- 您现在的位置：买卖IC网 > PDF目录13812 > LT3690MPUFE#PBF (Linear Technology)IC REG BUCK SYNC ADJ 4A 26QFN PDF资料下载
参数资料
| 型号： | LT3690MPUFE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 15/30页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 4A 26QFN |
| 标准包装： | 61 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 20 V |
| 输入电压： | 3.9 V ~ 36 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 138kHz ~ 1.5MHz |
| 电流 - 输出： | 4A |
| 同步整流器： | 是 |
| 工作温度： | -55°C ~ 150°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 26-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 26-QFN-EP（4x6） |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页当前第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页
LT3690
APPLICATIONS INFORMATION
C OUT =
Oneapproachtochoosingtheinductoristostartwiththe
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 LT3690 will be able to
deliver the required output current. Note again that these
equations assume that the inductor current is continu-
ous. Discontinuous operation occurs when I OUT is less
than ΔI L /2.
Input Capacitor
Bypass the input of the LT3690 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 10μF ceramic capacitor is adequate to bypass
the LT3690, and easily handles 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 significant 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 LT3690 and to force this very high frequency
switching current into a tight local loop, minimizing EMI.
A 10μF capacitor is capable of this task, but only if it is
placed close to the LT3690 (see the PCB Layout section).
A second precaution regarding the ceramic input capacitor
concerns the maximum input voltage rating of the LT3690.
A ceramic input capacitor combined with trace or cable
inductance forms a high quality (under damped) tank
circuit. If the LT3690 circuit is plugged into a live supply,
the input voltage can ring to twice its nominal value, pos-
sibly exceeding the LT3690’s maximum voltage rating.
See Application Note 88 for more details.
Output Capacitor and Output Ripple
The output capacitor has two essential functions. Along
with the inductor, it filters the square wave generated by the
LT3690 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
LT3690’s control loop. Ceramic capacitors have very low
equivalent series resistance (ESR) and provide the best
ripple performance. A good starting value is:
150
V OUT ? ? SW
where ? SW is in MHz, and C OUT is the recommended out-
put capacitance in μF. Use X5R or X7R types, which will
provide low output ripple and good transient response.
Using a high value capacitor on the output can improve
transient performance, but a phase lead capacitor across
the feedback resistor R1 may be required to get the full
benefit (see the Frequency Compensation section).
High performance electrolytic capacitors can be used for
the output capacitor. If using an electrolytic capacitor,
choose one intended for use in switching regulators, and
with a specified ESR of 0.03Ω or less. Such a capacitor
will be larger than a ceramic capacitor and will have a
larger capacitance because the capacitor must be large to
achieve low ESR. Table 3 lists several capacitor vendors.
Table 3. Capacitor Vendors
VENDOR PART SERIES COMMENTS
Panasonic Ceramic, Polymer, Tantalum EEF Series
Kemet Ceramic, Tantalum T494, T495
Sanyo Ceramic, Polymer, Tantalum POSCAP
Murata Ceramic
AVX Ceramic, Tantalum TPS Series
Taiyo Yuden Ceramic
Ceramic Capacitors
Ceramic capacitors are small, robust and have very
low ESR. However, ceramic capacitors can sometimes
cause problems when used with the LT3690 due to their
piezoelectric nature. When in Burst Mode operation, the
LT3690’s switching frequency depends on the load current,
and at very light loads the LT3690 can excite the ceramic
capacitor at audio frequencies, generating audible noise.
3690fa
15
相关PDF资料 |
PDF描述 |
|---|---|
| UST1E220MDD | CAP ALUM 22UF 25V 20% RADIAL |
| LT1074HVCT#06PBF | IC REG MULTI CONFIG ADJ TO220-5 |
| MAX6722AUTZID5+T | IC SUPERVISOR MPU SOT23-6 |
| RBA30DRMD-S273 | CONN EDGECARD 60POS .125 SQ WW |
| MAX6719AUTYDD1+T | IC SUPERVISOR MPU SOT23-6 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3692 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic Dual Tracking |
| LT3692A | 制造商:LINER 制造商全称:Linear Technology 功能描述:Monolithic Dual Tracking |
| LT3692AEFE#PBF | 功能描述:IC REG BUCK ADJ 3.5A DL 38TSSOP 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 |
| LT3692AEFE#TRPBF | 功能描述:IC REG BUCK ADJ 3.5A DL 38TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LT3692AEUH#PBF | 功能描述:IC REG BUCK ADJ 3.5A DL 32QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
发布紧急采购，3分钟左右您将得到回复。