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参数资料
| 型号： | LT1943EFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | IC REG SW QUAD TFT LCD 28-TSSOP |
| 标准包装： | 2,000 |
| 应用： | 转换器，TFT，LCD |
| 输入电压： | 4.5 V ~ 22 V |
| 输出数： | 4 |
| 输出电压： | 1.25 V ~ 40 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SOIC（0.173"，4.40mm 宽）裸露焊盘 |
| 供应商设备封装： | 28-TSSOP 裸露焊盘 |
| 包装： | 带卷 (TR) |
LT1943
OPERATIO
Table 3. Schottky Diodes
R4 should be 10k ? or less to avoid bias current errors. If
Part Number
V R (V)
I AVE (A) V F at 1A (mV)
V F at 2A (mV)
switcher 4 is used to generate a positive output voltage,
On Semiconductor
NFB4 should be tied to FB4.
MBRM120E
MBRM140
20
40
1
1
530
550
595
V OUT
Diodes Inc.
R3
B120
20
1
500
FB4
B130
B220
B230
30
20
30
1
2
2
500
500
500
R4
NFB4
1943 A1
B240
International Rectifier
40
2
500
Regulating Negative Output Voltages
10BQ030
20BQ030
30
30
1
2
420
470
470
The LT1943 contains an inverting op amp with its non-
inverting terminal tied to ground and its output connected
to the FB4 pin. Use this op amp to generate a voltage at FB4
Boost Pin Considerations
The minimum operating voltage of an LT1943 application
that is proportional to V OUT4 . Choose the resistors accord-
ing to:
is limited by the undervoltage lockout ~4V and by the
maximum duty cycle. The boost circuit also limits the
minimum input voltage for proper start-up. If the input
voltage ramps slowly, or the LT1943 turns on when the
R 6 =
R5 ? | V 0 UT |
1 . 245 V
–V OUT
output is already in regulation, the boost capacitor may not
be fully charged. Because the boost capacitor charges
with the energy stored in the inductor, the circuit will rely
on some minimum load current to get the boost circuit
R6
NFB4
running properly. This minimum load will depend on input
and output voltages. The Typical Performance Character-
C1
10pF
R5
10k
FB4
istics section shows a plot of the minimum load current to
start as a function of input voltage for a 3.3V output. The
minimum load current generally goes to zero once the
circuit has started. Even without an output load current, in
many cases the discharged output capacitor will present
a load to the switcher that will allow it to start.
INVERTER/STEP-UP CONSIDERATIONS
1943 A2
Use 10k for R5. Tie 10pF in parallel with R5.
Duty Cycle Range
The maximum duty cycle (DC) of the LT1943 switching
regulator is 85% for SW2, and 83% for SW3 and SW4. The
duty cycle for a given application using the step-up or
charge pump topology is:
Regulating Positive Output Voltages
The output voltage is programmed with a resistor divider
between the output and the FB pin. Choose the resistors
DC =
| V OUT | – V IN
| V OUT |
according to:
R3 = R4(V OUT /1.25 – 1)
The duty cycle for a given application using the inverter or
SEPIC topology is:
1943fa
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1944 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad DCDC Converter for Triple Outputs TFT Supply Plus LED Driver |
| LT1944-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Micropower Step-Up DC/DC Converter |
| LT1944-1EMS | 功能描述:IC REG BST ADJ 0.1A/175MA 10MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LT1944-1EMS#PBF | 功能描述:IC REG BST ADJ 0.1A/175MA 10MSOP 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 |
| LT1944-1EMS#TR | 功能描述:IC REG BST ADJ 0.1A/175MA 10MSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
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