參數(shù)資料
型號(hào): LT3645HMSE#TRPBF
廠商: Linear Technology
文件頁數(shù): 10/24頁
文件大小: 300K
描述: IC REG DL BUCK/LINEAR 12-MSOP
標(biāo)準(zhǔn)包裝: 2,500
拓?fù)洌?/td> 降壓(降壓)(1),線性(LDO)(1)
功能: 車載
輸出數(shù): 2
頻率 - 開關(guān): 750kHz
電壓/電流 - 輸出 1: 0.8 V ~ 16 V,500mA
電壓/電流 - 輸出 2: 0.8 V ~ 8 V,200mA
帶 LED 驅(qū)動(dòng)器:
帶監(jiān)控器:
帶序列發(fā)生器:
電源電壓: 3.6 V ~ 36 V
工作溫度: -40°C ~ 150°C
安裝類型: 表面貼裝
封裝/外殼: 12-TSSOP (0.118",3.00mm 寬)裸露焊盤
供應(yīng)商設(shè)備封裝: 12-MSOP,裸露焊盤
包裝: 帶卷 (TR)
LT3645
10
3645f
FB Resistor Networks
The output voltages are programmed with resistor dividers
between the outputs and the V
FB
 and V
FB2
 pins. Choose
the resistors according to
 
R1R2
V
OUT
0.8
1
R3R4
V
OUT2
0.797
1
R2 and R4 should be 20k or less to avoid bias current
errors. In the step-down converter, an optional phase
lead capacitor of 22pf between V
OUT
 and V
FB
 reduces
light-load ripple.
Input Voltage Range
The maximum operating input voltage for the LT3645 is
36V. The minimum input voltage is determined by either
the LT3645s minimum operating voltage of 3.6V or by
its maximum duty cycle. The duty cycle is the fraction of
time that the internal switch is on and is determined by
the input and output voltages:
  DC = (V
OUT
 + V
D
)/(V
IN
  V
SW
 + V
D
)
where V
D
 is the forward voltage drop of the catch diode
(~0.4V) and V
SW
 is the voltage drop of the internal switch
(~0.4V at maximum load). This leads to a minimum input
voltage of:
  V
IN(MIN)
 = ((V
OUT
 + V
D
)/DC
MAX
)  V
D
 + V
SW
with DC
MAX
 = 0.83 for the LT3645.
The maximum input voltage is determined by the absolute
maximum ratings of the V
IN
 and BOOST pins. For  xed
frequency operation, the maximum input voltage is de-
termined by the minimum duty cycle, which is:
  V
IN(MAX)
 = ((V
OUT
 + V
D
)/DC
MIN
)  V
D
 + V
SW
with DC
MIN
 = 0.075 for the LT3645.
Note that this is a restriction on the operating input voltage
for continuous mode operation. The circuit will continue
to regulate the output up until the overvoltage lockout
input voltage (38.5V). The part will tolerate transient input
 APPLICATIONS INFORMATION
voltages up to 55V, but once the input voltage exceeds
36V, the power switch will shut off and stop regulating
the output voltage until the input voltage falls below 36V.
Minimum On Time
The LT3645 will operate at the correct frequency while
the input voltage is below V
IN(MAX)
. At input voltages
that exceed V
IN(MAX)
, the LT3645 will still regulate the
output properly (up to 38.5V); however, the LT3645 will
skip pulses to regulate the output voltage resulting in
increased output voltage ripple.
Figure 1 illustrates switching waveforms for a LT3645
application with V
OUT
 = 1.2V near V
IN(MAX)
 = 21.3V.
Figure 1.
As the input voltage is increased, the part is required
to switch for shorter periods of time. Delays associated
with turning off the power switch dictate the minimum on
time of the part. The minimum on time for the LT3645 is
100ns. Figure 2 illustrates the switching waveforms when
the input voltage is increased to V
IN
 = 22V.
3645 F01
SWITCH
VOLTAGE
10V/DIV
INDUCTOR
CURRENT
0.5A/DIV
V
IN
 = 18V
V
OUT
 = 1.2V
I
OUT
 = 500mA
C
OUT
 = 10糉
L = 10糎
3645 F02
SWITCH
VOLTAGE
10V/DIV
INDUCTOR
CURRENT
0.5A/DIV
V
IN
 = 22V
V
OUT
 = 1.2V
I
OUT
 = 500mA
C
OUT
 = 10糉
L = 10糎
Figure 2.
相關(guān)PDF資料
PDF描述
LT3694IFE-1#TRPBF IC REG TRPL BUCK/LINEAR 20TSSOP
LT4220IGN#TR IC CTLR HOTSWAP DUAL 16-SSOP
LT4250LCN8 IC CONTRLR HOT SWAP NEG 48V 8DIP
LT4254CGN IC CTRLR HOTSWAP POSVOLT 16SSOP
LT4256-1IS8#TRPBF IC CTRLR HOTSWAP HV LATCH 8SOIC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT3645IMSE#PBF 功能描述:IC REG DL BUCK/LINEAR 12-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓?fù)?降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動(dòng)器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3645IMSE#TRPBF 功能描述:IC REG DL BUCK/LINEAR 12-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓?fù)?降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動(dòng)器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3645IUD#PBF 功能描述:IC REG DL BUCK/LINEAR 16-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓?fù)?降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動(dòng)器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3645IUD#TRPBF 功能描述:IC REG DL BUCK/LINEAR 16-QFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 拓?fù)?降壓(降壓)同步(3),線性(LDO)(2) 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動(dòng)器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應(yīng)商設(shè)備封裝:* 包裝:*
LT3650 制造商:LINER 制造商全稱:Linear Technology 功能描述:High Voltage High Current Controller for Battery Charging and Power Management