- 您现在的位置：买卖IC网 > PDF目录15310 > LT3759HMSE#PBF (Linear Technology)IC REG CTRLR BST INV PWM 12-MSOP PDF资料下载
参数资料
| 型号： | LT3759HMSE#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST INV PWM 12-MSOP |
| 标准包装： | 37 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 电源电压： | 1.6 V ~ 42 V |
| 降压： | 无 |
| 升压： | 是 |
| 回扫： | 无 |
| 反相： | 是 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 150°C |
| 封装/外壳： | 12-TSSOP （0.118"，3.00mm 宽）裸露焊盘 |
| 包装： | 管件 |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页当前第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页
LT3759
APPLICATIONS INFORMATION
operation improves efficiency by reducing gate drive cur-
rent and MOSFET and diode switching losses. However,
lower frequency operation requires a physically larger loop
inductor. Switching frequency also has implications for
loop compensation. The LT3759 uses a constant-frequency
architecture that can be programmed over a 100kHz to
1MHz range with a single external resistor from the RT pin
to ground, as shown in Figure 1. The RT pin must have
an external resistor to GND for proper operation of the
LT3759. A table for selecting the value of R T for a given
operating frequency is shown in Table 2.
The minimum on-time and minimum off-time and the
switching frequency define the minimum and maximum
switching duty cycles a converter is able to generate:
Minimum duty cycle = minimum on-time ? frequency
Maximum duty cycle = 1 – (minimum off-time ? frequency)
Programming the Output Voltage
The output voltage (V OUT ) is set by a resistor divider, as
shown in Figure 1. The positive V OUT and negative V OUT
are set by the following equations:
V OUT(POSITIVE) = 1.6V ? ? 1 +
?
V OUT(NEGATIVE) = –0.8V ? ? 1 +
?
Table2.TimingResistor(R T )Value
OSCILLATOR FREQUENCY (kHz)
100
200
300
400
500
600
700
800
R T (k Ω)
86.6
41.2
27.4
21.0
16.5
13.7
11.5
9.76
? R2 ?
? R1 ?
? R2 ?
? R1 ?
The resistors R1 and R2 are typically chosen so that the
error caused by the current flowing into the FBX pin dur-
ing normal operation is less than 1% (this translates to a
maximum value of R1 at about 158k).
900 8.45
1000 6.81
The switching frequency of the LT3759 can be synchronized
to the positive edge of an external clock source. By provid-
ing a digital clock signal into the SYNC pin, the LT3759 will
operate at the SYNC clock frequency. If this feature is used,
an R T resistor should be chosen to program a switching
frequency 20% slower than SYNC pulse frequency. The
SYNC pulse should have a minimum pulse width of 200ns.
Tie the SYNC pin to GND if this feature is not used.
Duty Cycle Consideration
Switching duty cycle is a key variable defining converter
operation. As such, its limits must be considered. Minimum
on-time is the smallest time duration that the LT3759 is
capable of turning on the power MOSFET. This time is
generally about 170ns (typical) (see Minimum On-Time
in the Electrical Characteristics table). In each switching
cycle, the LT3759 keeps the power switch off for at least
170ns (typical) (see Minimum Off-Time in the Electrical
Characteristics table).
Soft-Start
The LT3759 contains several features to limit peak switch
currents and output voltage (V OUT ) overshoot during
start-up or recovery from a fault condition. The primary
purpose of these features is to prevent damage to external
components or the load.
High peak switch currents during start-up may occur in
switching regulators. Since V OUT is far from its final value,
the feedback loop is saturated and the regulator tries to
charge the output capacitor as quickly as possible, resulting
in large peak currents. A large surge current may cause
inductor saturation or power switch failure.
LT3759 addresses this mechanism with the SS pin. As
shown in Figure 1, the SS pin reduces the power MOSFET
current by pulling down the VC pin through Q2. In this
way the SS allows the output capacitor to charge gradually
toward its final value while limiting the start-up peak
currents.
3759fc
For more information www.linear.com/3759
11
相关PDF资料 |
PDF描述 |
|---|---|
| LT1725CGN#TR | IC REG CTRLR FLYBK ISO CM 16SSOP |
| UCA2V330MHD1TN | CAP ALUM 33UF 350V 20% RADIAL |
| B41042A3827M | 820UF 10V 10X20 SINGLE END |
| LT3757HMSE#TRPBF | IC REG CTRLR PWM CM 10-MSOP |
| LTC3830-1ES8#TRPBF | IC REG CTRLR BUCK PWM VM 8-SOIC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3759IMSE#PBF | 功能描述:IC REG CTRLR BST INV PWM 12-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) |
| LT3759IMSE#TRPBF | 功能描述:IC REG CTRLR BST INV PWM 12-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) |
| LT375B | 制造商:EDSYN 功能描述:TIP SPADE 1.5X12.2MM |
| LT375-C | 制造商:EDSYN 功能描述: |
| LT376 | 制造商:EDSYN 功能描述: 制造商:EDSYN 功能描述:SOLDERING TIP, Tip / Nozzle Length:0.48" |
发布紧急采购，3分钟左右您将得到回复。