參數(shù)資料
型號: DSP56857BUE
廠商: 飛思卡爾半導(dǎo)體(中國)有限公司
英文描述: 16-bit Digital Signal Controllers
中文描述: 16位數(shù)字信號控制器
文件頁數(shù): 25/53頁
文件大?。?/td> 680K
代理商: DSP56857BUE
Supply Voltage Sequencing and Separation Cautions
56857 Technical Data, Rev. 6
Freescale Semiconductor
25
4.3 Supply Voltage Sequencing and Separation Cautions
Figure 4-2
shows two situations to avoid in sequencing the V
DD
and V
DDIO,
V
DDA
supplies.
Note:
1. V
DD
rising before V
DDIO
, V
DDA
2. V
DDIO
, V
DDA
rising much faster than V
DD
Figure 4-2 Supply Voltage Sequencing and Separation Cautions
V
DD
should not be allowed to rise early (1). This is usually avoided by running the regulator for the V
DD
supply (1.8V) from the voltage generated by the 3.3V V
DDIO
supply, see
Figure 4-3
. This keeps V
DD
from
rising faster than V
DDIO
.
V
DD
should not rise so late that a large voltage difference is allowed between the two supplies (2).
Typically this situation is avoided by using external discrete diodes in series between supplies, as shown
in
Figure 4-3
. The series diodes forward bias when the difference between V
DDIO
and V
DD
reaches
approximately 2.1, causing V
DD
to rise as V
DDIO
ramps up. When the V
DD
regulator begins proper
operation, the difference between supplies will typically be 0.8V and conduction through the diode chain
reduces to essentially leakage current. During supply sequencing, the following general relationship
should be adhered to:
V
DDIO
> V
DD
> (V
DDIO
- 2.1V)
In practice, V
DDA
is typically connected directly to V
DDIO
with some filtering.
Figure 4-3 Example Circuit to Control Supply Sequencing
3.3V
1.8V
Time
0
2
1
Supplies Stable
V
DD
V
DDIO,
V
DDA
D
3.3V
Regulator
1.8V
Regulator
Supply
V
DD
V
DDIO,
V
DDA
相關(guān)PDF資料
PDF描述
DSP56857E 16-bit Digital Signal Controllers
DSP56858E 16-bit Digital Signal Controllers
DSP56858FV120 16-bit Digital Signal Controllers
DSP56858FVE 16-bit Digital Signal Controllers
DSP56858VF120 16-bit Digital Signal Controllers
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DSP56857E 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:16-bit Digital Signal Controllers
DSP56857PB 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:120 MIPS Hybrid Processor
DSP56858 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:16-bit Digital Signal Controllers
DSP56858E 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:16-bit Digital Signal Controllers
DSP56858EVM 制造商:Freescale Semiconductor 功能描述:Microprocessor Support IC For Use With:D