参数资料
型号: LT3500IDD#PBF
厂商: Linear Technology
文件页数: 13/28页
文件大小: 322K
描述: IC REG DL BUCK/LINEAR 12-DFN
标准包装: 121
拓扑: 降压(降压)(1),线性(LDO)(1)
功能: 任何功能
输出数: 2
频率 - 开关: 500kHz ~ 2.4MHz
电压/电流 - 输出 1: 0.8 V ~ 38.9 V,2A
电压/电流 - 输出 2: 可调式,13mA
带 LED 驱动器:
带监控器:
带序列发生器:
电源电压: 3 V ~ 36 V
工作温度: -40°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 12-WFDFN 裸露焊盘
供应商设备封装: 12-DFN
包装: 管件
产品目录页面: 1331 (CN2011-ZH PDF)
LT3500
13
3500fc
APPLICATIONS INFORMATION
Note that the LT3500 will regulate if the input voltage is
taken above the calculated maximum voltage as long as
maximum ratings of the V
IN
 and BST pins are not violated.
However operation in this region of input voltage will exhibit
pulse skipping behavior.
Example:
V
OUT1
 = 3.3V, I
OUT1
 = 1A, Frequency = 1MHz,
Temperature = 25癈,
V
SW
 = 0.3V, V
D
 = 0.4V, t
ON(MIN)
 = 150ns,
t
OFF(MIN)
 = 110ns
 
DC
MAX
=1(110ns)1MHz=89%
V
IN(MIN)
=
3.3+0.4
0.89
0.4+0.3=4.06V
DC
MIN
=t
ON(MIN)
"Frequency=15%
V
IN(MAX)
=
3.3+0.4
0.15
0.4+0.3 =24.57V
Inductor Selection and Maximum Output Current
A good  rst choice for the inductor value is:
 
L=
(V
IN
V
OUT1
)"V
OUT1
V
IN
"f
where f is frequency in MHz and L is in 糎.
With this value the maximum load current will be ~2A,
independent of input voltage. The inductors RMS current
rating must be greater than your maximum load current
and its saturation current should be about 30% higher. To
keep ef ciency high, the series resistance (DCR) should
be less than 0.05?
For applications with a duty cycle of about 50%, the induc-
tor value should be chosen to obtain an inductor ripple
current less than 40% of peak switch current.
Of course, such a simple design guide will not always result
in the optimum inductor for your application. A larger value
provides a slightly higher maximum load current, and will
reduce the output voltage ripple. If your load is lower than
1.5A, then you can decrease the value of the inductor and
operate with higher ripple current. This allows you to use
a physically smaller inductor, or one with a lower DCR
resulting in higher ef ciency.
The current in the inductor is a triangle wave with an
average value equal to the load current. The peak switch
current is equal to the output current plus half the peak-to
peak inductor ripple current. The LT3500 limits its switch
current in order to protect itself and the system from
overload faults. Therefore, the maximum output current
that the LT3500 will deliver depends on the current limit,
the inductor value, switch frequency, and the input and
output voltages. The inductor is chosen based on output
current requirements, output voltage ripple requirements,
size restrictions and ef ciency goals.
When the switch is off, the inductor sees the output volt-
age plus the catch diode drop. This gives the peak-to-peak
ripple current in the inductor:
   
L
=
1DC
(
) V
OUT1
+V
D
(
)
L"f
where f is the switching frequency of the LT3500 and L
is the value of the inductor. The peak inductor and switch
current is:
   
I
SW(PK)
=I
LPK
=I
OUT1
+
L
2
相关PDF资料
PDF描述
ASM25DTAT-S189 CONN EDGECARD 50POS R/A .156 SLD
AGM25DTAT-S189 CONN EDGECARD 50POS R/A .156 SLD
GBC13DCMT-S288 CONN EDGECARD 26POS .100 EXTEND
LTC3104EMSE#PBF IC REG DL BCK/LINEAR 16-MSOP
LTC3446EDE#PBF IC REG TRPL BCK/LINEAR 14-DFN
相关代理商/技术参数
参数描述
LT3500IDD-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
LT3500IMSE#PBF 功能描述:IC REG DL BUCK/LINEAR 16-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压(降压)同步(3),线性(LDO)(2) 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:*
LT3500IMSE#TRPBF 功能描述:IC REG DL BUCK/LINEAR 16-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压(降压)同步(3),线性(LDO)(2) 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:*
LT3500IMSE-PBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller
LT3500IMSE-TRPBF 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic 2A Step-Down Regulator Plus Linear Regulator/Controller