R
MOSFETs in parallel so that the total conduction
loss is halved compared with using one MOSFET. In the typi-
cal application circuit, two Fairchild low R
(10 m
) MOS-
FETs, the NDS8410A, are used in parallel.
Diode Selection
Since current flows through the freewheeling diode when the
MOSFETs are off, efficiency is affected greatly by the for-
ward voltage drop of the diode. Generally a Schottky diode is
used here. Motorola MBR2515L Schottky diode has a for-
ward voltage drop of less than 0.4V at 20A which fits very
well in this application.
Output Voltage Adjustment
Different output voltages can be obtained by using different
combinations of feedback resistors. The formula to calculate
output voltage is VCORE=(R2/R3+1)X1.235V. In the “typical
application” circuit, two jumpers are used to adjust the value
of R2 so that four output voltages can be obtained. When
necessary, C9 and C10 can be used to further compensate
the converter to result in a more stable circuit, the penalty is
a slower transient recovery speed.
Label
C1
C2
C3
C4
C5
C6
C7
C8
C9
C10
L1
R1
R2
R3
Value
Type
Part Number
LXV16VB102M
LXV16VB102M
LXV16VB102M
Manufacturer
United Chemi-Con
United Chemi-Con
United Chemi-Con
1000μ
1000μ
1000μ
10μ
0.1μ
1500μ
1500μ
1500μ
1n
15n
2.5μ
300, 0.5W
3.65k 1%
2k 1%
Capacitor
Capacitor
Capacitor
Capacitor, Tantalum
Capacitor, Ceramic
Capacitor
Capacitor
Capacitor
Capacitor, Ceramic
Capacitor, Ceramic
Inductor
Resistor
Resistor
Resistor
6MV1500GX
6MV1500GX
6MV1500GX
Sanyo
Sanyo
Sanyo
5
www.national.com
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| M16450 | Universal Asynchronous Receiver/Transmitter(通用異步接收器/傳送器) |
| M16550 | Universal Asynchronous Receiver/Transmitter(通用異步接收器/傳送器) |
| M2035S | High-Voltage Trench MOS Barrier Schottky Rectifier |
| M2045S | High-Voltage Trench MOS Barrier Schottky Rectifier |
| M2125 | SINGLE-SUPPLY OPERTIONAL AMPLIFIER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LXV16VB121M6X11FTX | 功能描述:鋁質(zhì)電解電容器 - 帶引線 120UF 16V RoHS:否 制造商:Kemet 引線類型: 電容:220 uF 容差:20 % 電壓額定值:25 V 工作溫度范圍: 端接類型:Radial 外殼直徑:8 mm 外殼長(zhǎng)度:11 mm 引線間隔:5 mm 產(chǎn)品:General Purpose Electrolytic Capacitors 封裝:Bulk |
| LXV16VB122M10X30LL | 功能描述:鋁質(zhì)電解電容器 - 帶引線 1200uF 16V 10X30 RoHS:否 制造商:Kemet 引線類型: 電容:220 uF 容差:20 % 電壓額定值:25 V 工作溫度范圍: 端接類型:Radial 外殼直徑:8 mm 外殼長(zhǎng)度:11 mm 引線間隔:5 mm 產(chǎn)品:General Purpose Electrolytic Capacitors 封裝:Bulk |
| LXV16VB122M12X20LL | 制造商:United Chemi-Con Inc 功能描述: |
| LXV16VB152M12X25LL | 功能描述:鋁質(zhì)電解電容器 - 帶引線 1500uF 16V RoHS:否 制造商:Kemet 引線類型: 電容:220 uF 容差:20 % 電壓額定值:25 V 工作溫度范圍: 端接類型:Radial 外殼直徑:8 mm 外殼長(zhǎng)度:11 mm 引線間隔:5 mm 產(chǎn)品:General Purpose Electrolytic Capacitors 封裝:Bulk |
| LXV16VB222M16X20LL | 功能描述:鋁質(zhì)電解電容器 - 帶引線 2200uF 16V RoHS:否 制造商:Kemet 引線類型: 電容:220 uF 容差:20 % 電壓額定值:25 V 工作溫度范圍: 端接類型:Radial 外殼直徑:8 mm 外殼長(zhǎng)度:11 mm 引線間隔:5 mm 產(chǎn)品:General Purpose Electrolytic Capacitors 封裝:Bulk |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。