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参数资料
| 型号： | LTC3823EGN |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 4 A SWITCHING CONTROLLER, 200 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封装： | 0.150 INCH, PLASTIC, SSOP-28 |
| 文件页数： | 10/24页 |
| 文件大小： | 345K |
| 代理商： | LTC3823EGN |
LTC3823
3823fb
Differential Amplifier
Thisamplifierprovidestruedifferentialoutputvoltagesens-
ing.Sensingboththepositiveandnegativeterminalsofthe
output voltage benefits regulation in high current applica-
tions and/or applications having electrical interconnection
losses. Precision feedback resistors are integrated in the
IC with the amplifier already configured as a unity-gain
differential amplifier. It has a GBW product of 3.5Mhz and
an open-loop gain of >120dB. The amplifier can source
>2mA of current, and can be used in applications with
up to 3.3V output voltage. The amplifier is not capable of
sinking significant current, and must be resistively loaded.
A load of 20k
Ω or less is recommended for stability. The
amplifier is not designed to drive capacitive loads.
Phase-Locked Loop and Frequency Synchronization
The LTC3823 has a phase-locked loop comprised of an
internal voltage controlled oscillator and phase detector.
This allows the top MOSFET turn-on to be locked to the
rising edge of an external source. The frequency range
of the voltage controlled oscillator is ±30% around the
center frequency, fO. The center frequency is the oper-
ating frequency discussed in the previous section. The
LTC3823 incorporates a pulse detection circuit that will
detect a clock on the PLLIN pin. In turn, it will turn on the
phase-locked loop function. The pulse width of the clock
has to be greater than 400ns and the amplitude of the
clock should be greater than 2V.
During the start-up phase, phase-locked loop function is
disabled. When LTC3823 is not in synchronization mode,
PLLFLTR pin voltage is set to around 1.18V. Frequency
synchronization is accomplished by changing the internal
on-time current according to the voltage on the PLLFLTR
pin.
The phase detector used is an edge sensitive digital type
which provides zero degrees phase shift between the ex-
ternal and internal pulses. 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,
Δfh,
is equal to the capture range,
ΔfC:
Δfh = ΔfC = ±0.3 fO
Theoutputofthephasedetectorisacomplementarypairof
current sources charging or discharging the external filter
network on the PLLFLTR pin. A simplified block diagram
is shown in Figure 10.
If the external frequency (fPLLIN) is greater than the oscil-
lator frequency fO, current is sourced continuously, pull-
ing up the PLLFLTR pin. When the external frequency is
less than fO, 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
pinisadjusteduntilthephaseandfrequencyoftheexternal
andinternaloscillatorsareidentical.Atthisstableoperating
point the phase comparator output is open and the filter
capacitor CLP holds the voltage. The LTC3823 PLLIN pin
must be driven from a low impedance source such as a
logic gate located close to the pin.
The loop filter components (CLP, RLP) smooth out the cur-
rent pulses from the phase detector and provide a stable
input to the voltage controlled oscillator. The filter compo-
nents CLP and RLP determine how fast the loop acquires
lock. Typically RLP =10k and CLP is 0.01F to 0.1F.
Dead Time Control
To further optimize the efficiency, the LTC3823 gives us-
ers some control over the dead time of the Top gate low
and Bottom gate high transition. By applying a DC voltage
applications information
DIGITAL
PHASE/
FREQUENCY
DETECTOR
PLLIN
PLLFLTR
2.4V
CLP
3823 F10
RLP
VCO
Figure 10. Phase-Locked Loop Block Diagram
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相关代理商/技术参数 |
参数描述 |
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| LTC3823EGN#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP 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) |
| LTC3823EGN#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP 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) |
| LTC3823EUH#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:- 标准包装:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 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:8-TSSOP（0.173"，4.40mm 宽） 包装:带卷 (TR) |
| LTC3823EUH#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:- 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) |
| LTC3823IGN#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP 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:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 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:8-TSSOP（0.173"，4.40mm 宽） 包装:带卷 (TR) |
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