参数资料
型号: LTC3866EFE#TRPBF
厂商: Linear Technology
文件页数: 27/36页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM CM 24TSSOP
标准包装: 2,500
PWM 型: 电流模式
输出数: 1
频率 - 最大: 850kHz
占空比: 95%
电源电压: 4.5 V ~ 38 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 125°C
封装/外壳: 24-TSSOP(0.173",4.40mm)裸露焊盘
包装: 带卷 (TR)
LTC3866
APPLICATIONS INFORMATION
adequate starting point for most applications. The ITH series
R C -C C filter sets the dominant pole-zero loop compensation.
The values can be modified slightly (from 0.5 to 2 times
their suggested values) to optimize transient response
once the final PC layout is done and the particular output
capacitor type and value have been determined. The output
capacitors need to be selected because the various types
and values determine the loop gain and phase. An output
current pulse of 20% to 80% of full-load current having a
rise time of 1μs to 10μs will produce output voltage and
ITH pin waveforms that will give a sense of the overall
loop stability without breaking the feedback loop. Placing
a power MOSFET directly across the output capacitor and
driving the gate with an appropriate signal generator is a
practical way to produce a realistic load step condition. The
initial output voltage step resulting from the step change
in output current may not be within the bandwidth of the
feedback loop, so this signal cannot be used to determine
phase margin. This is why it is better to look at the ITH
pin signal which is in the feedback loop and is the filtered
and compensated control loop response. The gain of the
loop will be increased by increasing R C and the bandwidth
of the loop will be increased by decreasing C C . If R C is
increased by the same factor that C C is decreased, the
zero frequency will be kept the same, thereby keeping the
phase shift the same in the most critical frequency range
of the feedback loop. The output voltage settling behavior
is related to the stability of the closed-loop system and
will demonstrate the actual overall supply performance.
A second, more severe transient is caused by switching
in loads with large (>1μF) supply bypass capacitors. The
discharged bypass capacitors are effectively put in parallel
with C OUT , causing a rapid drop in V OUT . No regulator can
alter its delivery of current quickly enough to prevent this
sudden step change in output voltage if the load switch
resistance is low and it is driven quickly. If the ratio of
C LOAD to C OUT is greater than 1:50, the switch rise time
should be controlled so that the load rise time is limited
to approximately 25 ? C LOAD . Thus a 10μF capacitor would
require a 250μs rise time, limiting the charging current
to about 200mA.
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the IC. These items are also illustrated graphically in the
layout diagram of Figure 14. Check the following in the
PC layout:
1. The INTV CC decoupling capacitor should be placed
immediately adjacent to the IC between the INTV CC pin
and PGND plane. A 1μF ceramic capacitor of the X7R
or X5R type is small enough to fit very close to the IC
to minimize the ill effects of the large current pulses
drawn to drive the bottom MOSFETs. An additional
4.7μF to 10μF of ceramic, tantalum or other very low
ESR capacitance is recommended in order to keep the
internal IC supply quiet.
V IN
SW2
L1
DCR
V OUT
R IN
+
C IN
D1
SW1
C OUT
+
R L
3866 F14
BOLD LINES INDICATE HIGH, SWITCHING CURRENTS. KEEP LINES TO A MINIMUM LENGTH
Figure 14. Branch Current Waveforms
3866fb
27
相关PDF资料
PDF描述
EEM43DREF CONN EDGECARD 86POS .156 EYELET
VI-JWL-EW-F4 CONVERTER MOD DC/DC 28V 100W
LTC3865IFE#TRPBF IC REG CTRLR BUCK PWM CM 38TSSOP
VI-JWL-EW-F2 CONVERTER MOD DC/DC 28V 100W
EBA49DRMN CONN EDGECARD 98POS .125 SQ WW
相关代理商/技术参数
参数描述
LTC3866EUF#PBF 功能描述:IC REG CTRLR BUCK PWM CM 24-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)
LTC3866EUF#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 24-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)
LTC3866IFE#PBF 功能描述:IC REG CTRLR BUCK PWM CM 24TSSOP 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)
LTC3866IFE#PBF 制造商:Linear Technology 功能描述:BUCK REGULATOR CURRENT MODE SYNC TSSOP
LTC3866IFE#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 24TSSOP 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)