- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄378405 > AND8139D (ON SEMICONDUCTOR) Ultra-Low Voltage MiniGate Devices Solve 1.2 V Interface Problems PDF資料下載
參數(shù)資料
| 型號： | AND8139D |
| 廠商： | ON SEMICONDUCTOR |
| 英文描述： | Ultra-Low Voltage MiniGate Devices Solve 1.2 V Interface Problems |
| 中文描述： | 超低電壓MiniGate設備1.2 V接口解決問題 |
| 文件頁數(shù)： | 1/2頁 |
| 文件大?。?/td> | 35K |
| 代理商： | AND8139D |
Semiconductor Components Industries, LLC, 2003
December, 2003 Rev. 0
1
Publication Order Number:
AND8139/D
AND8139/D
UltraLow Voltage
MiniGate Devices Solve
1.2 V Interface Problems
Prepared by: Fred Zlotnick
ON Semiconductor
Many integrated circuits such as microprocessors and
DSPs need to operate at very low voltage in order to
conserve power and not over dissipate. Issues arise when the
designer has a device, like a DSP, operating at 1.2 V and
needs to interface with other semiconductors operating at
3.3 V or more.
When performing the interface between a 3.3 V (or any
voltage between 1.2 V and 3.3 V) the one single answer that
solves all problems, simply with a minimum of board space,
is the NL17SVyyyXV5T2 family. With the six available
devices, the signal can be applied to the input and brought
to the DSP in the fastest possible time (minimum delay),
while occupying minimum board space and consuming
minimum power.
The designer might ask why not simply use resistors to
perform voltage division Resistors can certainly be used for
some applications but they consume power and limit the
operating frequency and create a delay (when the designer
includes the C of the input device). Figure 1 illustrates the
use of two resistors to limit the voltage on the DSP. For
simplicity, this article will not take into account tolerance
issues. That will be left to the reader if he chooses this
approach. In all cases, we will use V
1
= 3.3 V, V
2
= 1.2 V,
f = 35 MHz, and C
IN
= 10 pf. If 640
and 330
resistors
are used, the circuit will perform the required voltage
division. The loading will be 330
and draw 1.0 mA when
the device is on. If it is assumed to be a 50% duty cycle, then
the power consumption for the simple resistor divider will
be 16 mW. This power consumption is so high that it would
be ruled out immediately. If we would have used larger value
resistors, the frequency response would be impaired and
35 MHz would be impossible. The delay time through this
circuit will be about 15 to 20 ns.
A second possible scheme might be to use a transistor. If
an NPN transistor were used, it would need a voltage
division scheme similar to Figure 1 and the values would
need to be the same in order to keep the frequency response
to > 50 MHz f
3dB
. Power dissipation would be actually
higher than for the passive case because we would have a
third resistor from 1.2 V to the collector (Figure 2). We
would have another 5.0 mW of power dissipation due to the
output resistor. This solution would consume > 20 mW of
power and again is outrageously high in the power budget.
In addition, the manufacturer would have to place three parts
(three resistors and one transistor or one BRT plus one
resistor). Delay time would be longer than the passive
solution above, hence more costly and would present
absolutely no advantage over the simple resistive divider.
R1
R2
3.3 V
1.2 V
Figure 1.
Figure 2.
220
640
3.3 V
1.2 V
1.2 V
220
APPLICATION NOTE
http://onsemi.com
相關PDF資料 |
PDF描述 |
|---|---|
| AND8199 | THERMAL STABILITY OF MOSFETS |
| AP87C54 | CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER WITH 16 KBYTES USER PROGRAMMABLE EPROM |
| AP87C54-20 | CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER WITH 16 KBYTES USER PROGRAMMABLE EPROM |
| Applications2SK3132 | Silicon N Channel MOS Type Chopper Regulator DC−DC Converter and Motor Drive Applications |
| APTM50DUM38TG | Dual common source MOSFET Power Module |
相關代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AND8199 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:THERMAL STABILITY OF MOSFETS |
| AND8220-D | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Thermal Considerations for the ON Semiconductor |
| AND8222-D | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Thermal Considerations for the ON Semiconductor |
| AND8223-D | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Thermal Considerations for the ON Semiconductor |
| AND8331 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Quasi-Resonant Current- Mode Controller for High- Power ac-dc Adapters |
發(fā)布緊急采購，3分鐘左右您將得到回復。