參數(shù)資料
型號: LT3507HUHF#TRPBF
廠商: Linear Technology
文件頁數(shù): 22/28頁
文件大?。?/td> 302K
描述: IC REG QD BUCK/LINEAR 38-QFN
產(chǎn)品培訓(xùn)模塊: More Information on LDOs
標準包裝: 2,500
拓撲: 降壓(降壓)(1),線性(LDO)(1)
功能: 任何功能
輸出數(shù): 4
頻率 - 開關(guān): 900kHz ~ 1.1MHz
電壓/電流 - 輸出 1: 0.8 V ~ 32.4 V,2.4A
電壓/電流 - 輸出 2: 0.8 V ~ 32.4 V,1.5A
電壓/電流 - 輸出 3: 0.8 V ~ 32.4 V,1.5A
帶 LED 驅(qū)動器:
帶監(jiān)控器:
帶序列發(fā)生器:
電源電壓: 4 V ~ 36 V
工作溫度: -40°C ~ 150°C
安裝類型: 表面貼裝
封裝/外殼: 38-WFQFN 裸露焊盤
供應(yīng)商設(shè)備封裝: 38-QFN(5x7)
包裝: 帶卷 (TR)
LT3507
22
3507fa
The maximum allowed power dissipation by the LT3507
can be determined by:
   
P
DISS(MAX)
=
T
J(MAX)
T
A
?/DIV>
JA
where T
JMAX
 is the maximum die temperature of 125癈
(150癈 for H-grade).
However, take care in determining T
A
 since the catch
diodes also dissipate power and must be located close
to the LT3507. Another potential heat source is the LDO
pass transistor. In a compact layout the pass transistor
will be located close to the LT3507. The inductors will
also dissipate some power due to their series resistance
and they must be close to the LT3507. All of these heat
sources will increase the effective ambient temperature
seen by the LT3507.
A thorough analysis of eight heat sources in a small PCB
area is beyond the scope of this data sheet, however a
number of thermal analysis programs are available to
calculate the temperature rise in each component (such
as PCAnalyze from K&K Associates or BETAsoft from
Mentor). The power dissipation of each component will be
needed to accurately calculate the thermal characteristics
of the system.
The contributors to power dissipation inside the LT3507 are
switch DC loss, switch AC loss, boost current, quiescent
current and LDO drive current. The total dissipation within
the LT3507 can be expressed as:
   
P
DISS
=  P
SWDCi
+P
SWACi
+P
BSTi
(
)
+P
Q
+P
LDO
i=1
3

The switch DC and AC losses in channel i are:
 
 
P
SWDCi
=
R
SWi
I
OUTi
(  )
2
V
OUTi
V
INi
P
SWACi
=17nsI
OUTi
(  )
V
INi
( )
f
( )
APPLICATIONS INFORMATION
where R
SWi
 is the equivalent switch resistance (0.18?for
channel 1 and 0.22?for channels 2 and 3) and f is the
operating frequency.
The boost loss in channel i is:
 
P
BSTi
=
V
OUTi
V
BOOSTi
(   )
I
OUTi
50
+0.02A
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
V
INi
The quiescent loss is:
  P
Q
 = V
IN1
(I
Q(VIN1)
) + V
BIAS
(I
Q(BIAS)
)
If the BIAS pin does not have a voltage of at least 3V ap-
plied, then V
IN1
 must replace V
BIAS
 in the equation. Also,
I
Q(VIN1)
 can be reduced by 0.2mA (typ) if the LDO is shut
off (see the LDO section).
The LDO drive loss is:
P
LDO
=(V
BIAS
V
LDO(OUT)
0.7V)
I
OUT(LDO)
?/DIV>
PASS
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
,
 if V
BIAS
eV
LDO(OUT)
+1.5V
or
P
LDO
=(V
IN1
V
LDO(OUT)
0.7V)
I
OUT(LDO)
?/DIV>
PASS
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
,
 if V
BIAS
<V
LDO(OUT)
+1.5V
where ?/DIV>
PASS
 is the current gain of the external pass
transistor.
Next, the power in the external components must be taken
into account. The diode power is given by:
   
P
DIODE
=
V
F
V
IN
V
OUT
V
F
(
)
I
OUT
V
IN
where V
F
 is the forward drop of the diode at I
OUT
.
The inductor power is:
  P
IND
 = (I
OUT
)
2
 ESR
IND
where ESR
IND
 is the inductor equivalent series resistance.
相關(guān)PDF資料
PDF描述
LT3570IFE#TRPBF IC REG BUCK/BST/LINEAR 20TSSOP
LT3645HMSE#TRPBF IC REG DL BUCK/LINEAR 12-MSOP
LT3694IFE-1#TRPBF IC REG TRPL BUCK/LINEAR 20TSSOP
LT4220IGN#TR IC CTLR HOTSWAP DUAL 16-SSOP
LT4250LCN8 IC CONTRLR HOT SWAP NEG 48V 8DIP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT3507IUHF#PBF 功能描述:IC REG QD BUCK/LINEAR 38-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3507IUHF#TRPBF 功能描述:IC REG QD BUCK/LINEAR 38-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3507IUHFPBF 制造商:Linear Technology 功能描述:Triple Voltage Regulator QFN38EP
LT3507IUHF-PBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Triple Monolithic Step-Down Regulator with LDO
LT3507IUHF-TRPBF 制造商:LINER 制造商全稱:Linear Technology 功能描述:Triple Monolithic Step-Down Regulator with LDO