- 您現在的位置：買賣IC網 > PDF目錄364211 > 19197 Microprocessor Family Low Voltage Power Supply Circuits Application Note? 54.9KB (PDF) PDF資料下載
參數資料
| 型號： | 19197 |
| 英文描述： | Microprocessor Family Low Voltage Power Supply Circuits Application Note? 54.9KB (PDF) |
| 中文描述： | 微處理器系列低壓電源電路應用筆記？ 54.9KB（PDF格式） |
| 文件頁數： | 1/1頁 |
| 文件大?。?/td> | 54K |
| 代理商： | 19197 |
Document #:
19197
Rev.
D
Amendment/
0
Issue Date:
August 1995
This document contains information on a product under development at Advanced Micro Devices. The information is
intended to help you evaluate this product. AMD reserves the right to change or discontinue work on this proposed
product without notice.
Advanced
Micro
Devices
Application Note
Am486
3.3-V CPUs and Am5
X
86
CPUs feature a 5-V tolerant signal interface, but require a +3.3-V
input for V
CC
. For cost effectiveness, AMD
recommends the use of a voltage regulator circuit to generate
the V
CC
input from a regulated +5-V source. This application note describes two such circuits that provide
a programmable voltage range (3.3 V–3.6 V). The note also includes filtering and routing guidelines for
incorporating these circuits into a motherboard design.
Low Voltage Power Supply Circuits
BACKGROUND
The CS-24 (0.5 micron) and CS-34 (0.35 micron)
manufacturing processes incorporate 5-V I/O tol-
erance. This means that 3.3-V Am486 processors
(0.5 micron) and Am5
X
86 processors (0.35 micron)
can accept both 3.3-V and 5-V input signals even
though they require 3.3-V input power. The input
circuit protects the microprocessor from potential
damage caused by the application of 5-V signals.
AMD has developed two circuit designs that can
generate a selectable input voltage range (3.3 V–
3.6 V) for the microprocessor V
CC
source. The linear
regulator circuit is the lower cost solution. The sec-
ond option is a switching regulator that provides a
higher efficiency output, but at a significant cost
increase. Design requirements (higher efficiency
vs. lower cost) determine which power solution to
use in a specific system design.
A second basic issue in power supply circuit design
is noise reduction. Excessive noise levels can im-
pair proper operation and contribute to possible
radio frequency transmissions that can affect com-
pliance with national and international agency reg-
ulations. This application note provides some basic
guidelines for reducing noise generated by or
transmitted through the power supply circuits.
LINEAR REGULATOR POWER CIRCUIT
The lower cost linear regulator power circuit is
shown in Figure 1. The circuit provides an output
of +5 V or 3.3 V–3.6 V depending on the state of
the VOLDET input from the microprocessor. On
AMD processors manufactured using the CS-24 or
CS-34 process, the VOLDET signal is set to the
V
SS
level used by the microprocessor. The actual
output range produced by the regulator circuit de-
pends on the ratio of the values of R1 and R2. Table
1 shows the recommended resistor sizes used to
produce specific voltage outputs (V
OUT
).
Figure 1
Variable Linear Regulator Microprocessor Power Supply Circuit
Table 1. R1 and R2
Resistor Values
Note:
All resistors are 1%
tolerance.
V
OUT
3.3 V
3.45 V
3.6 V
R1
R2
124
124
124
205
218
234
相關PDF資料 |
PDF描述 |
|---|---|
| 191 | SOLDER SOCKET PINS FEMALE |
| 19200000 | IR EMITTER PANEL MTG |
| 1920002 | *654310* LED INDICATOR GELB |
| 19210001 | LED 10 IN 16MM HELL VERCHROMT GRUEN |
| 19210003 | LED 10 IN 16MM HELL VERCHROMT HEROT |
相關代理商/技術參數 |
參數描述 |
|---|---|
| 19197-0006 | 功能描述:端子 SPADE AVIKRIMP (A-835-08) RoHS:否 制造商:AVX 產品:Junction Box - Wire to Wire 系列:9826 線規:26-18 接線柱/接頭大小: 絕緣: 顏色:Red 型式:Female 觸點電鍍:Tin over Nickel 觸點材料:Beryllium Copper, Phosphor Bronze 端接類型:Crimp |
| 19197-0013 | 制造商:Molex 功能描述: |
| 19197-0016 | 制造商:Molex 功能描述: |
| 19197-0020 | 制造商:Molex 功能描述:Avikrimp? Spade Tongue Terminal for 14-16 Heavy Duty AWG Wire |
| 19197-0021 | 制造商:MOLEX 功能描述: |
發布緊急采購，3分鐘左右您將得到回復。