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参数资料
| 型号： | LTC3838EUHF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 30/54页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 38-QFN |
| 标准包装： | 2,500 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 2MHz |
| 电源电压： | 4.5 V ~ 38 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： | 38-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
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LTC3838
APPLICATIONS INFORMATION
When a channel is configured to soft-start by itself, a ca-
pacitor should be connected to its TRACK/SS pin. TRACK/
SS is pulled low until the RUN pin voltage exceeds 1.2V
and UVLO is released, at which point an internal current
of 1μA charges the soft-start capacitor, C SS , connected
to the TRACK/SS pin. Current-limit foldback is disabled
during this phase to ensure smooth soft-start or track-
ing. The soft-start or tracking range is defined to be the
voltage range from 0V to 0.6V on the TRACK/SS pin. The
total soft-start time can be calculated as:
voltage. Ratiometric tracking could be achieved by using
a different ratio than the differential feedback.
Note that the 1μA soft-start capacitor charging current is
still flowing, producing a small offset error. To minimize
this error, select the tracking resistive divider values to be
small enough to make this offset error negligible.
The LTC3838 allows the user to program how its two
channels’ outputs track each other ramping up or down.
In the following discussions, V OUT1 refers to the LTC3838’s
t SS (SEC) = 0.6(V) ?
C SS (μF)
1(μA)
output 1 as a master channel and V OUT2 refers to the
LTC3838’s output 2 as a slave channel. In practice though,
either channel can be used as the master.
When one particular channel is configured to track an
external supply, a voltage divider can be used from the
external supply to the TRACK/SS pin to scale the ramp
rate appropriately. Two common implementations are co-
incidental tracking and ratiometric tracking. For coincident
tracking, make the divider ratio from the external supply
the same as the divider ratio for the differential feedback
V OUT1
V OUT2
By selecting different resistors, the LTC3838 can achieve
different modes of tracking including the two in Figure 9.
To implement the coincident tracking, connect an addi-
tional resistive divider to V OUT1 and connect its midpoint
to the TRACK/SS pin of the slave channel. The ratio of this
divider should be the same as that of the slave channel’s
feedback divider shown in Figure 9b. In this tracking mode,
V OUT1
V OUT2
TIME
TIME
3838 F09a
Coincident Tracking
Ratiometric Tracking
Figure 9a. Two Different Modes of Output Tracking
V OUT1
V OUT2
V OUT1
V OUT2
TO
TRACK/SS2
PIN
R FB2(2)
R FB1(2)
R FB2(1)
R FB1(1)
TO
V OUTSENSE1+
PIN
TO
TO
V FB2
PIN
R FB2(2)
R FB1(2)
TO
TRACK/SS2
PIN
R FB2(1)
R FB1(1)
TO
V OUTSENSE1+
PIN
TO
TO
V FB2
PIN
R FB2(2)
R FB1(2)
V OUTSENSE1–
PIN
Coincident Tracking Setup
V OUTSENSE1–
PIN
Ratiometric Tracking Setup
3838 F09b
Figure 9b. Setup for Coincident and Ratiometric Tracking
3838fa
30
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相关代理商/技术参数 |
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| LTC3838IFE#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 38TSSOP 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 |
| LTC3838IFE#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 38TSSOP 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 |
| LTC3838IUHF#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 38-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: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) |
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| LTC3838IUHF-1#PBF | 制造商:Linear Technology 功能描述:IC REG CTRLR BUCK PWM CM 38QFN 制造商:Linear Technology 功能描述:BUCK DUAL CNTRL 4.5-38V 2MHZ 38QFN 制造商:Linear Technology 功能描述:BUCK, DUAL, CNTRL, 4.5-38V, 2MHZ, 38QFN 制造商:Linear Technology 功能描述:DP-SWREG/Controller, Dual, Fast, Accurate Step-Down Controller with Differential 制造商:Linear Technology 功能描述:DC-DC CONTROLLER, DUAL, BUCK, ADJ, QFN-38, Primary Input Voltage:38V, No. of Outputs:2, Output Current:25A, No. of Pins:38, Operating Temperature Min:-40C, Operating Temperature Max:125C, MSL:MSL 1 - Unlimited , RoHS Compliant: Yes |
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