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参数资料
| 型号： | LT3507IUHF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/28页 |
| 文件大小： | 302K |
| 描述： | IC REG QD BUCK/LINEAR 38-QFN |
| 产品培训模块： | More Information on LDOs |
| 标准包装： | 2,500 |
| 拓扑： | 降压（降压）（1），线性（LDO）（1） |
| 功能： | 任何功能 |
| 输出数： | 4 |
| 频率 - 开关： | 900kHz ~ 1.1MHz |
| 电压/电流 - 输出 1： | 0.8 V ~ 32.4 V，2.4A |
| 电压/电流 - 输出 2： | 0.8 V ~ 32.4 V，1.5A |
| 电压/电流 - 输出 3： | 0.8 V ~ 32.4 V，1.5A |
| 带 LED 驱动器： | 无 |
| 带监控器： | 无 |
| 带序列发生器： | 是 |
| 电源电压： | 4 V ~ 36 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 38-WFQFN 裸露焊盘 |
| 供应商设备封装： | 38-QFN（5x7） |
| 包装： | 带卷 (TR) |
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LT3507
12
3507fa
Select an inductor greater than L
MIN
that keeps the ripple
current below 30% of I
LIM
.
The inductors RMS current rating must be greater than the
maximum load current and its saturation current should
be greater than I
LPK
. For highest ef ciency, the series
resistance (DCR) should be less than 0.1? Table 1 lists
several vendors and types that are suitable.
Table 1. Inductors
PART NUMBER
VALUE
(糎)
I
SAT
(A)
DCR
(?/SPAN>)
HEIGHT
(mm)
Sumida
CDC5D23-2R2
2.2 2.16 0.030 2.5
CDRH5D28-2R6
2.6 2.60 0.013 3.0
CDRH6D26-5R6
5.6 2.00 0.027 2.8
CDH113-100
10 2.00 0.047 3.7
Coilcraft
DO1606T-152
1.5 2.10 0.060 2.0
LPS6225-222ML
2.2 4.00 0.045 2.4
DO1608C-332
3.3 2.00 0.080 2.9
MSS6132-472ML
4.7 2.60 0.056 3.2
DO1813P-682HC
6.8 2.20 0.080 5.0
Cooper
SD414-2R2
2.2 2.73 0.061 1.35
DRA73-6R8-R
6.8 2.96 0.041 3.55
UP1B-100
10 1.90 0.111 5.0
Toko
(D62F)847FY-2R4M 2.4
2.5 0.037 2.7
(D73LF)817FY-2R2M 2.2
2.7 0.03 3.0
This analysis is valid for continuous mode operation
(I
OUT
> I
LIM
/2). For details of maximum output current in
discontinuous mode operation, see Linear Technologys
Application Note AN44. Finally, for duty cycles greater
than 50% (V
OUT
/V
IN
> 0.5), a minimum inductance is
required to avoid subharmonic oscillations. This minimum
inductance is:
SW1:L
MIN
= V
OUT
+V
F
(
)
"
0.45
f
SW
SW2, SW3:L
MIN
= V
OUT
+V
F
( )
"
0.9
f
SW
with L
MIN
in 糎 and f
SW
in MHz.
Output Capacitor Selection
The output capacitor lters the inductor current to generate
an output with low voltage ripple. It also stores energy in
order to satisfy transient loads and stabilize the LT3507s
control loop. Because the LT3507 operates at a high
frequency, minimal output capacitance is necessary. In
addition, the control loop operates well with or without
the presence of output capacitor series resistance (ESR).
Ceramic capacitors, which achieve very low output ripple
and small circuit size, are therefore an option.
You can estimate output ripple with the following
equations:
V
RIPPLE
=
擨
L
8"f"C
OUT
for ceramic capacitors
and
V
RIPPLE
=擨
L
"ESR for electrolytic capacitors
(tantalum and aluminum)
where 擨
L
is the peak-to-peak ripple current in the inductor.
The RMS content of this ripple is very low so the RMS
current rating of the output capacitor is usually not of
concern. It can be estimated with the formula:
I
C(RMS)
=
擨
L
12
Another constraint on the output capacitor is that it must
have greater energy storage than the inductor; if the stored
energy in the inductor transfers to the output, the resulting
voltage step should be small compared to the regulation
voltage. For a 5% overshoot, this requirement indicates:
C
OUT
>10"L"
I
LIM
V
OUT
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
2
The low ESR and small size of ceramic capacitors make them
the preferred type for LT3507 applications. Not all ceramic
capacitors are the same, however. Many of the higher value
capacitors use poor dielectrics with high temperature and
voltage coef cients. In particular, Y5V and Z5U types lose
a large fraction of their capacitance with applied voltage
and at temperature extremes. Because loop stability and
transient response depend on the value of C
OUT
, this loss
may be unacceptable. Use X7R and X5R types.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3508 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic 1.4A Step-Down Switching Regulator |
| LT3508EFE#PBF | 功能描述:IC REG BUCK ADJ 1.4A DL 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LT3508EFE#TRPBF | 功能描述:IC REG BUCK ADJ 1.4A DL 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LT3508EFEPBF | 制造商:Linear Technology 功能描述:Dual 1.4A Step-Down Regulator LT3508 |
| LT3508EFE-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic 1.4A Step-Down Switching Regulator |
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