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参数资料
| 型号： | LTC3823EUH#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/26页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 32-QFN |
| 标准包装： | 73 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 90% |
| 电源电压： | 4.5 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： | 管件 |
LTC3823
APPLICATIONS INFORMATION
2.0
1.5
1.0
0.5
improves ef?ciency by reducing MOSFET switching losses
but requires larger inductance and/or capacitance in order
to maintain low output ripple voltage.
The operating frequency of LTC3823 applications is de-
termined implicitly by the one-shot timer that controls
the on-time, t ON , of the top MOSFET switch. The on-time
is set by the current out of the I ON pin and the voltage at
the V ON pin according to:
0
–50
0 50 100
JUNCTION TEMPERATURE (°C)
150
t ON =
V VON
I ION
( 10 pF )
3823 F01
Figure 1. R DS(ON) vs Temperature
The resulting power dissipation in the MOSFETs at maxi-
Tying a resistor R ON to SGND from the I ON pin yields an
on-time inversely proportional to 1/3 V IN . The current out
of the I ON pin is:
mum output current are:
P TOP = D TOP I OUT(MAX)
2 ρ
T(TOP) R DS(ON)(MAX)
I ION =
V IN
3 R ON
+ k V IN2 I OUT(MAX) C RSS f
For a step-down converter, this results in approximately
P BOT = D BOT I OUT(MAX)
2 ρ
T(BOT) R DS(ON)(MAX)
constant frequency operation as the input supply varies:
Both MOSFETs have I 2 R losses and the top MOSFET in-
cludes an additional term for transition losses, which are
f =
V OUT
V VON ? 3 R ON ( 10 pF )
[ H Z ]
largest at high input voltages. The constant k = 1.7A –1 can be
used to estimate the amount of transition loss. The bottom
MOSFET losses are greatest when the bottom duty cycle is
near 100%, during a short-circuit or at high input voltage.
Operating Frequency
The choice of operating frequency is a tradeoff between
ef?ciency and component size. Low frequency operation
1000
V OUT = 3.3V
V OUT = 2.5V
To hold frequency constant during output voltage changes,
tie the V ON pin to V OUT . The V ON pin has internal clamps
that limit its input to the one-shot timer. If the pin is tied
below 0.6V, the input to the one-shot is clamped at 0.6V.
Similarly, if the pin is tied above 4.8V, the input is clamped
at 4.8V. In high V OUT applications, tie V ON to INTV CC . Figures
2a and 2b show how R ON relates to switching frequency
for several common output voltages.
1000
V OUT = 12V
100
V OUT = 1.5V
100
V OUT = 3.3V
V OUT = 5V
100
R ON (k Ω )
1000
3823 F02a
10
100
R ON (k Ω )
1000
3823 F02b
Figure 2a. Switching Frequency vs R ON (V ON = 0V)
Figure 2b. Switching Frequency vs R ON (V ON = INTV CC )
3823fd
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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) |
| LTC3823IGN#PBF | 制造商:Linear Technology 功能描述:IC SYNC STEP-DOWN DC/DC CTRL SSOP-28 |
| LTC3823IGN#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) |
| LTC3823IUH#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:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3823IUH#PBF | 制造商:Linear Technology 功能描述:IC SYNC STEP-DOWN DC/DC CONTROLLER QFN32 |
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