参数资料
型号: LT3682IDD#TRPBF
厂商: LINEAR TECHNOLOGY CORP
元件分类: 稳压器
英文描述: SWITCHING REGULATOR, PDSO12
封装: 3 X 3 MM, LEAD FREE, PLASTIC, DFN-12
文件页数: 6/24页
文件大小: 253K
代理商: LT3682IDD#TRPBF
LT3682
14
3682f
APPLICATIONS INFORMATION
For SYNC pin tied to 0.8V or more, or tied to a clock source
for synchronization:
II
I
ADC
I
OUT MAX
LIM
LL
()
.(
.
)
=
ΔΔ
2
118
10 29
2
Choosing an inductor value so that the ripple current is
small will allow a maximum output current near the switch
current limit.
Table 1. Inductor Vendors
VENDOR
URL
PART SERIES
TYPE
Murata
www.murata.com
LQH55D
Open
TDK
www.componenttdk.com SLF7045
SLF10145
Shielded
Toko
www.toko.com
D62CB
D63CB
D73C
D75F
Shielded
Open
Coilcraft
www.coilcraft.com
MSS7341
MSS1038
Shielded
Sumida
www.sumida.com
CR54
CDRH74
CDRH6D38
CR75
Open
Shielded
Open
One approach to choosing the inductor is to start with the
simple rule given above, look at the available inductors,
and choose one to meet cost or space goals. Then use
these equations to check that the LT3682 will be able to
deliver the required output current. Note again that these
equations assume that the inductor current is continuous.
Discontinuous operation occurs when IOUT is less than
ΔIL/2.
Input Capacitor
Bypass the input of the LT3682 circuit with a ceramic capaci-
tor of X7R or X5R type. Y5V types have poor performance
over temperature and applied voltage, and should not be
used. A 2.2μF to 10μF ceramic capacitor is adequate to
bypass the LT3682 and will easily handle the ripple current.
Note that larger input capacitance is required when a lower
switching frequency is used. If the input power source has
high impedance, or there is signicant inductance due to
long wires or cables, additional bulk capacitance may be
necessary. This can be provided with a lower performance
electrolytic capacitor.
Step-down regulators draw current from the input sup-
ply in pulses with very fast rise and fall times. The input
capacitor is required to reduce the resulting voltage
ripple at the LT3682 and to force this very high frequency
switching current into a tight local loop, minimizing EMI.
A 2.2μF capacitor is capable of this task, but only if it is
placed close to the LT3682 (see the PCB Layout section
for more information). A second precaution regarding
the ceramic input capacitor concerns the maximum input
voltage rating of the LT3682. A ceramic input capacitor
combined with trace or cable inductance forms a high-Q
(underdamped) tank circuit. If the LT3682 circuit is plugged
into a live supply, the input voltage can ring to twice its
nominal value, possibly exceeding the LT3682’s voltage
rating. For details see Application Note 88.
Output Capacitor and Output Ripple
The output capacitor has two essential functions. Along
with the inductor, it lters the square wave generated by the
LT3682 to produce the DC output. In this role it determines
the output ripple, and low impedance at the switching
frequency is important. The second function is to store
energy in order to satisfy transient loads and stabilize the
LT3682’s control loop. Ceramic capacitors have very low
equivalent series resistance (ESR) and provide the best
ripple performance. A good starting value is:
C
Vf
OUT
OUT SW
=
50
where fSW is in MHz, and COUT is the recommended
output capacitance in μF. Use X5R or X7R types. This
choice will provide low output ripple and good transient
response. Transient performance can be improved with
a higher value capacitor if the compensation network is
also adjusted to maintain the loop bandwidth. A lower
value of output capacitor can be used to save space
and cost but transient performance will suffer. See the
Frequency Compensation section to choose an appropriate
compensation network.
相关PDF资料
PDF描述
LT3682EDD#TRPBF SWITCHING REGULATOR, PDSO12
LT3682EDD#PBF SWITCHING REGULATOR, PDSO12
LT5554IUH#TRPBF SPECIALTY ANALOG CIRCUIT, PQCC32
LT5554IUH#PBF SPECIALTY ANALOG CIRCUIT, PQCC32
LTC1421-2.5CSW#PBF 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO24
相关代理商/技术参数
参数描述
LT3684 制造商:LINER 制造商全称:Linear Technology 功能描述:36V, 2A, 2.8MHz Step-Down Switching Regulator
LT3684EDD 制造商:LINER 制造商全称:Linear Technology 功能描述:36V, 2A, 2.8MHz Step-Down Switching Regulator
LT3684EDD#PBF 功能描述:IC REG BUCK ADJ 2A 10DFN 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
LT3684EDD#PBF 制造商:Linear Technology 功能描述:DC-DC CONVERTER BUCK 2.8MHZ 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, 2.8MHZ, DFN-10
LT3684EDD#TRPBF 功能描述:IC REG BUCK ADJ 2A 10DFN 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