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参数资料
| 型号： | LTC3809EMS-1 |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1 A SWITCHING CONTROLLER, 600 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封装： | PLASTIC, MSOP-10 |
| 文件页数： | 10/24页 |
| 文件大小： | 318K |
| 代理商： | LTC3809EMS-1 |
LTC3809-1
38091f
18
VAUX
VOUT
COUT
VIN
LTC3809-1
+
R6
R5
L1
1:N
MODE
BG
SW
TG
38091 F06
The auxiliary output voltage VAUX is normally set, as
shown in Figure 6, by the turns ratio N of the transformer:
VAUX = (N + 1) VOUT
Figure 6. Auxiliary Output Loop Connection
Figure 7. Line Regulation of VREF and Maximum Sense Voltage
INPUT VOLTAGE (V)
75
NORMALIZED
VOL
TAGE
OR
CURRENT
(%)
85
95
105
80
90
100
2.2
2.4
2.6
2.8
38091 F07
3.0
2.1
2.0
2.3
2.5
2.7
2.9
VREF
MAXIMUM
SENSE VOLTAGE
However, if the controller goes into pulse skipping opera-
tion and halts switching due to a light primary load current,
then VAUX will droop. An external resistor divider from
VAUX to the MODE sets a minimum voltage VAUX(MIN):
VV
R
AUX MIN
()
.
=+
04
1
6
5
If VAUX drops below this value, the MODE voltage forces
temporary continuous switching operation until VAUX is
again above its minimum.
Fault Condition: Short-Circuit and Current Limit
If the LTC3809-1’s load current exceeds the short-circuit
current limit (ISC), which is set by the short-circuit sense
threshold (
VSC) and the on resistance (RDS(ON)) of bot-
tom N-channel MOSFET, the top P-channel MOSFET is
turned off and will not be turned on at the next clock cycle
unless the load current decreases below ISC. In this case,
the controller’s switching frequency is decreased and
the output is regulated by short-circuit (current
limit) protection.
In a hard short (VOUT = 0V), the top P-channel MOSFET is
turned off and kept off until the short-circuit condition is
cleared. In this case, there is no current path from input
supply (VIN) to either VOUT or GND, which prevents
excessive MOSFET and inductor heating.
Low Supply Voltage
Although the LTC3809-1 can function down to below
2.4V, the maximum allowable output current is reduced as
VIN decreases below 3V. Figure 7 shows the amount of
change as the supply is reduced down to 2.4V. Also shown
is the effect on VREF.
Minimum On-Time Considerations
Minimum on-time, tON(MIN) is the smallest amount of time
that the LTC3809-1 is capable of turning the top P-channel
MOSFET on. It is determined by internal timing delays and
the gate charge required to turn on the top MOSFET. Low
duty cycle and high frequency applications may approach
the minimum on-time limit and care should be taken to
ensure that:
t
V
fV
ON MIN
OUT
OSC
IN
()
<
APPLICATIO S I FOR ATIO
WU
UU
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3809EMSE | 功能描述:IC REG CTRLR BUCK PWM CM 10-MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3809EMSE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 10-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3809EMSE#TR | 功能描述:IC REG CTRLR BUCK PWM CM 10-MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3809EMSE#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 10-MSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3809EMSE-1 | 功能描述:IC REG CTRLR BUCK PWM CM 10-MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
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