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参数资料
| 型号： | LTC3900MPS8 |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING REGULATOR, PDSO8 |
| 封装： | PLASTIC, SOP-8 |
| 文件页数： | 2/20页 |
| 文件大小： | 277K |
| 代理商： | LTC3900MPS8 |
LTC3900
10
3900fb
The value of the resistors, RCS1, RCS2 and RCS3, should
be calculated using the following formulas to meet both
the threshold and clamp voltage requirements:
k = 48 IRIPPLE RDS(ON) –1
RCS2 = {200 VIN(MAX) (NS/NP) –2200 (1 + k)} /k
RCS1 = k RCS2
RCS3 = {RCS1 RCS2} / {RCS1 + RCS2}
If k = 0 or less than zero, RCS2 is not needed and RCS1
= RCS3 = {VIN(MAX) (NS/NP) – 11V} / 5mA
where:
IRIPPLE = Inductor peak-to-peak ripple current
RDS(ON) = On-resistance of Q4 at IRIPPLE/2
VIN(MAX) = Primary side main supply maximum input
voltage
NS/NP = Power transformer T1, turn ratio
If the LTC3900 still operates in discontinuous mode with
the calculated resistance value, increase the value of RCS1
to raise the threshold. The resistors RCS1andRCS2andthe
CS+ pins input capacitance plus the PCB trace capacitance
form an R-C delay; this slows down the response time
of the comparator. The resistors and CS+ input leakage
currents also create an input offset error.
To minimize this delay and error, do not use resistance
value higher than required and make the PCB trace from
the resistors to the LTC3900 CS+/CS– pins as short as
possible. Add a series resistor, RCS3 with value equal to
parallel sum of RCS1 and RCS2 to the CS– pin and connect
the other end of RCS3 directly to the source of Q4.
SYNC Input
Figure 7 shows the external circuit for the LTC3900 SYNC
input. With a selected type of pulse transformers, the
values of the CSG and RSYNC should be adjusted to obtain
an optimum SYNC pulse amplitude and width. A bigger
capacitor, CSG, generates a higher and wider SYNC pulse.
The peak of this pulse should be much higher than the typi-
cal LTC3900 SYNC threshold of ±1.4V. Amplitudes greater
than ±5V will help to speed up the SYNC comparator and
reduce the SYNC to drivers propagation delay. The pulse
width should be wider than 75ns. Overshoot during the
pulse transformer reset interval must be minimized and
kept below the minimum SYNC threshold of ±1V. The
amount of overshoot can be reduced by having a smaller
RSYNC.
SYNC
FG
CG
3900 F06b
INDUCTOR
CURRENT
0A
ADJUSTED CURRENT
SENSE THRESHOLD
Figure 6b. Continuous Current Mode Operation
with Adjusted Current Sense Threshold
Figure 7. SYNC Input Circuit
RSYNC
470
T2
T2: COILCRAFT Q4470B
OR PULSE P0926
CSG
220pF
PRIMARY
CONTROLLER
SG
(SOUT)
LTC3900
SYNC
3900 F07
applicaTions inForMaTion
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3900MPS8#PBF | 功能描述:IC DRIVER RECT SYNC CONV 8SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 外部开关 系列:- 标准包装:5 系列:- 配置:低端 输入类型:非反相 延迟时间:600ns 电流 - 峰:12A 配置数:1 输出数:1 高端电压 - 最大（自引导启动）:- 电源电压:14.2 V ~ 15.8 V 工作温度:-20°C ~ 60°C 安装类型:通孔 封装/外壳:21-SIP 模块 供应商设备封装:模块 包装:散装 配用:BG2A-NF-ND - KIT DEV BOARD FOR IGBT 其它名称:835-1063 |
| LTC3900MPS8#TRPBF | 功能描述:IC DRIVER RECT SYNC CONV 8SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 外部开关 系列:- 标准包装:5 系列:- 配置:低端 输入类型:非反相 延迟时间:600ns 电流 - 峰:12A 配置数:1 输出数:1 高端电压 - 最大（自引导启动）:- 电源电压:14.2 V ~ 15.8 V 工作温度:-20°C ~ 60°C 安装类型:通孔 封装/外壳:21-SIP 模块 供应商设备封装:模块 包装:散装 配用:BG2A-NF-ND - KIT DEV BOARD FOR IGBT 其它名称:835-1063 |
| LTC3901EGN | 功能描述:IC DRIVER RECT SYNC CONV 16SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 外部开关 系列:- 标准包装:5 系列:- 配置:低端 输入类型:非反相 延迟时间:600ns 电流 - 峰:12A 配置数:1 输出数:1 高端电压 - 最大（自引导启动）:- 电源电压:14.2 V ~ 15.8 V 工作温度:-20°C ~ 60°C 安装类型:通孔 封装/外壳:21-SIP 模块 供应商设备封装:模块 包装:散装 配用:BG2A-NF-ND - KIT DEV BOARD FOR IGBT 其它名称:835-1063 |
| LTC3901EGN#PBF | 功能描述:IC DRIVER RECT SYNC CONV 16SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 外部开关 系列:- 标准包装:5 系列:- 配置:低端 输入类型:非反相 延迟时间:600ns 电流 - 峰:12A 配置数:1 输出数:1 高端电压 - 最大（自引导启动）:- 电源电压:14.2 V ~ 15.8 V 工作温度:-20°C ~ 60°C 安装类型:通孔 封装/外壳:21-SIP 模块 供应商设备封装:模块 包装:散装 配用:BG2A-NF-ND - KIT DEV BOARD FOR IGBT 其它名称:835-1063 |
| LTC3901EGN#TR | 功能描述:IC DRIVER RECT SYNC CONV 16SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 外部开关 系列:- 标准包装:5 系列:- 配置:低端 输入类型:非反相 延迟时间:600ns 电流 - 峰:12A 配置数:1 输出数:1 高端电压 - 最大（自引导启动）:- 电源电压:14.2 V ~ 15.8 V 工作温度:-20°C ~ 60°C 安装类型:通孔 封装/外壳:21-SIP 模块 供应商设备封装:模块 包装:散装 配用:BG2A-NF-ND - KIT DEV BOARD FOR IGBT 其它名称:835-1063 |
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