参数资料
| 型号： | ISL62771IRTZ |
| 厂商： | Intersil |
| 文件页数： | 31/36页 |
| 文件大小： | 0K |
| 描述： | IC PWM CTRLR MULTIPHASE 40TQFN |
| 标准包装： | 60 |
| 系列： | Robust Ripple Regulator™ (R³) |
| 应用： | 控制器，AMD Fusion? SVI 2.0 CPU GPU |
| 输入电压： | 4.5 V ~ 25 V |
| 输出数： | 2 |
| 输出电压： | 0.006 V ~ 1.55 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 供应商设备封装： | 40-TQFN-EP（5x5） |
| 包装： | 管件 |
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ISL62771
the DC current flowing through the inductors. Recommended
values are R s = 10k Ω and C s = 0.22μF.
Thermal Monitor Component Selection
The ISL62771 features two pins, NTC and NTC_NB, which are
used to monitor motherboard temperature and alert the AMD
CPU if a thermal issue arises. The basic function of this circuitry
Figure 30 shows the basic configuration of the NTC resistor,
a board temperature of +105°C, then the resistance change of
the thermistor can be calculated. For example, a Panasonic NTC
thermistor with B = 4700 has a resistance ratio of 0.03939 of its
nominal value at +100°C and 0.03308 of its nominal value at
+105°C. Taking the required resistance change between the
thermal warning threshold and the shutdown threshold and
dividing it by the change in resistance ratio of the NTC thermistor
at the two temperatures of interest, the required resistance of
the NTC is defined in Equation 35.
----------------------------------------------------- ) - = 317k Ω
R NTC , and offset resistor, R S , used to generate the warning and
shutdown voltages at the NTC pin.
( 21.3k Ω – 19.3k Ω
( 0.03939 – 0.03308 )
(EQ. 35)
The closest standard thermistor to the value calculated with B =
INTERNAL TO
ISL62771
+V
4700 is 330k Ω . The NTC thermistor part number is
ERTJ0EV334J. The actual resistance change of this standard
thermistor value between the warning threshold and the
30μA
VR_HOT_L
R
shutdown threshold is calculated in Equation 36.
( 330k Ω ? 0.03939 ) – ( 330k Ω ? 0.03308 ) = 2.082k Ω
(EQ. 36)
NTC
MONITOR
Since the NTC thermistor resistance at +105°C is less than the
330k Ω
R NTC
required resistance from Equation 38, additional resistance in
series with the thermistor is required to make up the difference.
8.45k Ω
R s
WARNING SHUTDOWN
640mV 580mV
A standard resistor, 1% tolerance, added in series with the
thermistor will increase the voltage seen at the NTC pin. The
additional resistance required is calculated in Equation 37.
19.3k Ω – 10.916k Ω = 8.384k Ω
(EQ. 37)
FIGURE 30. THERMAL MONITOR FEATURE OF THE ISL62771
As the board temperature rises, the NTC thermistor resistance
decreases and the voltage at the NTC pin drops. When the
voltage on the NTC pin drops below the thermal warning
threshold of 0.64V, then VR_HOT_L is pulled low. When the AMD
CPU detects VR_HOT_L has gone low, it will begin throttling back
load current on both outputs to reduce the board temperature.
If the board temperature continues to rise, the NTC thermistor
resistance will drop further and the voltage at the NTC pin could
drop below the thermal shutdown threshold of 0.58V. Once this
threshold is reached, the ISL62771 shuts down both Core and
Northbridge VRs indicating a thermal fault has occurred prior to
the thermal fault counter triggering a fault.
Selection of the NTC thermistor can vary depending on how the
resistor network is configured. The equivalent resistance at the
typical thermal warning threshold voltage of 0.64V is defined in
Equation 33.
The closest, standard 1% tolerance resistor is 8.45k Ω .
The NTC thermistor is placed in a hot spot on the board, typically
near the upper MOSFET of Channel 1 of the respective output.
The standard resistor is placed next to the controller.
Layout Guidelines
PCB Layout Considerations
POWER AND SIGNAL LAYERS PLACEMENT ON THE PCB
As a general rule, power layers should be close together, either
on the top or bottom of the board, with the weak analog or logic
signal layers on the opposite side of the board. The ground-plane
layer should be adjacent to the signal layer to provide shielding.
COMPONENT PLACEMENT
There are two sets of critical components in a DC/DC converter;
the power components and the small signal components. The
---------------- = 21.3k Ω
0.64V
30 μ A
(EQ. 33)
power components are the most critical because they switch
large amount of energy. The small signal components connect to
---------------- = 19.3k Ω
30 μ A
The equivalent resistance at the typical thermal shutdown
threshold voltage of 0.58V required to shutdown both outputs is
defined in Equation 34.
0.58V
(EQ. 34)
The NTC thermistor value correlates to the resistance change
between the warning and shutdown thresholds and the required
temperature change. If the warning level is designed to occur at a
board temperature of +100°C and the thermal shutdown level at
31
sensitive nodes or supply critical bypassing current and signal
coupling.
The power components should be placed first and these include
MOSFETs, input and output capacitors, and the inductor. It is
important to have a symmetrical layout for each power train,
preferably with the controller located equidistant from each
power train. Symmetrical layout allows heat to be dissipated
equally across all power trains. Keeping the distance between
the power train and the control IC short helps keep the gate drive
traces short. These drive signals include the LGATE, UGATE,
PGND, PHASE and BOOT.
FN8321.2
September 12, 2013
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL62771IRTZ-T | 功能描述:IC PWM CTRLR MULTIPHASE 40TQFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:Robust Ripple Regulator™ (R³) 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| ISL62773 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Multiphase PWM Regulator for AMD Fusiona?￠ Desktop CPUs Using SVI 2.0 |
| ISL62773HRZ | 功能描述:电流型 PWM 控制器 MULTI-OUTPUT CNTRLR FOR AMD FUSION UP RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL62773HRZ-T | 功能描述:电流型 PWM 控制器 MULTI-OUTPUT CNTRLR FOR AMD FUSION UP RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| ISL62773IRZ | 功能描述:电流型 PWM 控制器 MULTI-OUTPUT CNTRLR FOR AMD FUSION UP RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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