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參數(shù)資料
| 型號(hào)： | AAT1121 |
| 廠商： | Advanced Analog Technology,lnc. |
| 英文描述： | 1.5MHz, 250mA Step-Down Converter |
| 中文描述： | 1.5MHz的，250mA降壓轉(zhuǎn)換器 |
| 文件頁(yè)數(shù)： | 13/20頁(yè) |
| 文件大小： | 534K |
| 代理商： | AAT1121 |
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AAT1121
1.5MHz, 250mA Step-Down Converter
1121.2007.03.1.2
13
Thermal Calculations
There are three types of losses associated with
the AAT1121 step-down converter: switching loss-
es, conduction losses, and quiescent current loss-
es. Conduction losses are associated with the
R
DS(ON)
characteristics of the power output switch-
ing devices. Switching losses are dominated by
the gate charge of the power output switching
devices. At full load, assuming continuous conduc-
tion mode (CCM), a simplified form of the losses is
given by:
I
Q
is the step-down converter quiescent current.
The term t
sw
is used to estimate the full load step-
down converter switching losses.
For the condition where the step-down converter is
in dropout at 100% duty cycle, the total device dis-
sipation reduces to:
Since R
DS(ON)
, quiescent current, and switching
losses all vary with input voltage, the total losses
should be investigated over the complete input
voltage range.
Given the total losses, the maximum junction tem-
perature can be derived from the
θ
JA
for the
TDFN22-8 package which is 50°C/W.
T
J(MAX)
=
P
TOTAL
·
Θ
JA
+ T
AMB
P
TOTAL
= I
O
2
· R
DSON(H)
+ I
Q
· V
IN
P
TOTAL
I
O
2
· (R
DSON(H)
· V
O
+ R
DSON(L)
· [V
IN
- V
O
])
V
IN
=
+ (t
sw
· F · I
O
+ I
Q
) · V
IN
Figure 1: AAT1121 Schematic.
R1
Adj.
R2
59k
Ω
L1
4.7μF
C2
4.7μF
C1
VP
1
GND
3
N/C
5
EN
6
LX
7
PGND
8
VIN
2
FB
4
AAT1121
U1
VIN
GND
+VOUT
GND
C3
(optional)
100pF
LX
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AAT1121_07 | 1.5MHz, 250mA Step-Down Converter |
| AAT1121IES-0.6-T1 | 1.5MHz, 250mA Step-Down Converter |
| AAT1121IPS-0.6-T1 | 1.5MHz, 250mA Step-Down Converter |
| AAT1123_07 | 1MHz Step-Down Converter |
| AAT1123IJS-0.6-T1 | 1MHz Step-Down Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AAT1121_07 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:1.5MHz, 250mA Step-Down Converter |
| AAT1121IES-0.6-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:1.5MHz, 250mA Step-Down Converter |
| AAT1121IPS-0.6-T1 | 制造商:SKYWORKS SOLUTIONS INC 功能描述:0.6VADJ 1.5MHZ STEP DOWN TDFN22- TR 制造商:Skyworks Solutions Inc 功能描述:DC TO DC CONVERTER |
| AAT1123 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:1MHz Step-Down Converter |
| AAT1123_07 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:1MHz Step-Down Converter |
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