- 您现在的位置：买卖IC网 > PDF目录15239 > LTC3729EUH#TRPBF (Linear Technology)IC REG CTRLR BUCK PWM CM 32-QFN PDF资料下载
参数资料
| 型号： | LTC3729EUH#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 19/30页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 32-QFN |
| 标准包装： | 2,500 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 590kHz |
| 占空比： | 99.5% |
| 电源电压： | 4 V ~ 36 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： | 32-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
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页第11页第12页第13页第14页第15页第16页第17页第18页当前第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
LTC3729
APPLICATIONS INFORMATION
C LP
DIGITAL
t ON ( MIN ) <
400kHz. The nominal operating frequency range of the
LTC3729 is 250kHz to 550kHz.
The phase detector used is an edge sensitive digital type
which provides zero degrees phase shift between the ex?
ternal and internal oscillators. This type of phase detector
will not lock up on input frequencies close to the harmonics
of the VCO center frequency. The PLL hold?in range, ? f H ,
is equal to the capture range, ? f C :
? f H = ? f C = ± 0.5 f O (250kHz?550kHz)
The output of the phase detector is a complementary pair of
current sources charging or discharging the external filter
network on the PLLFLTR pin. A simplified block diagram
is shown in Figure 7.
2.4V
R LP
10k
PHASE
DETECTOR
EXTERNAL
OSC
PLLFLTR
PLLIN
PHASE/ OSC
FREQUENCY
50k DETECTOR
3729 F07
Figure 7. Phase-Locked Loop Block Diagram
If the external frequency (f PLLIN ) is greater than the os?
cillator frequency f 0SC , current is sourced continuously,
pulling up the PLLFLTR pin. When the external frequency is
less than f 0SC , current is sunk continuously, pulling down
the PLLFLTR pin. If the external and internal frequencies
are the same but exhibit a phase difference, the current
sources turn on for an amount of time corresponding to
the phase difference. Thus the voltage on the PLLFLTR
pin is adjusted until the phase and frequency of the ex?
ternal and internal oscillators are identical. At this stable
operating point the phase comparator output is open and
the filter capacitor C LP holds the voltage. The LTC3729
PLLIN pin must be driven from a low impedance source
such as a logic gate located close to the pin. When us?
ing multiple LTC3729’s for a phase?locked system, the
PLLFLTR pin of the master oscillator should be biased at
a voltage that will guarantee the slave oscillator(s) ability
to lock onto the master’s frequency. A DC voltage of
0.7V to 1.7V applied to the master oscillator’s PLLFLTR
pin is recommended in order to meet this requirement.
The resultant operating frequency will be approximately
500kHz.
The loop filter components (C LP , R LP ) smooth out the cur?
rent pulses from the phase detector and provide a stable
input to the voltage controlled oscillator. The filter compo?
nents C LP and R LP determine how fast the loop acquires
lock. Typically R LP =10k and C LP is 0.01μF to 0.1μF.
Minimum On-Time Considerations
Minimum on?time t ON(MIN) is the smallest time duration
that the LTC3729 is capable of turning on the top MOSFET.
It is determined by internal timing delays and the gate
charge required to turn on the top MOSFET. Low duty
cycle applications may approach this minimum on?time
limit and care should be taken to ensure that:
V OUT
V IN ( f )
If the duty cycle falls below what can be accommodated
by the minimum on?time, the LTC3729 will begin to skip
cycles resulting in nonconstant frequency operation. The
output voltage will continue to be regulated, but the ripple
current and ripple voltage will increase.
The minimum on?time for the LTC3729 is approximately
100ns. However, as the peak sense voltage decreases
the minimum on?time gradually increases. This is of
particular concern in forced continuous applications with
low ripple current at light loads. If the duty cycle drops
below the minimum on?time limit in this situation, a
significant amount of cycle skipping can occur with cor?
respondingly larger current and voltage ripple.
If an application can operate close to the minimum on?time
limit, an inductor must be chosen that has a low enough
inductance to provide sufficient ripple amplitude to meet
the minimum on?time requirement. As a general rule,
keep the inductor ripple current of each phase equal to or
greater than 15% of I OUT(MAX) /N at V IN(MAX) .
3729fb
19
相关PDF资料 |
PDF描述 |
|---|---|
| ELL-6PM1R0N | COIL PWR CHOKE 1UH 2.7A SMD |
| LTC3729EUH#TR | IC REG CTRLR BUCK PWM CM 32-QFN |
| SRP1040-R39M | INDUCTOR 390NH 24A SMD |
| SRP1040-R20M | INDUCTOR 200NH 32A SMD |
| SRP1040-8R2M | INDUCTOR 8.2UH 5A SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3729LEUH-6 | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3729LEUH-6#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3729LEUH-6#TR | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3729LEUH-6#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3730CG | 功能描述:IC SW REG CTRLR SYNC BUCK 36SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
发布紧急采购，3分钟左右您将得到回复。