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参数资料
| 型号： | LTC1772BES6#TRM |
| 厂商： | Linear Technology |
| 文件页数： | 10/16页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM SOT23-6 |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 650kHz |
| 占空比： | 100% |
| 电源电压： | 2.5 V ~ 9.8 V |
| 降压： | 是 |
| 升压： | 无 |
| 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 ~ 85°C |
| 封装/外壳： | SOT-23-6 细型，TSOT-23-6 |
| 包装： | 剪切带 (CT) |
| 其它名称： | LTC1772BES6 LTC1772BES6#TRMCT LTC1772BES6-ND |
LTC1772B
APPLICATIONS INFORMATION
size or height requirements in the design. Due to the high
operating frequency of the LTC1772B, ceramic capacitors
can also be used for C IN . Always consult the manufacturer
if there is any question.
The selection of C OUT is driven by the required effective
series resistance (ESR). Typically, once the ESR require-
ment is satis?ed, the capacitance is adequate for ?ltering.
The output ripple (ΔV OUT ) is approximated by:
1
V OUT I RIPPLE ESR +
4fC OUT
where f is the operating frequency, C OUT is the output
capacitance and I RIPPLE is the ripple current in the induc-
tor. The output ripple is highest at maximum input voltage
since ΔI L increases with input voltage.
Ef?ciency Considerations
The ef?ciency of a switching regulator is equal to the output
power divided by the input power times 100%. It is often
useful to analyze individual losses to determine what is
limiting the ef?ciency and which change would produce
the most improvement. Ef?ciency can be expressed as:
Ef?ciency = 100% – ( η 1 + η 2 + η 3 + ...)
where η 1, η 2, etc. are the individual losses as a percent-
age of input power.
Although all dissipative elements in the circuit produce
losses, four main sources usually account for most of
the losses in LTC1772B circuits: 1) LTC1772B DC bias
105
Manufacturers such as Nichicon, United Chemicon and
Sanyo should be considered for high performance through-
hole capacitors. The OS-CON semiconductor dielectric
capacitor available from Sanyo has the lowest ESR (size)
product of any aluminum electrolytic at a somewhat higher
price. Once the ESR requirement for C OUT has been met,
the RMS current rating generally far exceeds the I RIPPLE(P-P)
requirement.
100
95
90
85
80
V REF
V ITH
Low Supply Operation
75
2.0
2.2
2.4 2.6 2.8
INPUT VOLTAGE (V)
3.0
Although the LTC1772B can function down to approxi-
mately 2.0V, the maximum allowable output current is
reduced when V IN decreases below 3V. Figure 4 shows
the amount of change as the supply is reduced down to
2V. Also shown in Figure 4 is the effect of V IN on V REF as
1772 F03
Figure 4. Line Regulation of V REF and V ITH
V OUT
V IN goes below 2.3V.
Setting Output Voltage
The regulated output voltage is determined by:
LTC1772B
V FB
3
R2
R1
1772 F04
V OUT = 0.8 1 +
R2
R1
Figure 5. Setting Output Voltage
For most applications, an 80k resistor is suggested for
R1. To prevent stray pickup, locate resistors R1 and R2
close to LTC1772B.
1772bfa
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC1772BIS6#PBF | 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Step Down 2.5V to 9.8V Input 6-Pin TSOT-23 |
| LTC1772BIS6#TRMPBF | 功能描述:IC REG CTRLR BUCK PWM TSOT23-6 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) |
| LTC1772BIS6#TRPBF | 功能描述:IC REG CTRLR BUCK PWM TSOT23-6 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) |
| LTC1772CS6 | 制造商:Linear Technology 功能描述:Swithed-Mode Power Supply Controller, Current Mode Type, 3 Pin, Plastic, TO-236 |
| LTC1772CS6#PBF | 制造商:Linear Technology 功能描述:DC DC Cntrlr Single-OUT Step Down 2.5V to 9.8V Input 6-Pin TSOT-23 制造商:Linear Technology 功能描述:BUCK 2.8 - 20V 5A 1.23-18V 6SOT23 制造商:Linear Technology 功能描述:BUCK, 2.8 - 20V, 5A, 1.23-18V, 6SOT23 |
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