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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： | 4/24页 |
| 文件大小： | 345K |
| 代理商： | LTC3823EGN |
LTC3823
3823fb
The resulting power dissipation in the MOSFETs at maxi-
mum output current are:
PTOP = DTOP IOUT(MAX)2 ρT(TOP) RDS(ON)(MAX)
+ k VIN2 IOUT(MAX) CRSS f
PBOT = DBOT IOUT(MAX)2 ρT(BOT) RDS(ON)(MAX)
Both MOSFETs have I2R losses and the top MOSFET in-
cludes an additional term for transition losses, which are
largestathighinputvoltages.Theconstantk=1.7A–1canbe
used to estimate the amount of transition loss. The bottom
MOSFET losses are greatest when the bottom duty cycle is
near100%,duringashort-circuitorathighinputvoltage.
Operating Frequency
The choice of operating frequency is a tradeoff between
efficiency and component size. Low frequency operation
improvesefficiencybyreducingMOSFETswitchinglosses
but requires larger inductance and/or capacitance in order
to maintain low output ripple voltage.
The operating frequency of LTC3823 applications is
determined implicitly by the one-shot timer that controls
the on-time, tON, of the top MOSFET switch. The on-time
is set by the current out of the ION pin and the voltage at
the VON pin according to:
t
V
I
pF
ON
VON
ION
=
(
)
10
Tying a resistor RON to SGND from the ION pin yields an
on-time inversely proportional to 1/3 VIN. The current out
of the ION pin is:
I
V
R
ION
IN
ON
=
3
For a step-down converter, this results in approximately
constant frequency operation as the input supply varies:
f
V
R
pF
H
OUT
VON
ON
Z
=
(
)
[ ]
3
10
Toholdfrequencyconstantduringoutputvoltagechanges,
tie the VON pin to VOUT. The VON 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
at4.8V.InhighVOUTapplications,tieVONtoINTVCC.Figures
2a and 2b show how RON relates to switching frequency
for several common output voltages.
JUNCTION TEMPERATURE (
°C)
–50
ρ
TNORMALIZED
ON-RESISTANCE 1.0
1.5
150
3823 F01
0.5
0
50
100
2.0
Figure 1. RDS(ON) vs Temperature
applications information
RON (kΩ)
100
SWITCHING
FREQUENCY
(kHz)
1000
3823 F02a
VOUT = 3.3V
VOUT = 1.5V
VOUT = 2.5V
RON (kΩ)
10
100
SWITCHING
FREQUENCY
(kHz)
1000
100
1000
3823 F02b
VOUT = 3.3V
VOUT = 12V
VOUT = 5V
Figure 2a. Switching Frequency vs RON (VON = 0V)
Figure 2b. Switching Frequency vs RON (VON = INTVCC)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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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