参数资料
| 型号： | ISL62881CIRTZ |
| 厂商： | Intersil |
| 文件页数： | 25/37页 |
| 文件大小： | 0K |
| 描述： | IC REG PWM SGL PHASE 28TQFN |
| 标准包装： | 75 |
| 应用： | 控制器，Intel IMVP-6.5? |
| 输入电压： | 4.5 V ~ 25 V |
| 输出数： | 1 |
| 输出电压： | 0.013 V ~ 1.5 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 管件 |
| 配用： | ISL62881CCPUEVAL2Z-ND - EVAL BOARD ISL62881CCPU 28QFN |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页当前第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页
ISL62881C, ISL62881D
For example, given Panasonic NTC thermistor with
B = 4700, the resistance will drop to 0.03322 of its
54μA
60μA
nominal at +105°C, and drop to 0.03956 of its nominal
at +100°C. If the required temperature hysteresis is
------------------------------------------------------ = 467k Ω
( 0.03956 – 0.03322 )
+
V NTC
-
NTC
R NTC
R s
1.24V
SW1
-
+
SW2
1.20V
INTERNAL TO
ISL62881C
VR_TT#
+105°C to +100°C, the required resistance of NTC will
be as shown in Equation 38:
2.96k Ω
(EQ. 38)
Therefore, a larger value thermistor such as 470k NTC
should be used.
At +105°C, 470k Ω NTC resistance becomes
(0.03322 × 470k Ω ) = 15.6k Ω . With 60μA on the NTC pin,
the voltage is only (15.6k Ω × 60μA) = 0.937V. This value
is much lower than the threshold voltage of 1.20V.
FIGURE 25. CIRCUITRY ASSOCIATED WITH THE
THERMAL THROTTLING FEATURE OF THE
ISL62881C
Therefore, a regular resistor needs to be in series with
the NTC. The required resistance can be calculated by
Equation 39:
---------------- – 15.6k Ω = 4.4k Ω
When temperature increases, the NTC thermistor
resistance decreases so the NTC pin voltage drops. When
1.20V
60 μ A
(EQ. 39)
the NTC pin voltage drops below 1.20V, the comparator
changes polarity and turns SW1 off and throws SW2 to
1.24V. This pulls VR_TT# low and sends the signal to
start thermal throttle. There is a 6μA current reduction
on NTC pin and 40mV voltage increase on threshold
voltage of the comparator in this state. The VR_TT#
signal will be used to change the CPU operation and
decrease the power consumption. When the temperature
drops down, the NTC thermistor voltage will go up. If
NTC voltage increases to above 1.24V, the comparator
will flip back. The external resistance difference in these
two conditions is shown in Equation 37:
4.42k is a standard resistor value. Therefore, the NTC
branch should have a 470k NTC and 4.42k resistor in
series. The part number for the NTC thermistor is
ERTJ0EV474J. It is a 0402 package. NTC thermistor will
be placed in the hot spot of the board.
Layout Guidelines
Table 5 shows the layout considerations. The
designators refer to the reference designs shown in
Figures 26 and 27.
---------------- – ---------------- = 2.96k
1.24V 1.20V
54 μ A 60 μ A
(EQ. 37)
One needs to properly select the NTC thermistor value
such that the required temperature hysteresis correlates
to 2.96k Ω resistance change. A regular resistor may
need to be in series with the NTC thermistor to meet the
threshold voltage values.
TABLE 5. LAYOUT CONSIDERATIONS
NAME
GND
CLK_EN#
PGOOD
RBIAS
VR_TT#
NTC
VW
COMP
FB
LAYOUT CONSIDERATION
Create analog ground plane underneath the controller and the analog signal processing components. Don’t let the
power ground plane overlap with the analog ground plane. Avoid noisy planes/traces (e.g.: phase node) from
crossing over/overlapping with the analog plane.
No special consideration.
No special consideration
Place the R BIAS resistor (R 16 ) in general proximity of the controller. Low impedance connection to the analog ground
plane.
No special consideration.
The NTC thermistor (R9) needs to be placed close to the thermal source that is monitor to determine thermal
throttling. Usually it’s placed close to phase-1 high-side MOSFET.
Place capacitor (C4) across VW and COMP in close proximity of the controller.
Place compensator components (C3, C5, C6 R7, R11, R10 and C11) in general proximity of the controller.
25
FN7596.0
March 8, 2010
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| ISL62881CIRTZ-T | 功能描述:直流/直流开关调节器 1-PHS PWM BUCKG FOR MICROPROC PWR SUPPLY RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881D | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Single-Phase PWM Regulator for IMVP-6.5a?￠ Mobile CPUs and GPUs |
| ISL62881DHRTZ | 功能描述:直流/直流开关调节器 1 PHS CNTRLR W/INTEG DRVR 32LD 5X5 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881DHRTZ-T | 功能描述:直流/直流开关调节器 1 PHS CNTRLR W/INTEG DRVR 32LD 5X5 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| ISL62881HRTZ | 功能描述:直流/直流开关调节器 1 PHS PWM BUCKG FOR MICROPROCESR PWR SUP RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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