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参数资料
| 型号： | A8287SLBTR |
| 厂商： | Allegro Microsystems Inc |
| 文件页数： | 12/18页 |
| 文件大小： | 0K |
| 描述： | IC REG LNB SUPPLY/CTRL 24-SOIC |
| 标准包装： | 1,000 |
| 应用： | 转换器，模拟和数字式卫星信号接收器 |
| 输入电压： | 9 V ~ 16 V |
| 输出数： | 1 |
| 输出电压： | 12.7 V ~ 20.4 V |
| 工作温度： | -20°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 24-SOIC W |
| 包装： | 带卷 (TR) |
A8285 and
A8287
Power Dissipation
LNB Supply and Control Voltage Regulator
and it rises by 2.7 m Ω /oC with respect to the specified figure,
To ensure that the device operates within the safe operating
temperature range, several checks should be performed. An
approximate operating junction temperature can be determined by
R DSBOOST(25oC) , when T j equals 25oC.
Actual R DSBOOST = R DSBOOST(25oC) + [(T j – 25)
× 2.7 m Ω ]
estimating the power losses and the thermal impedance character-
istics of the printed circuit board solution. To do so, perform the
following procedure:
1. Estimate the maximum ambient temperature (T A ).
2. Define the maximum running junction temperature (T J )of
A8285/A8287. Note that the absolute maximum junction tem-
perature should never exceed 150oC.
3. Determine worst case power dissipation:
(a) Estimate the duty cycle D:
D = 1 – [V IN / (V OUT + V D + Δ V REG )]
where:
V D is the voltage drop of the boost diode, and
Δ V REG can be taken from the specification table.
(b) Estimate the peak current in boost stage I PK :
I PK = V OUT × [ I LOAD / (0.89 × V IN )]
(c) Estimate boost R DS (R DSBOOST ) at maximum running junc-
tion temperature. R DSBOOST is a function of junction temperature
Status (Read) Register Table
(d) Determine losses in each block P TOT ; based on the relative
value of V IN , perform either (i) or (ii):
(i) When V IN < V OUT + V D + Δ V REG . Note that worst case dis-
sipation occurs at minimum input voltage.
P TOT = Pd_Rds + Pd_sw + Pd_control + Pd_lin
where
Pd_Rds = I 2PK × R DSBOOST × D
Pd_control = 15 mA × V IN
Pd_lin = Δ V REG × I LOAD
and Pd_sw (switching losses estimate); worst case = 70 mW.
(ii) When V IN > V OUT + V D + Δ V REG . Note that worst case dis-
sipation in this case occurs at maximum input voltage.
P TOT = Pd_control + Pd_lin
where:
Pd_control = 15 mA × V IN
Pd_lin = (V IN – V D – V OUT ) × I LOAD
Step 4. Determine the thermal impedance required in the solu-
tion:
Bit
0
1
2
3
4
5
6
7
Name
TSD
OCP
PNG
DIS
VUV
Function
Thermal Shutdown
Overcurrent
Reserved
Reserved
Power Not Good
LNB output disabled
Reserved
V IN Undervoltage
R ?JA = (T J – T A ) / P TOT
The R ?JA for one or two layer PCBs can be estimated from the
R ?JA vs. Area charts on the following page.
Note: For maximum effectiveness, the PCB area underneath the
IC should be filled copper and connected to pins 4 and 13 for
A8285, and pins 6, 7, 18, and 19 for A8287. Where a PCB with
two or more layers is used, apply thermal vias, placing them adja-
cent to each of the above pins, and underneath the IC.
12
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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相关代理商/技术参数 |
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| A8287SLBTR-T | 功能描述:IC LNB SUPPLY/VOLTAGE REG 24SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:2,000 系列:- 应用:控制器，DSP 输入电压:4.5 V ~ 25 V 输出数:2 输出电压:最低可调至 1.2V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:30-TFSOP（0.173"，4.40mm 宽） 供应商设备封装:30-TSSOP 包装:带卷 (TR) |
| A8290 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Single LNB Supply and Control Voltage Regulator |
| A8290SETTR-T | 功能描述:IC VOLTAGE REG SGL LNB 28-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 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 |
| A8290SETTR-TB | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Single LNB Supply and Control Voltage Regulator |
| A8291 | 制造商:ALLEGRO 制造商全称:Allegro MicroSystems 功能描述:Single LNB Supply and Control Voltage Regulator |
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