- 您现在的位置：买卖IC网 > PDF目录44986 > LT3689EUD-5#TRPBF (LINEAR TECHNOLOGY CORP) 1.95 A SWITCHING REGULATOR, 2160 kHz SWITCHING FREQ-MAX, PQCC16 PDF资料下载
参数资料
| 型号： | LT3689EUD-5#TRPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.95 A SWITCHING REGULATOR, 2160 kHz SWITCHING FREQ-MAX, PQCC16 |
| 封装： | 3 X 3 MM, LEAD FREE, PLASTIC, MO-220WEED-2, QFN-16 |
| 文件页数： | 14/32页 |
| 文件大小： | 2188K |
| 代理商： | LT3689EUD-5#TRPBF |
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页当前第14页第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页第31页第32页
LT3689/LT3689-5
21
3689fd
Another way to lower the start-up voltage is by using a
resistor divider on the EN/UVLO pin (see the Shutdown
and Undervoltage Lockout section). A resistor divider on
EN/UVLO pin programs the turn-on threshold to slightly
higher than the minimum VINvoltagerequiredtorunatfull
load. Below the EN/UVLO high voltage, the part will stay
shut off and the output cap will remain discharged during
the worse case slow VIN ramp. When the EN/UVLO pin
crosses the EN/UVLO high threshold, the part will turn on
and the empty output capacitor will provide enough load
to bring the output voltage in regulation. This technique
significantly lowers the start-up voltage of the circuit. The
plot in Figure 7 depicts the minimum load required to start
and run (as a function of input voltage). It also depicts the
benefit of programming the EN/UVLO threshold to lower
the start-up voltage at low load currents. At light loads, the
inductor current becomes discontinuous and the effective
dutycyclecanbeveryhigh.Thisreducestheminimuminput
voltagetoapproximately300mVaboveVOUT.Athigherload
currents, the inductor current is continuous and the duty
cycle is limited by the maximum duty cycle of the LT3689,
requiring a higher input voltage to maintain regulation.
Soft-Start
The LT3689 has an internal soft-start that gradually ramps
uptheswitchcurrentlimitfromabout100mAtotheswitch’s
maximum current limit in typical value of 150s, as shown
in Figure 8. This feature limits the inrush current during
start-upandpreventstheswitchcurrentfromspikingwhen
the EN/UVLO pin crosses the UVLO threshold. A soft-start
sequence is also initiated right after a VIN overvoltage/
undervoltage lockout, or thermal shutdown fault in order
to prevent the switch current from suddenly jumping to
its maximum current limit.
APPLICATIONS INFORMATION
Figure 7. LT3689 Minimum VIN to Start and Run vs Load
Figure 8. Internal Soft-Start
20s/DIV
VOUT
2V/DIV
VIN = 12V
VOUT = 5V
f = 2MHz
CIN = 1F CERAMIC + 100F ELECTROLYTIC
IVIN
0.2A/DIV
IL
0.5A/DIV
3689 F08
LOAD (mA)
1
7.0
V IN
(V
)
7.5
10
100
1000
6.5
6.0
5.5
5.0
8.0
3589 F07a
TO START:
EN/UVLO TIED TO VIN
TO RUN
VOUT = 5V
L = 8.2H
fSW = 800KHz
TA = 25°C
TO START: EN/UVLO HIGH
THRESHOLD = 6.15V
LOAD (mA)
1
5.0
V IN
(V
)
5.5
10
100
1000
4.5
4.0
3.5
3.0
6.0
3589 F07b
TO START:
EN/UVLO TIED TO VIN
TO RUN
VOUT = 3.3V
L = 8.2H
fSW = 800KHz
TA = 25°C
TO START: EN/UVLO HIGH
THRESHOLD = 4.85V
相关PDF资料 |
PDF描述 |
|---|---|
| LT3689EMSE-5#PBF | 1.95 A SWITCHING REGULATOR, 2160 kHz SWITCHING FREQ-MAX, PDSO16 |
| LT3689IUD-5#TRPBF | 1.95 A SWITCHING REGULATOR, 2160 kHz SWITCHING FREQ-MAX, PQCC16 |
| LT3689IMSE-5#TRPBF | 1.95 A SWITCHING REGULATOR, 2160 kHz SWITCHING FREQ-MAX, PDSO16 |
| LT3692IUH#TRPBF | 5.8 A DUAL SWITCHING CONTROLLER, 2750 kHz SWITCHING FREQ-MAX, PQCC32 |
| LT3692IUH#PBF | 5.8 A DUAL SWITCHING CONTROLLER, 2750 kHz SWITCHING FREQ-MAX, PQCC32 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3689EUD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:700mA Step-Down Regulator with Power-On Reset and Watchdog Timer |
| LT3689EUD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:700mA Step-Down Regulator with Power-On Reset and Watchdog Timer |
| LT3689HMSE#PBF | 功能描述:IC REG BUCK ADJ 0.7A 16MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:MIC23xxx HyperLight Load™ Regulators 标准包装:5,000 系列:HyperLight Load® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.8V 输入电压:2.7 V ~ 5.5 V PWM 型:混合物 频率 - 开关:4MHz 电流 - 输出:2A 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:8-VFDFN 裸露焊盘，8-MLF? 包装:带卷 (TR) 供应商设备封装:8-MLF?（2x2） 产品目录页面:1094 (CN2011-ZH PDF) 其它名称:576-3303-2 |
| LT3689HMSE#TRPBF | 功能描述:IC REG BUCK ADJ 0.7A 16MSOP 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 |
| LT3689HMSE-5#PBF | 功能描述:IC REG BUCK 5V 0.7A 16MSOP 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。