参数资料
| 型号： | NE57811S/G,518 |
| 厂商： | NXP Semiconductors |
| 文件页数： | 6/13页 |
| 文件大小： | 0K |
| 描述： | IC DDR TERM REGULATOR SOT756 |
| 标准包装： | 2,000 |
| 应用： | 转换器，DDR，DDR2 |
| 输入电压： | 1.6 V ~ 3.6 V |
| 输出数： | 1 |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | SPAK-5 |
| 供应商设备封装： | 5-SPAK |
| 包装： | 带卷 (TR) |
Philips Semiconductors
Advanced DDR memory termination power
with shutdown
TECHNICAL DISCUSSION
Product data
NE57811
The NE57811 supplies power to the DDR memory bus termination
This yields the worst case current loading equation:
resistors at nominally 1 / 2 the voltage supplied to the memory ICs or
DIMMs. DDR memory output drivers source and sink current into
and out of their outputs. A typical DDR memory system is seen in
I O(max) +
N DDR V DD
2(R T ) R S )
Figure 1 (page 2). Each input/output pin on the bus has a series
20 ? resistor connected to it. The bus is terminated to the DDR
terminator though a 27 to 50 ? resistance. The memory system will
then require current from the V TT terminator bus only when the
instantaneous value of the aggregate bus state are not equal
amounts of 1s and 0s. When memory bus speeds are in the
200–300 MHz region, the period of any single bus state is extremely
small. This permits the DDR bus termination regulator to be a linear
‘power Op Amp’ that can source and sink current instantly to the
DDR bus from the V DD supply voltage.
Figure 6 models the V TT loading condition of each bus line
equivalent circuit during operation and with terminating resistors.
Where:
N DDR is the total number of terminated control, address and data
lines within the DDR memory system. (typically 192)
R T is the value of the terminating resistors.
R S is the value of the series resistors from the active output
driver.
Hence the worst-case current loading condition, where there are
either all 1s or all 0s for an instant, and R T is 27 ? and R S is 20 ? ,
produces an instantaneous output current of either + or –
3.5 Amperes.
V DD
V DD
V DD
V DD 2
OVER
OVER
V TT
V TT
100 k ?
CURRENT
TEMPERATURE
1
V TT
RefOut 5
V SS
V SS
V SS
SL01692
V SS 3
100 k ?
2003 Apr 02
Figure 6. V TT loading conditions.
6
4
SHTDWN
Figure 7. Block diagram.
SL01693
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NE57814 | 制造商:PHILIPS 制造商全称:NXP Semiconductors 功能描述:DDR memory termination regulator with standby mode and enhanced efficiency |
| NE57814DD | 制造商:NXP Semiconductors 功能描述: 制造商:NXP Semiconductors 功能描述:DDR TERM W/STANDBY 8SOIC |
| NE57814DD,518 | 功能描述:线性稳压器 - 标准 DDR TERMINATOR REG RoHS:否 制造商:STMicroelectronics 输出类型: 极性: 输出电压:1.8 V 输出电流:150 mA 负载调节: 最大输入电压:5.5 V 线路调整率: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-323-5L |
| NE57814DD518 | 制造商:Rochester Electronics LLC 功能描述: 制造商:NXP 功能描述: 制造商:NXP Semiconductors 功能描述: |
| NE57835 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:TRANSISTOR | BJT | NPN | 11V V(BR)CEO | 30MA I(C) | SOT-173 |
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