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參數(shù)資料
| 型號： | NCP5208DR2 |
| 廠商： | ON SEMICONDUCTOR |
| 元件分類： | 通用總線功能 |
| 英文描述： | DDR-I/II Termination Regulator |
| 中文描述： | BUS TERMINATOR SUPPORT CIRCUIT, PDSO8 |
| 封裝： | SO-8 |
| 文件頁數(shù)： | 7/10頁 |
| 文件大?。?/td> | 82K |
| 代理商： | NCP5208DR2 |
NCP5208
http://onsemi.com
7
DETAILED OPERATING DESCRIPTIONS
General
The NCP5208 is a linear regulator with both sink and
source current capabilities used for active termination of
fast switching logic, DDRI/II SDRAM terminations and
active buses termination of SSTL2/3 logic. This device
can be operated from a single supply voltage as low as 1.7
V. For DDRI applications, the device is capable of
sourcing and sinking current up to 1.5 A with output
voltage regulated to within
±
3%. The separate voltage
remote feedback pin ensures superior load and line
regulation with fast tracking capability.
Protective features include SoftStart, Source/Sink
Current Limits and internal Thermal Shutdown.
Additionally, an opendrain VTT OK output signal (POK)
is provided for system monitoring. The shutdown pin (SD)
can be used to tristate the regulator output for Suspend To
RAM (STR) state. This device is available in a low profile,
space saving SO8 package.
Supply Voltage Inputs
For added flexibility, separate input pins are provided for
each required supply input. AVIN is the device operating
voltage, VDDQ is used to generate the internal reference
for VTT output voltage control and PVIN is the power rail
for the linear regulator. The device will regulate the output
voltage, VTT, with respect to the internal voltage reference
generated from VDDQ input and track the VDDQ changes
closely. The separate PVIN pin allows the designer to
isolate the high current PVIN line changes from coupling
into the noise sensitive AVIN and VDDQ inputs. Since the
AVIN supplies the control to the output power MOSFETs,
PVIN should always be lower than or equal to AVIN.
Generation of Internal Reference Voltage
The prime function of a termination regulator is to
provide a termination voltage, VTT at its output, which can
track the midpoint of the logic voltage level closely, i.e.
(VDDQ). The VTT voltage is used to terminate the bus
resistors. The NCP5208 generates a precise reference
voltage internally with a built in deadband to avoid upper
and lower MOSFET shoot through.
Remote Voltage Feedback Sensing
The NCP5208 has a separate feedback pin to monitor the
output voltage at the remote point. With this capability, the
output voltage can be controlled precisely at the output
capacitor so that any noise and fluctuations along the power
path can be eliminated.
Termination Voltage Output Regulation
The NCP5208 includes a simple linear series regulator
with a pair of control error amplifiers, which takes care of
the current source and sink operations separately. The error
amplifiers control a pair of MOSFETs to maintain the
output voltage equal to the internal reference voltage for
both current sink and source conditions. In order to avoid
the MOSFETs turning on at the same time, a deadband is
implemented internally for safe operation.
Regulator Shutdown Function
The operation of the NCP5208 can be suspended by
pulling the Shutdown (SD) pin to ground. When the device
is stopped, the regulator output will be tristated for
Suspend To RAM (STR) state in PC applications. The
shutdown pin is internally pulled high by a small current
source, if this feature is not used, this pin can be left open.
VTT Power OK for System Monitoring
NCP5208 provides an additional VTT power OK signal
for system monitoring. The VTT Power OK (POK) pin
goes low when the VTT voltage is in regulation and has
settled within the allowed window. For memory
termination applications, the system can check this pin to
ensure the termination voltage quality before accessing the
memory. The POK output is connected to a opendrain
switching FET and the designer is free to pull this pin to any
logic voltage level externally. When the VTT output is in
regulation, the internal FET is turned on and pulls the
power OK pin to ground.
Overcurrent Protection for Sink and Source Operation
In order to provide protection for the internal power
MOSFETs, bidirectional current limit protection circuits
are implemented. Current limit levels are internally set at
2.1 A typical for current source and 2.0 A typical for current
sink at 2.5 V operation.
Thermal Shutdown with Hysteresis
To guarantee safe operation, NCP5208 provides onchip
thermal shutdown protection. When the chip junction
temperature exceeds 135 C typical, the part will
shutdown. When the junction temperature falls back to
105 C typical, the device resumes normal operation.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NCP5208DR2G | 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) DDR-I/II Termination RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L |
| NCP5209/D | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-In-1 PWM Buck and Tri-Linear DDR Power Controller |
| NCP5210 | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:3-in-1 PWM Dual Buck and Linear DDR Power Controller |
| NCP5210/D | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:3-In-1 PWM Dual Buck and Linear DDR Power Controller |
| NCP5210MNR2 | 功能描述:DC/DC 開關(guān)控制器 3-in-1 DDR Power RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
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