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參數(shù)資料
| 型號： | A8287 |
| 廠商： | Allegro MicroSystems, Inc. |
| 英文描述： | LNB Supply and Control Voltage Regulator |
| 中文描述： | LNB電源和控制穩(wěn)壓器 |
| 文件頁數(shù)： | 11/17頁 |
| 文件大小： | 527K |
| 代理商： | A8287 |
11
Worcester, Massachusetts 01615-0036 (508) 853-5000
115 Northeast Cutoff, Box 15036
www.allegromicro.com
D
P
2
A8285/A8287
LNB Supply and Control Voltage Regulator
Bit
Name
Function
0
TSD
Thermal Shutdown
1
OCP
Overcurrent
2
Reserved
3
Reserved
4
PNG
Power Not Good
5
DIS
LNB output disabled
6
Reserved
7
VUV
V
IN
Undervoltage
Power Dissipation
To ensure that the device operates within the safe operating
temperature range, several checks should be performed. An
approximate operating junction temperature can be deter-
mined by estimating the power losses and the thermal imped-
ance characteristics of the printed circuit board solution. To
do so, perform the following procedure:
1.
Estimate the maximum ambient temperature (T
A
).
2.
De
fi
ne the maximum running junction temperature (T
J
)of
A8285/A8287. Note that the absolute maximum junction
temperature should never exceed 150oC.
3.
Determine worst case power dissipation:
(a)
Estimate the duty cycle D:
D = 1 – [V
IN
/ (V
OUT
+ V
D
+
V
REG
)]
where:
V
D
is the voltage drop of the boost diode, and
V
REG
can be taken from the speci
fi
cation 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 tempera-
ture and it rises by 2.7 m
/oC with respect to the speci
fi
ed
fi
gure, R
DSBOOST(25oC)
, when T
j
equals 25oC.
Actual R
DSBOOST
= R
DSBOOST(25oC)
+ [(T
j
– 25)
×
2.7 m
]
(d)
Determine losses in each block P
; based on the relative
value of V
IN
, perform either (i) or (ii):
(i)
When V
< V
+ V
+
V
. 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 =
V
REG
×
I
LOAD
and Pd_sw (switching losses estimate); worst case = 70 mW.
(ii)
When V
> V
+ V
+
V
. Note that worst case
dissipation 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
solution:
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
fi
lled 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 adjacent to each of the above pins, and under-
neath the IC.
Status (I
2
C Read) Register Table
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| A8287SLB | 功能描述:IC REG LNB SUPPLY/CTRL 24-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,000 系列:- 應用:電源，ICERA E400，E450 輸入電壓:4.1 V ~ 5.5 V 輸出數(shù):10 輸出電壓:可編程 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:42-WFBGA，WLCSP 供應商設備封裝:42-WLP 包裝:帶卷 (TR) |
| A8287SLB-T | 制造商:Allegro MicroSystems LLC 功能描述: |
| A8287SLBTR | 功能描述:IC REG LNB SUPPLY/CTRL 24-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 產(chǎn)品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,000 系列:- 應用:電源，ICERA E400，E450 輸入電壓:4.1 V ~ 5.5 V 輸出數(shù):10 輸出電壓:可編程 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:42-WFBGA，WLCSP 供應商設備封裝:42-WLP 包裝:帶卷 (TR) |
| A8287SLBTR-T | 功能描述:IC LNB SUPPLY/VOLTAGE REG 24SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:2,000 系列:- 應用:控制器，DSP 輸入電壓:4.5 V ~ 25 V 輸出數(shù):2 輸出電壓:最低可調至 1.2V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:30-TFSOP（0.173"，4.40mm 寬） 供應商設備封裝:30-TSSOP 包裝:帶卷 (TR) |
| A8290 | 制造商:ALLEGRO 制造商全稱:Allegro MicroSystems 功能描述:Single LNB Supply and Control Voltage Regulator |
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